Cr85 engine problem

Avster556

Avster556

PR Member
My younger brother and I were riding at briarcliff a few days ago. He was pushing his bike so I got off to see what happened. He said it made a really weird noise and ran funny so he turned it off. I kicked it a few times and it started for barely a second and made a noise like something was spinning. It wouldn't start again but it still kicks over. I know it is not electrical. It's a 2005 cr85. Please help. Also the bike still has the original piston. My dad thinks that it may be a hole in the top of the piston.
 
Could be anything without more info and not everything can be diagnosed on a forum. Pull the top end off after a comp check.
 
Good compression. The fact that the bike won't start makes me think it's the crank or piston. It has fuel, air, spark, and compression. When it did start though it made a noise like two things were spinning up against each other coming from the right case. I'll pull off the head and see what's up. Thanks.
 
If you have good compression I would pull the clutch side cover off and see if something came loose in there
No need to pull the head yet
This is just from what we cant here or see from where we are at
Hard to pinpoint a problem this way
Does the motor not start because it cant turn freely?
Im thinking of different reasons and a loose flywheel that has sheard the key comes to mind but thats other side
Cant think what in the right ase would cause it not to start if you do have fuel,compression,spark and proper ignition timing
unless something came loose and wont let the motor turn freely
one step at a time I guess
 
I am going to start by taking the clutch side cover off. I pulled the engine from the bike and by shining a flashlight in the exhaust port the piston is fine. (May do a top end because engine is already out). It is kind of hard to tell if the motor was moving freely but I do think something was grinding from the sound it made. Thanks.
 
I've had a couple cr bottom ends squeel before completly seizing up due to the outter crank bearing spinning in the case, most likely happens from a previous bottom end failure or improper bottom end bearing rplacement resulting in not having the correct fit in the case when replaced. Don't know if that relates to what you heard without having heard it myself. Could be something simple and easy to fix in the outter case cover.
 
That seems like the sound it was making. What do u mean by the outer case cover? Also the kick start lever does not fully spring back into place after turning it over.
 
Already took off clutch cover and there are no signs of a problem. We Will split cases soon and if we still have trouble we can always take it to iron pony. Thanks for all info
 
Avster556 said:
Already took off clutch cover and there are no signs of a problem. We Will split cases soon and if we still have trouble we can always take it to iron pony. Thanks for all info
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If you split the cases and the bottom end is the problem you will know it.
 
Going to have to pull the topend off to split the cases so youll be able to tell by turning the motor over with the connecting rod
if the bottom end is out of it
 
Little bit slow on this bike but we did get the top end off and pistons fine. It turns over but the bearings in the bottom end seem bad. Probably will split cases today. Thanks
 
Avster556 said:
Little bit slow on this bike but we did get the top end off and pistons fine. It turns over but the bearings in the bottom end seem bad. Probably will split cases today. Thanks
Click to expand...
Thought thats what it sounded like, I used to run hondas back in my 2 stroke days and have had the same issue a couple times. At least you didnt lock it up.
 
Finally got the bike fixed a couple weeks ago. Did a full top and bottom end rebuild new crank, seals, and bearings. Runs great!
 
Yeah and when you do the work yourself its much cheaper than having a shop do it. Anyways the 2 strokes are easy to work on.
 
O yeah, most of the time you can get a complete top and bottom end kit for around 300 bucks. Bout the cost of a good top end rebuild on a 4 stroke. Lol
 
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