My bike just won't run correctly. It is a 1988 cbr1000 and it all started with the carbs getting clogged from the rusty tank. I kreemed the tank and replaced the fuel filter and cleaned the hell out of the the carbs several times. It would be kinda hard to start and wouldn't start at all with the choke. Once it got running it was fine, but wouldn't idle very well. I soaked the carbs in cleaner for a few days, set the float levels to specs and set the pilot screws to 2.75 turns out and then blew out all the passage ways again with air then synced the carbs but it still won't idle that well. It does alright for a few seconds after I get off the freeway then dies. Two plugs are fine one, is way lean, and one is gas fouled. I don't know what to do anymore. Any ideas? Thanks

 

I see that he is from California. Maybe his Cane is a California bike. I would check for a vaccum leak.

 

The float level was the last thing I did, so I couldn't have screwed it up. The needles and seats both looked fine, not old and decrepit. How much would the idle screws have to be off do this? I don't think there are any air leaks, and the caps are on tight, and I double checked the vacuum lines. What do you mean: mixture screws are set / "balanced" correctly. How do you balance them?

I had vacuum problems before and they had different problems. Bogging down mostly. I checked them all anyway.

 

I am thinking that maybe I didn't adjust the pilot screws perfectly. But before I take the carbs out again I want to make slightly more sure. If one was too lean and one was too rich, would it affect the plugs noticably, or would the 45min of highway riding, on the main jets just turn the plugs normal color?

 

I took out the carbs and checked the pilot screws and the were a;; where they should be, so I rode it for awhile today and it was almost over heating, on the freeway. I got it home and checked the plugs and they were the same as before. Now it will kinda start with full choke but as soon as I give it gas it dies. When it does cut out though it will make a kinda loud pop and then there was a little bit of smoke coming out of the hole on the right side of the airbox. It is also leaking a little bit of gas out of the overflow tube after I run it.

Does anyone know what is going on?!

 

Mate, what a ba5tard of a problem! If there's fuel coming out of the overflow then surely the seats in the float valves must damaged. Next time you take the carbs off (sorry, but I'm sure you'll be doing it again) hook them up to a fuel supply, and take off the bowls one at a time. Hold the carbs upright and push the floats up by hand gently several times to see if the fuel shuts off properly. It sounds like you've got the carbs spotless and adjusted at least well enough to run and this is all I can think of.

You could check with the float valves with the carbs still on still on I suppose by pulling the vacuum pipe, that operates the fuel petcock thingo, off the carbs, turn on the fuel and suck on the pipe to open the valve (you'll hear it click). If the carbs overflow it must be the float valves.

Sorry if you've already tried this as I don't know what else you've done..It's just the only thing I can think of. If you get it going again swap the plugs around and try to get a good run (not far from home ) then kill the motor still at highish revs. Then check the plugs.

Good luck mate!

 

Just for grins, on each carb, lift up each piston/needle with your finger to it's top and let go. What happens? Does the black-plastic piston come down smoothly with a plastic ping noise when it hits the bottom? Does it not come down? Does it come down slowly? Does it not go up? Is there no resistance when it goes up? Is there a lot of resistance when going up?

 

Thanks guys, I'll try both of those things tomorrow. Wish me luck.

 

Check your coil leads too - they may be cracked and causing the misfire .............
all I can think of that hasn't already been mentioned above.