Fire in the hole!

[gibbo]

Untill recently my bike was kept in a nice warm garage. It was great, easy winter starting, nice & dry etc. Now its out in the cold & suffering a bit.
On particularly cold mornings it is quite reluctant to start, taking quite a while on the starter button (ie a few seconds rather than instantly). When it does eventually spark up it does so with a massive cracking backfire, accompanied by a nice shot of flame. Whilst I take some pleasure in waking the neighbours, frightening small children (live near a school) & inducing coronary arrest in any elderly folk who happen to be passing (also near a rest home), I cant help but think this is not good.
1. Is this normal?
2. Is is causing any damage? (other than split eardrums)

Cheers
Gibbo

[YEN_POWELL]

Mine gives a little pop/backfire when starting up first thing on a cold morning, I never use the choke unless it's a dire emergency.

A backfire usually means a leak in the exhaust or airbox.

[robelst]

I never use the choke unless it's a dire emergency.

Wow, mine does not even start without choke in summer
How do you manage to do this?
use a rusty choke-cable perhaps...?

[gibbo]

Mine gives a little pop/backfire when starting up first thing on a cold morning, I never use the choke unless it's a dire emergency.

A backfire usually means a leak in the exhaust or airbox.

I often get a little pop as well but its the really cold mornings that it sounds like a shotgun. I do use a K&N filter & remus GP pipe, I think they seem to create more backfiring for whatever reason.

[YEN_POWELL]

I never use the choke unless it's a dire emergency.

Wow, mine does not even start without choke in summer
How do you manage to do this?
use a rusty choke-cable perhaps...?

I hold the throttle with my right hand, press the button with my left, so that my right hand can work the throttle with more finesse. Then I have to carefully keep the engine running gently and I pull away almost straight away.

If it's very cold, I may keep the bike ticking over for a count of say 15 and then pull away. The only time this doesn't work is when I've left the bike standing for a week and it's cold. Then it's choke time.

Keeps the mpg down, especially as there's less chance for the choke to stick on.

[YEN_POWELL]

Mine gives a little pop/backfire when starting up first thing on a cold morning, I never use the choke unless it's a dire emergency.

A backfire usually means a leak in the exhaust or airbox.

I often get a little pop as well but its the really cold mornings that it sounds like a shotgun. I do use a K&N filter & remus GP pipe, I think they seem to create more backfiring for whatever reason.

Sounds like symptoms of lean running. Is the bike rejetted to suit?

[SteveLee]

I used to get some pretty good backfires when starting when I had the BSM exhaust on. That was one of the reasons I put the original back on, as I leave for work at 6:30 on a morning!

Steve

[gibbo]

Sounds like symptoms of lean running. Is the bike rejetted to suit?

As far as I know it has not been rejetted. The bike had the pipe & filter when I bought it. How would I know if it had? The guy had a pretty comprehensive service history & reciepts but cant remember seeing anything about jets. From what I have read, rejetting isnt absolutely necessary for a K&N & race pipe.
In normal circumstances it very rarely backfires, only when cold starting.

[tjompen]

Check the spark plugs. They will tell you if it goes to lean or to rich. Back firing is a sign of lean mixture. To lean mixture is not good for the engine. Valves and combustion chamber can become torn. Use the choke when you start the bike. You can also check if the engine goes lean by putting on the choke when the engine is hot. If it runs smoother you have lean mixture. If it starts to behave strange it is probably not lean. I tried this and found that the intake rubbers on my bike where leaking air. ..

[kiroh]

You can also check if the engine goes lean by putting on the choke when the engine is hot. If it runs smoother you have lean mixture. If it starts to behave strange it is probably not lean.

I'll definitely try this, since my bike started back firing a lot since I've fitted the Remus. Usually does it when deccelerating. Don't get the loud bang when I'm starting it up though...