Lifan auto-revving option... :?

[zundapp2]

tightened the slack with the adjusting nut on the handlebar.

Did you leave the proper amount of slack in the cable?

i now have a very similar problem but mine seems to be almost random. sometimes idles like a champ at 1500 other times wants to go to 3500. if i rev it up good...it sometimes fixes it. its intermittant and annoying but i reckon i can sort it out.

Bike healed overnight.

[AKTV8]

TeamCheap; thx for the tips, bought a can of starter fluid to chase down an air leak. Now I only need the time to do it - too many other projects on the go and more being added daily by family members. IF we only didn't have the same blood....

Zundap: hmmm, too tight a throttle cable? Don't think so but as I don't know what is loose or too tight, hmmm. Seems ok.

OK, I must admit, I bought the 200III and been whizzing around on that lately as well and taking advantage of this AZ sunshine. No time to fix, gotta ride now! Which happens to be the name of a local dealer.
Great name. Man, can't believe how cheap these bikes are. And buying them with a credit card and not even getting close to the credit limit is just too crazy.

And tomorrow, mom's booked me for home reno's so, I hope to get to it this weekend.

i think that sounds cool.

[AKTV8]

ok, for the curious few - my auto revving option since new on my 150gy.
Happen to have 2 so I did some swapping from my second bike which works/idles fine. Swapped carbs, no change, still revs to 4000 rpm and holds after going up the gears. Inspected inside of both carbs - slider, cap, spring, needle, all looks fine. Then I swapped out the throttle cables with handle grip and cable. No change. Then I swapped out the spark plug cable just for fun and still same problem. Sprayed the outside of the carb, intake, valve cover, upper block and lower block with starter fluid to see if idle would be affected - nothing.

So far changed linkage and carb, still revs to 4k rpm. Pulled the plug and it all looked good - electrode looks dark grey and insulator is still all white.
I have 500 kms on the bike in this condition.
Eliminated sticking throttle, sticky slider, air leaks, carb, manifold leak, and looseness from throttle to block.

Like I said before, I can sort of choke it back to low idle and she will stay but the minute i rev, back up she goes. Electrical???

[MATT]

did you try swapping out the black box (cdi)?

i know you may have already done this but, when it is revving like that have you tried turning the idle screw back once the engine is nice and warm? mine did something similar and I resolved it by turning the idle back. see my thread about cold starting and see if my explanation is at all similar to what is happening with your bike.

[AKTV8]

Thx for the reply Zapkin;

Playing with the idle screw was the first and easiest thing that I played with and hoped that it would make the difference. This would bring down the idle/rpm but then the engine would die as this would be too low for "normal" operating and it would die first chance it would get and then would have to richen it to get it running again.

Playing with the idle, choke or braking while running, I can choke the air inlet and gradually force the idle back down to normal if I stop rpm runaway before the "choke" action would totally kill it. But this is a pain and safety hazard for me and the bike because on trails and downshifting or in neutral, the rpms stay over-revving @ 4000 rpm. Hard on my oil and engine.

As for swapping the CDI, I have a dumb question - which one is it?
This was my next approach, going over the electricals.

[mblas3]

Check the intake manifold for cracks, also check both o-rings. Better yet replace both o-rings. If you have a airbox check the boot between it and the carb for cracks too.

M

[AKTV8]

thx mb, but I did a carb/manifold/throttle switch as I have 2 bikes and the problem remains on the same bike. The second bike runs perfect before and after the carb/manifold/throttle switcheroo. Was supposed to try a cdi box switch today but I got busy working on my bike hauler trailer.

[katoranger]

Follow the wire from the coil to a black box. That one should be your CDI.

Sounds like the next logical thing.

Allen