Racing with the clutch in/in neutral or stalling.

[manuel labor]

Hey guys, I'm having a hell of a time figuring out what's going on with my liitle bike, it's a 1980 xs 400 and here's what's happening: when I'm idling at a light, it either wants to dive and stall, or, if I give it some gas to keep the revs up, if I give it too much, (idling at about 3500rpm) it races and seems to stick open until I let the clutch out a bit then it brings it back down to its regular idle. I checked the throttle cable and the routing to see if it was an issue with the cable, but it seems in fine order. I've already got the idle set kind of high, at just below 2000, and usually it's ok, I think there's an issue with my charging system as the whole thing works better when I put it on the trickle charger overnight, but I don't know why it would be racing. I'm sure it's something dumb, but before I take the carbs all apart, I feel like I need to figure out the racing thing. Any ideas?

 

[manuel labor]

Re: Racing with the cluth in/in neutral or stalling.

I should add that the minute I'm up to highway speed, or as close to it as this little POS will allow, it's all fine, and I've done a few longish (300-700km) rides and had no problems.

 

[xb33bsa]

if it has a mechanical advancer it could be causing the issue.if it is worn.sticking ,fuctioning badly etc

 

[manuel labor]

I'll check, I don't think the 80's do, I thought that was post 1980 for the xs400s, but I'm sure I can find that out. I also put super fancy gas from the Esso (canada) that claims to have more/better detergents in it, and this eve, when I was taking it out for another attempt at a diagnostic spin after letting her cool down, I noticed she was running like total garbage, than gave the "CRACK!!" out the tailpipe, like you get when you dump a ton of fuel or carb cleaner into an old gunky engine, and then seemed to be running better. I should have taken a longer ride after that, but I didn't. I guess I'll have to find out tomorrow.