Yamaha Starbike Forum banner

Back fire

1101 Views 13 Replies 8 Participants Last post by  Brad_G
My 08 roadstar has cobra pipes. Before I put my baffles back in it was back firing and popping real bad. I put the baffles back in and it still back fires. I’ve already put new spark plugs in it and it still does it. It was a California bike with all the omissions on it. I’m 3rd owner and the charcoal canister has been removed by previous owner but the AIS lines are still on. Not real savvy on fuel injections. Does anyone have any ideas on how I get rid of the back firing?
1 - 14 of 14 Posts
I have a 08 looks just like yours. I also have Cobra long shots and a Baron big air intake. I removed the ais. I also have a Vance and Hines Fuelpak. It has a throttle setting to shut the fuel off and when it turns back on. No fuel no pop. I would take off the ais, you don't hear the popping with a stock exhaust. I don't get any popping on deceleration. Nice bike. I used the Baron AIS removal kit. Or you could just pull the plug on the ais and see how it acts. Ours are electric activated.
Wheel Tire Fuel tank Plant Automotive lighting
See less See more
  • Like
Reactions: 2
Nice I appreciate the info and I’ll try that. Nice looking bike
The Warrior engine is similar so I'll chime in. Yes, remove the AIS. Then, if you still have backfiring issues, a fuel tuner will help a lot. There should be another option called a CO bump. Each cylinder is tuned separately. I'm not familiar with how to do it on the Road Star but the Warrior requires "shorting" out wire 29 from the ECU to ground (there's a precise procedure, don't risk doing it without the procedure or you'll fry your ECU) and then some button pushing on the dash. This is common on the Warrior to help tune the fuel map in the ECU for when the throttle is closed. This will help to eliminate the backfiring during deceleration.

Hope this helps.
  • Like
Reactions: 1
I appreciate that. I was not aware of that procedure but I’ll look into it thanks.
Nice I appreciate the info and I’ll try that. Nice looking bike
Yours looks pretty sweet as well would love to see more pics of it
My 950 has aftermarket exhaust and pops a bit on deceleration. Doesn't bother me so I haven't worried about it.
These 3 most common things will cause excessive, loud backfiring:
  • Too rich air / fuel mixture
  • Too lean
  • Air leaks at the exhaust manifold gasket where it meets the head
This can also be caused by ignition problems, or valve, or valve timing issues.
These 3 most common things will cause excessive, loud backfiring:
  • Too rich air / fuel mixture
  • Too lean
  • Air leaks at the exhaust manifold gasket where it meets the head
This can also be caused by ignition problems, or valve, or valve timing issues.
I appreciate the info. I’m going to check those out thanks
  • Like
Reactions: 1
question, why would the exhaust turn blue, is it running to rich? can something be adjusted?
question, why would the exhaust turn blue, is it running to rich? can something be adjusted?
I believe turning blue is due to excessive heat and more likely a lean condition. Have you pulled the plugs to see what they look like?
  • Like
  • Helpful
Reactions: 3
Brad nailed it - excessive heat due to a lean condition.
I'd start by looking at the plugs. If they look good then maybe you have an exhaust leak allowing air in such as the head to pipe connection.
  • Like
Reactions: 1
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top