Drained the tank today. Fuel does smell weird, so I have my fingers crossed some new fresh will fix this strange issue (when I can afford some!)
Weird engine problem got me stumped
- Thread starter maniac57
- Start date
my bgf z80 did the same thing...
seals weren't seated correctly...
new seals...bing...fixed.
rip her apart check the seals and check the bottom end fer sludge from the seals leaking...
also gas left out has a tendency to separate ethanol has water in it
seafoam
steal ur gas...its cheaper
gl homey
seals weren't seated correctly...
new seals...bing...fixed.
rip her apart check the seals and check the bottom end fer sludge from the seals leaking...
also gas left out has a tendency to separate ethanol has water in it
seafoam
steal ur gas...its cheaper
gl homey
Yeah. I'm thinking it's the seals. I swapped for some fresh gas today and checked all possible air leaks with no success. Ran for three minutes and overheated.
I'm pulling it down for seal replacement as soon as I can scrape up the price of a set. Nothing else it can be...
I figure maybe when the head loosened up on my last good ride it might have pressurized the case and popped the seals. They look fine but it's all I have left to try.
It's not timing or a gasket leak.
I'm pulling it down for seal replacement as soon as I can scrape up the price of a set. Nothing else it can be...
I figure maybe when the head loosened up on my last good ride it might have pressurized the case and popped the seals. They look fine but it's all I have left to try.
It's not timing or a gasket leak.
you may want to make sure you have everything air tight , mine done the same thing and I noticed air bubbles in fuel line and used to blow gas out the gas cap from overheating , make sure carb is tight all lines to it depending which carb you have you will need to seal it up to
If your gas tank is overheating and venting through the cap, I'd be thinking there's something not right. And definately not safe.
I was thinking the same thing. How was the fuel tank "overheating"? Are you sure it wasn't just the normal seepage around the fuel tank cap?
Tom
Tom
no , the gas would actually blow out all over the place , at the time I was running an nt carb , I noticed air bubbles coming from carb to fuel tank through the line , once I sealed it up air tight it was fine ,
How old is the engine? Sounds like it's overheating from a bearing failure. I had a drive side clutch shaft bearing fail and it heated the entire case. Other than another bearing failing, you're running super lean or fuel with no oil mixture at all. (didn't grab the wrong can in the garage on last re-fuel maybe?) Drain the fuel and mix up some 20:1 and throw it in.
Not a bearing failure. Engine is brand new GenV. It overheats from the top down, but thanks for the input!
I'm pretty sure now it's bad crank seal(s) It's the only thing left I have not checked or replaced.
Swapped the motor out for a stocker I had on the sale chopper because I HAVE to make a doctor appt and cannot wait till it's fixed.
I'm pretty sure now it's bad crank seal(s) It's the only thing left I have not checked or replaced.
Swapped the motor out for a stocker I had on the sale chopper because I HAVE to make a doctor appt and cannot wait till it's fixed.
After reading everything here carefully, I'm going to guess first that it's a carb issue after it gets hot it's leaning out... It could also be a exhaust issue (build up as it gets hot)??
Also... did you try a colder plug??
Another possibility... I once has a piston that was slightly warped & was lightly rubbing on the cylinder wall & getting hot.... Could that be?? :/
You'll know if it's a crank seal just by running the engine with the side covers off.
Another thing to try is to add a second head gasket to lower the compression.
Also... did you try a colder plug??
Another possibility... I once has a piston that was slightly warped & was lightly rubbing on the cylinder wall & getting hot.... Could that be?? :/
You'll know if it's a crank seal just by running the engine with the side covers off.
Another thing to try is to add a second head gasket to lower the compression.
Last edited:
After reading everything here carefully, I'm going to guess first that it's a carb issue after it gets hot it's leaning out... It could also be a exhaust issue (build up as it gets hot)??
Also... did you try a colder plug??
Another possibility... I once has a piston that was slightly warped & was lightly rubbing on the cylinder wall & getting hot.... Could that be?? :/
You'll know if it's a crank seal just by running the engine with the side covers off.
Another thing to try is to add a second head gasket to lower the compression.
Tried a different carb with no joy. Plug looks fine as does the top of the piston with no abnormal build up to cause hot spots. This is why it took me so long to decide it might be crank seals. I am baffled since it shows no other signs of a lean mixture (like high idle or choke affecting how it runs.)
Have not pulled the jug (just the head)as the cylinder wall shows no signs of abnormal wear or binding.
I really hope it's the seals as I have nothing left to try.
Keep in mind this is not my first two stroke....but it is the first difficult issue I have ever had with a HT motor. NEVER seen anything like it before.
It acts like someone milled the head 1/2 an inch while I wasn't looking....
I thought about a second head gasket, but I can't justify removing compression to fix an issue that it did NOT have the first three weeks of use!
This is being caused by something that happened AFTER the engine was running(quite well by the way) so it should be something I can diagnose and fix.
I have my pride and a simple tinfoil and beercan motor is NOT going to beat me!
*Puffs chest out and gets belligerent*
I will not give up until it runs right once again!
WILL ONCE AGAIN BE
!
I know you're not a noobie at this... Trust me this one has me scratching my head too!! :/
Maybe it's possible that a bearing wore out just enough to let the piston travel up a little to raise the compression?? IDK... try the second gasket for the h*ll of it. (or a colder plug).
Maybe it's possible that a bearing wore out just enough to let the piston travel up a little to raise the compression?? IDK... try the second gasket for the h*ll of it. (or a colder plug).
Last edited:
I checked the mains for slop or grit with no bad results so I don't think it is the mains.
Got a set of seals coming soon so if THAT doesn't fix it, I'll try the double gasket.
What really gets me is the fact it ran so good before this issue. Nothing I can think of could cause this except some major failure like con rod or mains.
I would EXPECT to see other signs if it were simply a lean mixture but the plug and top end look fine and I see no sign of a lean mix.
Like I said.
Baffled.
(Oh BTW, I also checked for small end con rod wear and everything feels nice and tight)
Got a set of seals coming soon so if THAT doesn't fix it, I'll try the double gasket.
What really gets me is the fact it ran so good before this issue. Nothing I can think of could cause this except some major failure like con rod or mains.
I would EXPECT to see other signs if it were simply a lean mixture but the plug and top end look fine and I see no sign of a lean mix.
Like I said.
Baffled.
(Oh BTW, I also checked for small end con rod wear and everything feels nice and tight)
Last edited:
Try installing a different magnet.... If it's not a friction problem or a 'air/fuel' problem, it has to be something in the ignition system! :/
Thought about that Norm, but the engine ran great when I first got it so I doubt it's a timing issue.(Already checked the keys too!)
I'm going to slap a new set of seals in it and probably seal the cylinder studs as well after talking to Neil today. It's got to be air/fuel and these are the only other possibilities not already checked out.
I miss my bullet even more now that I have a stock motor on the bike again....
*sobs and curls into a fetal position on the floor*
I'll be sure to post updates once my new seals arrive!
I'm going to slap a new set of seals in it and probably seal the cylinder studs as well after talking to Neil today. It's got to be air/fuel and these are the only other possibilities not already checked out.
I miss my bullet even more now that I have a stock motor on the bike again....
*sobs and curls into a fetal position on the floor*
I'll be sure to post updates once my new seals arrive!
Got the new set of seals today...along with several other handy gaskets I sorely needed to tear down and replace them. It's nice dealing with ethical people in these days of apathy and greed.
MotorBicycleRacing sent me needed replacement parts quickly and was a pleasure to deal with through the entire process. Very helpful and friendly helping me figure out this headscratcher.
Hope we finally got it pinned down! *crosses fingers and toes*
My Thanks as well to all those who responded to my posts with helpful advice!
Even after 40+ years as a two-stroke fanatic, I always learn new stuff here and appreciate everyone's input.
Should have some down time to install the new seals and swap motors again next week hopefully.
While the stock ebay engine on The Pig now is a great little chinagirl, I'm was quickly spoiled by the GenV and can't wait to get it back in the belly of The Pig!
MotorBicycleRacing sent me needed replacement parts quickly and was a pleasure to deal with through the entire process. Very helpful and friendly helping me figure out this headscratcher.
Hope we finally got it pinned down! *crosses fingers and toes*
My Thanks as well to all those who responded to my posts with helpful advice!
Even after 40+ years as a two-stroke fanatic, I always learn new stuff here and appreciate everyone's input.
Should have some down time to install the new seals and swap motors again next week hopefully.
While the stock ebay engine on The Pig now is a great little chinagirl, I'm was quickly spoiled by the GenV and can't wait to get it back in the belly of The Pig!
Theoretically shouldnt take ya more than 4-5 hours total teardown/rebuild...
Whats ur stud size? I have m6 x 1, and maybe enough m8 x 1.25 this is 12.12 hardened aerospace grade threaded rod
Both motorkits i had i used this
My 68mph e50 race ped uses the m6...
Track tested in auburn ny @ mopedmayhem in october
Let me kno and ill cut ya a set...have flanged hex nuts fer the m6 too
Get rippin brutha
Whats ur stud size? I have m6 x 1, and maybe enough m8 x 1.25 this is 12.12 hardened aerospace grade threaded rod
Both motorkits i had i used this
My 68mph e50 race ped uses the m6...
Track tested in auburn ny @ mopedmayhem in october
Let me kno and ill cut ya a set...have flanged hex nuts fer the m6 too
Get rippin brutha