I have an 82 vision that seems to start and run fine. however I have noticed the last few rides of 15 miles or more that it will start acting up. feels as if it isn't getting gas in the back carb. if I open the throttle seems to be fine but if I let off only sounds like its firing on one cylinder. I have checked spark plugs, plug wires, installed a good inline fuel filter, It is sporadically happening. any suggestions
Lucky would tell you to check your float levels :)
You should also check that your float needle and seat aren't getting hung up.
probably has nothing to do with it, but I have heard of and experienced vapor lock quite frequently with the vision once it gets warmed up. try taking the gas cap off once this starts to happen and listen for a hissing sound. then try it again. Though if your hearing what sounds to be only one cyclinder firing that is probably not it. But it doesnt cost anything to try....
Quote from: Mkelley1976@gmail.com on August 29, 2012, 12:26:26 PM
I have an 82 vision that seems to start and run fine. however I have noticed the last few rides of 15 miles or more that it will start acting up. feels as if it isn't getting gas in the back carb. if I open the throttle seems to be fine but if I let off only sounds like its firing on one cylinder. I have checked spark plugs, plug wires, installed a good inline fuel filter, It is sporadically happening. any suggestions
What makes you think the problem is with the back carb? So it runs and idles fine but under deceleration it sounds different? Are there any other symptoms like lack of power at certain RPM etc?
If it runs fine when you open the throttle it would seem to be getting fuel. It sounds like a new problem and float height doesn't arbitrarily change on it's own although there may be other causes keeping fuel from entering the carb. You can verify when it starts to act up. Pull over, kill the engine and disconnect the vacuum line from the petcock. Bring a screwdriver with you and drain both bowls to see if they both have the same amount of fuel. You could also try pulling the plugs and checking the color is the same.
Another cause of dropping one cylinder is ignition. I've not experienced this myself but apparently if the rev limiter circuit is malfunctioning it can drop one cylinder. It's supposed to but only at a predetermined high RPM. Many have cut the black/yellow at the TCI to avoid potential problems.
You can also remove the rev limiter wire from the gauge cluster if you're not looking to cut it. It's yellow with a black stripe.
If you're extra suspicious about an ignition issue, you can measure the impedance of your ignition coils. If you suspect something, switch them and see if the problem follows. Are you absolutely sure that your plug wires are good?
I've never had vapor lock occur at less the 100 to 105 deg. f.
do you just cut the wire to eliminate the limiter? i want to kill it on my street fighter
The wire terminates in a plastic molex connector at the ignition unit, and it's a crimped eyelet that a screw goes through at the other end of the wire inside of the gauge cluster. I pulled out the screw, taped up the eyelet, put a zip tie over the tape in case it looses its sticky, and put the screw back in so that I don't lose it if I ever want to hook it up again.
And it is the yellow wire with a black tracer, not the other way around. There's historically been some confusion about this, but I've seen it with my own eyes. Plus, there isn't a black wire with a yellow stripe anyway :)
I stand corrected, it is identified as yellow/black. I made the mistake of going from memory but hopefully anyone searching at the TCI would find the yellow/black and recognize my mistake. To those that did not put two and two together and searched on to eventually find and cut the black/yellow for the starting circuit cutoff relay all I can say is: take advice from the board but be responsible for your own homework! :P ::) :D
I had previously read about the rev limiter and disconnected it after getting the bike. what I do know is when I start having the issues I can set the choke about halfway and seems to run fine
tested YICS have internal leak. can someone assist with how to disable? Is there anything that I need to do to just cap off the ports on the head?
Go to an auto parts store and get a rubber cap kit , be sure its rubber not plastic, select the proper size and install them where the YIKS hoses go. Or stuff a ball bearing in each hose and put them back on.
I bought a kit with vinyl caps and the blew off when the engine warmer up. Also check the caps frequently , chinese rubber cracks easily, I know from experience!
runs pretty good now but is a little more difficult to start. Has better throttle response. a bit harder to start. but a new battery may help that
I went to Ace hardware and got a couple big aluminum rivets and use them to plug short lengths of tubing on the YICS ports on the engine.
Once you get the YICS out of the picture, if you are still having good performance with the throttle rolled on, but poor performance at low rpm, for me this has always turned out to be clogged low speed jets.