Cleaned Carbs... what next?

So here's the story so far.

Got fuel in the float bowls, got a good fat spark in all plugs. Removed carbs and cleaned everything. Then removed them again and cleaned again. Checked all the little holes and I am sure thay are clear. Doesn't want to start. If I spray in some cleaner and start then she will run as long as I crank the throttle and keep it att 5000rpm. Back off and the engine dies. Checked the carb boots for leaks -none. Replaced the vacuum hose for the petcock. So could this be a sync problem? I need help as my wife does not believe that I will ever get this running and you know how I have just got to prove her wrong!

Hi Thistle,

Been there many time myself, likely I'll be there many times again.

The short and less than sweet of it is you still got somptin plugged.

I doubt that carb sync is the immediate problem. Have you observed the slides or butterflys to see that the openings appear equal? If they are, the bike should come closer to idling than 5K.




KZCSI

Post edited by: KZCSI, at: 2007/08/18 18:21

Check that the advancer isn't rusted up too.

My '82 650 CSR had similar symptoms. It has Mikuni BS32 carbs. It was either way too lean, or the carbs were flooding. Would not run unless the RPM was at least 3500 or more. The problem was that a previous owner had replaced a vent hose on the carbs and effectively capped off the vents making the fuel bowls become pressurized when filling with fuel and forcing fuel up through the main jets before the fuel level was even up to proper level.

There are two "T" fittings between the carbs and toward the rear of them. One is between carb #1 & #2. The other between #3 & #4. Each "T" should have a hose that leads to another "T" fitting. From this "T", a single hose should then be routed down to the underside of the bike near the swingarm. That way, if the bike should become horzontal, fuel will not spill on the hot engine and cause a fire hazard. Mainly the two hoses need to be OPEN to the atmosphere so the carbs can vent. The previous owner had connected a hose between the two "T"s, which is almost like capping them off.

You might check this. It was like night and day on mine. Good luck.

Thanks all!

WABBMW I think that you may be onto something here. The PO had replaced the petcock vacuum hose with one of the hard thin carb overflow tubes. I thought that this seemed wrong, that it may not be able to create enough vacuum to allow fuel to flow easily so I recently changed that. No difference yet. But this idea that the carbs have some kind of incorrect vacuum is possible. You described that carbs on the 650. The 550 has a different carb any ideas? Also here's a pic.....