From perfect little get around motor to dog in one gasket replacement?!? (FIXED IT!!!)

[markjs]

OK, here's the plug color, and a look under the mag cover...

The magneto is not centered, is that a problem? It's worse than I could get the pic to show, almost no gap at top and big gap on bottom.

Plug looks right to me, anyone agree?

 

[markjs]

Well s**t, I tried my Yamaha spark boot and it holds the plug properly and it works fine, but there was no real difference in performance. At least it's one more variable checked off as "not the issue" at least.

 

[Sloppyslopster]

I may have made a mistake due to bad info... (Please someone clarify for me?)

Are you supposed to tighten the cylinder and head studs to the bottom of the case before assembly? I saw a video right before I built mine, saying just finger tight was good, but I have since seen folks saying they use Loctite or even JB on the bottom to prevent leaking?

If there is a need for them to be very tight at the bottom of the case, that could very likely be my problem, because mine were just finger tight from the beginning, and I must confess, I did not re check that when I did the upper end gaskets.

I wonder if I go in to try and remedy this (if y'all suggest I should), it might be best not to pull the head or jug, and use two sandwiched nuts to drive the studs in tight, then retorquing the nuts so even if the torque is off for a minute, there is less chance of the head or base seal being disturbed?

Definitely give it a shot just tighten the studs snuggly no need to over tighten. And yes don’t use acorn nuts they’re a nightmare to work with and can cause very preventable problems.

OK, well I did the compression and what I got was a solid 120?!?

I'm just guessing, but a standard compression auto usually reads between 140 and 180 when in tip top shape, so with the lower compression of a two stroke, wouldn't 120 be a good reading? Is so then I'm as baffled as ever, still wondering where the issue could be.

I can't imagine that could be low for this engine, but you guys know more than I?

Also once again, is there anything I should check under the magneto cover for?

If that compression number is as good as I think, makes the loose spark boot even more sus!

Anywhere from 120-170 is considered good.
You’re issue I bet you 5 bucks its going to be air/fuel related. I saw you mention that when you initially bought it and ran you changed the needle once and it made all the difference. And now that you’ve swapped gaskets out, it runs bad. My analysis is that your old gasket was causing an air leak and now that you’ve fixed it. It messed up your carb tuning and now is running rich most likely. Try and swap you carb back to stock jetting.

 

[Chainlube]

OK, here's the plug color, and a look under the mag cover...

The magneto is not centered, is that a problem? It's worse than I could get the pic to show, almost no gap at top and big gap on bottom.

Plug looks right to me, anyone agree?

View attachment 212078View attachment 212079

The plug looks great. You can center the mag by loosening the four screws on the coil and reposition the coil, a standard business card should fit in all the way around. That will generate the most electricity. I see a little oil on the bottom of the cylinder, you might have a small intake leak. Did you try tightening the allen screws on it?

Both of your chains look dry, put a little oil on them. A lubed chain uses less power and less chance of breakage.

 

[markjs]

The plug looks great. You can center the mag by loosening the four screws on the coil and reposition the coil, a standard business card should fit in all the way around. That will generate the most electricity. I see a little oil on the bottom of the cylinder, you might have a small intake leak. Did you try tightening the allen screws on it?

Both of your chains look dry, put a little oil on them. A lubed chain uses less power and less chance of breakage.

I still suspect it could be crappy compression. The oil, I think is from the original gasket, not the new one. I cleaned the surfaces, but not the fins.

I will check the intake though, tomorrow, when I can get busses.

I suspect when it ran good the compression might have been higher but IDK.

 

[Wyvern]

Did you happen to check the clutch?

Are you 4 stroking up top or lean bogging?

What oil/fuel ratio have you been feeding it?

The plug actually looks decent which makes me wonder if your clutch is burned or out of adjustment.

 

[markjs]

Did you happen to check the clutch?

Are you 4 stroking up top or lean bogging?

What oil/fuel ratio have you been feeding it?

The plug actually looks decent which makes me wonder if your clutch is burned or out of adjustment.

Just recently adjusted the clutch. I was gonna try and tackle it a couple of days back but ended up not. I'm gonna get into it today I think. I will re-check the clutch anyway.

 

[markjs]

Well I tightened the studs into the block and they were quite loose and not bottomed out. I just took two acorn nuts off, tightened both studs and then replaced the acorn and original split washers, replaced them with new, tightened them down then did the other two, so the head seal was never really broken. Then I set the carb needle at the leanest it can be. It runs noticeably better, but without a trip down the big hill I can't really tell for sure if all the power is back. Its's definitely better and I'm about 90% sure it will get up the hill, but until I try, won't know for sure.

Wish me luck, BRB will let y'all know...

 

[markjs]

I got it!!! Now it gets up[ the hill again with no pedal assist! Back to full power!

The problem(s) were STUPID simple, as I thought, still took a couple hours to figure.

IDK if the studs not being fully sunk mattered or not, but that's fixed and the acorn nuts are replaced.

Yes with a tight head and base gasket it did need to be leaned down one position (or maybe two, the clip came off the first time I went to adjust), but anyway...

The stupid part, that I think has been plaguing me the whole time but I did not notice. The damn choke!!! The thing was so loose it could vibrate itself closed or partially. I tightened the nut until it's almost impossible to close, this time of year I don't need it, but I noticed if I try to use it at all it loosens the nut and creates the problem again, so for now, it's warm, thing starts easy, I'll leave it super tight. It will need Loctite (if that works on that?) in the future or it will just always be a problem, IDK, but anyway she pulled up the hill so I'm happy again!

 

[Sloppyslopster]

I got it!!! Now it gets up[ the hill again with no pedal assist! Back to full power!

The problem(s) were STUPID simple, as I thought, still took a couple hours to figure.

IDK if the studs not being fully sunk mattered or not, but that's fixed and the acorn nuts are replaced.

Yes with a tight head and base gasket it did need to be leaned down one position (or maybe two, the clip came off the first time I went to adjust), but anyway...

The stupid part, that I think has been plaguing me the whole time but I did not notice. The damn choke!!! The thing was so loose it could vibrate itself closed or partially. I tightened the nut until it's almost impossible to close, this time of year I don't need it, but I noticed if I try to use it at all it loosens the nut and creates the problem again, so for now, it's warm, thing starts easy, I'll leave it super tight. It will need Loctite (if that works on that?) in the future or it will just always be a problem, IDK, but anyway she pulled up the hill so I'm happy again!

Glad to see you're back up and running again. If you're having carb trouble and the thing is just crap I would just get a better quality one. Not sure who sells good stock replacements. But hey I always suggest getting a windowed piston, g2 reed, 21 pwk, and a good pipe like an mz65. Safe easy upgrade are just a pipe and a high comp head. But that's something for a later date for you.

Last suggestion I would make to you would be to still play with the clip a bit, maybe move it rich one notch and see how it runs. Don't want to run the engine too lean or it will become a mess of metal chunks and could send you to the hospital if not careful enough.

Again happy to see its working again, safe riding!