Engine won't rev / HELP!
Posted: Tue May 09, 2006 2:08 pm
Hi!
I bought my -72 450 SCR cylinder and head apart and now I'm trying to get it on the road.
Renewed parts:
- wiring (except the ones coming from the alternator)
- contact breakers (Zanussi)
- condencer
- spark plug + lead
- carburettor (PHBH 28 AS)
- gas pipes
- air filter
- gaskets
The ignition is checked million times with and without the automatic advance, which seems to work. Spark is ok, one grade hotter and colder plug has been in test. Battery is weak but functioning. There is gasoline coming from the tank to the carburettor. There is no excessive smoke and compression is above 9.
The problem is that the engine starts up nicely and rews perfectly up to approx 4000 RPM, but then nothing; the engine stalls and cuts the revs. I can ride the bike, but only on really low rews. The postition of the throttle does not influence on the running after that certain amount of RPM.
The plug is carbon black but I don't think it is because of rich mixture; I have tried two carburettors; the original with standard settings and the new one with factory settings.
Everything is double checked except the coil, regulator and alternator.
Finally I'm starting to doubt the function of the breaker points. Although they're new they can fail? Should I try another points? Or move to electronic ignition?
Please give me some kind of advice, I have been struggling with this for too long now. I really don't have a clue anymore.
Greetings
Antero
I bought my -72 450 SCR cylinder and head apart and now I'm trying to get it on the road.
Renewed parts:
- wiring (except the ones coming from the alternator)
- contact breakers (Zanussi)
- condencer
- spark plug + lead
- carburettor (PHBH 28 AS)
- gas pipes
- air filter
- gaskets
The ignition is checked million times with and without the automatic advance, which seems to work. Spark is ok, one grade hotter and colder plug has been in test. Battery is weak but functioning. There is gasoline coming from the tank to the carburettor. There is no excessive smoke and compression is above 9.
The problem is that the engine starts up nicely and rews perfectly up to approx 4000 RPM, but then nothing; the engine stalls and cuts the revs. I can ride the bike, but only on really low rews. The postition of the throttle does not influence on the running after that certain amount of RPM.
The plug is carbon black but I don't think it is because of rich mixture; I have tried two carburettors; the original with standard settings and the new one with factory settings.
Everything is double checked except the coil, regulator and alternator.
Finally I'm starting to doubt the function of the breaker points. Although they're new they can fail? Should I try another points? Or move to electronic ignition?
Please give me some kind of advice, I have been struggling with this for too long now. I really don't have a clue anymore.
Greetings
Antero