Backfire through carburetors

When i run my motor, it keeps backfiring through all the carburetors. The motor lacks tons of power. Are the contact breakers bad? The carburetors all piss when i turn on the gas. Also, i think the timing might be off. What do you think? any help is greatly appreciated.

Youch Kz650sandrail..you should change your user name to Rusty Points. Those things need some serious TLC and are possibly a partial cause of your problems.

(I just read your other post after posting this message and realised the motor is in a sandrail. What kinda air filters were on the carbs? There is a good chance that the carbs sucked up some fine dust particles and need a good long soaking in carb cleaner.)

If I were you I'd get my hands on a new set of points and condensors, they aren't very expensive, or at least clean the ones you have and have them checked for proper gapping.

It would also be a good idea to remove the points plate and lubricate the little felt pad behind the plate. With respect to the carbs, I suspect they are probably pretty gummed up if they are in the same kind of shape as the points.

The most common cause of pissing carbs are sticking floats in the bowls. Shut off the fuel supply at the tank petcock, drain the carbs through the bottom drain screws then remove the carb bowls. If you see dirt and crap in the carb bowls you will likely need to remove them and give 'em a good cleaning and possibly a rebuild.

It would also help to let us know when the bike last ran properly.

Cheers-Colin Firth-Ontario Canada
1977 Kz650 Custom, 14,000 original miles, 810 Wiseco kit with lottsa go-fast goodies tucked hidden away.

Post edited by: reborn650, at: 2006/08/22 00:56

Take care,
Backfiring through the carbs will roach them...

what do you mean by roach them?

I have a friend's bike here. Backfiring through the carb (Kaw single) when we got it. The slide part of the slide diaphragm no longer was a tight fit in the carb body as a result. Hence the carb body was "roached" unusable and had to be replaced. No matter how I adjusted the carb it would not "dial in" and run smoothly. Not sure what kind of carbs you are running.

The valves were way out of adjustment and the timing was way off.

Not a gearhead and just relating personal experience.

Post edited by: tganek, at: 2006/08/22 03:18

Software gets "roached"

Hardware gets "toasted or fried"

hwms wrote:

Software gets "roached"

Hardware gets "toasted or fried"

and my "frosted" ass...


:pinch: