Hoping someone can help me out. This is a 78 CB750F that I have rebuilt the engine with the following modifications; bored to an 836, mild port job, and a mild cam. The porting and cylinder boring were done by MRieck and the cam is the CX-2 cam from Cycle Exchange. The carbs are stock, but have been cleaned and rebuilt.
My issue is the engine will start and idle fine, but the minute I give it any gas it wants to die unless I feather the throttle to keep it going. Once above 3,000 rpm it runs ok. I have double checked the point gap, timing, carb float level, sync the carbs, set pilot screw to 1 1/2 turns out and up to 2 turns out with no change. Replaced the coils and spark plug caps with no change. I have also checked the tappet clearance and that checks out. Spark plugs are also new. I have also replaced the carb-to-intake boots as the originals were hard as a rock. I have checked and rechecked the slow circuit in the carbs and the accelerator pump works on all four.
I did degree the camshaft. Initially I set the cam to the cam card, but it ran like carp. Figured out the cam card was wrong once I looked up the specs for the cam. Had initially set the intake to 5 ATDC opening, when it should be 22 BTDC. I don't think that damaged anything, but haven't taken the head off to look at it as compression is around 150 psi.
When checking the point gap and timing, again today, I noticed there was a lot of arcing coming from the 1-4 point set. I checked the condensers and they both checked out at 24pf as the shop manual states. I also can not get the 2-3 cylinder correctly timed. It is currently halfway between the "T" and "F" mark and I have no more adjustment. The 1-4 cylinders are good.
Sorry for the book, but I am at my wits end on this. Anyone have any suggestions? Thanks for the help.
