Triumphrat

03-20-2005, 04:05 PM

well after the carb / airbox fire, the bike is back on the road, however there is a bad misfire at 5000rpm, in every gear, at any load, under harsh or mild acceleration, due to the fact that i now have 3 used carbs, (supposedly the 3carbs were from the same bike, but i have my doubts) would i be right in thinking that even though i was told they were re-jetted as standard, that the jetting could possibly be the cause, i can accelerate beyond 5000rpm but with a severe misfire and very slow acceleration past this rpm. bike idles nicely, and low to mid acceleration feels normal.

Slinky · 03-20-2005, 04:43 PM

I expect your bike had Mikunis originally- did you switch to Keihins, and if so did you replace the carb rubbers with the later ones?

jimmyj900 · 03-20-2005, 10:37 PM

Quote:

...there is a bad misfire at 5000rpm, in every gear, at any load, under harsh or mild acceleration, ...3 used carbs... i was told they were re-jetted as standard, that the jetting could possibly be the cause, i can accelerate beyond 5000rpm but with a severe misfire and very slow acceleration past this rpm. bike idles nicely, and low to mid acceleration feels normal.

5,000 rpm is about where you're running on the main jets, so the highest probability is that the main jets are oversize for an otherwise stock engine.

The stock size main jet for the Keihins is a #98, so I'd check that first.

If that's not it, check for a stuck slide or damaged diaphragm.

Jim

03-21-2005, 01:31 PM

it has mikuni's with derestricted rubbers (originals were damaged) i had the rubbers free with the carbs, thanks for the replies, i'll have to strip the carbs to check, i'll keep you posted.

Slinky · 03-21-2005, 02:50 PM

Min ran like a dog with Mikunis and unrestricted rubbers on it, on stock jetting.

But ut was not so much a misfire, more a huge bogging down when I opened the throttle.

05-22-2005, 03:48 PM

well it's been a long time since i was here last due to work and stuff, anyway thanks for the replies, the bike has offroad pipes, and unrestricted rubbers, mikuni carbs. any jetting recommendations?

BigVinny · 06-15-2005, 04:31 AM

On a 97 Tbird converted to Keihin CVK carbs with unrestricted inlet rubbers I opted to change the main jets from #98 to #120. The unpassable flat spot at 5000 rpm ish disaapeared and the bike now has real grunt right accross the rev range.

As you are based in the UK I got my jets from Dynojet UK Ltd Tel 01995 600500 over the phone and they only cost £6.47 delivered next day - bargain awaken the sleeping beast with new jets !

Big Vinny