Pack a spark plug wrench (and hot gloves or rag) and head out on a ride. Get up to 80+ and run for several miles with the missing problem happening. Pull in clutch and quickly turn off engine. Coast to a stop and check plugs and read them for mixture condition and report back. Good luck and watch out for the fuzz. My guess is main jet is partially plugged on one/two carbs
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Helg Bredow Sent: Saturday, April 03, 2004 9:03 PM To: Multiple recipients of list Subject: Engine misses at high speeds I'm hoping that one of you mechanics out there can give me some tips. I've got an old CB750 that runs well at anything up to 80kmph but anything over and the engine starts missing on one or more cylinders. I've just adjusted the needle position in an attempt to rectify it and the spark plugs are now a nice tan colour, instead of black so that's done something useful but hasn't fixed the engine missing. I've also adjusted the float levels but that hasn't helped either. Fuel flow seems to be OK; I've opened the carburetor drain while the fuel tap is on to see that fuel is flowing through the system. The Clymer suggests that the main jet might be too large but in order to test it I'd have to spend money :( There's got to be something else that I can try...
