Guys I was pulling my thundercat over testing spark, plugs out, times off, and then all of the sudden,DINK, my sled locked up. I can turn the clutch one rotation to the left, one rotation to the right and it just stops!?!?!?! What happened???? The Pistons move up and down all of them for that one rotation. Please help
It could be a lot of things, but is probably crank related. You won't know until it's apart. I would take the exhaust and carbs off and see if you can look in to see if there are any visible problems, like a broken piston skirt or failed bearing. I would also pull the plugs and look at the piston crown to see if there's something that is on top of the piston...
You may have to get it apart completely to find the problem. The good news is, it didn't happen at 8000 rpm...
There are a lot of pieces to a triple crank, and if one part goes bad, that part can be repaired. A good crank shop can replace bearings and such for a lot less than that amount. You could also have had a wrist pin circlip fall out, a piston ring snap, a needle bearing fail, a piston skirt break, or something that got ingested by the carb and ended up on the piston crown. You won't know until you have it apart to look.
I would send it to a shop that does a lot of cranks. Most machine shops may be able to press one apart, but pressing them back timed correctly could be an issue. It's better with a shop that deals with cranks a lot. A shop that deals with 2-stroke cranks will also have the specialized tools and jigs to do it quickly and correctly. JMHO, mind you.
Since it will go one rotation before stopping, look through the plug holes and see which piston is at TDC or BDC when you start to turn it and vice versa when it stops.
This will point you to which one is the problem.
My bet is that you have caught a ring end and snapped it off.
You may also be able to use a harmonic balancer puller. Or there are less expensive pullers out there that may work. www.denniskirk.com would be one place to look online.
I made a better one! Just take the cage off the flywheel,after you get the center nut off.
Don't forget the heavy washer too.
Then use the cage as a pattern and drill the 3 holes threw a small piece of like 1/2" plate steel (a 3" circle or square is good)
Then with the nut back on and flush with the threads, put the plate over the end and measure the distance the bolts will need to be (like 1 1/2"?) and account for them to go into the flywheel.
Then get the highest grade bolts you can get!
Put them in and make sure it is square.
Then just go around in a circle and tighten and tap on the center until it pops!
It will scare you!
Now if yours has the bolt instead of the nut, I got a bit longer one and then cut a piece of 3/8" pipe about a 1/2" long and used it as a spacer!
Okay if I can't get one I'll try that. I know this is kind of off the topic, but if I have to get into the case, is it hard to split it? I feel like maybe this is a sign after how many times I have had this motor in and out, that I should finally replace the seals and water pump impeller with a factory oem one. For anyone joining the thread late, my model sled is a 1999 thundercat 1000
Dont be to scared yet lol take the top end off and see whats going on if you take the top end off and it turns freely then you know it isnt the crank, also you may want to replace the gaskets when you put it back together and replace all the rings, like RJ said i bet its ring related.
OK here ya go!
Take the plugs out, look at them!
If no tell tale signs, put a screw driver into eack plug hole and rotate the crank!
If one doesn't move it is your problem!
If they all move it's Your stator/flywheel!
Well guys I took flywheel off and there was nothing there obstructing anything.... All of the sudden once everything was off, then reinstalled it started urging over fine again.... I have no idea.
So tomorrow I'm going to be starting up my sled. I have my coat hanger to pull the oil injection lever over at idle, to bleed it basically from what u guys tell me.
I wish I would have known this earlier, but everyone I've talked to says wiseco pistons suck. Why is that, and what should I do preventatively to make sure nothing stupid happens??????
Hang on man!
There HAD to be a reason it stopped!
A piece of rust is Not gona stop that crank from turning!
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