Weird problem with Lexmoto XTRS

Hi.

I've been trying to get the boyfriend's XTRS working and I'm running in to a weird issue. Basically it wasn't starting which I narrowed down to a compression issue; I replaced the piston rings and the compression tests fine.

Now it kinda starts but dies after a few seconds or if I touch the throttle. I believe the problem is with the carb since there's a good spark and compression is fine. While experimenting I found that for whatever reason, turning the idle mixture screw all the way in and applying maximum throttle allows the bike to idle perfectly fine and, with a little throttle, it will rev up but too much throttle will kill it.

It feels like a fueling issue but what exactly is a mystery; as far as I can tell there are no intake leaks, the carb is new and the problem persists with the old carb too, I've tried cleaning and replacing the spark plug but it makes no difference.

So if anyone could throw me some ideas on what to try to fix the problem that would be great because I am really confused at the moment xD

Tune the valve clearance to spec 1st

Nice to see that you're still active :)

I forgot to mention that I've already set the valve clearances to 0.08mm on the inlet and 0.15mm on the outlet though I will double check those.

I just bought a can of carb cleaner so I'll give the carb another clean as a matter of course.

Yeah it turned out to be water in the fuel tank lol

Quote:

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Originally Posted by spencer2004

...set the valve clearances to 0.08mm on the inlet and 0.15mm on ...

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Those are Suzuki spec for Sinns Max II. (c)Honda are 0.1mm in/ex .

I was reading conflicting information on what they should actually be, thanks for letting me know.

Well I completely drained the contaminated fuel and it seems a bit better but I think there's more to it.

The problem is somewhat intermittent; sometimes it will idle more or less fine and will rev up with a very gentle application of the throttle, other times it will idle rough and die as soon as any throttle is applied. Adjusting the choke makes little to no difference, if anything it makes it worse.

Pretty sure it's not an intake leak because spraying carb cleaner around the intake boot and carb has no effect, however periodically spraying carb cleaner in to the air intake makes it run better.

If it's of interest to anyone, it turns out the fuel tap was faulty and causing an intake air leak via the vacuum tube.