Global mix

[Fizzyhair]

Can I adjust the fuel air mix for entire bike or is it one carb at a time. Mine backfires at revs

[BassCliff]

Hi,

The only "global" setting is the main idle set knob.

As for fuel/air mixture, yes, you must adjust each individual carb. Have a look at my website for the "highest idle method" for adjusting the idle mixture screws and the carb synchronization article to adjust vacuum/butterfly valve openings. If necessary, install larger or smaller jets to acheive proper mix in all circuits, then fine tune. Is your bike stock? What bike are we talking about? The carbs must be cleaned properly, the air intake system can have no leaks, etc.

Thank you for your indulgence,

BassCliff

[tom203]

Can I adjust the fuel air mix for entire bike or is it one carb at a time. Mine backfires at revs

Put the bike year/ model in your signature so others can follow without backtracking your previous posts. You're refering to a 650 ,right? Anyways, on each carb at top on side closest to engine head, there's a little verticle tower which houses an idle mixture screw- once again, visit Basscliff's site for glorious pics- this screw might be covered with plug, but probably not. When does it backfire? as you rev it, or as you close the throttle?

[Fizzyhair]

I changed the exhaust for an after Market with the back baffle... Ahem... Missing :-)

Since however it bogging down at revs over 3500ish and there's a pop on the up side of the rev and not at the release. It can't be ridden untill MOT has been done witch is another issue lol. So all revs are with no load on engine. My experience with this stuff has always been with modern sports bikes where there's a master idle screw etc. I don't have the equipment to balance the carbs. And to be fair I can't ride it to a garage so I'm snookered I think. I just wan to get it so it can be ridden a couple of miles to a garage. Thankyou by the way. Good idea bike in signature!

[tom203]

I changed the exhaust for an after Market with the back baffle... Ahem... Missing :-)

Since however it bogging down at revs over 3500ish and there's a pop on the up side of the rev and not at the release. It can't be ridden untill MOT has been done witch is another issue lol. So all revs are with no load on engine. My experience with this stuff has always been with modern sports bikes where there's a master idle screw etc. I don't have the equipment to balance the carbs. And to be fair I can't ride it to a garage so I'm snookered I think. I just wan to get it so it can be ridden a couple of miles to a garage. Thankyou by the way. Good idea bike in signature!

So the "MOT" is to determine the bike's roadworthiness, and not yours? Aftermarket exhaust-altered! Do you still have airbox/air filter assembly?

[BassCliff]

Hi,

Yes, modifications to the intake and/or exhaust require jetting changes to the carbs in order to maintain proper air/fuel mixtures.


Thank you for your indulgence,

BassCliff

[Fizzyhair]

The exhaust is a 4-1 motad that was the only thing really available. It's baffle was drilled out because it's the quietest exhaust you've ever heard (still quieter than stock bike) and I like cars around me to know I'm there for safety as much as anything.

I've got a mate coming to balance em again now