New VMax 2005 backfiring on blips

[VMaxJunkie]

Hello everybody.

Got a new 2005 LE VMax gen1 (3000kms) last July. I could not be happier. Winter is much longer this year, like forever. Fantastic ride. Anyhow....

The only puzzle I have is trying to figure out what could cause the motor to backfire when I blip the gaz slow down when matching engine RPM to the next gear downshifted. I don't know enough about carbs, timing, A/F mis, etc. to point me in a specific direction.

I changed to new NGKs but no change. It seems to be more present when the engine is very hot or when its cooled after a distance at a good speed with a lot of fresh air.

I am planning to synch the carbs, change oil, air filter and upgrade to Irridium NGK as part of spring setup before starting to ride.

Any suggestions would be appreciated. Thanks.

Great forum!

 

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Is it an actual backfire out the exhaust or some slight popping thru the carbs?
Is the bike all stock, if not, what mods?
Save your money and stick with regular NGK plugs

 

[VMaxJunkie]

Hum!? Now that you mention it. It might actually be from the intake/carb. From memory it's more of a asshhhssssssss choking sound that an exhaust pop. It doesn't do it at rest whatever you do to the gaz handle.

Its all stock with no dust on it. I have not check the air filter yet. It never saw rain either. Now I'mm longing for it! Will have to verify any air leak first thing.

 

[MaxMidnight]

I think you are correct to make sure that the basics (air filter and carb synch.) are correct before delving any deeper.

If the tamper proof plugs are out of the carbs it would be worthwhile seeing what they are set at - 2 1/2 is a good starting point.
Make sure that the screwdriver is a very good fit though - it's quite easy to chew off a head (often the RH side) if you aren't careful.
DON'T force them - put in some penetrating fluid and gently work them.

However, if the tamper proof plugs are still in place dis-regard the paragraph above.

If the noise is still there after your ministrations then I would check for a leak on either the exhaust or inlet.

Finally, I second Mr Mabdcmb comments on the Iridiums.

 

[VMaxJunkie]

Allright! Will approach this slowly. Thanks.