Hi all i am new to the forum i think (long story) anyway i have run an xjr400 and have had to purchase an new exhaust system for her which is a 4 into 1 straight through with a removable baffle. I ran it for a week and it was running a bit lean so i put back the old system and now she fine, but how many jet size's do you normally go up by in a situation like mine?
Standard air box, 4 degree advance on the timing and standard main jet size of 90 and a standard pilot jet of 15?

Many thanks for looking, i am only after a ball park figure so i don't waste to much money on 4 jets i don't need.
RCT

The best thing to do is get it dyno tuned - that won't thoughp but it should run properly and it will save you having to case settings.
The next way is to raise the needles. To do this you need to open the carb tops, be careful theres a big (softish) spring under the top, carefully remove the diapham and the slide. You can see the needle sticking out the bottom, you need to lift the spring, and plastic carrier free then the needle.
On the needle theres a round circlip note the position take it off and place it one position lower, this raises the needle making the mixture richer.
Do it on all 4 of the carbs.
See what happens

Really though I'd get it dyno'd

Evilchicken0 wrote:The best thing to do is get it dyno tuned - that won't thoughp but it should run properly and it will save you having to case settings.
The next way is to raise the needles. To do this you need to open the carb tops, be careful theres a big (softish) spring under the top, carefully remove the diapham and the slide. You can see the needle sticking out the bottom, you need to lift the spring, and plastic carrier free then the needle.
On the needle theres a round circlip note the position take it off and place it one position lower, this raises the needle making the mixture richer.
Do it on all 4 of the carbs.
See what happens

Really though I'd get it dyno'd

The dyno will be my birthday prezzi to myself in feb next year i think.
many thanks RCT

Go up 5-10 on mains

Problem now solved without the cost of the dyno.