Where is my compression

[metor]

I was out having fun showing off. The bike was running strong. When in 5th gear and ? RPM's the bike just died. IT rolled to a stop and I tried to start it. I noticed right away that the motor was easy to kick. This is not good I said to myself, with  alot of other things, which made me feel better. All I had time to do today was remove the plug. The plug was perfect.  No oil,metal chips water nothing but the color of a good burning plug. Is there anything else that would cause this? I think It is a blown top end. I hope this is all. Shifting has been a little hard lately. I did change the transmission oil. This was the first ride. I used Maxima mtl fluid 80 wt.
This sucks.

[gowen]

Did you happen to mix the fuel? It sounds like you friend your rings. Usally an easy fix, but you will need to pull the cylinder off and check either way. I'd suggest getting a REAL service manual. I'm happy with Clymers, but Kawasaki has a decent one too. Your transmission has nothing to do with your top-end. Let me know

[metor]

The fuel was mixed a couple of weeks ago. My son used the same fuel in his yz 125 I think. I guess it is possable the wrong fuel got in there as I also have a xr 80 and an xr 100. I have a repair manual somewhere. I will pull the head and cylinder todayand hope.

[gowen]

metor, something to consider, when you mix fuel with oil and leave it over time, the oil will fall to the bottom, unless shook up well. I fried my 500 last year by not shaking up the can well. Good luck and keep us posted!

[FIVE-HUNGE]

Sounds like top end, break out the old compression tester to see if you should even bother pulling the cylinder off. a few months ago my 500 was kicking over like a 125, thought I burned up the top end, turned out to be ignition side crank seal.
dirtbike motors are funny like that. Just when you think you've got it figured out by it's symptoms. It turns out being something else.
Don't overlook anything.

[metor]

Well found the problem. The exaust  side of the piston and rings are one piece now. Not too much damage to the cylinder but there are a couple of groves that worry me by the ports. The pistion is perfect condition except in a 2 inch area top to bottom. Everything else seems to be fine. I called a local cycle shop and was told that it would cost 250.00 for the plating and 250.00 for the top end rebuild. Is there a cheaper place to have the replating done?

[metor]

on second look I do not think I need replating. I think that the scratcher appear to be alumium deposits. But now I see a crack, only one. does it have to be repaired?

[gowen]

Yes, it needs to be repaired, either welded, then replated. Here is my suggestion, send it to Eric Gorr. It is like $125 for a replate from him and like $50 to have the crack replaced. http://www.ericgorr.com Everybody here knows I'm a fan of his, as he has done great work for me and my many bikes (I send all to him). For $500, you could have him do you a 520cc big bore (including all labor and parts!!!). Check his site out.

Gabe

[metor]

Well I will be sending in my cylinder and head tomorrow to have the cracks and cylinder liner fixed. I am also having the compression release installed at the same time. About 550.00 bucks for all including pistions and rings. Should take about three weeks before I am up and running