I jumped on my bike today for a quick spin, and it ran terrible. It would die every time I let off, and would only start with full choke. I figured it was in my fuel switch (which has been flakey), so I rebuilt it with a new kit. Still it ran terrible, and backfired big time. I tried adjusting the air fuel mixture and discovered that the front cyl carb was non responsive. I could turn the screw all the way in and the bike still ran the same. So, now I am thinking I have an air leak in that carb. I checked the diaphram and it seems to be ok. I guess I will take the carb off and see if I can find a leak. Interestingly, the idle stays around 3K for a long time after I close the throttle. I think I have reached the limit of my vast expertise (make that half-vast experience). May have to call in the experts.
Is it leaking amy gas from around the petcock? I had similar symptoms last summer. I was able to goose it over to the shop, and he said that both carb holders (the rubber thingies that attach the carbs to the cylinders) had leaks, and the diapragm in the petcock was blown. He replaced both holders and rebuilt the pectock - fixed it right up! The idle staying up when you back off the throttle could be caused by leaks in the carb holders, I think. Try spraying WD40 on them while the bike is running - if the idle picks up, you have a leak. Luckily those rubber carb holders are not too expensive (around $22, IIRC). Jim "Pick" Foster Dixon, IL VROC #9492, TNVROC #0020 H.M. 1986 VN750 "Babe", 1982 KZ440 LTD
Have you tried replacing a battery, it may crank, but it may not be all the way charged. I had the same problem on mine, I charged the battery and all was solved. (still can't explain it!)
Check the basics:
fuel shutoff valve? My 2000 when cold likes full choke, and don't touch the throttle, or it'll die. Re-adjust the choke to keep rpm below 2000 until it gets warmed up some - maybe a minute or more. Backing out the carb mixture screws helped this hard starting - have you ever done that?
Do you have the stock battery? If so, check water levels and for tight connections. If a sealed Westco or Yuasa, check connections only. If you have a volt meter, check the battery voltage prior to doing anything. Should be 12+ or you have a bad battery, right?
Speaking of fuel shutoff valve.. How about bad gas? Some of the newer additives that they are putting in gas seem to break the gas down faster and they don't vaporize well. If it still won't start or stay running try draining the carb bowls, see what comes out of them. Bad gas will look milky or crudy. Are you a seafoam convert yet?
First off...you should not be running premium fuel..it can actualy damage your engine. Do you ever use Seafaom?..Make sure the boots holding the carbs are tight and the ones from your airbox. ( make sure the cable linkage is working right also) Buy some gumout in the spray can and blow it through all the carb tubes..Check your plugs...try that and see what happens........
I have also experienced the acceleration problems that are caused by the breather hose bottoming out as Preach mentioned in his post. Behind the right ear, there is a breather hose that fits into a channel of molded inside the ear cover. If that hose is pressed all the way into the channel so that the end butts up against the ear case, it will cause problems at higher Rams. The bike will sputter and choke as if it is running out of gas but it never died on me. This is an easy check and an easy fix (just slide the hose back a little so that the end is not butted up against the case) but your problem more closely resembles my original problem which I solved with a crab rebuild. I paid to have it done but that was before I joined this group or bought a Climber's manual. If I had to do it again, I might consider rebuilding them myself.
Q: II have a new Vulcan 750. It seems like there is excessive play in the drivetrain. It feels like the damper pad in the rear drum is missing. It is most noticable in first and second gear. Does anyone else feel this jerkiness (or is it just me)?
A: Two things come to mind...actually, three.
1. The vent hose fromt the tee over the carbs to the back of the right ear (air filter housing) may be bottoming out. Pull it back slightly; better yet, cut it off at a 45º angle, so it can't shut off the vent.
2. The tank vent under the cap may be closing off, or the tank vent tube is stopping up. The vent in the cap itself is very tiny, and it doesn't take much. BTW, that tiny vent benefits from being drilled out with the next size up wire guage bit. Take the cap apart before you drill it, tho! ;-)
3. The most likely one--trash in the carb needle seats. Take the drain plug out of the bottom of each carb and let the fuel drain out, then use the little red spray tube with a can of Gumout to load the float bowl with it, holding a finger over the drain plug hole, and spraying up thru the drain hole. Flood the float bowl with the Gumout, then remove the spray tube and your finger. Couple of times with each carb oughta do it. It's easier to tell when the bowl is flooded if you pull the vent hose out of the right ear and let it dangle out the side; Gumout will come out the tube when it's full. Replace the drain plug, leaving it slightly open, put the vent tube back in the right ear, put the tank back on, turn the petcock to Off 'til fuel starts coming out the drain, and close the drain plugs. Turn the petcock on, fire up the bike, and see how she runs then. hth Jim
Q: Starting problem Went to start my bike this a.m. Turned the key to "on," had lights and all, hit the start button, and it made this sorta clicking sound from under the seat. No sound of the engine trying to fire at all. No problems prior to this. Coulda got a little damp in my garage yesterday as it was close to the door, the door was open and we had storms yesterday. What up with this? TIA Stewart
A: the battery is probably dead, try charging it, then check the charging system after you get it to crank. that buzzing is the start solenoid engaging, then disengaging when the starter pulls the voltage too low for the coil to stay magnetized, then it repeats. Thanks, just my 2 cents....... Beavis
A: The noise is the starter relay (aka solenoid) which is located behind the right side cover. The reason that it is making noise is low voltage - check the fluid level in the battery (it should be between the lines on the side of the battery - use water [preferably distilled water] to bring it to the line). If the fluid is OK, charge the battery.
Q: I charged the battery overnight. I cleaned the terminals/connections. Still just clicking when I try to start. Now what? Time for a new battery? This one, I believe, is two years old, max.
A: I'd take the battery to a shop that carries my favorite flavor of battery and have it load tested. Most likely it's shot. Get a new battery and away you go. If the battery tests ok, you have more detective work to do.
A: Hook it up to your car battery as if you were to jump start it. But do not start up the car. This will help rule out the battery if it still won't start. Ken