Fuel being blown back through carbs and out side of ram air

[Ben Coyle Racing]

Before I had my bike rebuilt and set up properly it was running terrible

- Say I was at 5000 RPM and gave it full gas, it wouldn't pick up as quick as if I had half throttle after 10000 RPM full throttle was really responsive

-When I had rode the bike, I had all unburnt fuel coming from the sides of my ram air box which happend when I was riding it

-I had exhaust fumes coming from the carbs

-I had hardly any exhaust fumes coming from the exhaust even at 6000rpm or so

-I didn't have ram air box sealed

(My vacuum ports are all blocked off )

My bike is all good now runs perfect at 76 bhp

I'd just like to know what the cause of this would be incase I come accross it in the future ?

Cheers guys

[stevezx7r]

As no one else has replied, I'll have a go.

It could be overfueling, possibly down to one or probably more stuck/badly adjusted floats/jets. Was the overflow pipe from the carb re-routed into the airbox (mad but possible). Otherwise it's probably back pressure from the combustion forcing the unburnt fuel back into the airbox. I'm guessing you were getting terrible mpg along with bad fueling. It would explain why it was fine at high revs - the engine was able to use the huge amounts of fuel being thrown at it.

Hope that helps.

Steve.

[cargo]

After every race I there is always a certain amount of mess escapeing from the ram air box on my bike it make a mess on the frame............seems to me it's just the wasy it is and perhaps it proves the box is actually under pressure. I've tried various tricks to seal it better but not much success.
My breather pipe vents into the air box too so that could be part of the cause.

I dont much see it as a problem