Gy6 125cc with 26mm OKO carb

[bradswims11]

I have a Cnell joker which is a copy of a Honda Joker. I installed a 26mm OKO flatside carb onto it yesterday and I rejetted it so it runs with a good mixture etc.

I havent really gained any speed from this or acceleration, but I have been told on the stock motor I should be able to reach 100km/h or 60mph. I have been trying to get a bit more out of it by upgrading the carb, changed the engine oil and gear oil, got a kevlar drive belt, a performance cdi and coil. I put a new spark plug in too. So far I have been able to get up to 80km/h or 47mph.

Why wont my scooter go any faster? I thought the 26mm carb vs the 24mm would help me get a bit more speed etc??? Is there a reason why nothing good has come out of this?

Any feedback would be good, especially from people that have had experience with increasing the power from these motors. Do I need a big bore kit for the larger carb?

Thanks

[Deleted]

a bigger than stock carb on a motor with stock valve head, cam and exhaust will give little to no gain and can actually rob power . are you using the stock air filter? what weight contra spring and rollers? some trans tuning will help. what do you weigh? what does the bike weigh?

[90GTVert]

I also think it's time to look at the CVT. You can mark the drive face on the front pulley (variator) with a marker and make a top speed run. Then come back and you will be able to see how much belt travel you're getting. That will do a lot for telling you if the CVT is at fault for your lack of speed. Carb should be OK, but it's not unusual not to gain with a larger carb. I think your money would have been better spent with a 150cc cylinder and head, but I also think you should be able to do better than 47MPH unless you're pretty heavy or like to ride into the wind or something.

[Fox]

I agree you should get a 150cc barrel and piston. I don't think you have to do any machining to the engine case. Just need a new head gasket and base gasket. Also, try not to carry a bunch of unnecessary crap in the cargo box/tub. Weight and wind resistance play a role as well as engine size. If you lean into the wind you should see 50mph as it is right now but even with a bigger piston 50-55 is about all you are gonna get out of that thing especially since that model only has 10 inch wheels. Maybe a slightly taller tire will fit?

[bradswims11]

Ok so basically my scooter has completely crapped out now. I put the old carb back on, I drove in the rain and the rain got into the auto choke and killed it. When ever i accelerate now it bogs and runs rich, black smoke starts coming out the back. I have come to the conclusion that chinese parts are complete shit and that I am going to do a complete revamp of the engine.

I am going to get:

1 x 160cc, 58.5mm Nikasil Cylinder kit
1 x 58.5mm, 60mm thick performance cylinder head
1 x Valve cover
1 x A10 Camshaft
1 x Rocker arms
1 x Cam Chain Guide
1 x V8 Oval exhaust system for short case gy6 engine
1 x CR8HSA spark plug
1 x 13, 14 & 15g motoritec roller set to tune the transmission

All of the stuff is coming from Carlos at Autotech355 on ebay. I have emailed him a lot and he has really helped me out. Most of the stuff he is getting me is Kymco brand. Are there any other tips that people can give me that have done up 152qmi or 157qmj engines before?

Cheers

[Deleted]

Mar 26, 2012 19:44:10 GMT -5 bradswims11 said:

chinese parts are complete shit

both my 82cc qmb motors were built with china parts and run like a cat with its tail on fire.

[bradswims11]

You must have been lucky aye. I have had so many problems with my scooter its not even funny. Ive only done 3100km or nearly 2000 miles

[bradswims11]

Also with regards to my joker specifically, it is 105kg dry and I only weigh 70kg. So thats like my scooter is 230 pounds and I am 150. Im only little

[Deleted]

i would use an iridium plug, orange coil and cdi with 93 octane on it too.

enviromoto.ecrater.com/p/3809787/ngk-cr7hix-iridium-ix-spark

[bradswims11]

I already have the orange coil and a performance cdi rev limited to 9000rpm. Iridium plug i am getting for free from carlos. The fuel we have here in New Zealand is 91 octane for lowest and 98 octane for the highest because we use the RON scale; i think America uses the MON scale. Your 93 octane is the same as our 98 I believe.

Does anyone know what kind of power I could expect from this set up with the parts listed above? And what kind of fuel consumption I could expect? I am getting about 60mpg at the moment with the rubbish set up I have and I believe that it should increase when I put the upgrades on. Hopefully I can achieve 100mpg

[Deleted]

you wont ever see 100mpg on a 125cc even on flat roads (unless you weight less than 100 lbs) and NZ sure aint flat lol...75mpg is a more realistic goal.

Specs on New 2012 Genuine buddy 125 and Zuma 125 say:

90 mpg (125cc)*
*Depending on road conditions, riders weight and altitude.

In other words....downhill with a 90lbs girl at sea level lol

I think 90mpg is VERY optimistic. My 82cc wont even get 90mpg riding easy. Best I ever got was 75mpg.

[bradswims11]

Allright cool I might just build a new fuel tank then, make it a bit bigger. Is the list of my upgrades reasonable? I will work on the CVT later, when I have the money

[Deleted]

Mar 26, 2012 23:30:42 GMT -5 bradswims11 said:

Iridium plug i am getting for free from carlos.

1 x CR8HSA spark plug

thats a standard plug.

[bradswims11]

CR8HSA was just for size reference. Other than that I told him to get me an iridium one

[bradswims11]

Can anyone recommend a good jet that I should start with so I dont have to guess too much? Remember it is a 26mm oko carb