Over heated engine and lost compression??

[XS650D]

Trying to fix a problem,let the bike idle way to long and overheated it .Noticed something wasent rite when smoke started coming out the pipe and quickly shut er down but too late.(i should know better on an air cooled bike) I had 134 both cylinders prior to testing.Now i have 95 and 120.I added some oil thru spark plug hole cranked it over a bit and retested and back to 134 both sides but after a quick ride back to 120/95.Other than installing new rings is there anything else that can be done,would the cylinder walls be glazed and maybe adding a teaspoon off baking soda (xsjohn) help or could the compression come back after a good long ride.Just reaching here.Im not experienced enough to do rings i feel.Strangely the bike still runs pretty good but down a bit off power.thx

 

[Paulrxs650]

One thing to try would be re torquing the head. Certainly easier than a rebuild. After that you may want to get into the engine

 

[650mark]

symptoms sound very similar to my sr500 when the head gasket blew right after replacing the head gasket. I was riding through death valley at the time and the temps were about 108 degrees F. ended up replacing the piston, rings, and all top end gaskets as well as having the cylinder rebored to clean up the damage. mostly my fault for letting a vendor talk me into installing his "economy, but just as good" head gasket. a $400 lesson learned the hard way. hey, shit happens......

 

[XS650D]

Dosent sound good,what will a top end cost approx,will cylinders probably need rebored and should i still be able to keep pistons (just change rings)
If i continue to drive as is what symptoms will i experience.I just came in from a ride and
strangly the bike still runs pretty good,kinda shocked really.

 

[nj1639]

Maybe things are getting lubed and back to normal?
I'd run her till she smoked.

 

[650mark]

labor charge to clean up the cylinder bore was about $40.00. he also did a mild valve clean-up job as well for $40.00 if the top end is badly damaged and you continue to ride the bike like that expect to spend a bunch of money on parts damaged by metal shavings running around in there. bearings most likely, oil pump, etc. it could be extensive but if you catch the problem early you just might get by with a simple repair.
when my sr500 engine went kaput I shut it down immediately when the engine lost all power on the hiway. when I got the bike home I took the entire top end apart, got the repairs done and flushed the entire engine out with kerosene to get all of the bits and pieces out of the bottom end and the transmission. got a fair amount of stuff out but when reassembled the engine purred for many many miles afterwards.

 

[XS650D]

Thx,hopefully no debri as it dident seize tight but definitely hot enough to wear rings and prob liners may need replaced or at lease re honed,wont know till I get into it I guess,hopeing to be able to save pistons.Mark I see your from Mesa Arizona,was down there last winter,loved it.Thats were I will be spending my Canadian winters in a few more years.

 

[650mark]

good luck with your engine repairs. here in Arizona you'll find lots of great riding, when the temps are not too hot lately though it's been about 110-117 a lot for the past couple of months so most of us haven't been on the bikes much.

 

[XS650D]

LOL! Not sure whats better,freezing cold in Canada or boiling Hot in Mesa.