Engine cutting out at high rpm By dozer187 (Read 7,174 times)

[dozer187]

Ok so i ran the bike without the muffler and it ran great, so now how can i mod the stock exhaust to increase flow

[Alleyoop]

Can you Weld, do you have welding equipment? if not then you can try drilling some holes in the back to help the exhaust flow out more quickly. If not then you need to get a performance muffler.
Alleyoop

[jct842]

Or.....you can pretend it's a Harley

[dozer187]

so would this pipe work? www.ebay.com/itm/Scooter-Performance-Exhaust-50cc-GY6-Black-/121121611631?vxp=mtr&hash=item1c33691f6f ..... im seeing other exhausts in the 150+ range and they look like the same crap, any recommendations on a good exhaust? im running the 50mm top end so def need something with alot of flow, dont care about noise, as half the other scooters around are heavily modified and extremely loud.

[jct842]

What I did on my 150 was to cut off the muffler then made an adapter out of a black pipe 3/4" coupling on the lathe so it would be easy to weld it to the head pipe. I then screwed on a brigg's muffler. Worked as good as a factory set up and I only had about 10 bucks in it. I bought one for a 10 to 15hp lawn tractor.

[Alleyoop]

Yes that exhaust on ebay will work. The problem with most exhaust systems out there is that they are generic and not specific to a certain scoot so most have to be modified a little to make them fit.
Alleyoop

[dozer187]

Thx for the info, if i still jad my welding equipment id make one myself but o sold it all b4 i moved

[dozer187]

Well im at wits end with this damn bike. Cant get her to run right on topend. Only way she actually revs out at wot is when theres only a little fuel left in the carb after shutting off my fuel flow. I have no airleaks anywhere. Freeflow filter and exhaust and 50mm topend, tried everything from an 88 to 98 main jet, im out of ideas

[Alleyoop]

Do you have a performance MUFFLER ON IT?


If it revs high running LEAN then you have to much fuel at top end. Are you adjusting the FUEL RATIO MIXTURE screw or is it PLUGGED and you cannot adjust it?

What does it do at top end DOES it make any sounds like POPPING or BRAT or BACKFIRES ETC..?

Get a Video of it on the center stand and giving it throttle I want to hear what it is doeing.

[dozer187]

Yes theres a performance exhaust, carb is a 18mm japanese,forget the brand, something with a k...i have adjusted the carb all its done is make my idle and low end better or worse. I took a vid i duno how to post it from my phone though

[Alleyoop]

I can't help you with a video on the phone, but if you can get it onto your computer then it is very easy to insert it in your post.


What does it do at WOT? Does it SPUTTER, BOG etc..

[jerryscript]

You can upload videos from your phone straight to YouTube. On android, it's usually done by tapping the share button while watching the video, then selecting YouTube.

When you copy & paste the YouTube URL here, remove the s from https.

[dozer187]

i uploaded the vid to youtube

[Alleyoop]

Sounds like it wants more fuel.

Do this rev it up again and when it starts to act up BACK OFF the THROTTLE about 1/8 to 1/4 of an INCH and hold it there.
A. If it speeds up it is LEAN.
B. If it settle down it is RICH.
Alleyoop

[dozer187]

I noticed on the carb there is a gold cap above the adjustment screw,could that be a capped topend adjustment ? Its directly opposite the throttle rotation point