why did my 250R blow up again?
#13
why did my 250R blow up again?
Originally posted by: Bubba297
1/4 throttle in 6th has quite a load on the motor, and is about the leanest spot on the carb. The exhaust bridge also needs to be relieved slightly on the LT's to keep it from pushing into the piston. That would be the only 2 reasons for sticking the rings into the piston on the exhaust side (if that happened again)
1/4 throttle in 6th has quite a load on the motor, and is about the leanest spot on the carb. The exhaust bridge also needs to be relieved slightly on the LT's to keep it from pushing into the piston. That would be the only 2 reasons for sticking the rings into the piston on the exhaust side (if that happened again)
#14
#15
why did my 250R blow up again?
This piston and rings were installed the correct way. Everything went back together real smooth. It actually ran great for about 3 hours and then when I started to really run it, it tore up the front of the piston.
It just seems like something strange is going on since both times it destroyed the front of the piston. There is no evidence of being too lean either. Looks like someone took a file to the front of the piston.
It just seems like something strange is going on since both times it destroyed the front of the piston. There is no evidence of being too lean either. Looks like someone took a file to the front of the piston.
#18
#19
why did my 250R blow up again?
The piston had 2 small holes on the exhaust side beneath the rings. I assume these were the relief holes?
As the cylinders are bored can you start to have clearance issues with the exhaust power valve? Could the exhaust valve when fully opened be sticking out just enough into the cylinder to hit the piston at high rpms?
When I first got this thing back from being rebuilt the power valve was not functioning right. Once I took it all apart and reassembled according to the book it worked great. Instead of a real "jerky" powerband and 4th thru 6th gear being dead the thing ran the way it should have.
Then as soon as I ran it hard the first time and really used the higher gears this powervalve would be opening and fully functional for the first time. Next thing ya know it's dead and the front of the piston is destroyed.
As the cylinders are bored can you start to have clearance issues with the exhaust power valve? Could the exhaust valve when fully opened be sticking out just enough into the cylinder to hit the piston at high rpms?
When I first got this thing back from being rebuilt the power valve was not functioning right. Once I took it all apart and reassembled according to the book it worked great. Instead of a real "jerky" powerband and 4th thru 6th gear being dead the thing ran the way it should have.
Then as soon as I ran it hard the first time and really used the higher gears this powervalve would be opening and fully functional for the first time. Next thing ya know it's dead and the front of the piston is destroyed.