In the JD jetting instructions isn't there a thin ring that is suppose to site inside the throttle slide housing before the needle with or without the shim and clip. I didn't see you use that. I'm just reading the instructions on mine now and haven't installed it yet, but wondering if this was overlooked or perhaps it's different on your kit. I have a 2017 300 XCW 'm trying to tune. Great videos as usual.
Jason Keddy - Yes, there is a ring and it’s important that it’s installed if using the shim. When I was using this kit I always left the ring installed and put the shim on top of the needle clip if 1/2 clip adjustment wasn’t required.
Yesterday I have installed Lectron carburator (38mm hi velocity) into my 300 exc 2017. The bike behaves literaly like electric engine. Perfect jetting from 0 to wide open throttle. Fuel metering automatically adjusts by pressure and temp. It doesnt have overflow. It cant get any better, as for 470 usd u get fuel injection like functionality, but without additional electronic crap, that can fail. Since youve put somuch money into your ride, i strongly suggest to consider ;).
One of my friends is using a Lectron on his 2017 250EXC. I've ridden it and it performs well. For the elevations I ride at (typically 500 ~ 1,800m) I don't see any advantage asI already have my carb dialed in (jetting and float height) and is working great. Fuel economy doesn't seem to be any different from the Lectron, probably because I adjusted float height. Very happy with my setup...
stock mikuni...which is shit I know...but I played a lot with my 36mm keihin on my Beta RR 300 (previous bike). I have lowered the fuel level there and was running NECJ needle for smoothness. It was a good setup, but lectron is another game.
Ah. I haven't heard many people able to get the Mikuni running well with stock jetting. The JD Jetting kit secret sauce is the needle provided. So the real question is whether to buy a JD Jetting kit, or Lectron (or SmartCarb)...
I faced the same dilemma, here elevation on a ride can go from 4,000 to 10,000 ft so the Lectron made sense. You already have your jetting dialed in, I wouldn't waste the money.
Hi mate, great videos! Most informative and comprehensive on TH-cam! What fuel range are you getting? I've got a 17 250exc and it runs perfect, plug chops are showing spot on and I've tilted the carb 7deg as recommended by KTM to increase economy, but still seems thirsty! Using approx 8 litres per 3 hour ride which is about 2 litres more than my old 2005 250exc.
I too had poor fuel economy initially. The Mikuni float level is set high in the factory for some reason, resulting in fuel spilling out from the overflow very easily during riding. I reset mine to 8.7mm +/-1mm which is the published specification. I show this in my bike mods video at 1:20: th-cam.com/video/h3J6EUR45es/w-d-xo.html. If you still have issues you could try looping your overflow tube up and over.
Tokyo Offroad I've don't the overflow loop, perhaps I need to check against others riding the same bike to compare, thanks again mate, keep up the awesome videos! 😁
Hi, Great video, thanks! I have a 300 (2017) and have just ordered the JD Kit. Should i consider the S1 needle jet as well, or is this only applicable to the 250? Thanks!
Excellent Video. I bought the JDJetting kit for my 2019 KTM 300 XC. Bought also the Seal Block kit.! Installed today!! Question... I did get the small washer for 1/2 sizing for needle. Thats understood. They sold me with this small washer....A "Retainer Spacer Ring" too. From what I read from JDJetting is that the "Retainer Spacer Ring" goes inside the slide below FROM WHERE Cable Retainer was removed. What is the "Retainer Spacer Rings" function underneath the Cable Retainer? No needle pilot was in this package? Using the stock OEM one that came on TMX Mikuni 38. Your Video had a change out on Needle Pilot. Must I too change this?? Setting now from JDJetting today now // Pilot #30, Red Needle 3rd position, with MainJ @ 420. Technical Trail for 2000 to 7000 Ft. Should I think about changing the Needle Pilot? Muffler is not stock. Its a FMF TurbineCore 2.1 Does this effect the Breathing of new setup?
If you use the washer (for 1/2 clip adjustment) you should also use the provided ring to stop the retainer pinching the needle clip due the the extra thickness. If not using Groupon the washer you can store it on top of the needle clip and leave the ring fitted
You can purchase directly from JD Jetting. You also may be able to find it on Ebay, or some online motorcycle accessory stores. I highly recommend that you replace the standard Mikuni block gasket as the stock one invariably fails, impacting the bottom end performance. JD Jetting have a much improved block gasket kit. I recently made a video which shows about the Mikuni block gasket problem which you might be interested in: th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html
I just bought a left over 2017 te250, I ordered pretty well everything that you have done for this set up. What grade of octane do you have in Japan. I will be running 91 and in one of your other videos you must have a buddy that has a te 250. is he running your set up?
I use premium gasoline which is 100 RON (about 93-94 AKI Octane). Yes, both my friends with TE250s are running the same carb setup (JD Jetting kit) with VForce4 reed valve and SX head.
Dana Gorman - The TE airbox is quite restrictive. I modded a friend's TE300 by making some large holes in the top lip of the airbox and fitting a VForce4 reed valve, and the bike was transformed from running very poorly, to crisp and responsive. It already had a JD Jetting kit fitted.
I mount my Gopro under my visor, but the mount is actually stuck to the helmet. If you're interested check out the video I made which shows how it's mounted: th-cam.com/video/DHk75INq3Rg/w-d-xo.html
I have a 2017 Husky TE250 and just bought the JD jet kit but it doesn't look like it comes with a new needle jet and I'm having trouble finding the S1 you mentioned. Even Rocky Mountain only carries the R8. Where do I get the S1?
Hey Tokyo (or anyone else), just wondering if you use the "spacer ring" (not the 1/2 clip washer) that comes in the JD kit and is supposed to sit at the base of the needle around the clip head in the slide. As you do not mention anything about it
johnpaulstez - The JD Jetting Kit for the Mikuni comes with a simple chart (altitude) but it doesn’t include temp, so you need to figure that out yourself.
I'm using JD kit on my 2017 xc 300 and running it on blue needle #2.5. Iddle jet is 30 main 420. Most riding is done at sea level. Bike running a little bit to rich now what should I do rise the clip on same needle or just change needle to red.. maybe just change the pilot jet as most of my riding is technical 1st and 2nd gear... Please help
There is a known issue with the Mikuni TMX 38 block gasket: th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html JD Jetting sell a kit which includes an improved design block gasket and oring which resolves this issue. Before attempting further tuning I'd recommend purchasing and installing this kit. Once the block gasket has been replaced, if the bike still runs rich off the bottom I would suggest first try opening the air screw in 1/4 turn increments and see how it performs.
The 300 setting would be similar, but the optimal settings are probably going to be slightly different. I can only comment on the 250 though as I don't have a 300.
you ride at around sea level correct? I know you have since moved on to the Keihin, but did you not find those Mikuni settings to be too rich. I have the JD kit and run 30 pilot, blue needle clip 2.5 and a 420 main and find there''s a rich stutter (4 stroking) at 1/4 throttle through 1st, 2nd, 3rd gear. Even in temperatures as low as -5C I find it stutters at that same spot. I just can't see having to move to a 27.5 pilot or turning the air screw out any further than the current 2 turns. I wonder if the S1 needle jet would help me out in any way. Considering an RK tek head as well.
Jason Keddy - I sometimes ride at sea level, but more often in the mountains (typical typical elevation about 500~1,000m). I’ve been using an Keihin PWK 38mm Air Striker fitted with a STIC metering block for a few years now (which I sell and can highly recommend) and haven’t run standard carburetors (either Mikuni, or Keihin) for a long time so find if difficult to recommend settings for those.
I’m wondering what the interaction is between the jetting and the needle. Everyone seems to go after the jet to change lean or rick but can’t this also be done with the needle position or a different needle? Especially since the jet is only in play at full throttle.
Yes, the needle taper, diameter and clip position have a great influence. The needle starting diameter will influence lower rpm performance and the needle tip diameter will influence higher rpm performance. Lowering the needle (move clip from 3rd to 2nd position) will make it run leaner from about 1/4 to 3/4 throttle opening and raising the needle (move clip from 3rd to 4th position) will make it richer.
Thanks. I'm sure you'll love the 300. If you don't like the Mikuni have a look at a Keihin 38mm PWK Air Striker Short. I went that route a really like it. More bottom end, better response and less sensitive to temp and elevation changes.
Hi , i have a question , i have an 2017 ktm exc in 2 stroke ,and everytime when i start the engine , has very high speeds, without changing the adjustment carburetor,and when i change the adjustment carburetor, nothing happens
Florin Farcas - What carb is fitted in your 2017 EXC. Is it the stock Mikuni TMX, or a Keihin? If you’re using the Mikuni I recommend you take it off and examine the block gasket. I made this video recently which shows how to do it. th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html Whatever carb you are using I recommend taking it off, inspect everything and clean all the parts. If any of the seals are damaged and leaking you should replace them. Also check that the flange is not leaking (connection between the carb and reed valve.
+richard williams - Yes, the float height was too high in mine too. I described the spec I used to reset it in my bike modifications video: th-cam.com/video/h3J6EUR45es/w-d-xo.html
Yes, that's correct. If you haven't already replaced the block gasket I highly recommended replacing it with one from the JD Jetting gasket kit (JDMK05). The original OEM block gaskets deform and leak causing issues as discussed in this video: th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html
Hello, how can I know which starter nozzle my 300exc 2017 eu has, I mean where the main screwed gum goes, in the manual it says 50 and (80) I have looked at it and it does not put numbering on the part, thank you very much and gas with the 300 carburetor
The stock carburetor for MY 2017 300EXC was a Mikuni TMX 38mm carb. The stock baseline 300 setting was a 37.5 idle jet. To check what you have you can remove the idle jet using a flat bladed screwdriver (size is marked on the side of the jet).
@@TokyoOffroad Thank you for your answer, but I am referring to the starting jet where the high 430 440 etc gum is threaded, which can come from 50 or 80 and does not have any numbering to identify it, thanks in advance
the part you are holding in your hand at 2:15 - the 'main jet holder' - do you know the part number or real name for this? Cannot find anywhere online..
The correct name for the part is the "needle jet". The 2017 Mikuni TMX carbs came stock with an R8 needle jet (KTM part # 55431021000). 2018 bikes came stock with S1 needle jets (KTM part # 55431021100) which is what I fitted.
Tokyo Offroad I’m referring to the part that the main jet threads in to... I called Mikuni head office today and spoke with a pretty friendly guy there who gets this question all the time... it’s not actually listed in the KTM schematics but it is indeed called the main jet holder, and if you lose it like I did you need to ask for a Jet Holder for a YZ125 (any year from 04-18) and parts department might carry it or at least can order it. This is more for future reference for anyone reading these comments...
Mark, its 40 f and changing jetting for cold ride, i put in 38 powerjet, 168 main, moved needle from 2 position to 3, should that help . Ktm 300 xc 2014 keihin 36 pwk
Assuming your bike had been running well in warm weather I'd probably try one size larger pilot and main jets than you warm weather setting and see how it runs. The bottom end can be fine tuned with the airscrew (screw clockwise to richen, anti-clockwise to lean out).
I typically ride between about 500~1,800m (1,666~6,000ft). I no longer use the Mikuni carb (switched to a Keihin). But when I was using the Mikuni I used the following settings with a JD Jetting kit: Summer (+15C to +35C): Pilot Jet=30; Needle Jet=S1; Needle=Blue; Clip=2.5; Main Jet=420 Winter (-5C to +15C): Pilot Jet=32.5; Needle Jet=S1; Needle=Blue; Clip=3.0; Main Jet=430 Ran pretty well, with tweaks to the air screw necessary depending on elevation and temp.
what is the difference between S-1 and S-4 needle jet. I ask because the husqvarna/ktm service bulletin shows a kit to help with jetting... I purchased this kit which from my understanding is closer to what they have done to the 2018`s for jetting. also sounds like you have no pipe bang.... i haven't been able to find good info on the causes of that... but seems some do it and some don`t... mine is the unfortunate one that does have annoying pipe bang.
im currently running the kit which im set at the s-4, 25PJ, and 460 main, needle 43-75... bike still loads up if idled for abit, have to clear it out.. and ive fouled plugs if i dont just WOT it to clear it...... been a real pain in the butt.
BRRAAPPP250 - I recommend you try a JD Jetting kit as I never fouled a plug while using it and the bike ran crisp with no loading up. Or you could go a completely different route and try a Keihin Airstriker PWK 38 Short body. I fitted one recently and the bike is running very well
I have a jd jetting kit and my bike is STILL having the same problem from lower rpm,videos like this made me buy this kit but it was all for nothing It seem to me all tge videos are made from jd side or their dilers
I can assure you that I'm not a JD dealer and that I purchased the JD Jetting kit with my own money. What issue are you experiencing at low RPM? What other modifications have you made? I found the bike ran so much better with a high compression head (fitted a KTM OEM 250 SX head).
I have rk tec head,i am expiriencing hard blurbing below 1/4 of throttle And I am using main 420 Pilot 30 Blue needle Just as the jd manual says is should for sea level
tn sp - From your description it sounds like it’s too rich down low. What needle jet do you have fitted? What needle clip position are you using? Also check your airscrew setting. A good air screw setting to start from is 1.5 turns out from full in. If it still feels blubbery down low then try opening the air screw more (in 1/4 turn increments). If adjusting the air screw doesn’t result in the improvement you are looking for then try dropping the needle 1/2 a position in the clip. The JD kit comes with a needle shim which can be used under the clip to raise the needle 1/2 a position. When not using the shim just put it on top of the clip so you don’t lose it. On my 2017 KTM 250EXC these are the settings I came up with when I was using the Mikuni: Summer setting: PJ=30, AS~1.5, Needle Jet=S1, Needle=Blue, Needle clip=2.5, MJ=420 Winter setting: PJ=32.5, AS~1.5, Needle Jet=S1, Needle=Blue, Needle Clip=3, MJ=430
Tokyo Offroad Thank you for your reply I have tried all the solutions what you have mentioned and no improvement. Now my neddle is on 3 place when I go on 2 it just loses the power at high rpm I even tryed 17.5 pilot and it was not so good The newest thing that i tried is cutting the slide and it seems better,now I will cut it a bit more and see the results
What was air screw setting range with these settings? I just ordered the S1 and JD kit for my newly purchased old stock 2017 XC 250 cost was a factor I can't justify the lectron and even the keihn carb is a bit much for me. Im really hoping I will be happy with this set up! All ready set the float height it was very high! I ride at sea level in the great lakes region Thanks!! Heres a video of the day I bought it! :) th-cam.com/video/Sa6kUkl4xHg/w-d-xo.html
Not impressed with the JD jetting kit on my 2018 Husky te 300 for 3500 to 9500 ft. 410 main, 32.5 pilot, BFY42-44 needle, #2 clip, are spot on. Never waste money on JD kit again.
Carl Atamanczyk - A friend’s 2017 Husky TE300 ran really badly (even with a JD Jetting kit) until we opened up the airbox and fitted a VForce reed valve. Night and day difference. What other mods have you made to your 18?
Did you try changing the needle clip position? Going from 3 to 3.5 would have richened it in the area you found lean. My settings in the video were for my ‘17 KTM 250 EXC fitted with an SX Head, VForce reed valve and modified air box. It’s to be expected that a 300, or bike with different mods may require different settings. Also temperature and elevation will affect the carb and require different settings to run optimally. Anyway, it sounds like you are happy now using a different needle. I went a different route because I found the Mikuni was quite sensitive to temp and elevation changes and purchased a Keihin 38mm PWK Air Striker Short, which I’m very happy with. Bottom end power and response is much better than the Mikuni and the Keihin is much less sensitive to temp and elevation changes. Highly recommend checking it out if you’re still not happy with the Mikuni.
You call and Main Jet holder. The proper name for that is a emulsion tube Okay you replace the emotion tube was that a number 9 stock and you replaced it with a number 7? The numbers are scribe on the side of the jets. And for the needles They have a total of 3 tapered needles if you can give us the stock numbers of what you switched it to we appreciate it 65 72 82 Which needle did you start at in which we needle did you go to? For where you have your clip on your needle your bike is lazy. Put your clip on sec to top or put it on top. You give your bike a hand Full Throttle and it will bog out. Try It
250race - Yes, you are correct. I usually call it the needle jet though. The settings in the video we’re with the JD jetting kit. The needles in the kit are not numbered, they just have a colored paint mark on them (red, or blue). I’m not sure what you mean by emotion tube. I had no problem with bogging. I no longer use this carb so can not do any further testing, or tuning. My current carburetor setup is a Keihin PWK 38mm Air Striker Short with a STIC metering block. This performs much better than the Mikuni. Excellent response, strong power from low to high rpm, no bogging and not sensitive to elevation, or temperature changes. Highly recommended.
@@TokyoOffroad I ran the pwk 40.5 ESR carb. I wish I could have had that metering back when I raced. Do you still have your 38 mmmm Mikuni? And do you want to get rid of it? The emulsion tube is what you took out of the carburetor and put the Jd emulsion tube in it.
250race - The emulsion tube (or needle jet) was not supplied with the JD Jetting Kit. I purchased it (S1 size) separately. The JD jetting contains two needles (red & blue), a pilot jet and various main jets.
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great video man, i just didn't know what that jet needle is and where and thanks to you i found out. tomorrow im installing the s4 kit
I ordered the JD Jetting kit and the jet block gasket kit do I still need the s1 needlejet? Thanks again for all help.
great vid!!! that fog is cool.... was waitin' for the ronin to jump outta the forest.....
In the JD jetting instructions isn't there a thin ring that is suppose to site inside the throttle slide housing before the needle with or without the shim and clip. I didn't see you use that. I'm just reading the instructions on mine now and haven't installed it yet, but wondering if this was overlooked or perhaps it's different on your kit. I have a 2017 300 XCW 'm trying to tune. Great videos as usual.
Jason Keddy - Yes, there is a ring and it’s important that it’s installed if using the shim. When I was using this kit I always left the ring installed and put the shim on top of the needle clip if 1/2 clip adjustment wasn’t required.
Yesterday I have installed Lectron carburator (38mm hi velocity) into my 300 exc 2017. The bike behaves literaly like electric engine. Perfect jetting from 0 to wide open throttle. Fuel metering automatically adjusts by pressure and temp. It doesnt have overflow. It cant get any better, as for 470 usd u get fuel injection like functionality, but without additional electronic crap, that can fail. Since youve put somuch money into your ride, i strongly suggest to consider ;).
One of my friends is using a Lectron on his 2017 250EXC. I've ridden it and it performs well. For the elevations I ride at (typically 500 ~ 1,800m) I don't see any advantage asI already have my carb dialed in (jetting and float height) and is working great. Fuel economy doesn't seem to be any different from the Lectron, probably because I adjusted float height. Very happy with my setup...
BTW What carb settings were you using before you switched to the Lectron? Stock, or JD Jetting kit?
stock mikuni...which is shit I know...but I played a lot with my 36mm keihin on my Beta RR 300 (previous bike). I have lowered the fuel level there and was running NECJ needle for smoothness. It was a good setup, but lectron is another game.
Ah. I haven't heard many people able to get the Mikuni running well with stock jetting. The JD Jetting kit secret sauce is the needle provided. So the real question is whether to buy a JD Jetting kit, or Lectron (or SmartCarb)...
I faced the same dilemma, here elevation on a ride can go from 4,000 to 10,000 ft so the Lectron made sense. You already have your jetting dialed in, I wouldn't waste the money.
Hi
Thank you for the video
I have a 2016 KTM EXC and I purchased a JD jetting kit.
Do you know what is the optimal setting for me?
Hi mate, great videos! Most informative and comprehensive on TH-cam! What fuel range are you getting? I've got a 17 250exc and it runs perfect, plug chops are showing spot on and I've tilted the carb 7deg as recommended by KTM to increase economy, but still seems thirsty! Using approx 8 litres per 3 hour ride which is about 2 litres more than my old 2005 250exc.
I too had poor fuel economy initially. The Mikuni float level is set high in the factory for some reason, resulting in fuel spilling out from the overflow very easily during riding. I reset mine to 8.7mm +/-1mm which is the published specification. I show this in my bike mods video at 1:20: th-cam.com/video/h3J6EUR45es/w-d-xo.html.
If you still have issues you could try looping your overflow tube up and over.
Tokyo Offroad I've don't the overflow loop, perhaps I need to check against others riding the same bike to compare, thanks again mate, keep up the awesome videos! 😁
Hi, Great video, thanks! I have a 300 (2017) and have just ordered the JD Kit. Should i consider the S1 needle jet as well, or is this only applicable to the 250? Thanks!
I’d recommend trying it first with the standard R8 needle jet, then try the S1 later
Excellent Video. I bought the JDJetting kit for my 2019 KTM 300 XC. Bought also the Seal Block kit.! Installed today!! Question... I did get the small washer for 1/2 sizing for needle. Thats understood. They sold me with this small washer....A "Retainer Spacer Ring" too. From what I read from JDJetting is that the "Retainer Spacer Ring" goes inside the slide below FROM WHERE Cable Retainer was removed. What is the "Retainer Spacer Rings" function underneath the Cable Retainer?
No needle pilot was in this package? Using the stock OEM one that came on TMX Mikuni 38. Your Video had a change out on Needle Pilot. Must I too change this??
Setting now from JDJetting today now // Pilot #30, Red Needle 3rd position, with MainJ @ 420. Technical Trail for 2000 to 7000 Ft.
Should I think about changing the Needle Pilot? Muffler is not stock. Its a FMF TurbineCore 2.1 Does this effect the Breathing of new setup?
If you use the washer (for 1/2 clip adjustment) you should also use the provided ring to stop the retainer pinching the needle clip due the the extra thickness. If not using Groupon the washer you can store it on top of the needle clip and leave the ring fitted
Thanks for all the great videos. I have a 2019 250 XC interested in trying this kit. Do you know where I might be able to purchase this JD kit.
You can purchase directly from JD Jetting. You also may be able to find it on Ebay, or some online motorcycle accessory stores.
I highly recommend that you replace the standard Mikuni block gasket as the stock one invariably fails, impacting the bottom end performance. JD Jetting have a much improved block gasket kit. I recently made a video which shows about the Mikuni block gasket problem which you might be interested in: th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html
I just bought a left over 2017 te250, I ordered pretty well everything that you have done for this set up. What grade of octane do you have in Japan. I will be running 91 and in one of your other videos you must have a buddy that has a te 250. is he running your set up?
I use premium gasoline which is 100 RON (about 93-94 AKI Octane). Yes, both my friends with TE250s are running the same carb setup (JD Jetting kit) with VForce4 reed valve and SX head.
Tokyo Offroad stock air box or modified for there te's
Dana Gorman - The TE airbox is quite restrictive. I modded a friend's TE300 by making some large holes in the top lip of the airbox and fitting a VForce4 reed valve, and the bike was transformed from running very poorly, to crisp and responsive. It already had a JD Jetting kit fitted.
Thank you!
your camera settnig is awesome when you r riding. I think u mount the camera on bottom part of sun visor , don't you.
I mount my Gopro under my visor, but the mount is actually stuck to the helmet. If you're interested check out the video I made which shows how it's mounted: th-cam.com/video/DHk75INq3Rg/w-d-xo.html
Tokyo Offroad okey , thanks
I have a 2017 Husky TE250 and just bought the JD jet kit but it doesn't look like it comes with a new needle jet and I'm having trouble finding the S1 you mentioned. Even Rocky Mountain only carries the R8. Where do I get the S1?
Curious what you use to film your videos? Looks great man
Currently I use a Canon 80D DSLR.I have various lens from wide to tell and change depending on the shot.
I really enjoy your videos, thank you for sharing.
17 KTM 300 XC-W
U.S.A.
Excuse me... No JET Needle came with this Package. Omit Needle Pilot below. Please advise on Jet Needle. Thank you.
Nice vid.
You still use Vforce4 reeds whit this setting?
Yes, still using the VForce4 reed cage
Hey Tokyo (or anyone else), just wondering if you use the "spacer ring" (not the 1/2 clip washer) that comes in the JD kit and is supposed to sit at the base of the needle around the clip head in the slide. As you do not mention anything about it
Hi. Yes I do use the spacer.
Does JD give you a complete jetting chart with the carb?
johnpaulstez - The JD Jetting Kit for the Mikuni comes with a simple chart (altitude) but it doesn’t include temp, so you need to figure that out yourself.
I'm using JD kit on my 2017 xc 300 and running it on blue needle #2.5. Iddle jet is 30 main 420. Most riding is done at sea level. Bike running a little bit to rich now what should I do rise the clip on same needle or just change needle to red.. maybe just change the pilot jet as most of my riding is technical 1st and 2nd gear... Please help
There is a known issue with the Mikuni TMX 38 block gasket:
th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html
JD Jetting sell a kit which includes an improved design block gasket and oring which resolves this issue. Before attempting further tuning I'd recommend purchasing and installing this kit. Once the block gasket has been replaced, if the bike still runs rich off the bottom I would suggest first try opening the air screw in 1/4 turn increments and see how it performs.
Put in the red. Its leaner from 0 till 1/4 throttle
Nice video. Where did you get the S1 Needle Jet? Can't find it anywhere.
I ordered the S1 needle jet from my local KTM shop. The KTM part number is 55431021100. I just added the information to the video description.
Hi, thanks for the info. Do you think a 300 would run the same settings with success?
The 300 setting would be similar, but the optimal settings are probably going to be slightly different. I can only comment on the 250 though as I don't have a 300.
you ride at around sea level correct? I know you have since moved on to the Keihin, but did you not find those Mikuni settings to be too rich. I have the JD kit and run 30 pilot, blue needle clip 2.5 and a 420 main and find there''s a rich stutter (4 stroking) at 1/4 throttle through 1st, 2nd, 3rd gear. Even in temperatures as low as -5C I find it stutters at that same spot. I just can't see having to move to a 27.5 pilot or turning the air screw out any further than the current 2 turns. I wonder if the S1 needle jet would help me out in any way. Considering an RK tek head as well.
Jason Keddy - I sometimes ride at sea level, but more often in the mountains (typical typical elevation about 500~1,000m). I’ve been using an Keihin PWK 38mm Air Striker fitted with a STIC metering block for a few years now (which I sell and can highly recommend) and haven’t run standard carburetors (either Mikuni, or Keihin) for a long time so find if difficult to recommend settings for those.
Drop the needle a half clip at a time until it cleans up.
I’m wondering what the interaction is between the jetting and the needle.
Everyone seems to go after the jet to change lean or rick but can’t this also be done with the needle position or a different needle?
Especially since the jet is only in play at full throttle.
Yes, the needle taper, diameter and clip position have a great influence. The needle starting diameter will influence lower rpm performance and the needle tip diameter will influence higher rpm performance. Lowering the needle (move clip from 3rd to 2nd position) will make it run leaner from about 1/4 to 3/4 throttle opening and raising the needle (move clip from 3rd to 4th position) will make it richer.
As always, good job. Im considering selling 450 factory edition for 300 2 stroke
Thanks. I'm sure you'll love the 300. If you don't like the Mikuni have a look at a Keihin 38mm PWK Air Striker Short. I went that route a really like it. More bottom end, better response and less sensitive to temp and elevation changes.
What elevations and temps were you riding when u made this vid?
CanadianMike 600-800m, temp was about 20-25degC
Hi , i have a question , i have an 2017 ktm exc in 2 stroke ,and everytime when i start the engine , has very high speeds, without changing the adjustment carburetor,and when i change the adjustment carburetor, nothing happens
Florin Farcas - What carb is fitted in your 2017 EXC. Is it the stock Mikuni TMX, or a Keihin? If you’re using the Mikuni I recommend you take it off and examine the block gasket. I made this video recently which shows how to do it. th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html
Whatever carb you are using I recommend taking it off, inspect everything and clean all the parts. If any of the seals are damaged and leaking you should replace them. Also check that the flange is not leaking (connection between the carb and reed valve.
Have you had to re set the float height in the Mikuni carb ? I have a '17 150 and as delivered from factory was c 2 mm out.
+richard williams - Yes, the float height was too high in mine too. I described the spec I used to reset it in my bike modifications video: th-cam.com/video/h3J6EUR45es/w-d-xo.html
Did you just basicaly use the JD jetting kit settings with SI needle jet?
Yes, that's correct. If you haven't already replaced the block gasket I highly recommended replacing it with one from the JD Jetting gasket kit (JDMK05). The original OEM block gaskets deform and leak causing issues as discussed in this video: th-cam.com/video/xAhsn8RJcCQ/w-d-xo.html
@@TokyoOffroad Great!! Thank you so much.
Hello, how can I know which starter nozzle my 300exc 2017 eu has, I mean where the main screwed gum goes, in the manual it says 50 and (80) I have looked at it and it does not put numbering on the part, thank you very much and gas with the 300 carburetor
The stock carburetor for MY 2017 300EXC was a Mikuni TMX 38mm carb. The stock baseline 300 setting was a 37.5 idle jet. To check what you have you can remove the idle jet using a flat bladed screwdriver (size is marked on the side of the jet).
@@TokyoOffroad Thank you for your answer, but I am referring to the starting jet where the high 430 440 etc gum is threaded, which can come from 50 or 80 and does not have any numbering to identify it, thanks in advance
Awesome videos by the way!
the part you are holding in your hand at 2:15 - the 'main jet holder' - do you know the part number or real name for this? Cannot find anywhere online..
The correct name for the part is the "needle jet". The 2017 Mikuni TMX carbs came stock with an R8 needle jet (KTM part # 55431021000). 2018 bikes came stock with S1 needle jets (KTM part # 55431021100) which is what I fitted.
Tokyo Offroad I’m referring to the part that the main jet threads in to... I called Mikuni head office today and spoke with a pretty friendly guy there who gets this question all the time... it’s not actually listed in the KTM schematics but it is indeed called the main jet holder, and if you lose it like I did you need to ask for a Jet Holder for a YZ125 (any year from 04-18) and parts department might carry it or at least can order it.
This is more for future reference for anyone reading these comments...
Sorry, misunderstood your question. It's good to know that you can order one from Yamaha if necessary...
Mark, its 40 f and changing jetting for cold ride, i put in 38 powerjet, 168 main, moved needle from 2 position to 3, should that help . Ktm 300 xc 2014 keihin 36 pwk
Assuming your bike had been running well in warm weather I'd probably try one size larger pilot and main jets than you warm weather setting and see how it runs. The bottom end can be fine tuned with the airscrew (screw clockwise to richen, anti-clockwise to lean out).
What altitude do you average at.im arond 2500 4000 ft in calgary canada. Whats your jetting at currently.
I typically ride between about 500~1,800m (1,666~6,000ft).
I no longer use the Mikuni carb (switched to a Keihin). But when I was using the Mikuni I used the following settings with a JD Jetting kit:
Summer (+15C to +35C): Pilot Jet=30; Needle Jet=S1; Needle=Blue; Clip=2.5; Main Jet=420
Winter (-5C to +15C): Pilot Jet=32.5; Needle Jet=S1; Needle=Blue; Clip=3.0; Main Jet=430
Ran pretty well, with tweaks to the air screw necessary depending on elevation and temp.
What are youre summer settings for the keihin I'm curious to switch over aswell.
Jessica Hegion - I ran the same Jetting all year, just adjusted the air screw depending on the conditions.
where did you get the s-1 needle jet? thanks
I ordered the S1 needle jet from my local KTM dealer
what is the difference between S-1 and S-4 needle jet. I ask because the husqvarna/ktm service bulletin shows a kit to help with jetting... I purchased this kit which from my understanding is closer to what they have done to the 2018`s for jetting. also sounds like you have no pipe bang.... i haven't been able to find good info on the causes of that... but seems some do it and some don`t... mine is the unfortunate one that does have annoying pipe bang.
BRRAAPPP250 - The S4 is one rank richer than the S1. I haven't tried the service bulletin kit.
im currently running the kit which im set at the s-4, 25PJ, and 460 main, needle 43-75... bike still loads up if idled for abit, have to clear it out.. and ive fouled plugs if i dont just WOT it to clear it...... been a real pain in the butt.
BRRAAPPP250 - Fitting the SX head on mine really reduced pipe bang on mine. Doesn't bother me at all.
did yours have a decent amount of pipe bang prior?
BRRAAPPP250 - I recommend you try a JD Jetting kit as I never fouled a plug while using it and the bike ran crisp with no loading up. Or you could go a completely different route and try a Keihin Airstriker PWK 38 Short body. I fitted one recently and the bike is running very well
Thanks!
You never gave me the price on your carburetor?
Please send contact me here if you’re interested: www.tokyooffroad.com/contact/
I have a jd jetting kit and my bike is STILL having the same problem from lower rpm,videos like this made me buy this kit but it was all for nothing
It seem to me all tge videos are made from jd side or their dilers
I can assure you that I'm not a JD dealer and that I purchased the JD Jetting kit with my own money. What issue are you experiencing at low RPM? What other modifications have you made? I found the bike ran so much better with a high compression head (fitted a KTM OEM 250 SX head).
I have rk tec head,i am expiriencing hard blurbing below 1/4 of throttle
And I am using
main 420
Pilot 30
Blue needle
Just as the jd manual says is should for sea level
tn sp - From your description it sounds like it’s too rich down low. What needle jet do you have fitted? What needle clip position are you using? Also check your airscrew setting. A good air screw setting to start from is 1.5 turns out from full in. If it still feels blubbery down low then try opening the air screw more (in 1/4 turn increments). If adjusting the air screw doesn’t result in the improvement you are looking for then try dropping the needle 1/2 a position in the clip. The JD kit comes with a needle shim which can be used under the clip to raise the needle 1/2 a position. When not using the shim just put it on top of the clip so you don’t lose it. On my 2017 KTM 250EXC these are the settings I came up with when I was using the Mikuni:
Summer setting: PJ=30, AS~1.5, Needle Jet=S1, Needle=Blue, Needle clip=2.5, MJ=420
Winter setting: PJ=32.5, AS~1.5, Needle Jet=S1, Needle=Blue, Needle Clip=3, MJ=430
Tokyo Offroad
Thank you for your reply
I have tried all the solutions what you have mentioned and no improvement. Now my neddle is on 3 place when I go on 2 it just loses the power at high rpm
I even tryed 17.5 pilot and it was not so good
The newest thing that i tried is cutting the slide and it seems better,now I will cut it a bit more and see the results
What was air screw setting range with these settings? I just ordered the S1 and JD kit for my newly purchased old stock 2017 XC 250 cost was a factor I can't justify the lectron and even the keihn carb is a bit much for me. Im really hoping I will be happy with this set up! All ready set the float height it was very high! I ride at sea level in the great lakes region Thanks!! Heres a video of the day I bought it! :) th-cam.com/video/Sa6kUkl4xHg/w-d-xo.html
Needle Jet... My Bad!
set fuel level, not float hight. Throw that lectron carb in the scrap bin . save your money.
MrKidkiller159 - But I'm not using a Lectron. It's the Mikuni with a JD Jetting kit...
Not impressed with the JD jetting kit on my 2018 Husky te 300 for 3500 to 9500 ft.
410 main, 32.5 pilot, BFY42-44 needle, #2 clip, are spot on. Never waste money on JD kit again.
Carl Atamanczyk - A friend’s 2017 Husky TE300 ran really badly (even with a JD Jetting kit) until we opened up the airbox and fitted a VForce reed valve. Night and day difference. What other mods have you made to your 18?
I have already opened the airbox and changed the reed valve. The KD kit made it run lean from 1/8 throttle to just under half throttle.
Did you try changing the needle clip position? Going from 3 to 3.5 would have richened it in the area you found lean. My settings in the video were for my ‘17 KTM 250 EXC fitted with an SX Head, VForce reed valve and modified air box. It’s to be expected that a 300, or bike with different mods may require different settings. Also temperature and elevation will affect the carb and require different settings to run optimally. Anyway, it sounds like you are happy now using a different needle. I went a different route because I found the Mikuni was quite sensitive to temp and elevation changes and purchased a Keihin 38mm PWK Air Striker Short, which I’m very happy with. Bottom end power and response is much better than the Mikuni and the Keihin is much less sensitive to temp and elevation changes. Highly recommend checking it out if you’re still not happy with the Mikuni.
I tried different needle positions. I am tempted to swap the carb with my grandson's 300 Beta's Keihin, he won't know the difference. LOL.
You call and Main Jet holder. The proper name for that is a emulsion tube
Okay you replace the emotion tube was that a number 9 stock and you replaced it with a number 7?
The numbers are scribe on the side of the jets.
And for the needles
They have a total of 3 tapered needles if you can give us the stock numbers of what you switched it to we appreciate it
65
72
82
Which needle did you start at in which we needle did you go to?
For where you have your clip on your needle your bike is lazy.
Put your clip on sec to top or put it on top.
You give your bike a hand Full Throttle and it will bog out. Try It
250race - Yes, you are correct. I usually call it the needle jet though.
The settings in the video we’re with the JD jetting kit. The needles in the kit are not numbered, they just have a colored paint mark on them (red, or blue). I’m not sure what you mean by emotion tube. I had no problem with bogging. I no longer use this carb so can not do any further testing, or tuning.
My current carburetor setup is a Keihin PWK 38mm Air Striker Short with a STIC metering block. This performs much better than the Mikuni. Excellent response, strong power from low to high rpm, no bogging and not sensitive to elevation, or temperature changes. Highly recommended.
@@TokyoOffroad
I ran the pwk 40.5 ESR carb.
I wish I could have had that metering back when I raced.
Do you still have your 38 mmmm Mikuni? And do you want to get rid of it?
The emulsion tube is what you took out of the carburetor and put the Jd emulsion tube in it.
250race - The emulsion tube (or needle jet) was not supplied with the JD Jetting Kit. I purchased it (S1 size) separately. The JD jetting contains two needles (red & blue), a pilot jet and various main jets.
I do have the Mikuni TMX 38mm and would sell it if you’re interested.
@@TokyoOffroad
How much?