Hi, my 919 blade engine is popping like a good un on idle and when lifting off the throttle.
I took it out of winter storgage 2 weeks ago and went for the MOT today. It is fine when under load, accelerating or just tootling along. But as soon as i lift off the load, it pops again.
I have 2 thoughts,
1, needs new plugs - I cant however get any at the moment. my local halfords had a total of 5, but at 3 different stores LOL.
2, carbs want cleaning - I was kind of hoping that if this was the case then they might have settled down after a 30 minute run (took the long way back - the VERY long way back

Any thoughts on what it is? I am going to change the plugs and clean the carbs out but I am wondering if anybody knows what it is.
Thanks.

Air entering the exhaust is one possible cause, Have you got a leak somewhere, .
Steve.

Sounds like low Batt or the dredded Regulator
just the same symtoms i had.

The battery is new and on an optimiser when in the garage. i dont think there is an exhaust leak.

I'd go for exhaust leak.

Popping on overrun - classic symptom

[Edited on 4/5/07 by trikerneil]

Have a listen to the BSB bikes when they are on the TV on Mon. They all pop etc etc on the overrun and I doubt they have leaking exhausts.

My Bird pops like mad on high rev overruns in 4th and 3rd. Sounds cool!!!

Not sure if it causes any damage though.

If you think about it a BEC has alot more pipework than a bike.... will this make a difference???

MOz

Might blow your wadding out if you have any, apart from that you should be fine. I would put some carb/injector cleaner through it if it's been stood for a while though.

It just sounds to me like unburnt fuel igniting in the end of the exhaust when it get near to the O2. Nowt wrong with that!!! only if its overfueling excessively as it'll cause bore wash!

I have put new plugs in and cleaned all the jets out with carb cleaner and the airline. At first it had no effect but the I squirted more carb cleaner down the inlets, after almost cutting out it got a lot better. It now onlydoes it as you lift of the accelerator.
A chap down the road from me who races F2 sidecars thinks I just need to balance the carbs up now and that will go.
Thanks for the suggestions.