Would Airleak Cause bike to Run Rich?

[danni22041990]

Hi,

so iv cleaned the carbs (although were spotless anyways)the bikes choke was stuck on so released that and now the bike is running so much better it actually accelerates now! Que happy me!

BUT the seal at top of carbs between the butterfly valves and the air intakes is broke (so will be replacing it ASAP) but I'm assuming its causing an airleak there?.... Would this cause my bike to run rich.

As now the chokes been released I went to start it yesterday wouldn't start on any choke not even 1/3 choke but started on the button after some persuasion of opening the throttle. Reved its self up and held its own revs high about 2/3K rpm then come back down to 2/2.5k rpm..... if I change the idle down to 1/1.5krpm the bike just dies on me and sale when pulling up at lights unless I'm holding the revs at 2k or more the bike just does....

So I'm thinking carbs are still flooding themselves due to the leak?

PLEASE HELP before I send it on a DYNO for full work up!

[banner001]

Hi,

so iv cleaned the carbs (although were spotless anyways)the bikes choke was stuck on so released that and now the bike is running so much better it actually accelerates now! Que happy me!

BUT the seal at top of carbs between the butterfly valves and the air intakes is broke (so will be replacing it ASAP) but I'm assuming its causing an airleak there?.... Would this cause my bike to run rich.

As now the chokes been released I went to start it yesterday wouldn't start on any choke not even 1/3 choke but started on the button after some persuasion of opening the throttle. Reved its self up and held its own revs high about 2/3K rpm then come back down to 2/2.5k rpm..... if I change the idle down to 1/1.5krpm the bike just dies on me and sale when pulling up at lights unless I'm holding the revs at 2k or more the bike just does....

So I'm thinking carbs are still flooding themselves due to the leak?

PLEASE HELP before I send it on a DYNO for full work up!

the seal at the top of your carbs is less important than the one at the bottom, you will be getting a bit more induction noise, you will be taking in some unfiltered air, and some of the vacuum/pressure pulses will be disturbed...it wont affect the fuelling that much, but its good to fix it, check the plastic edge of the airbox, they are known for warping and causing the airbox to "ride high" onthe edge of the carbs and not cause a seal.

by giving it some throttle you are allowing a greater charge of air to mix with the fuel pulled in by the vacuum of the engine upon startup...ie. you are too rich, you need to screw in your pilot adjuster screws 1/8 of a turn clockwise and see if that makes a difference to the starting, this should also show itself as being rich on a dyno, is your bike hard to start when its warm?

[danni22041990]

can I get to the pilot screw with out taking the carbs out again?

was a bit of a nightmare day un bolting everything etc?

and yes it struggles to start when warm unless I give it some throttle same issue.

thanks

[banner001]

yes, so need a short flat headed screwdrived, no more than 3" long otherwise you wont be able to get to the screws, you need to remove the fuel tank and that should get you to them.

there is one for each carb, from the horizontal they point downwards at about a 20 degree angle, its probably easier if you look inthe manual, you will see the positioning of them, you can then locate them with your finger and then slot in the screwdriver, you need to make a mark on the screwdriver so you can see how much you are turning it, but go in 1/8 turn increments, or 1/4 turn if you think they are massively out of adjustment, and write down everything that you modify so you can put it back to standard.

it could be that, it could be your float heights, you may have too bit a main jet, you may have dirt in your pilot air jets, you make have a very restricted/blocked air filter...it can be a number of things, you need to make an adjustment, see over a few days if its any better, then go back and adjust it again, and repeat.