Great info on the oversized main jet! I came to this conclusion on my last jetting endeavor. The needle taper and needle jet orifice is critical. I couldn't get my bike to clean out otherwise, even with the correct main jet at wot. I even suspected weak spark/ignition. I ended up trying 4 different needles, and quite a few needle jets, and finally got it. I would have saved alot of time with a sudco manual, I'll have to get one!
Did you find the manual somewhere? I'm Brazilian and I haven't made mikuni carbs since 1999, but there are still some 2 strokes running and I really like working with them
When they say to put the clip in position 1 is that the top setting? I haven't been able to figure out if settings 1 through 4 starts from the top and goes down or is the bottom setting #1? Thanks.
Love your vids brother. I'm having problems with mine. Cleaner than new and replaced all rubbers and nomore leak past the needle/seat. Its idling perfect, but dies upon throttle as if jets were clogged but arent. Dies on throttle every time unless I spray the carbs while it's running, then it'll rev normal and not die. I've done everything and just don't get it. All stock parts on the mikuni aswell.
Thanks ,,, my question is should the needle touch the main jet nozzle when in off position, for no more fuel to enter .. can you please give explanation
After watching this video I went and looked at my needle setting. Carb is a clone VM32 on a 2002 arctic cat 250 atv. The atv was bogging very badly right off idle (idles fine) and all the way through mid range. The needle clip was set to position 5. I moved it to position 1 with no change in the off idle and mid range bog/dying. Does that mean the needle and needle jet are too big?
Sorry for the late reply, I hope you got it figured out. It's hare to tell a rich or lean condition with things being that for out. Testing is necessary, I would think the needle jet is too small.
i just bought a new carb (keihen 38 a/s)...it idles nice blip the throttle sounds good,put under load and it takes off fine but seams to hesitate you push the throttle wot itll pick up and turn on....the plug color seems a lil bit dark but it doesn't foul plugs...really racking my brain trying to figure what my problem is would you know?
my question is i thought that main keys controls the 80 percent to full throttle and needle jest controlled half like mid way throttle and pilot control idle and barley gas
@@aylorengineering.5513 thanks I think I found the problem or problems I'll know soon. For one the pilot jet I bought to rebuild was much thinner, longer, and a whole different tip than original even though a 35 size. 2 the fuel shut off valve was not working causing it to flood etc... I'll let you know if it fixes it. Thanks 👍
Is the stumble in the mid range generally a lean issue? With a bigger main jet, due to the needle not rising high enough to let more fuel in. would shimming fix it.
Yes my midrange is blaaa then picks up. I have a 4 into 1 header and Pods air filters I upped the main jet I think the next above 110. So I'm thinking I need to raise the needle jet. I have 3 tiny washers on there now replacing the stock plastic washer. I have a 1980 Suzuki GS1000 BS34 carbs. Dang can't remember the size of the main jets. should have wrote it down. thanks
He kinda correct but he left something out the e clip can be adjust down the needle in the slots for more fuel or up the needle for less fuel, so if are jetting the carb you probably should have the needle valve in the lean or less fuel position until you have done the jetting then move e clip down by one slot at a time for more fuel again
i have bandit 1200 2005. i installed exhaust and 2mm bigger air intake box hole.. I already drill my Main jet to 110 and a lill on pilot jet also.. i got it good. bike run well but.. past 7000rpm i get RICH 11.6:1AFR everybody sayd... reduce your main jets.. so i made my calculation and went for 105 main instead of 110... Yesss my TOP END 8 9 10k rpm is good now 13.0:1 But All my mid range 1/2 throttle 3/4 DONT ANSWER anymore.. LEAN LEAN as fuck.. YES CHANGING MAIN JETS i LEAN mid range And top end WOT of course. so i raise the needle.. it did fuck all. I reinstalled the 110 jets. the bike run so good now.. But rich past 7000rpm at WOT
These carbs get clogged up and fail so often and cause everybody a world of grief, I wish I could just change everything I have to fuel injectors and a fuel map. I don't know why we are still using 1880's technology in 2024.
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Great info on the oversized main jet! I came to this conclusion on my last jetting endeavor. The needle taper and needle jet orifice is critical. I couldn't get my bike to clean out otherwise, even with the correct main jet at wot. I even suspected weak spark/ignition. I ended up trying 4 different needles, and quite a few needle jets, and finally got it. I would have saved alot of time with a sudco manual, I'll have to get one!
Thank you sir. Helped me out in the first two min. Had no idea those manuals existed.
Did you find the manual somewhere? I'm Brazilian and I haven't made mikuni carbs since 1999, but there are still some 2 strokes running and I really like working with them
Nice explanation!!
Very useful! Thanks you!
I have a 38 VM on my Shovelhead. This is a good video.
Thanks, that made a lot of sense 👍
thank you for a great explanation
Good video sir
great info!! thanks
Great content thank yoi
Nice!! Thanks.
Do the outside screws on the carb adjust the needle clip or do they adjust something different
You said that right on.
Thank you for the video.
My SkiDoo 470 will idle fine, but i have to feather the throttle to get the RPMs up or it bogs and wants to die on take off. Suggestions? Thanks
Good stuff please make more on a tm-40 please!
Sorry, I have never messed with the TM 40s. But, you can get the Sudco mikuni carb manual which will probably answer all your questions.
When they say to put the clip in position 1 is that the top setting? I haven't been able to figure out if settings 1 through 4 starts from the top and goes down or is the bottom setting #1? Thanks.
1 is at the top.
Love your vids brother. I'm having problems with mine. Cleaner than new and replaced all rubbers and nomore leak past the needle/seat. Its idling perfect, but dies upon throttle as if jets were clogged but arent. Dies on throttle every time unless I spray the carbs while it's running, then it'll rev normal and not die. I've done everything and just don't get it. All stock parts on the mikuni aswell.
i’m having a problem with mine idling to high
Thanks ,,, my question is should the needle touch the main jet nozzle when in off position, for no more fuel to enter .. can you please give explanation
I'm wondering this too 🤔
Hello brother, I'm Brazilian. I would like to know if I can get a manual on this subject? thanks in advance for your attention.
After watching this video I went and looked at my needle setting. Carb is a clone VM32 on a 2002 arctic cat 250 atv. The atv was bogging very badly right off idle (idles fine) and all the way through mid range. The needle clip was set to position 5. I moved it to position 1 with no change in the off idle and mid range bog/dying. Does that mean the needle and needle jet are too big?
Sorry for the late reply, I hope you got it figured out. It's hare to tell a rich or lean condition with things being that for out. Testing is necessary, I would think the needle jet is too small.
Do needle and needle jets ever wear from old age rubbing against each other over time and possibly cause a rich condition? Thanks good explanation
Yes they do. Especially on high vibration engines. But it does take time, the needles are anodized so are very hard for aluminum.
@@aylorengineering.5513 I have a gx200 7.0 I installed my makini pz30 it wouldn't start up it had a lil gas in the carb can u give me some advice
i just bought a new carb (keihen 38 a/s)...it idles nice blip the throttle sounds good,put under load and it takes off fine but seams to hesitate you push the throttle wot itll pick up and turn on....the plug color seems a lil bit dark but it doesn't foul plugs...really racking my brain trying to figure what my problem is would you know?
So many factors to deal with tuning carbs. What motor, and where exactly is the hesitation throttle setting.
@@aylorengineering.5513 trx 250r...has the esr 330 big bore...the hesitation comes a little past 1/4 to 1/2 throttle
Then raise the needle. Tuning sometimes is just adjust and test. You are luck not having to do 3 carbs at a time!
my question is i thought that main keys controls the 80 percent to full throttle and needle jest controlled half like mid way throttle and pilot control idle and barley gas
Would a bad needle cause gas in the diaphragm area where you take the cover off?
I would say no, unless parts are missing from the needle assembly.
@@aylorengineering.5513 thanks I think I found the problem or problems I'll know soon. For one the pilot jet I bought to rebuild was much thinner, longer, and a whole different tip than original even though a 35 size. 2 the fuel shut off valve was not working causing it to flood etc... I'll let you know if it fixes it. Thanks 👍
Nothing about part throttle?
Is the stumble in the mid range generally a lean issue? With a bigger main jet, due to the needle not rising high enough to let more fuel in. would shimming fix it.
A stumble is "usually" a rich condition. Lean get you that UUUUUHHH lack of throttle response. The main really has little to do with your midrange.
Yes my midrange is blaaa then picks up. I have a 4 into 1 header and Pods air filters I upped the main jet I think the next above 110. So I'm thinking I need to raise the needle jet. I have 3 tiny washers on there now replacing the stock plastic washer. I have a 1980 Suzuki GS1000 BS34 carbs. Dang can't remember the size of the main jets. should have wrote it down. thanks
He kinda correct but he left something out the e clip can be adjust down the needle in the slots for more fuel or up the needle for less fuel, so if are jetting the carb you probably should have the needle valve in the lean or less fuel position until you have done the jetting then move e clip down by one slot at a time for more fuel again
why is the pilot jet higher than main jet.
❤😂
i have bandit 1200 2005. i installed exhaust and 2mm bigger air intake box hole.. I already drill my Main jet to 110 and a lill on pilot jet also.. i got it good. bike run well but.. past 7000rpm i get RICH 11.6:1AFR everybody sayd... reduce your main jets.. so i made my calculation and went for 105 main instead of 110... Yesss my TOP END 8 9 10k rpm is good now 13.0:1 But All my mid range 1/2 throttle 3/4 DONT ANSWER anymore.. LEAN LEAN as fuck.. YES CHANGING MAIN JETS i LEAN mid range And top end WOT of course.
so i raise the needle.. it did fuck all. I reinstalled the 110 jets. the bike run so good now.. But rich past 7000rpm at WOT
Clear as mud. Manual says never drill out jets.
sorry, I can't make it any easier to understand.
These carbs get clogged up and fail so often and cause everybody a world of grief, I wish I could just change everything I have to fuel injectors and a fuel map. I don't know why we are still using 1880's technology in 2024.