T3 Rebel 200cc ATV hold high rev a bit too long.

[Brainsquishy]

I've been doing some circuits with the atv in the shop parking lot when I can and the Rebel T3 seems to be holding the revs high, a bit too long. Maybe even a bit longer than a bit too long after I let off the throttle.
I don't think it's a cable problem as it seems to move freely and there are no tight bends etc. Any suggestions or is that normal.
I am still breaking this new motor in as it is a replacement on the smoker I got originally from Gio.

[Weldangrind]

Vacuum leak. Been there.

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[FastDoc]

Yup. W&G beat me to the answer! :D

[katoranger]

Another member just posted about a cracked manifold on his T3.

[Brainsquishy]

This problem seems to have disappeared now. I opened the carb to change the jets (which turned out to be the wrong ones :( ) and once I put it back on, the run on problem was gone. hmmmmm.....

[Weldangrind]

Did you take the carb off to swap jets? If so, maybe the vaccuum problem was where the carb meets the intake tube, and you solved it.

[Brainsquishy]

I would agree with that. One of the nuts seemed a bit loose. :)

[Weldangrind]

Sounds like most of the China Riders around here. :lol:

[FosterVS]

Another member just posted about a cracked manifold on his T3.

Got the replacement, and installed. Note to others - get some good gasket material, and cut your own. A tip - cut it rough to size, then "glue" it on the intake with gasket compound. Once it's dry, use an Exacto knife to cut it exactly to shape. Also, when reinstalling use Loctite on nuts/bolts. Twice now I have been out riding, thing was running crap, discovered nuts/bolts previously well-tightened were almost falling out.

EDITED TO ADD: I have noticed the "slide" in the carb gets sticky. Lubed it up with some light silicone lube, works much better.

[Weldangrind]

That silicone lube trick is an excellent idea. It hadn't occurred to me that the slide might get sticky.

[Brainsquishy]

Well the "holding revs high" problem is back, and all the intake stuff is tight and sealed. I think the slide is the issue, so I am going to lube it up with the aforementioned silicone lube... Thanks on that one FosterVS.

[Weldangrind]

Have you removed the intake tube to be sure? If the o-ring groove is cut too deep, it simply won't seal. Doesn't matter if it's tight.

[Brainsquishy]

Have you removed the intake tube to be sure? If the o-ring groove is cut too deep, it simply won't seal. Doesn't matter if it's tight.
Ya, I checked that when I had it off the last time. The O ring was raised.

[mizke]

i had this same problem for over a year before i fixed it.. it was a combo of a sticky throttle cable, sticky slide and a leak at the carb to intake manifold oring (the oring wasnt there)

[Brainsquishy]

I removed the two screws on the throttle housing and disconnected my cable, added several drops of 3and1 oil down the throttle cable...problem solved. It took about 15 minutes for the oil to work it's way in.

Also, I couldn't get my rear brakes to work anymore. Bled the system over and over but couldn't get the think to grab. I finally checked the two bolts on the caliper. (hex head) They where loose. Tightened them up and I now can brake once more. :wink:

[Weldangrind]

Good news!

If you pick up a cable luber, you can really force lube down the cable housing quickly and effectively. It doesn't hurt to spray some silicone lube on the handlebar to make the throttle tube even smoother.

BTW, Loctite is your friend on caliper bolts.

[Brainsquishy]

Well, maybe I was a bit premature about this fix. The problem is that the rev bit is intermittent. It comes and goes, but I noted something that seems to coincide with the revving. The fuel bowl drain screw has always been a problem on this mikuni carb. It leaked all the time. I tried to tighten it down, clean it out and so on but it seems to leak when it wants to. The threads are good and stripped now so no getting it off or tighter. When the revs go high, the fuel squirts out the drain. This might be the vacuum leak I am thinking. Any thoughts on that. Perhaps taking off the bowl and dripping red lock-tight into the drain point at the tip of the screw.
BTW, my son and I spent 7 hrs out on the T3 in the hard crusted snowy forest on Sunday. We had a great time and the machine did pretty good. Except the intermittent high rev crap. It was loaded with ice by days end. Terrible wind chill in the open.

[Weldangrind]

I think I would try a small blob of black RTV, because it's fuel resistant.

[waynev]

One thing to remember about the fuel drain screw it that the line is shared with the overflow, so just because fuel is leaking out that line doesn't mean that it's your drain screw being loose, could be the float level is a bit high and it drips out that line, or there's some small particles of dirt that won't allow the needle and seat to close all the way so the fuel keeps slowly filling the bowl and then drips out the overflow tube/drain tube.

My beast does it too, and i know my drain screw is tight, i still have to get around to putting a better fuel filter on it to keep those pesky dirt particles out of the carb.

[Brainsquishy]

One thing to remember about the fuel drain screw it that the line is shared with the overflow, so just because fuel is leaking out that line doesn't mean that it's your drain screw being loose, could be the float level is a bit high and it drips out that line, or there's some small particles of dirt that won't allow the needle and seat to close all the way so the fuel keeps slowly filling the bowl and then drips out the overflow tube/drain tube.

My beast does it too, and i know my drain screw is tight, i still have to get around to putting a better fuel filter on it to keep those pesky dirt particles out of the carb.

I never thought about that. I will put a filter on it and see if that helps....can't hurt it.