Engine seizes up and then restarts???

Jul 13, 2011
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I took it up north this past weekend for a 3 day ride. It ran good, however 4,5,6 the clutch was slipping. I installed tusk clutches in it the day we left and I adjusted the nut behind the plate up snug to the plate. Well that must of been to close, after the first day of ridding and trying to not push the clutch I had to pull the case cover off because it started to slip in 3rd. I was able to turn the nut 1 1/2 turns back in. That helped but it would still slip when I got on it. I'm sure the clutch is fried already.
I also put the first carb back on it. That came back the day we left. That one had the 6.0 slide in it. I had a 48 pilot and a 160 main. That carb had better response and it didn't pop anymore like the quad vent carb with the 4.5 slide with a 45 pilot and a 155 main. The first day when we hit the old railroad tracks and I started getting up to over 60mph and held it there for a couple of minutes, the engine seized right up. I stopped and let it sit while the group caught up to me. By the time they caught up and it sat for a couple of mins. I kicked it and it started right back up. Well it did that 3 times during the weekend after I had in high gear and keep on the throttle for a short period of time. The last time it did it to me, it killed while moving. I downshifted into 3rd gear and popped the clutch. The tires slid on pavement. I let it sit and once again it fired. The only thing I can think is that the crank bearings are too tight and when they get warm they start slowing down the crank. I'm probably going to send the whole motor to Ken. I just want it to run 100%. It still blew away the other machines that we brought with.
 
either your oil mix isnt right and not getting enough lube
your running it lean and getting hot
clearances for the rings or pw arent correct
air leak causing it to overheat

look up heat seize and you can read about others who have experienced this
 
I did a leak down test before hand. I can rule that out. I took a look at the plug and its a light black color, so I think that its not lean. I am manually mixing it 32:1.
I think that the rings might be the problem. Its the only thing that wasn't checked. I didn't even think of it when I installed them. Its easy enough to pull the cylinder and check them.
 
either your oil mix isnt right and not getting enough lube
your running it lean and getting hot
clearances for the rings or pw arent correct
air leak causing it to overheat

look up heat seize and you can read about others who have experienced this

i'll x2 that
unless it ran fine before you fooled with the clutch ????, but even then i don't recall changing the clutch plates having anything to do with anything that could heat seize
and i never run mine wide open throttle for any long periods, thats just asking for trouble on these air cooled's
 
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This was a complete rebuild, so it ran fine before the rings melted to the piston. I wrote about everything that happened this weekend looking for input. I'm just wondering what my options are on the clutch to stop it from slipping.
 
the clutch needs to be adjusted... you may have however glazed your clutch disks. you can check them to see if they look blueish in some areas. i have sanded them with some 400 grit and clean them really good reinstall them and adjust the clutch properly
 
How do I adjust it properly? At first I adjust the cable for the best feel on the handle. That was the wrong way. Then I adjusted it so I had to most cable travel and then I adjust the nut behind on the basket.
 
you have to properly adjust the center rod/nut
unhook the cable from the actuator above the shifter, it has a pointer on it, that must be, and stay alinged with the notch on the case, right under the carb bowl
then turn the rod in till you fell it touch the other rod/ball, back it off a 1/2 turn and lock the jamb nut tight with locktite on it,
do not let the pointer get off that notch or the rod spin while tightening the jamb nut

edit....the adjuster on the handle is just that, it adjusts the free play when the cable stretches. period
it is not to adjust the clutch
 
This was a complete rebuild, so it ran fine before the rings melted to the piston. I wrote about everything that happened this weekend looking for input. I'm just wondering what my options are on the clutch to stop it from slipping.

"This was a complete rebuild, so it ran fine before the rings melted to the piston."

That statement worries me, it ran fine before the rings melted to the piston, could you have been running on the lean side before the melt down. A motor running slightly lean will perform extremely well, really rip, at the expense of overheating and frying the piston.

If you have not changed the jetting since the re build, the chances are you are frying the new piston.

Pull the pipe off and have a look at the piston and rings.
 
"This was a complete rebuild, so it ran fine before the rings melted to the piston."

That statement worries me, it ran fine before the rings melted to the piston, could you have been running on the lean side before the melt down. A motor running slightly lean will perform extremely well, really rip, at the expense of overheating and frying the piston.

If you have not changed the jetting since the re build, the chances are you are frying the new piston.

Pull the pipe off and have a look at the piston and rings.

this sounds like good advice to me
 
It is unlikely an issue with ring gap. What you have described is most likely a lean condition. If the jetting is within the range that makes sense for the setup, I would suspect an air leak. I would start with a leak-down test. Something like a torn intake boot can easily go undetected because it might not leak much at idle. A Reed gasket, base gasket, crank seal etc. will likely be evident by a poor idle.
Another possibility is that you main jet is partially plugged/clogged/dirty. Just a few quick thoughts ...
 
I finally had some spare time today so I pulled my cylinder. I found significant wear on the sides of the skirt and on one side of the cylinder. There was enough wear that it keep the wrist pin from freely sliding out. I had to tap it with a punch to get it out far enough to pull the piston. I also pulled a ring and put it in the cylinder and the gap was at .030. Any ideas why this happened? There is only about 150 miles on the motor.