Big bang starting the bike when cold.

[granty92]

so when the bike is cold and i start it, it usually idles at 2000rpm before the auto choke thing lowers the idle to around 1200 which it stays at, but for the past couple of mornings i start the bike and it initially idles at 1300rpm and then there is a bang which shakes the tank and the idle goes up to 2000 and the bike carrys on as normal? any ideas what this could be? its a 2003 pointy with a recent service, could it be spark plugs?

[daveyrach]

Just unburnt fuel, my Curvy does it sometimes, it is nothing to worry about as long as it only does it the once on start-up.

[granty92]

it does it most times i start the bike unless the bike is already hot? so just unburnt fuel? mot is tomorrow so may ask them just to look/confirm it :) cheers

[granty92]

also the bang seems to be from the throttle body area and not the exhaust

[daveyrach]

Yeah, it don't half make you jump when you have the airbox off balancing the carbs when it does it (I speak form experience!)

[granty92]

cool nice one, was starting to duck when starting the bike just incase it blew up on me or something

[warrenhewitt10]

From your photo you have a pointy? So carb balancing issues are non existant as such.

I have got mine to misfire which sounds like more of a cough than a bang, but the sound comes from the airbox area. Dodgy spark plugs could cause this. Are they new / gapped properly?

[granty92]

I've had the bike 2 years and not changed the plugs, should I?

[warrenhewitt10]

Im not 100% sure of the proper service interval, but I have changed mine every 8k miles or 2 years since I got my bike. You could always pull them out and see what state they are in! Theres a good amount of charts online you can compare them to to see if they are healthy!

[granty92]

Gonna pull them out tonight to have a check :) cheers

[granty92]

http://img.tapatalk.com/d/13/06/06/eqe3e7uh.jpghttp://img.tapatalk.com/d/13/06/06/qy4ezuqy.jpghttp://img.tapatalk.com/d/13/06/06/tyta6evy.jpg
I'm not sure if this is oil or fuel but should it be in the air box? And over the air filter?

[DJ123]

That's oil. There is a breather hose that goes to the crankcase from the air box, nothing to worry about.

IIRC spark plugs are every 10/12k on the SV

[granty92]

So I looked and couldn't get a picture but basically the throttle body had pulled out of the clamp holding it to the cylinder, all sorted now though