'90 Warrior - need help testing electronics

[tyler]

Ya its running lean.

 

[yamarider]

If it's still dumping fuel out of the overflow you either need to adjust the height or replace the float and needle.

Exactly how bad was the header glowing after you rode it? If it was just 6 inches or less away from the engine you can consider that acceptable, but if it's glowing bright red all around the bend it's definitely too lean. If you're on the throttle and it's glowing it's not going to help to change the fuel screw, that only affects the fuel mix at idle speed, gotta change the needle height and main jet above idle. If it's dying at idle it's probably still lean on the idle circuit too. If you start it up and just let it idle will it glow red or does it only glow once you start riding it? Does it backfire, cough into the carb, etc. when it dies, or does it just quit?

If you have something inside your exhaust rattling take it off, point the inlet down, and shake the hell out of it like a madman. After my exhaust sat in my shed unused for 3 years I found that a family of mice and possibly a small squirrel were living in it for some time. Among other things I dumped about 15 acorns out of it, some fiberglass insulation, and a few feathers. Started it up and even more blew out of the other end. It's likely that whatever is rattling inside it just fell into it while it wasn't installed on the quad, and can be removed by shaking it enough.

 

[boston350]

ok, sounds like the carb needs to come off then.
the header didn't appear to be much brighter while running than it did when it was sitting there warming up. it was red near the bend, so probably 6" or so away from the motor.
if the quad had an aftermarket exhaust on it, it would have been jetting for that and acting differently with the beat up stock pipe?
it was idling fine once it warmed up and ran for a bit, don't know how long it had been sitting before I got it. I stalled it a couple times going around a corner, no backfire. it did backfire on me when I used the kill switch to shut it down.
thanks, I'll pull the pipe off again and bang on it

 

[yamarider]

If it was rejetted for an aftermarket exhaust it would likely be set richer than factory, what you're showing is it being too lean so if it ever was rejetted, it was probably set back to stock before it was sold.

Backfiring on shutdown is a sign of it being too lean as well, that means your exhaust is getting so hot that the unburnt fuel that makes it through after you kill spark is igniting just on the surface temperature of the exhaust.

One thing to keep in mind though is that cold weather will make any carbureted engine run lean because the colder air is more dense, more oxygen content. My warrior was always too lean in the winter if I didn't rejet it when the cold weather hit, that may be a big part of why yours is lean right now, not actually because the carb was set up wrong.

 

[boston350]

ok, good to know. still should pull the carb and clean it for the fuel coming out of the over flow, but if I leave it lean is that going to hurt anything for now. don't want to bake the motor now that I have it running.

 

[yamarider]

I really don't know how to answer that, it's sort of a judgement call that has to be made, and without being able to actually see it/ride it/hear it I don't have a way to give my opinion on if it's too lean to be worried about it or not. I would say though that if you have stock components, stock jetting, and the carb at factory specs you should be safe. These are jetted borderline lean from the factory to pass emissions requirements, but with 4 strokes it has to almost be lean to the point of it running like **** before you're running the risk of serious damage. With 2 strokes it's a much bigger concern because the leaner they are, the faster they get until they hit the point that they grenade, there aren't a lot of warning signs.

I think if it seems like it's running smooth and isn't cutting out and missing as you run it through the gears you're fine. To tell you the truth my dual sport actually does run too lean in the winter to the point that there are bad flat spots as you run it through the gears, and i've yet to hurt it. I don't riide it much though because it's just too damn cold out, I only get it out about once a month over the winter because I don't like to see it sitting unused for that long.

 

[boston350]

ok, thanks. I'll check the jets to see if they are factory size.
worked on the rear brake today - it didn't have one. picked up a used caliper. the piston was stuck in place but cleaned it up and I think it will be OK.
the quad has no Ebrake cable on it so it should be ok leaving the mechanism on the caliper from what I've read. I backed it off a few turns too, just to make sure it doesn't cause any drag.

 

[tyler]

Ya thats what i had to do before got my parking brake block off, Just make sure you dont take the bolt out that would be pretty bad if you rode with it like that.