Since my engine decided to die on me, I did plan to rebuild it to a higher spec.
Firstly, I'm having my cylinder head ported, and I was thinking of fitting an Acropovic exhaust this winter.
If I do this, which changes will have to be done on the carb? As the engine breathes better more fuel will be needed, but how? I have absolutely no experience on these carbs. Give me an SU, then we're talking
Of course this depends on how well the head's been modified, but a guesstimate is better than running lean.
With 11:1 compression, running lean is NOT a good idea.
On another note, the valve seats were cut so that the seats were situated 1mm away from the edge of the valve. This means more power could be had with smaller valves. What I've done, is to cut the seats in the head so that they will be on the far edge of the valve. The engine thus sees the valve as being 2mm bigger. This is without changing valves!!
Valves are35/30 as stock, which should suit a 450cc bike well. On a 650 these might be small, but I do think that the same heads are used on the larger displacment bikes as well.
Base line is: What will have to be done to the carb to get fueling right?
What if I at a later date fit an uprated exhaust?
Firstly, I'm having my cylinder head ported, and I was thinking of fitting an Acropovic exhaust this winter.
If I do this, which changes will have to be done on the carb? As the engine breathes better more fuel will be needed, but how? I have absolutely no experience on these carbs. Give me an SU, then we're talking
Of course this depends on how well the head's been modified, but a guesstimate is better than running lean.
With 11:1 compression, running lean is NOT a good idea.
On another note, the valve seats were cut so that the seats were situated 1mm away from the edge of the valve. This means more power could be had with smaller valves. What I've done, is to cut the seats in the head so that they will be on the far edge of the valve. The engine thus sees the valve as being 2mm bigger. This is without changing valves!!
Valves are35/30 as stock, which should suit a 450cc bike well. On a 650 these might be small, but I do think that the same heads are used on the larger displacment bikes as well.
Base line is: What will have to be done to the carb to get fueling right?
What if I at a later date fit an uprated exhaust?
