no suggestions?

 

It sucks instead of blows? I'm just speculating but that would sure have me wondering if the cam were somehow installed incorrectly or (since you say it's not) that it was ground incorrectly. Strange. Or....maybe the exhaust valvespring is broken? I take it that cylinder is not firing so perhaps with a broken spring on the exhaust side it's sucking in on the combustion stroke.

 

My guess would be that you still have the cams installed incorrectly, if you think about it though, if the outer gears are correct, the rear cannot be off because of the fact that the front cylinder cam is driven off of the rear, so if the inner cam drive is the problem it would seem as though the front cylinder would be the odd one. Go back in and check the cam to cam alignment, if you have chain drive be sure and check the dots with the tensioner released, I had a bike in once with this problem and I looked at the dots for 15 minutes and would have sworn they were correct, after releasing the tensioner to take the slack out of the chain it was easy to see they were off a tooth, and yes, it had an odd exhaust note, also when examining SERT data log theMAP was around 50 instead of the 35 range like it should have been. Doubt you hurt the valvetrain or you would not have compression, 150 sounds about right for 37's with no other work.

 

you don't have to go smaller... heck i have 89cc heads and 10.5.1 comp w/10.5.1 J&E pistons..... you just have to get the cam you want and have the head porter work from there..he needs to know the lift/duration of the cam and he can sugest the kind of pistons to go with..


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I was basing the head cc volume on stock 88 pistons. He was inquiring about stock compression 88 so I assume he is using stock flat tops.

 

If you hold the throttle at 1/4 turn (in neutral) it seems to stumble every now and then on therear cylinder. Sends a vibration thru bike when it stumbles. Front cylinder never misses a beat. Throttle response seems to be ok.