Weird problem , please help !!

JdubMotorMan · May 23, 2011

Hey guys ,

Ok so I thought my engine had seized but now I'm not so sure ... when I manually turn the magneto nut , the piston goes up and down, but when I pop the clutch while I'm riding , the back tire just skids .

I've inspected all the easy to get to parts and can't find anything visibly wrong, except for the large gear being slightly wobbly , but not to the point where it's locking up at the gears....

here's the other weird thing ... when I loosen the clutch nut on the right side, and pop the clutch , the engine doesn't start at all , but when I tighten the clutch nut to the point where it would get the engine to start up when I pop the clutch , that's when the rear tire completely locks up....

I am at a total loss of what to do at this point except to ask for help ...

thanks , - Jdub

rohmell · May 23, 2011

It sounds to me like you need to be going faster before you pop the clutch, so that your forward momentum can overcome the resistance from compression.

2door · May 23, 2011

Sounds to me like your chain is way too loose and is binding (bunching) up in the clutch actuator cover. If the chain has too much slack it will try to roll over itself in front of the drive sprocket and bind against the engine case. This will certainly make the rear wheel lock up.

Tom

JdubMotorMan · May 23, 2011

rohmell said:
It sounds to me like you need to be going faster before you pop the clutch, so that your forward momentum can overcome the resistance from compression.

speed wasn't really an issue before this problem happened... I could literally peddle 3 or 4 times and pop the clutch while twisting the throddle and it would start right up and take off like a champ.... now it doesn't matter how fast i'm going, as soon as i pop the clutch the rear tire just locks up ...

JdubMotorMan · May 23, 2011

2door said:
Sounds to me like your chain is way too loose and is binding (bunching) up in the clutch actuator cover. If the chain has too much slack it will try to roll over itself in front of the drive sprocket and bind against the engine case. This will certainly make the rear wheel lock up.

Tom

hi Tom ,

that makes total sense , but the chain is actually pretty tight with minimal play.... also , when I loosen the clutch nut , and the clutch handle is released , I can pedal with the chain moving ... it's only when I tighten the clutch nut that I try and pop the clutch and the rear tire locks up... which is really weird because that never happened before... it's like the engine is seized , but it's not because I can still manually get the piston to go up and down ...

2door · May 23, 2011

Have you inspected the two gears on the engine right side. Check for gear mesh and alignment.
Remove the spark plug and turn the engine while observing the gears. Do they mesh and rotate easily?
As far a s chain tension you don't want it too tight. You'll want 1/2 to 3/4" of slack in the top run measured with the bike moved forward against a compression stroke. A too tight chain can cause problems but I doubt that's why you're having this one.

Can you rotate the crankshaft by turning the drive sprocket? That's the small sprocket on the left side that drives the chain. Again, remove the spark plug and try turning that sprocket and see if the piston moves full stroke (two revolutions of the crank).

Your thread title is right, it is sort of a weird situation.
Tom

ducedave · May 24, 2011

Take a look behind the clutch at the loos ball bearings-I'll bet you'll find the problem with them or the sealed bearing on that same side something binding there I would think good luck

bairdco · May 24, 2011

can you forcefully move the rear tire by hand? take the clutch cover off so you can watch the gears, then get a good grip on the wheel and see if you can push it through a compression stroke.

normally, you should be able to do it with minimal force.

check the clutch gears, make sure they're not loose and wobbly, and that the nuts are tight on them.

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Weird problem , please help !!

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