Still bl**dy backfiring!

[T-Bird]

Hi all,

I posted a similar thread a few weeks ago, which mentioned my bike (which is standard) backfiring and momentarily losing power when slowing down and blipping the throttle to change down. I thought a service might fix it, but it hasn't. It doesn't do it all the time, only a handful of times on an average ride, but it is really beginning to annoy me!

The guy who serviced it said the air filter and carbs were all fine, and he couldn't see a problem. So now I'm not sure what to do. At least one other person on the last thread said their bike did it too, but I just can't believe it should be as bad as it is.

Can anyone confirm whether this model normally does this, cos if it shouldn't then I'll have to spend a bit of cash getting it dynoed, etc. I did note from some other posts that a leak in the exhausts could cause the problem, but mine look OK. It doesn't do it when the bike is under power, just when blipping the throttle.

Cheers.

[stormy 1]

Hi mate,dont worry too much mine does it on and off and theres a mod on the carb breather but i havent done it yet.It involves rerouting the pipe out of the bit where it seems to be crushed.Look at the side of your carbs and its the black pipe just stitting there.Others on the site have more info.
take care and ride full throttle that will solve it

[CaperJ]

Dont worry I was told this when I bought it.

[Sham]

Same problem here mate -
It's 90% likely to be the carbs and there's apparently a couple of ways to sort it -

1- Get a Dynojet kit fitted and tested out on a Dyno/Rolling road.

2- Do the carb modification mentioned above -
details of how to do this are on the following websites;

http://webpages.charter.net/gnemish/index.html

see section on carb synchronisation

OR

http://www.bluepoof.com/motorcycles/how ... stem_mods/

this one is also very helpful...

There is an outside possibility that the Valve Timings or Valve Clearances are buggered up which is a bigger job and costly -but it's unlikely that this is the problem so look to the carbs first dude..
I'm doing the same as my VTR sounds like Chittychittybangbang with influenza and a throat infection at the moment.

Ta

Sham

[T-Bird]

Brill, thanks alot Sham, and to everyone else who replied and made me feel less paranoid about buying a duff bike!

[gpember2]

Tbird,

What you are proberly experiencing is a design fault with Firestorms which due to the size of the inlet manifolds being very big, there isnt enough air velocity passing through the carb with throttle shut. Therefore not pulling enough fuel through, making the engine run lean causing misfire/backfire!
Honda in there wisdom for later models to cure this issue, reduced the diameter of the manifold internally by circa 5mm.

I came across this info on some web site, unfortunatly cant remmember the address.....

By the way mine too does it too, although since turning out idle mixture screw to 2.75 and fitting Dyno Jet kit it know happens far less

Hope this helps

Gary

[Pipstorm]

Don't know about anyone else but i love the popping and farting on the overrun, it's even better since fitting the art cans.

Phil