Yamaha YZF R125 Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
1,712 Posts
Discussion Starter · #1 ·
hi all, have just came back from a spin with my dad, i knew my bike was backfiring sometimes when changing gear, he just informed me that there is flames coming out the pipe everytime it backfires, im just wondering is it normal for the bike to be backfiring, and normal for flames to be shooting out? (remus exhaust fitted, currently baffle-less) thanks guys
 

·
Premium Member
Joined
·
6,114 Posts
Well actually, it is NOT really backfiring. We get a lot of posts here like "my bike is backfiring, what can I do about it?" So maybe this sticky will help clear some thngs up. Backfiring, is actually fairly rare these days because of electronic ignitions and the high reliablilty of engines, and the lack of things we can actually mess up on an engine. Real backfiring means the engine is out of proper timing and the fuel/air mix is getting a spark and ignition at the wrong time, when the intake valve is open. Real backfiring is actually the bike "spitting up" in a sense, backwards through the carb or intake.

So, the popping you are hearing is not back-firing. It is a popping resonating sound generated by a lean condition on decel. When you suddenly close the throttle, the incoming air is choked off and the closed throttle also causes the bike to return to idle on the very lean idle circuit of the carb(s). However, momentum of the bike is actually "driving" the engine in a sense, and that engine is still spinning at rpm that needs far more gas than the closed throttle/carb can provide. The engine is still spinning but the incoming fuel rate is very low, until just enough builds up in the combustion chamber to "fire" on the exhaust stroke of the engine.
=] I believe its normal mate ;0
 

·
Premium Member
Joined
·
5,218 Posts
SHORT version...

It's very normal, and most of us strive to make it happen as MUCH as possible, as it looks and sounds pretty cool :)
It happens because some fuel isn't burnt in the engine, makes it in to the exhaust, and ignites there creating the bang sound.

If it happens EXCESSIVELY then you may be running to lean. A trip to your dealer can sort that out as they can plug the bike in and make an adjustment.

Right?
 

·
Premium Member
Joined
·
6,114 Posts
SHORT version...

It's very normal, and most of us strive to make it happen as MUCH as possible, as it looks and sounds pretty cool :)
It happens because some fuel isn't burnt in the engine, makes it in to the exhaust, and ignites there creating the bang sound.

If it happens EXCESSIVELY then you may be running to lean. A trip to your dealer can sort that out as they can plug the bike in and make an adjustment.

Right?
Yeah if not you can invest in a power commander :)
 

·
Administrator
Joined
·
10,703 Posts
yea my one do stuff like flames and pop my right ears hurts now
 

·
Registered
Joined
·
1,712 Posts
Discussion Starter · #7 ·
cool thanks guys, again its something i like about it, now that i know its not a mechanical problem :) just listening to my dad (been biking since he was my age) and him being the voice of reason made me wonder if he was right, he is doing all in his power to make me either remove the pipe, or baffle it, until i get cautioned by the gards its staying as it is, sounds too sweet :D thanks for all your help again guys ;)
 

·
Registered
Joined
·
1,712 Posts
Discussion Starter · #9 ·
as i dont have the original baffle, baffling it requires making one, which could be done but is alot of effort, and would not do any favours aesthetically, also im a bit worried about messing up my engine if i dont make it right >.<
 
1 - 9 of 9 Posts
Top