KZ400 - Hesitation and dies after high rev...

I have a '76 KZ400 which seems to have a struggling engine issue. The bike will idle just fine and sounds great but it has a lag between giving throttle and the response of the engine. Furthermore, when I rev up to 8k it will return to about 1k and then sputter and die.

I thought maybe it was running too lean so I opened it up a bit but it still had the problem. Last weekend I replaced the spark plugs with new stock ones from the owners manual.

I have been researching the problem and found several similar issues. I have not tried any of these yet, but was wondering what everyone else thought.

1) Fuel filter needs replacement
2) Clogged fuel lines
3) Clean carbs (maybe re-jet even)
4) Electrical issue (I have another post today about a dead battery after 7 days)
5) Air filter needs replacement

Anything else it could be?

Get your charging/ electrical sorted before going into the carbs. It could be related sounds like, from your other posts.

Motor Head wrote: Get your charging/ electrical sorted before going into the carbs. It could be related sounds like, from your other posts.

+1 !! Messing with the carbs before sorting out your electrical problem will only give you headaches. Ed

check your advancer might need lube should snap back when rotated