Flaming exhaust

[mrloudly]

Went out for a good blat at the weekend and the R400 that was trying to keep up commented I have a lot of flame on the over-run but from one bank only??? Is this OK/Normal?

[AlanN]

Mine does this too

Alan.

[davefiddes]

Mine only seems to spit lots of flame when I miss a shift (as if ) but not much on the over run. Will depend on how rich the carb is running particuarly on idle I think as it's only the idle circuit that's in play when you slam the throttle shut. That can vary from side to side. Also if you have an air leak in the exhaust it will have an effect on whether the flame happens in the silencer or out the back.

If you're going to have crumby fuel consumption then it might at least be spectacular?!?!

[jschwartz]

I got 26 miles per US gallon last week on my 700 mile trip to Run and Gun. I don't consider it crumby, Still flames some though.
jeff s

[P15TON]

It's most probably an air leak on your header flange.
To ignite gasses on the over-run, you ususally need an air source, and a leaking exhaust gasket is just the ticket.

[mrloudly]

Thank's Piston I'll loosen the other one :

[steve_D]

mrloudly said:

Thank's Piston I'll loosen the other one :

Not a conventional approach but I like the way you're thinking.

Steve

[jeremyc]

mrloudly said:

Thank's Piston I'll loosen the other one :

[davefiddes]

Probably wrong but... The hot fuelly exhaust gasses will reach the air eventually. If the exhaust tip is hot (which it does get on an Ultima because of the short system) then the flames come out of the back... If there is a leak in the manifold or between the headers and silencer then air will get in there and cause the mixture to ignite in the pipes and or silencer boxes. This can't be a good thing because there will be lots of heat and it'll eat the silencer wadding.