Stoney
CB750 Member
Hi everyone.
I recently purchased a k7 SOHC running Keihin round-top carbs and a 4 into 1 exhaust with stock airbox.
It starts well and gets good all-round performance (smooth with good MPG) but I've been having a few issues:
Boggy low revs
SLIGHT spitting/popping if held at 3k +
SLIGHT smoke from exhaust if held at reasonably high revs
Dry black carbon on all plugs (1 and 4 slightly worse)
Idle will creep up slowly from 1k to 1.5/2k when fully warmed up, blipping the throttle brings it back down most times.
So far I've changed out the air filter, plugs, cleaned the carbs a half dozen times, set the air mix (2 turns out seems to provide highest idle, much leaner/richer and it's rough) and also replaced the spark plug caps and ht leads (the bike is fitted with dyna coils). Checked for vacuum leaks and replaced all hose clips around carb boots as some were worn out and loose. Checked air box for leaks.
I'm yet to check points/valves and they are next on the list, but I'm fairly sure I need to re-jet for the exhaust and need some advice as to the correct idle and main sizes. Also, if anyone could advise on float height that'd be a huge help!
Many thanks in advance.
I recently purchased a k7 SOHC running Keihin round-top carbs and a 4 into 1 exhaust with stock airbox.
It starts well and gets good all-round performance (smooth with good MPG) but I've been having a few issues:
Boggy low revs
SLIGHT spitting/popping if held at 3k +
SLIGHT smoke from exhaust if held at reasonably high revs
Dry black carbon on all plugs (1 and 4 slightly worse)
Idle will creep up slowly from 1k to 1.5/2k when fully warmed up, blipping the throttle brings it back down most times.
So far I've changed out the air filter, plugs, cleaned the carbs a half dozen times, set the air mix (2 turns out seems to provide highest idle, much leaner/richer and it's rough) and also replaced the spark plug caps and ht leads (the bike is fitted with dyna coils). Checked for vacuum leaks and replaced all hose clips around carb boots as some were worn out and loose. Checked air box for leaks.
I'm yet to check points/valves and they are next on the list, but I'm fairly sure I need to re-jet for the exhaust and need some advice as to the correct idle and main sizes. Also, if anyone could advise on float height that'd be a huge help!
Many thanks in advance.
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