Siezed?

[littlewing78]

I went out for a little ride today and broke my toy.  I had been riding for about two hours and was on my way out of the hills.  I was just coasting along and then tried to climb one last little hill.  For some reason this time It took a lot of throttle to get any speed.  I turned around and went back down.  The problem kept getting worse and worse as I tried to get back to the road.  I was able to put it in first gear and let off the clutch and the bike would just sit there like it was in neutral.   At very high revs and me nearly sitting on the gas tank I was able to get it moving.  When I decided to shut it down it seemed to sieze up.  The kick starter wont budge.  This all happened in about five minutes from when I noticed something was odd.

Any ideas what I have done?  I haven't started to tear it apart yet.  Just now started to drain the oil.  Where should I start looking? 

[cbxracer30]

oil was a good start. Anything in the oil ? like pieces of clutch plate , metal flakes. Does it smell burnt? If your lucky you broke a clutch plate and a piece of plate is lodged in the big gear on the back of the basket.This sounds like a clutch problem to me Does it have anti-freeze in it ? check the little things first.CBX

[littlewing78]

Coolant was fine.  Oil looked like normal.  Milky because I need a need water seal.  Didn't see any metal pieces in the oil.  But when I took off the silencer a small chunk of metal fell out.  Looks like possibly part of the ring (@#$%).  Time to keep digging.

[cbxracer30]

Im thinking that looks a little to wide & thick to be ring . If it idled the last time you got it started I'm still thinking clutch but I've been known to be wrong.CBX

[littlewing78]

I took of the clutch cover and rotated the basket by hand and metal chunks started coming out of the exhaust port. 


So I drained the coolant and took of the head.  Looks like a new piston is in order.


The sleeve feels smooth to the touch and I don't seen and significant gouges.  Need to tear it down more now. Now I am thinking that my ring went bad and that's why I lost all power.  Then me being an idiot kept running it until the ring unseated itself.  Maybe. 

[littlewing78]

It just keeps getting worse.

[sandblaster]

That's called a shred-o-matic.
Wow!!!

[1989kawasaki]

thats awful

[littlewing78]

Ok I have reached a stopping point.  I need a rotor puller to get the case opened up.  I think I may be able to get away with just a new piston and rings.  And some new gaskets.  This is my first bike and my first time ever tearing it down this much.  It appears that there is no way that any of those metal pieces could have gotten into the clutch chamber.  Is that correct?

[Motorrad]

Ok I have reached a stopping point.  I need a rotor puller to get the case opened up.  I think I may be able to get away with just a new piston and rings.  And some new gaskets.  This is my first bike and my first time ever tearing it down this much.  It appears that there is no way that any of those metal pieces could have gotten into the clutch chamber.  Is that correct?

Correct..

But keep in mind.... main bearings and rod bearing all had pieces go through  most likley...


Ooooh the joy of cast pistons.

[sandblaster]

I know you don't want to hear it but your better off splitting the cases and replacing the main bearings and seals.
There is nothing worse than short changing yourself and then having to do it any way.
Then again, it's only time and money 

[cbmoor]

That pistom looks the same as the one i just removed from my bike. The reason for my failure was the bike over heated and melted mine the same as yours. You say you needed a new water seal maybe your bike airlocked at the head and your bike overheated just a thought as most of the damage is on the exhaust side where it is the hottest part of the piston.

[jonny500]

I know you don't want to hear it but your better off splitting the cases and replacing the main bearings and seals.
There is nothing worse than short changing yourself and then having to do it any way.
Then again, it's only time and money 

sorry to hear of the problems
sand blaster is right. i would do nothing less the a full rebuild its just not worth cutting corners. expensive i know but in the long run its defo cheaper. the last thing you want is your expensive new parts getting destroyed by the worn out parts. new piston kit, conrod,mains and seals and recoat cylinder.
while i am here i will give my opinion as to why this has happen. from what you say in the first post it sounds like you had a clutch problem causing the motor to over rev also when rolling down hills in gear the engine can become starved of oil/petrol as you probably have the throttle closed. go karters when braking from a long fast straight pat there hand on the back of the carb to give a choking effect. this gives the motor a few quick blasts of oil and fuel. you cant do this on a bike so i normaly just pull the clutch in and give few quick revs.

[Goat]

That's brutal! I agree with everyone else. I would split the cases and throw in new bearings and seals. Also check the crank journal for cracks or broken pieces. It would not surprise me if a chunk of piston lodged itself in between the case and crank. There isn't much clearance and if it did happen it could cause all kinds of issues if it's not fixed. Take lots of pics and if you have any questions there are enough of us on here to get a solid answer for you.

[greencannon]

Ive blown one up pretty bad before too. The piston was melted on top and there was quite abit of shrapnel everywhere too. Turned out to be lean jetting and extremely cold air temp.  But man, there looks to be quite a bit of dirt residue on the crank, inside of piston and cases in your pictures. Did you knock that in there while pulling it apart or could have you been sucking in dirt to cause that catastrophe ?  I think Cbmoor is mistaken, that appears to be intake side of the piston right where dirt would get sucked in first and begin the damage process. Ive seen plenty blown up by a poor intake and aged piston, that sure looks like one.

 Whatever the cause may be, I agree with others, if budget allows...complete rebuild if you want it to run strong  and last.
good luck