You are dealing with a nearly 50 year old two stroke. You need to do a full tear down of the engine. You need to inspect your piston and bore. Measure your piston and bore. Take appropriate action based on measurements. Piston kit Rings Bore job if needed Measure your crank tolerances. Replace your crank seals and cylinder gaskets base and head. After reassembly, do a leak down test your engine! A requirement for two stroke engines! You have a gem of a bike here. Do it the right way.
I wish we had such vidoes in 1975! I had and loved that bike (I was 14) but it never seemed to run the same two days in a row, my friends, (rival) Yamaha DT250 usually got the best of me I believe the bike would stay "crisper" if it was built with a reed valve.
I've been enjoying following the build on this. That said, for the idle jet screw, 1.5 turns out is just the initial setting to get it running. Based on your elevation, air pressure and phase of the moon (j/k), you will then adjust it in or out to attain the highest possible idle speed. If while adjusting it the idle speed gets to high that you start running on the main jet, lower the idle speed screw back down then go back to the idle jet screw adjustment. Basically, keep turning it out until the idle starts dropping, then turn it back in 1/4 turn. To give context, my XS400 spec is 1.25 turns out initial, but after full adjustment, I run it at 2.75 turns out.
Hey again GG.. I've had a blast following your 250cc series,. And have then donated some dollars for ya!. I encourage everyone who follows Mason on this series to donate a sum of money, so that we can see this fine bike back to a "original" state.. We all know these parts will cost a fair amount of money!. Thank you GG for your great entertaining channel!.
@@GoldGuyRides could you share links to the seal and gasket kits you bought? I'm in the same boat. Just picked up my barn find MT250 and loving your videos!
@@externalgaming4219 yeah man, I'm in the middle of the rebuild now. Video will be out soon! Here are the links: www.ebay.com/itm/271661284188?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=UfWQYvBRTFy&sssrc=2349624&ssuid=AKZ0U4kDSEu&var=&widget_ver=artemis&media=COPY www.ebay.com/itm/195123387297?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=RiJFPSKpQOS&sssrc=2349624&ssuid=AKZ0U4kDSEu&var=&widget_ver=artemis&media=COPY
Man when you redo the engine and you hit that 60 mph in 8.99 sec it will all be worth it !!!! Thats a keeper man unless you make serious profit it may be more valuable to keep it 👍👌
Crank seals and gaskets need to be replaced. While your there check the cylinder for wear or scratches and at the very least replace the rings as well. It's in great shape fersure definitely worth putting a little money into
Put the original air box on and standardise the carb, problem solved and don’t rake the crap 💩 out of her, don’t forget she’s no spring chicken 🍗, 70 was about the top speed when she was new, they were not that fast. Niiiiiiiiiice video
I was thinking the same thing 2 stroke oil ratio I used to own the yamaha RD350LC and power valve and the best way was to remove the 2 stroke oil pump and run pre mix in the tank especially because it was 2 cylinder so the mixture has to be 💯% or it runs like shit ! At least mr G is only dealing with 1 carb 1 cylinder etc so a lot easier to trouble shoot but jetting etc in carbs can be tricky until you know how.
@@naturesrecorder9099 so true. I love oem Honda parts in specific. Sure it’s super expensive but at least you’re getting the same part the manufacturer uses.
If the exhaust smoke smells of burnt gear oil, then you have a crank case to gearbox failed sealant issue. OEM factory sealant is RTF, which ethanol contaminated fuel will rapidly dissolve & wash away. I've rebuilt 3 engines where E5 had caused this to happen (twice on the same engine within 40 miles!!). Ethanol contaminated fuel will also very rapidly dissolve & wash away silicone engine sealant, so never use it with 2 strokes again. I use blue Hylomar, because it is claimed to be ethanol resistant. I've had no oil burning issues since.
Couple of things. First, the plug in the bottom of the float bowl unscrews so you don't have to take the bowl off to change the main jet. Second, factory timing marks are notoriously in accurate, get yourself a DTI for 2T timing. The uni filter has given you a variable on an unknown bike. I'd start by putting a stock filter in there and setting the carb to stock settings.if you have a problem in this area you could end up just masking it rather than sorting it out. As for drilling the main jet not all jets are sized in mm, some are sized by flow rate so it would be better to just buy jets of the right size. They're cheap! It may well be a crank seal issue but I'd check the cheap stuff first. Good luck.
It's out of time it sounds like it's leaking in the right seal but do both the right side you do have to crack the case it's not a bad job think of it this way once apart it's half done??
Hey GG! Your 250cc are a great bike, you did a great job on the restoration! 👍👍. In my opinion the bike will blow a smoke when the bike have been sitting for a while.. Didn't you also set it a bit rich on the oil-mix, +gave it more oil from pre-mixed fuel ?.. As somebody mentioned: it could be your rings, not sealing perfectly,. Anyways, a option on using some detergent, like "STP complete system cleaner" in the fuel, try to run it out for some time, - to burn off carbon and crud.. Check out the setting on the oil-delivery next..? There are also some 2-stroke oil's which will produce more smoke, how are your oil in that matter ?.
Using STP in a 2 stroke will kill it. STP is well known to destroy the big end,, small end & journal bearings on 2 strokes. That's why its labelled for use with 4 strokes only.
Yo u cant use a drill bit like that on a jet, you need a microdrill bit set. 1.25mm is NOT the same as a 125 jet. Ur probably 3-4 times bigger jet than you need. You had the same issue on the TS185 and RX50.
Yeah I thought so too so I checked timing with a multimeter set to 200 ohms in series with the coil ignition wire and it dead on jumps up at the fire mark. Timing is good, it has to be engine related.
Mine will do 0 to 60 in about 9seconds Time the points with a squak box that's how You time the old 2 strokes not with a gap Gauge the gap gage is only for ware limit check 012 to 016 these engines like it leaner 15 jet and two down on the needle But I can't strees how important it is To properly set the timing and when it's write on you can't see it open it's microscopic that's Wy you use a squak box and when you turn The flywheel with your hand it will change pitch when it reaches the f mark the sound box always hums when hooked up but changes pitch when the points just crack It's the only way to do this bike you can not Do it any other way sure it will run but it will sound weak it's your timing trust me??
You're never going to be able to tune the carb when you're burning all that oil. Change your seals. Period. Also buy a cheesy jet kit on eBay. They aren't expensive like real Mikunis
You are dealing with a nearly 50 year old two stroke. You need to do a full tear down of the engine.
You need to inspect your piston and bore.
Measure your piston and bore.
Take appropriate action based on measurements.
Piston kit
Rings
Bore job if needed
Measure your crank tolerances.
Replace your crank seals and cylinder gaskets base and head.
After reassembly, do a leak down test your engine! A requirement for two stroke engines!
You have a gem of a bike here. Do it the right way.
I wish we had such vidoes in 1975! I had and loved that bike (I was 14) but it never seemed to run the same two days in a row, my friends, (rival) Yamaha DT250 usually got the best of me I believe the bike would stay "crisper" if it was built with a reed valve.
I've been enjoying following the build on this. That said, for the idle jet screw, 1.5 turns out is just the initial setting to get it running. Based on your elevation, air pressure and phase of the moon (j/k), you will then adjust it in or out to attain the highest possible idle speed. If while adjusting it the idle speed gets to high that you start running on the main jet, lower the idle speed screw back down then go back to the idle jet screw adjustment. Basically, keep turning it out until the idle starts dropping, then turn it back in 1/4 turn. To give context, my XS400 spec is 1.25 turns out initial, but after full adjustment, I run it at 2.75 turns out.
Hey again GG.. I've had a blast following your 250cc series,. And have then donated some dollars for ya!. I encourage everyone who follows Mason on this series to donate a sum of money, so that we can see this fine bike back to a "original" state.. We all know these parts will cost a fair amount of money!. Thank you GG for your great entertaining channel!.
Thanks so much gorgon! Your dollars and others went right into a complete gasket and seal kit for the Mt250!
@@GoldGuyRides - that's great!. Waiting for the next vids then!.. - have a great time on restoring!. 😀👍
@@GoldGuyRides could you share links to the seal and gasket kits you bought? I'm in the same boat. Just picked up my barn find MT250 and loving your videos!
@@externalgaming4219 yeah man, I'm in the middle of the rebuild now. Video will be out soon! Here are the links: www.ebay.com/itm/271661284188?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=UfWQYvBRTFy&sssrc=2349624&ssuid=AKZ0U4kDSEu&var=&widget_ver=artemis&media=COPY
www.ebay.com/itm/195123387297?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=RiJFPSKpQOS&sssrc=2349624&ssuid=AKZ0U4kDSEu&var=&widget_ver=artemis&media=COPY
Man when you redo the engine and you hit that 60 mph in 8.99 sec it will all be worth it !!!! Thats a keeper man unless you make serious profit it may be more valuable to keep it 👍👌
Lol at 11:46 you're shifting up and going wide up throttle past the speed limit sign that says 25 mph, very funny
I think its running super rich right now so I would play with the fuel/air mix screw and see if it runs better with the screw turned in more
"wooooo! 70!" flies past a 25mph sign lol
That was funny I saw that lol
🤣🤣🤣
Crank seals and gaskets need to be replaced. While your there check the cylinder for wear or scratches and at the very least replace the rings as well. It's in great shape fersure definitely worth putting a little money into
Put the original air box on and standardise the carb, problem solved and don’t rake the crap 💩 out of her, don’t forget she’s no spring chicken 🍗, 70 was about the top speed when she was new, they were not that fast. Niiiiiiiiiice video
And 70 is pretty quick for a 250
Does your dad work on bikes or sumthing, lol how do you know so much about bikes? Love ur vids btw 😊👍🏼
Sounds rich on the top end. Seemed lean before cause of the intake so drilling the jet helped but with the new intake it just made it too rich.
I was thinking the same thing 2 stroke oil ratio I used to own the yamaha RD350LC and power valve and the best way was to remove the 2 stroke oil pump and run pre mix in the tank especially because it was 2 cylinder so the mixture has to be 💯% or it runs like shit ! At least mr G is only dealing with 1 carb 1 cylinder etc so a lot easier to trouble shoot but jetting etc in carbs can be tricky until you know how.
Your jets are probably too big now for the less lean mixture with extra air
I think you’re correct
@@CoralReefkid that’s why I just like to stick with stock everything. Makes life much easier.
@@naturesrecorder9099 so true. I love oem Honda parts in specific. Sure it’s super expensive but at least you’re getting the same part the manufacturer uses.
@@naturesrecorder9099 Too easy for me. I like challenges. 😁
1.25mm you dont say.. Jet size isnt the same as drill bit size
If the exhaust smoke smells of burnt gear oil, then you have a crank case to gearbox failed sealant issue. OEM factory sealant is RTF, which ethanol contaminated fuel will rapidly dissolve & wash away. I've rebuilt 3 engines where E5 had caused this to happen (twice on the same engine within 40 miles!!). Ethanol contaminated fuel will also very rapidly dissolve & wash away silicone engine sealant, so never use it with 2 strokes again. I use blue Hylomar, because it is claimed to be ethanol resistant. I've had no oil burning issues since.
Get the jug off and measure it up. Crank seals have probably dried out. And check the plug to see what the jetting is doing to it.
Have you been able to get a PA title with the vermont registration on a bike that's been titled in PA before?
Hello GG love your videos. When you coated your tank with POR15, did you have to remove the petcock? Thank you. Your fan Dave.
I bought a new petcock so I just left the old one on while I sealed it.
👍👍👍
Couple of things. First, the plug in the bottom of the float bowl unscrews so you don't have to take the bowl off to change the main jet. Second, factory timing marks are notoriously in accurate, get yourself a DTI for 2T timing. The uni filter has given you a variable on an unknown bike. I'd start by putting a stock filter in there and setting the carb to stock settings.if you have a problem in this area you could end up just masking it rather than sorting it out. As for drilling the main jet not all jets are sized in mm, some are sized by flow rate so it would be better to just buy jets of the right size. They're cheap! It may well be a crank seal issue but I'd check the cheap stuff first. Good luck.
put the proper jet back in and take her in the woods !! never mind how fast she runs on the road, sweet bike
It's out of time it sounds like it's leaking in the right seal but do both the right side you do have to crack the case it's not a bad job think of it this way once apart it's half done??
Hey GG! Your 250cc are a great bike, you did a great job on the restoration! 👍👍. In my opinion the bike will blow a smoke when the bike have been sitting for a while.. Didn't you also set it a bit rich on the oil-mix, +gave it more oil from pre-mixed fuel ?.. As somebody mentioned: it could be your rings, not sealing perfectly,. Anyways, a option on using some detergent, like "STP complete system cleaner" in the fuel, try to run it out for some time, - to burn off carbon and crud.. Check out the setting on the oil-delivery next..? There are also some 2-stroke oil's which will produce more smoke, how are your oil in that matter ?.
Using STP in a 2 stroke will kill it. STP is well known to destroy the big end,, small end & journal bearings on 2 strokes. That's why its labelled for use with 4 strokes only.
That little line past 3/4" is 13/16".
Yo u cant use a drill bit like that on a jet, you need a microdrill bit set. 1.25mm is NOT the same as a 125 jet. Ur probably 3-4 times bigger jet than you need. You had the same issue on the TS185 and RX50.
It could just need an exhaust clear out......
There's always something next to do lol I feel it
Sure looks good! 👌
Good news for us if you do engine rebuild video
Dude go back to the stock airbox and stock setting in the carb.
Spray stuff in it to loosen the rings?
You sure the timing is right? When it gets that hot its often wrong timing.
Yeah I thought so too so I checked timing with a multimeter set to 200 ohms in series with the coil ignition wire and it dead on jumps up at the fire mark. Timing is good, it has to be engine related.
It sounds good gold
It's still lean you can hear the idle hang when you rev it. Probably a bad crank seal or its leaking oil from the transmission
To much tinkering with the carb!! More tinkering required!! Good luck 8
Mine will do 0 to 60 in about 9seconds
Time the points with a squak box that's how
You time the old 2 strokes not with a gap
Gauge the gap gage is only for ware limit check 012 to 016 these engines like it leaner
15 jet and two down on the needle
But I can't strees how important it is
To properly set the timing and when it's write on you can't see it open it's microscopic that's
Wy you use a squak box and when you turn
The flywheel with your hand it will change pitch when it reaches the f mark the sound box always hums when hooked up but changes pitch when the points just crack
It's the only way to do this bike you can not
Do it any other way sure it will run but it will sound weak it's your timing trust me??
Bro !don’t touch carb! Why make problems for yourself 😃
Rings
0-60 times woupd improve if you knew how to launch a bike especially a 2T w8th no torque. Get the revs up high boy.
You're never going to be able to tune the carb when you're burning all that oil. Change your seals. Period. Also buy a cheesy jet kit on eBay. They aren't expensive like real Mikunis
sounds way too rich
First?