Hello all again, I am having trouble with the carb back firing if you "Blip" the throttle. I have also been told it is too rich. How can I adjust this and lean it out a bit. Currently there is a K&N filter speedstar system and longshots by Vance and Hines. Current needle setting is #3 and 172 jet. Thanks in advance. This is on an o3 midnightstar

If the "K&N filter speedstar system" is the Yamaha Stage I then I would recommend that you change the 172 to a 170.

Leave the needle at 3 (from the blunt end) for the moment but you will probably need to go to the 4th.

Doc

Thanks Doc. I will give it a shot tonight and give you feed back Monday. Thanks again.

If you have the stock Mikuni 40mm CV carburetor you will get backfiring when "blipping" the throttle no matter how you jet and adjust the carburetor.

It is vacuum actuated with a delayed throttle response then a big squirt of fuel, so when you "blip" the throttle it causes the backfire.

Sitting at stop signs or just idling the engine and "blipping" or revving the throttle is like a bikers international signal of "hi" or "hello" or "hola" or ""I'm cool" or "whatever". We all do it!

Just realise with the Roadstar...No "blip"...no backfire.

In addition, you may have an intake manifold leak either at the cylinder heads, the carburetor or at the exhaust gasket/s which are common causes of backfireing on the Roadstars.

Good luck and ride safe!<br><br>Post edited by: wchenss, at: 2006/03/04 05:18