Fueling Problem

[custard-rallye 25]

I recently fitted a vtr bottom end with a ax gt head and drilled the jet on the right hand side but if I go over 4k it goes flat like a missfire it happens on straights and corners so not fuel surge any ideas I read about it being to tight on the manifold would that cause it to happen ?

[custard-rallye 25]

Anybody? Any help would be great

[burr_2000 1]

did you have the carb on this engine before you drilled jet?

[custard-rallye 25]

Yeah it has the rallye carb

[miamichris 9]

could be worth trying a spare ignition amp as they give bother like this?

 

Its probably to do with you drilling the jet though if it worked alright before, sounds like its overfuelling to me. You could try putting a standard jet back in to rule this one out.

 

Also check your choke cable/accelerator cable to make sure they're adjusted properly, fully releasing the choke and giving you max throttle. And check you've got the timing set right too!

 

Just going to have to work through all the usual, you'll find the problem eventually.

Edited May 31, 2010 by miamichris

[custard-rallye 25]

I ran it on the std jet originally so ruled that out when I first did the conversion it was pinking quite bad when under load so I adjusted the dizzy which made it better but it occasionaly still did it until I changed the jet it also keeps running sometimes when you turn it off but it doesn't seem to be running hot