bike wont start just pop, pop, pop, pop, BANG!

So ill start from the beginning. i recently aquired a 77 kz 1000. it was recieved as part of a trade. The man said it had NOT ran in 11 years but it was all there. He told me the last time it ran was before he had a guy work on the carb and rejet them. I get the bike home and start with the carbs. imediatly i discover what happened. the guy that worked on the carbs turned the mixture screws all the way down and broke them off inside the carbs (the ha.d the mixture screw on the bottom of the carb at the edge of the bowl)

Now theres the back story. I went to a local kawi sales counter and get a set of used carbs and cleaned the up and rebuilt them (these were the same size but had the mixture screw on the side and the screws were thicker so i like that idea a lil better). put the carbs on, hooked of the batter charger, put in fresh plugs, and hit the starter button.

BEHOLD!!! it started within 1 minute. Ran it for aboutt 2 minutes then shut it off and performed an oil change. Started it back up and it fired up again but took about 10-15 seconds like the first time. I ran it in the shop until i burned that whole tank of gas.

NOW FOR THE PROBLEM!!! school and work had gotten at me and i wasn't at my shop for a month. THE BIKE WONT START NOW!!!! i took the carbs back off and cleaned them again just to make sure... nothing. Checked the plugs, a lil wet but getting a nice spark so i let them air out. When i try to start it all it will do i crank. if i put the choke on it will pop when every cilynder hits top and they are just like no back pressure pops but ocasionally it will backfire so loud it sounds like i just shout my 30-06 off. :ohmy: any ideas? im guessing vacuum leak somewhere but why out of no where? :huh:

You are trying to start if using a battery charger instead of a good, fully charged battery? In addition to whatever other problems the bike has, doing this can fry the electrical (charging) system if it hasn't done so already. Ed

no it has a good battery in it now, but i do leave a maintainer on it.

Clean your carbs again, this time make sure all the small little passagways in the idle circuits are clean and clear this includes the pilot jets. Next time when you store the bike add a stabizing agent to your gas and drain your carb bowls. This modern gas starts to break down in as little as 2 weeks. I would also take off the manifolds, clean them up and install them using something like yamabond #4, let them dry overnight. Once you have cleaned the carbs thouroughly get a new set of plugs, do not just clean up the old ones. Insure your battery is fully charged. Make sure your points are set properly and the timing advancer is working.
Once all the above is doen fire it up. It will probably need some minor tuning like carb synching and air screw sdjustment.

Does have new plugs clean carbs and full charged battery. I'm thinking its the intake rubbers. I've seen how to fix the mating surface but why do they say not to fix the sides?

It has been my experience when people bring me carburetors that they say have been cleaned, by "cleaning" they mean they took the bowls off off sand sprayed carburetor cleaner all over it. This does "clean" the bowl surface but does nothing for the passageways. I will take the carbs apart and find all the small passegways clogged up. Now were your carbs "cleaned" and if so by you or someone else. If someone else cleaned them I would do them myself. That way I know for sure they are done correctly, eliminating another problem area.
The reason you usually do not have to fix the side of the manifolds is because theat is not where they leak even if they have visible cracks. Even with visible cracks the manifolds are so think theat crack does not go all the way through. If they did the manifold would start to fall apart and that would be an abvious problem. They usually leak at the mounting surface.

baldy110 wrote: It has been my experience when people bring me carburetors that they say have been cleaned, by "cleaning" they mean they took the bowls off off sand sprayed carburetor cleaner all over it. This does "clean" the bowl surface but does nothing for the passageways. I will take the carbs apart and find all the small passegways clogged up. Now were your carbs "cleaned" and if so by you or someone else. If someone else cleaned them I would do them myself. That way I know for sure they are done correctly, eliminating another problem area.
The reason you usually do not have to fix the side of the manifolds is because theat is not where they leak even if they have visible cracks. Even with visible cracks the manifolds are so think theat crack does not go all the way through. If they did the manifold would start to fall apart and that would be an abvious problem. They usually leak at the mounting surface.

+1

Would assure:
• Valve clearances are within specs;
• Ignition timing is correct;
• Timing advancer is properly functioning.

Would sniff-test and physically examine the crankcase oil to determine whether there's fuel contamination inside the crankcase. If so, change the oil and filter. And correct a then suspected carb overflow issue.

A leaking carb holder should not prevent the engine from starting and running. But once running, the air leak will typically cause a racing idle.

Good Fortune!

A rusty advancer isn't good.





Neither are worn out carb holders.



Good Fortune!

you can also get set of working carbs any day of the week for 100-150 on fleabay...and fix yours as you have time

your idle circuit is clogged...if you start it on full ckoke and no throttle what happens...

dont let the bike run for more than a minute/2 without air running over it...turn it off for a few imo

when you cleaned the carbs did you take these out and clean them like this?


scroll down a ways on this page for pics and comment

www.kzrider.com/forum/11-projects/354860...1?limit=20&start=300

What about the 11 years worth of junk in the tank, did you clean it out when you did the carbs ? if you didnt the carbs are all plugged up again