okay, the LT80 has now drained my wallet of $832.75 Cdn., about $600 US, and my dealer has discounted a lot of parts.That is 100% parts, no labor. I got the starter working!! VERY happy about that. It was the starter control relay. Tried to post 4 different times to help another fellow who crossed battery terminals, but I always got "bad error "message. How frustrating!! I had lots of good tips to share.

I'm so close now I can taste it!! My top speed and top rpm are lacking. I'm convinced it's carburator. I've played with the jet needle setting, leaner seems better. I tried adjusting throttle cable.... I think that's only for freeplay. Is it possible to have too LITTLE freeplay affect speed? I noticed when I slacked it off too much, it definitely did NOT reach same acceleration, so I tried to make sure there was little or no freeplay.

I can't adjust the air/fuel mixture, and there's no float adjustment. I've taken apart carb and cleaned everything, including jets. Used a piece of wire brush to poke out holes in jets. SO, when do I know if it's time to replace float? What about putting a jet kit in? Will that do anything? Seems to use more oil than necessary. I'm running Amsoil 50:1 synthetic injector oil, through stock injection.

I've changed petcock to Banshee style, no vacuum.I've plugged the vacuum line. If I leave petcock on for a few days, gas flows into engine. Could a worn out needle/ needle valve affect my top speed? I'm assuming this is how gas seeps past when I leave petcock on.

last thing, whenever i cold start, I never need to choke, it starts 1st or second pull and goes to high idle right away, like it's been choked (but it hasn't been).

okay you carb experts, launch away with your great advice!Thanks.

jack, if you were near me, this thing would have been in your shop awhile ago!

 

OK, If you tighten the throttle cable too much, the only thing it will effect is the idle and it will be higher.Your not loosing speed there UNLESS your throttle limit screw is in too far (limits the thumb throttle travel).
You replace the float when it gets a hole in it and it doesn't float anymore.Any machine with the throttle left on will seep into the motor. It's a matter of hydraulic weight against the needle.
I don't think jetting is a issue here.ALTHO, carbs do wear out. They get dirt in the lil passages and it does effect rpm's.I have a pile here that is junk. So, 2 things to try here. 1) find a friend and borrow his carb to try,,2) I have a brand new carb here I can send you to try.
You say your missing speed, I'm wondering just how fast/slow it is?

 

20-25MPH. I'll double check with a side by side ride. I still have original front tires with lots of tread left. The previous owner really neglected routine maintenance, but the unit wasn't really abused, just neglected. I don't think it's got a lot of use in it. It almost seemed like at 80-90% throttle, it ran a little higher RPM than when I opened it wide. It was difficult to hold that one spot. Limiter screw is all the way out, and isn't restricting. Overall, RPM seems low when pinned.

I'd take you up on your offer if you don't mind shipping to Canada, or i could get it sent to my uncle in Everett,WA, near Seattle. I'll give you some type of security deposit if you want. If it works, I could buy it from you?? Maybe send you my old one and if you get it to work, just tell me what you think is fair. Somehow, i think it wouldn't be worn out. I can somehow pre-pay your shipping?? Please PM me and let me know if we can work this out. THANKS!!

 

does it fumble or sputter at WOT? I am sure 80s of rev limiter, are you hitting that? Did you slack the adjusters at the thumb throttle?

 

does it have a restictor, in the exhaust? My 50 did, and when i removed it, it reved much easier. Could try cleaning out the baffle in the exhaust too... if its using lots of oil, that baffle will collect alot of carbon.

 

Good thinking buster. I PM'd him this morning witht hat possibility. I think your onto something [img]i/expressions/face-icon-small-smile.gif[/img]
My motors rev to 9800 and never hit a rev limiter. Not sure it has one. [img]i/expressions/face-icon-small-smile.gif[/img]

 

I took the pipe off awhile ago and have since put on 5-10 hours of use. When i removed pipe, I heated it with a propane torch. It smoked and flamed. I probably spent 15-20 minutes going back and forth heating it up. just kept smoking.

since then it filled with gas once when I left petcock on for a few days. i've run it several times since then. You guys still think I need to remove pipe and apply more heat? Is there a spark arrestor to clean out?

Dan250race, it gets up to top rpm and just stays there with the throttle open, no sputter, no cut out, just maxes out at ??RPM (I'd be guessing maybe 5000 RPM, but that'a a guess). Can i check it with a regular tach, or do i need a specialty one? I tried my tach, and it didn't register properly (maybe my tach is for 4-strokes??, is there a difference in tachs?).

Exhaust restrictor is removed. Carb restrictor is gone (I don't see anything under the throttle valve cap, just a spring).

Adjustments at thumb throttle; only appears to be the rev limiter screw, and no other adjustment. The screw is fully out.

Would new plug help?What do you recommend for stock engine?

If nothing else guys, sincere thanks for all the input and ideas. Something's gonna hafta work eventually!Then lookout!

 

So, Do I need to clean pipe more, or is what I described good enough?

 

I'd say you did a good job of pipe cleaning.[img]i/expressions/face-icon-small-confused.gif[/img] So much for that idea.Remove the bolt/plug at the bottom and leave that out.
Plug: stock is BP7HS. That's a good plug untill you mod the motor.
Tach: you may be able to use the one you have, you double the reading/divide by 2 or something like that (I think) [img]i/expressions/face-icon-small-smile.gif[/img] LOL

 

I tried to check the rpm with my tach. Even on the high tach setting, it just buried the needle on idle. It was a little cold and idling around 1500rpm.