View Full Version : Float Bowl Adjustment
Sun May 25th, 2003, 01:40 PM
I have been having some funky carb issues. I went through and cleaned it, had the carbs off the bike 4 times in as many weeks. By the feel of it the carb float level is off. I have the manual and read up on the procedure and even gave it a shot. I put the carbs in a vise and made them level, then with the clear hose measured the level of the fuel on the outside carbs. It seemed as though they were a tad high. But when I took the bowls off the float hight was higher than the specs which would indicate the the feul level is too low :? Give me a V-twin sport bike with 2 seperate carbs any day! WTF. I feel like the bike is dumping fuel into the carbs because it will occasionally idle at 3k then drop down to the normal idle or just die after a spirited run and a close of the throttle. plus when I start up I blow out some smoke depending on the angle of the bike and it is kinda tough to start. I have to give it 1/8th throttle to start.. I have lost some of the power as well. Most has been in the lower end. Mid throttle at mid reves is good and top end wide open is OK but I know it is lacking because it it seems like each time I take the carbs out and put them back int the bike runs great for a day or so, Great power easy starting . I have checked the needle valves and seats and they seem to be good, but they have the rubber tips so they are hard to really tell the condition. I did give the float bowl a quick BJ and the air I was blowing in would not come out unless I lift the float up(if the carb is upsidedown
Is that enough information? :roll: Can a carb Guru come to the wrenching party and enlighten me? Should I just buy a rebuild kit and start over from there, drill out the air screw caps and synch em up?
Sun May 25th, 2003, 02:02 PM
Pull your plugs - what do the tips look like? (i.e. white, grey, black-carbony, black-wet-looking, etc) That will tell you real quick if you're running rich/lean/or something else is going on.
It does sound like your carb just needs a decent kick in the arse. I'm not sure I really know enough about them to do a safe job of it at the wrenching gig, but someone will (which I want to watch).
And yes - we like the V-twin... :D
Mon May 26th, 2003, 01:10 PM
I'm no carb guru by any means, but I'll give it a shot.
It's hard to say exactly what the problem is without actually looking at it, but some things that come to mind are:
Float level is off - When you set it, make sure the float tab is just touching the back of the needle. Don't press on it or let the weight of the float push on the needle. This will cause the level to be too low. I usually set the float level with the carbs setting on their side at a slight angle.
Pilot jet is clogged - If the bike has been sitting in storage with fuel in the carbs, they could gum up the jets. After doing this multiple times, a buildup could easily clog the pilot jet because the passage is so small. The only way to properly clean them is to unscrew and remove the jets (main & pilot) and clean them out with toothbrush brissles. If you use wire, you risk scratching the jet orifice and changing the dimensions.
Which carbs are they anyway? Mikuni's or Keihins?
Tue May 27th, 2003, 01:49 PM
I had a similar experience with my 98 ZX-9R. Sounds like it's getting bogged down because it's running too rich. I did the following things: Cleaned the air filter (go easy on the re-oiling) and made sure the battery had a good charge. Did those things and that helped but what really did the trick was adjusting the pilot screws 1/4 turn clockwise. Easy to do.
My carb is a Keihin. The screws have a little aluminum plug over them. Drill it out with a small drill bit and pull it with a nail or screw. The plugs on my carb are located on the bottom so you'll have to take off the carb to do the drilling (unless you have a pin-vise and small hands). Accessing the screws is possible with the carb mounted.
The EPA doesn't like you messing with the pilot screws so most mechanics would sooner change out the pilot jets than mess with pilot screws.
Hope this helps. Trust me, it's really easy to do. And I bet it will help with your bike.
vBulletin® v3.8.6, Copyright ©2000-2013, Jelsoft Enterprises Ltd.