Backfiring...

[Cheshire Cat]

Lately I've noticed my bike is backfiring alot when I'm changing gear and when I'm riding at 50 and 70k's. I don't like it to scream so I stay in 5th till about 60k.....could I be in too higher gear? Or is it tuning? Or is this just normal? haha


Help....

[MSTRS:Me]

More info pls

[kevfromcoro]

No......... your bike shouldnt backfire.
its not normal...
sounds like it needs a tune up..
has it lost any power??
backfiring is usually to do with timing
more imfo would help.

[Cheshire Cat]

what do you want to know?

[MSTRS:Me]

What sort of bike/engine would be a good start...

[Cheshire Cat]

No......... your bike shouldnt backfire.
its not normal...
sounds like it needs a tune up..
has it lost any power??
backfiring is usually to do with timing
more imfo would help.

haven't noticed any power loss....but it seems the revs are higher at 100ks now 8000rpm instead of 7500.



Info...05 CBR150R
changed the oil about 250kilometres ago
done 5300ks

Anything else?

[MSTRS:Me]

haven't noticed any power loss....but it seems the revs are higher at 100ks now 8000rpm instead of 7500.



Info...05 CBR150R
changed the oil about 250kilometres ago
done 5300ks

Anything else?

Revs changing usually means the clutch is slipping or a sprocket has been changed. Nothing to do with the backfiring.
Does it backfire whilst riding at a steady speed, or when you roll off the throttle (to slow down).

[samgab]

FYI, a backfire is when unburnt fuel/air ignites in the exhaust system (or intake system sometimes). Obviously this is not ideal for economy, because it means not all of the potential energy of the fuel has been used to drive the pistons in the combustion chamber.
It could be to do with the timing, or the carb adjustment. Valve clearances or something. Running too lean or too rich...
A good tune-up will likely solve it.

[Cheshire Cat]

Revs changing usually means the clutch is slipping or a sprocket has been changed. Nothing to do with the backfiring.
Does it backfire whilst riding at a steady speed, or when you roll off the throttle (to slow down).

Oh ok.Sprocket has been changed? explain please?

Both.

[Cheshire Cat]

FYI, a backfire is when unburnt fuel/air ignites in the exhaust system (or intake system sometimes). Obviously this is not ideal for economy, because it means not all of the potential energy of the fuel has been used to drive the pistons in the combustion chamber.
It could be to do with the timing, or the carb adjustment. Valve clearances or something. Running too lean or too rich...
A good tune-up will likely solve it.

Ok.Where is the best place to get my bike tuned?(in rotorua or tauranga, I don't mind travelling)

[MSTRS:Me]

Oh ok.Sprocket has been changed? explain please?

Both.

Your chain rides around a small sprocket at the engine end and a large one fixed to the back wheel. Those sprockets have X amount of teeth. If you wish to have better acceleration or higher cruising speed, then best way is to change one or both sprockets to Y amount of teeth, to change the gearing of the bike.

Can't recommend any particular shop, but a Honda dealer is probably best since your bike should still be inside the warranty period.

It might be something as simple as a loose baffle. But is more likely to be a faulty plug or fuel/air mixture.

[samgab]

Ok.Where is the best place to get my bike tuned?(in rotorua or tauranga, I don't mind travelling)

I'm not sure sorry, cos I'm not from that area, but you could try Rowlinson Honda for a start.
Also, does your bike have the standard (factory) exhaust system, do you know?
Does it backfire when you're decelerating, down a hill with high revs and the throttle closed?

[kevfromcoro]

Oh ok.Sprocket has been changed? explain please?

Both.

nah.. changing the drive sprocket wouldnt make it backfire....
iam sure someone will be along shortly with some good advice

[MSTRS:Me]

Also, does your bike have the standard (factory) exhaust system, do you know?

If it's the one in her album, then it appears to have a non-standard can. When was this put on?

[samgab]

If it's the one in her album, then it appears to have a non-standard can. When was this put on?

Okay, just looked at the album picture. Yes, that's a bigger than standard, aftermarket, can. That could well be causing the backfiring, especially if the carb jets weren't changed at the same time... as they often aren't when someone puts a bigger can on a small bike to make it sound louder...
Solution could be a matter of new jets.
Again, a good motorcycle mechanic could confirm that.
Also, by looking at the state of the spark plug they could get an idea of the cause too. Wet, dry, black, brown, etc.