Author Topic: Carb Prob (Read 2852 times)

bombhead · « **on:** December 10, 2005, 03:16:34 PM »

Hi all
I've got an RF 400 with a strange carb problem. The carb is being fed with petrol but only the 1st and 2nd cylinder's are receiving fuel. The fuel bowls of all the carbs have fuel in them and I can't seem to find a blockage anywhere. Anyone have any ideas ???

Hellllpppppp !!!!!

Darren

stripes1976 · « **Reply #1 on:** December 11, 2005, 05:05:35 PM »

is your fuel supply a twin outlet petcock? and if so have you checked fuel comes out of both sides?

bombhead · « **Reply #2 on:** December 12, 2005, 09:18:14 AM »

I'm currently feeding the carb with fuel from an external tank. There's only one line into the petrol pump so that doesn't seem to be the problem.
Fuel is getting to all the carbs as all four float bowls are full. It just seems that the 1st and 2nd engine cylinders are the only ones receieving fuel. The 3rd and 4th cylinders are bone dry !!!!

Hope this helps.

pmackie · « **Reply #3 on:** December 12, 2005, 07:00:53 PM »

A couple of things to check...
- Is the compression OK? If the engine isn't sucking through the intake, it's not going to draw fuel. Also, check for any damage to the intake manifold.
- Any chance that youv'e got some goop in these two carbs? Can you drop the float bowls and look?

How are you sure that you're not getting fuel? Is there a chance that these two cylinders are firing, and that the two wet cylinders actually have no spark?

stripes1976 · « **Reply #4 on:** December 13, 2005, 09:31:13 AM »

if there is no spark it seems strange as the inner two cylinders and outer two cylinders share coils not left and right! Check to see which of your downpipes get hot to make sure that the wet ones aren't flooding and washing the spark out and that the other two are in fact firing hence not wet! If that is the case change the o-rings!