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1979 750 dohc wont rev past 6500 under load

DDay

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Hi, I have a twin cam 750 that is stock a part from a 4 into 1 exhaust. It won't rev past 6500 while riding and it seems to be rich. It revs in neutral.
I have rebuilt the crabs and noticed it has 68 primary and only 75 secondary mains tried 95 and it was worse.
Can anyone help
 
Normal secondary jet is around 102ish. I'd say something wrong there. Check compression before going any further, commonly it's way down from all the people who refuse to set the valves, it then shows up in engine not revving in the higher numbers. Then the average American male IQ/testosterone ratio being what it is drives owner to mess with carbs next, the killing stroke then. They run rich when the engine runs crappy enough to not burn it all. They're CV carbs, they don't lift slides with a dead motor sucking on them and that goes rich. Nobody gets that. Does bike still have the stock airbox?

Compression with hot battery, all plugs out and throttle held wide open should be around 170 psi, I'd bet you're nowhere near it.
 
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