Glowing downpipe

Originally Posted by MrTom

Just run my bike for a few minutes to keep it ticking over every now and again through the winter.

It was running for about 3 minutes with a good dose of choke and when I came to switch it off the downpipe was glowing, I mean really GLOWING!!

When I did switch it off it let out a load bang with accompanying fireworks show from the exhaust.

So what do you think the problem is?

Putting my optimistic hat on I'd say that the engine turning at above idle speed (choke on) without cooling airflow is bound to warm the pipe a little, and the backfire was just coincidentle, or caused by a little unburned fuel ingniting in the hot pipe.

Or, could an exhause valve been not completely closing, exposing the exhaust to the combustion.

Mine glows too. I only noticed after the dark nights came in and I was in my shed. I've got a multi meter with a temperature gauge which I used on the pipes. All seemed in order. I wouldn't worry about it. Mine's a race bike and I've got it ideling at 2500 rpm so that'll be about the same as yours on the choke I think.

[yorkie_chris]

Why idling at 2500rpm?

I'd love to give you a technical reason but truth is I just prefer it that way. I've got drilled slide holes and the on / off throttle response is truly horrific. I play with idel speed to try and reduce it. It's handy round slow corner. It's not so bad now I have stiff suspension but when I had a standard front and rear susp when I put some beans on the front was up and down like a yo-yo.

The glowing front pipe happened to me once while I was testing the radiator fan sensing switch, left it idling for too long with no airflow in the garage....
They all do that sir...!

[northwind]

Originally Posted by boo86

I'd love to give you a technical reason but truth is I just prefer it that way. I've got drilled slide holes and the on / off throttle response is truly horrific. I play with idel speed to try and reduce it. It's handy round slow corner. It's not so bad now I have stiff suspension but when I had a standard front and rear susp when I put some beans on the front was up and down like a yo-yo.

Nothing wrong with setting things up how you like, but drilled slides shouldn't do that... Unless maybe they're SERIOUSLY drilled Wonder what's causing it

[yorkie_chris]

High idle kills the engine braking though. Are they balanced and what's the mixture like at tickover?

Are the pipes titanium? I am surprised stock ones heated that quickly ... the thin titanium ones glow a gooden in no time mind

Originally Posted by yorkie_chris

Why idling at 2500rpm?

When Chris Walker raced the then National Tyres Crescent Suzuki GSXR750 in BSB, they ran a very high idle speed (3000 rpm I recall?). Apparently it helped stop the bike unwantedly backing into corners off the throttle

Originally Posted by alpinestarhero

When Chris Walker raced the then National Tyres Crescent Suzuki GSXR750 in BSB, they ran a very high idle speed (3000 rpm I recall?). Apparently it helped stop the bike unwantedly backing into corners off the throttle

Its a standard thing to do .... it is not just walker!!

Originally Posted by Blue_SV650S

Its a standard thing to do .... it is not just walker!!

Yea, i realise that - at brands hatch you can hear the race bikes going from the paddock to the pits idling quite high.

Do you run a higher tick-over on your trackbike? I do notice on my bike when I pull away in the mornings and the bike is not warm (idles at 1100 rpm), the engine braking is harsher than when its warmed up (idles at a tade below 1500 rpm).