TOPIC:

MY 1978 KZ 650 STALLS AND HAS A LACK OF POWER AT THE START OF EACH GEAR. WHEN I AM AT A STAND STILL, I HAMMER THE THROTTLE AND IT STALLS. I CLEAND THE CARBS AND EVERYTHING LOOKS FINE. BESIDES CLEANING THE CARBS I CHANGED THE OIL, OIL FILTER, AND SPARK PLUGS. MY JEST ARE 102.5 MAIN AND 15 PILET. I HAVE PODS AIR FITLERS AND HAVE STAIGHT PIPES. I HAVE TALKED TO A FEW FOLKS AND THEY SAY IT MIGHT BE MY TIMING, POINT, OR AND COILS. IN SHORT I REALLY NOT SURE WHAT IS CAUSING THIS. ANY HELP?

Actually if you have a vacuum line coming from the gas tank to the carbs that is too soft or is softened by the gas that same problem can occur, but that could be a long shot. I had a prob when from a stop the bike would make burbling noises and I would rev it high and it would clear out and it happened to be the vacuum line sucking on itself and stopping fuel flow to the carbs. Gotta go!

Marky, Welcome. Just a word, please stop typing in all caps. Caps are considered shouting on the internet.

OK... what airbox / pipes do you have on the bike? Sounds like it is lean coming off the pilot circuit. If the airbox has been removed in favor of aftermarket air filters or aftermarket pipes have been installed and the bike hasn't been rejetted, it will be lean in the off-idle transition. The carbs' idle mixture may also be mis-adjusted.

Or that too! Still have alot to learn from you George

NO AIR BOX/ NO PIPES. I HAVE INDV. SINGLE POD AIR FILTERS (4 TOTAL) AFTERMARKET. AND I HAVE 4 INDV. OPEN HEADERS WITH NO PIPES. I SYNC. THE CARBS AND PLAYED AROUND WITH THE AIR MIX SCREW FOR HOURS.

Sorry about the caps.

George is right dude, just rejet to a bigger jet. Open headers? You really are running lean ain't ya?

I am not sure how larger should I go. I been searching on the net for days now to find out what jet sizes would be best. I am thinking of going with 110 main and 17.5 of the pilot. Any say if this is the right choice or what I should use. They are 102.5 main and 15 pilot right now.

Well, it will be hard to jet with NO airbox and no baffling at all... You can try the jetting you mentioned as it will be a decent start. I used this jetting today on a 78 CSR KZ650 with Canada spec carbs... #17.5 pilots and #110 mains BUT I have baffles and pods on the bike. Also the Canadian bike has 5CN18 jet needles which you won't have. If you get a flat spot, try reclipping the jet needles to raise them... in other words, clip to 4th slot. I would stick some cheap Emgo pods on those carbs at a minimum to ensure I didn't suck bugs down the carb venturis and put a pipe on with baffles to ensure that the powerband was fairly linear. With no back pressure you will lose power.