KaTooMer
~SPONSOR~
- Jul 28, 1999
- 435
- 0
The bike: 1999 KTM 300EXC
The symptoms: Loss of compression, coolant level low.
The story: My last ride was a race, and could tell that compression wasn't what it used to be. Ran O.K., noticed the smell of antifreeze after dropping the bike a couple times, finished my race, but near the end the engine didn't feel right (blamed in on a very dusty race and a dirty air filter). In prepping the bike for a pleasure ride yesterday, I had to add a lot of coolant. Engine wouldn't start yesterday, so I pulled off the cylinder head today. Guess that flaky stuff on the piston is coolant residue. Kind of cool - sort of peeled right off and the piston was still shiny underneath.
Cylinder head has some carbon residue on the front side where the leak must have been. However, the O-rings appeared to be fine. No melting, no nicks or breaks (Cometic o-rings). On a flat surface, cylinder head shows no signs of warping.
Would seem to be a case of a bad O-ring, but before I put it back together, does anyone have any other ideas, things to check out, take apart, etc?
Thanks.
The symptoms: Loss of compression, coolant level low.
The story: My last ride was a race, and could tell that compression wasn't what it used to be. Ran O.K., noticed the smell of antifreeze after dropping the bike a couple times, finished my race, but near the end the engine didn't feel right (blamed in on a very dusty race and a dirty air filter). In prepping the bike for a pleasure ride yesterday, I had to add a lot of coolant. Engine wouldn't start yesterday, so I pulled off the cylinder head today. Guess that flaky stuff on the piston is coolant residue. Kind of cool - sort of peeled right off and the piston was still shiny underneath.
Cylinder head has some carbon residue on the front side where the leak must have been. However, the O-rings appeared to be fine. No melting, no nicks or breaks (Cometic o-rings). On a flat surface, cylinder head shows no signs of warping.
Would seem to be a case of a bad O-ring, but before I put it back together, does anyone have any other ideas, things to check out, take apart, etc?
Thanks.