carb problems

I just put a different set of carbs on my 79 kz650. Now it is idleing high(around 3400rpm) and back fireing shooting flames when rev up. Any ideas?

I do not think you have given us enough info. Did the bike run fine before you changed carbs? Have you checked valve clearances? What type of carbs have you installed. Are they just like the ones you took off? What sort of air filter and exhaust?

Make sure you do not have any air/vacuum leaks on the carbs holders or any of the vacuum ports.

Shooting flames from where? Exhaust or carb? Underneath a side cover? :ohmy:

Good Fortune!

Sorry i shoulda been more clear the carbs are supposet to be stock 24's miluki's. It back fires gas out the carbs when it carnking but dose start after about 3-4 turn overs. Goes right to high chopy idle then when u rev it up back fires and shoots a flame thats about a foot. I rode the bike and the first 1/3 throttle is chopy but opens up to decent responce but back fires in between shifts while letting off the gas. Im trying not to take it to a shop as i already have 3x's in it what i paid for it. And my cheap get around is becomming a money pit. Any ideas on what i might be able to do? The bike ran great before the slide froze up. Im running an open header with the stock air box.

rideing soon 1980 wrote: Sorry i shoulda been more clear the carbs are supposet to be stock 24's miluki's. It back fires gas out the carbs when it carnking but dose start after about 3-4 turn overs. Goes right to high chopy idle then when u rev it up back fires and shoots a flame thats about a foot. I rode the bike and the first 1/3 throttle is chopy but opens up to decent responce but back fires in between shifts while letting off the gas. Im trying not to take it to a shop as i already have 3x's in it what i paid for it. And my cheap get around is becomming a money pit. Any ideas on what i might be able to do? The bike ran great before the slide froze up. Im running an open header with the stock air box.

slide froze up :huh:

Good Fortune!

RS 1980, You don't say what carbs you put on. With the baffles out of the mufflers, the bike will run lean because of the extra flow of exhaust. The carbs you put on could be plugged or dirty. One size up on the mains, will probably be OK, if it's a 24ss. Check the holders for cracks and such. Check timing and coils etc. Why did you put a different carb on, instead of just cleaning the one on it? These 650s love to run with the parts they came with. Any alteration usually messes the mixture and causes a lot of un-necessary woe. Bob

Sorry again for the lack of info. Where would i find what carb modle they would be so i can post for sure what they r? I running a open header. The carbs that were on the bike altho ran awesome when i fisrt got the bike after setting a couple months due to work and what not wouldnt run when i went to start it. I took the carbs off to have them cleaned and realized two to the bodies had huge cracks in them that were patched with jb weld and the slides on those two were beat to heck so when i opened it compleatly up they stuck in the full open possition. I babyed the bike so i never opened it up so i never had a problem with it. I figured they were to beat up to try to mess with so i got a defferent set for them. I do know the mains in the old carbs were 95.5 piolets (?) And the ones in the new set were 117.5 i changed the to a new set of 115.5 hopeing that would help. The carb holders and all vac hoses r new also. If theres antthing else one needs to know i will try to answer. Thanks for all the help.

There should be an ID number stamped on the flange just below the choke lever. You many need a magnifying glass to see them as they are rather small and I know my old eyes do need the help. There are certainly differences between jets, slides and needles between some of the carbs used on the 650s. There are also differences between what type of adjustment screw are used. Some have only a pilot screw, some have both a pilot and air screw and some only the air screw.

If you were to post the IDs from the carbs I may well be able to tell you what models / years they were used as stock carbs.

See pics for location of ID stamp and some tables I created with what I think are the stock carbs and internal used on the 650s. Just keep in mind I in no way wish to indicate the tables are 100% accurate, but I do feel they are close.

Carbs r a 108 with a 4 underneath the 108

You think yours has flame problems, be glad you're not this guy..... :whistle: