hi all am needing help !!!!!!!!!!!
my Honda cbr400rr nc29 runs fine till 8000 revs then splutters and wont have no pull at all,,,,,
ive balanced the carbs but still has the problem
please help

any one ????????????????

Sounds like a fuelling issue. get it on a rolling road to identify what the AFR is doing.


You could also do a plug chop at full revs which will indicate if its running rich or lean.

When did it start happening? Has it always done it?

What has changed on the bike?

Balanced the carbs? Using which method?

Bikes just don't fuck up usually..so am sure it can be sorted. They are simple beasts

hi and thank you for your replys
I got the bike last year and have just got time to paint it all up
I put it all together and it sounds beutifull but when oput on road it struggles at 8000 revs
I balanced the carbs using a carb tune ive done them twice now and are spot on
I think its fuelling and am wondering if these have carb issues

it seems to be under load it splutters,,,
at standstill it revs all the way round to the red

So - is the airbox standard and are the carb settings standard?

ten pence says someone fitted a "hi flo" air fliter...or decided to fuck about with airbox "to get more air in it"

so will be running terribly lean and cannot rev out.

SO - details on the carbs, airbox, exhaust


Have you actually had it on the road? Is it in all gears?