Fuel problems ?

[phunkynova]

Hi all.
I've got a problem with the rally car only on very hot days and about a 1km in to the stage the car will start to loose some power and run off song.
I know the bike carbs are running too rich, could this be the problem or could it be some thing different, as it is a intermittent problem it going to be had to find.
Thanks for any help. :thumb:

[mowgli]

fuel lines getting too hot? maybe knock up a heat shield or a cool air duct?

do you have a large cold air duct to the carb intakes?

[Will F]

Lol at fuel getting too hot!

Surely its more to do with the less dense air/heat soak?

What induction/filtration are you running?

[mowgli]

fuel gets hot, it thins, it then gets more in thru the jet than cool fuel would, thus it runs richer, causing loss of power

[phunkynova]

I have a large Subaru type air duct on the car and I even ran without the bonnet on the car for a few stages.
I think it is down to the over rich setting on the carbs plus the hot weather making them run even more rich to the point of there is too much fuel to air mix.
I believe I'll have to buy some new standard main jets and start again with the setup as the jets came with the carbs already drilled out.

As for the Fuel lines they are away from any heat source and should not be getting to hot.