Ok guys; New Findings.......FUEL IN THE OIL. I rode it around the block one more time before tearing it apart. I thought I would change the oil while it was warm (& because it's been in there for a couple of years), and I smelt fuel when I opened the oil fill cap. I drained it and it is a fuel/oil mix. Is this a bad float, or still part of the "dirty carb" problem? Is there anything that I can/should do before tearing them apart to try and isolate the bad carb?
Clean/replace the petcock. (if it is vacuum operated chances are the diapragm has failed). Clean the carbs. Drain/fill/drain/fill/drain/fill the oil to make sure you get the fuel out of the crankcase.
I'm with Acree. Sounds like the petcock seal has deteriorated, and gas is going down the vacuum line straight to the front of the carb, then leaking down through the cylinder. You should be able to get a petcock rebuild kit from K&L. On the other issues, it just sounds like crud and varnish buildup. Tear the carbs down completely, soak the jets, blow everything out, etc. Make sure the slides are clean, needles aren't gunked up, etc etc.
?Leaking petcock? ?vacuum line on petcock? I'm a little lost. My petcock has 3 lines; fuel in, fuel rsrv in, and fuel out to carbs. Which one or were is the vacuum line? Also, doesn't the fuel run from the petcock to the fuel bowls inside the carbs? This happens freely with the petcock open (which I never close). Is it not the fuel bowls/floats that stop fuel from running it to the carbs?
leave it open long enough (intentionally or unintentionally) and fuel will get past the valve seats in the carb and into the crankcase. At least I know it can on a '95 YZF600.
Hey guys. I cleaned the the carbs (found a small amount of jelly on the filters@ fuel inlet) but my problem did not go away. Bike still starts and runs "fouled". It goes away and "clears up" while accelerating. findings @ teardown: Plugs; #1-light black, #2- looked good, #3-black # 4-dark black & wet. Clips on the needles were at the 2nd slot from the top w/ 2 washers on top. With the washers, the needles were even higher than if at the #1 slot. Main jets are 180's. Why are the needles set so lean? I took off the two washer when I put i back togetther. It runs a little better but I'm not sure if it was the cleaning or the adjustment. Haven't ck'd the oil for fuel yet. Any ideas on what is causeing the fouling? Remember, it just started fouling while riding in the montains, not after any maintenance or adjustments.
The filter under the float valve may be blocked, or the float valve may not be working to stop the flow of gas and over flowing into engine. Start the blike turn off the gas and ride down the street if the bike runs fine for 100 yards or so the float valve is leaking fuel. Your bike should run for a block or so with the gas turned off. Just take care not to get ran over while doing this. Oh the vent they are talking about is the float bowl vent even bikes that do not have ram air have flaot vents they are just short tubes (about 3-4 inches) that point down from the carbs some are longer. They vent the carb so air can get out of the float bowls when gas goes in. On a ram air bike they keep the bowls at the same pressure as the airbox so the gas is not pushed out of the carbs through the vents.
The slow return to idle seems to indicate an air leak. Have you checked the CV boots on top of the carbs and ensured they have not shrunk and leak? Have you taken the choke plungers out and looked at the rubber seals (I think that model has them) to make sure they have not shrunk? Is a ring stuck on #4 (compression test)? Did you do the brake cleaner air leak test? While at idle (and with a fire extinguisher handy) spray a little around all the carb inlets, outlets and sealing surfaces. When you sealed the tank and removed the rust- did you check and clean out any rust that may havee gotten past the tank filter? Valve adjustment ever performed? If not- jetting may be a waste of time until you make sure clearances are good. I think you said you changed the plugs already too. With the age of the machine, a cheap and at the least preventative measure is to change the float needles and seats. Check float height while there. in other words, sometimes an old bike that gets parked is easier to get running (and keep reliable) by throwing some money at it with new parts.
Stem; thanks for the inputs, I'll try and answer the beat I can. Did not take out the plungers( but did make sure that the choke slide was working and that no plungers were sticking). No compression ck. Did not ck w/ brake cleaner. After sealing the tank, new fuel filter and yesterday disassembled and cleaned carbs. Bike has 20,000 miles, valves adjusted at 12,000 ish. At cleaning I insp'd floats and needles; no sign of deformation or excessive wear. All seem to be at the same hight.
