Decelleration backfire/popping

[hammertime]

Hi all,
Can someone please clarify If the popping noise that I experience when slowing down is normal for the NTV? it only happens when slowing down but not when I hold the clutch in. Someone explained that it was something to do with the air coming through the exhaust because it's v-twin but it's very loud. I've just fitted a DB killer which has softened the tone slightly (Micron race cans are very loud) but the popping is still very much there. The way I have learnt to overcome this is to keep a very small amount of throttle on when slowing down but I just wondered if someone could clarify.
Also not sure if this is relevant but there is a small crack in between the join pipe where the rear section goes into 2, could this be making the noise worse??

Any help greatly appreciated!!

[McF]

Jun 5, 2011 10:01:58 GMT 1 hammertime said:

Hi all,
Can someone please clarify If the popping noise that I experience when slowing down is normal for the NTV?

It's not normal, but it's also not unusual

Jun 5, 2011 10:01:58 GMT 1 hammertime said:

it only happens when slowing down but not when I hold the clutch in

That's because when you hold the clutch in the engine isn't under load (engine braking). I would not recommend that you make a habit of slowing down with the clutch in, you need the control from the engine to help your overall control of the bike

Jun 5, 2011 10:01:58 GMT 1 hammertime said:

Someone explained that it was something to do with the air coming through the exhaust because it's v-twin but it's very loud.

Modern engine systems are so finley tuned that any imbalance (eg a hole in the exhaust) can cause secondary detonation (ignition of unburnt fuel vapour in the exhaust)

Jun 5, 2011 10:01:58 GMT 1 hammertime said:

Also not sure if this is relevant but there is a small crack in between the join pipe where the rear section goes into 2, could this be making the noise worse??

It's probably this that's causing the imbalance and therefore the noise.

It's worth doing something about this before:
Plod takes a close interest
You scare the bejesus out of a horse/grandma or child
A really bad backfire blows the whole baffle out

You might be able to patch with an exhaust gum, or exhaust bandage, but the only real solution (and very elegant!) is a new exhaust - check out RJ's with a 10% discount from Fuel.
ntvhonda.proboards.com/index.cgi?action=display&board=general&thread=1961&page=1
The more members that use this generous offer from Fuel the better it is for all of us and the more likely we are to get a second year of it.
The product is excellent and sounds very nice. It has a removable baffle so you can stay road legal and have a nice throaty roar on track days

[hammertime]

Ah McF you do tempt me with a nice new exhaust but at the moment it'll have to be the one I already have on. My next door neighbour is a mechanic and welder so I'll get him to patch the little hole up and see if it helps. Thanks for the clarification on the backfiring though. I had a feeling the hole would have at least made it sound louder.
I'll let you know how I get on once it's welded. If no change then Fuel it is!!