$500 on parts and I'm still so slow??????  By  played1 (Read 3,372 times)

Interesting.... The first time I've seen a 117mm (claimed)....

I know on the 115mm variators, the stock sized belt does fine. I would have no idea on the 117mm, tho... and I don't recall anyone running one either. It would be interesting to try one.

The taller gears and the carb are killing you here. The taller gears need more torque to push but try the stock carb first.

I'd put the carb on a shelf, and if you ever decide to get a big bore kit and stroke it, you already have the carb. Get a stock un-sealed carb and you will be ahead of the game. You can drill out the screws on the old stock one, and punch the cap for the a/f screw, but consider this, Scrappy has them for 45.00 bucks, online and if yours is sealed, you may or may not be able to even raise or lower the metering needle on the slide. This is very common with C. A. R. B. certified bikes (california). I won't even mess around with a sealed carb and I'm cheap.

There are a few problems with running a larger carb. Large carbs don't like low rpms nor do they like small displacement engines with stock compression. A smaller carb is going to give you more low end torque and will behave better on a small displacement engine in the mid range and top end. It's about the velocity thru the carb throat. If the air moves too slow thru the carb throat, the fuel will not atomize correctly and you are going to have a heck of a time to get the jetting to work right. You are always going to fight being too rich in the mid range, or too lean on the top end. You just don't have the displacement to support the bigger carb and the engine just can't pull the air fast enough thru the carb throat on the larger carb.

Using my bike as a bench mark, It's a Verano 150 built by Znen.

It has a 115mm Hoca variator, 12gram roller weights, stock sized belt, stock carb, stock exhaust, jetting is about right, although I've never torn into the carb on it, so I don't know what jets it's using, it's always run well, so I didn't feel the need.... It's short case 150 with 10" wheels, and I weigh 300lbs. I've GPS's the bike on level ground all out at 58mph (70 indicated on the Speedo). I can cruse all day at 52 or so. The only mod on my bike, besides relocating the battery, is the variator. Valves are set at .004, intake and exhaust. 11 gram sliders made the bike fun, but beat the heck out of the gas milage. I'm also running a stock CDI and just a normal NGK plug (again, I'm cheap). Other things of note, I'm running an older bike so I don't have an EGR head. A non-EGR head will give you about 3/4 additional horse power. Of course, I've probably have lost about 1/2 a horse, as I have over 7k on my bike, so the top end is probably getting a little tired. You get the picture, it's nothing really special.

The next thing I'd do is mark the variator and see if the belt is making it all the way up the pulley face. If it is not making it all the way up the face, then start going heavier with the weights. But you need to get it running right before you tune the variator. The peak of the power band on these bikes is about 7500 rpm... My bike turns about 8000 when run WOT for an extended period of time.

The taller gears throw a lot of this out the window but if you can go back to the stock gearing in the gearbox, you should be able to do 55 plus without too much trouble. The weights you currently have in your vairator is probably a good ball park start, if you can go back to stock gearing, easily. Stock, these engines just can't push too much more gear then they came with. If it was a stroker, then yes, taller gears would be a good thing on a stock long block, not so much.

At this point I would rule out the fuel pump. I only mention it as you did say something about it in the original post. Where you run into problems with the fuel pumps in these bikes is when you run WOT for an extended period of time... The bike will all the sudden act like it's run out of fuel. This is normal with a stock pump. It's vacuum actuated, and when you run WOT, the manifold pressure increases (lack of vacuum) and the fuel pump quits working. You just close the throttle for a sec, and everything goes back to normal. The only real fix for that is to put in an electric pump. I even tried a mukuni pump and the problem was worse then running stock. The Mukuni is a smaller pump and needs a little more vacuum then the stocker and doesn't recover as well. The stock fuel pumps, unless you run WOT all the time, are more the adequate for a stock bike or even a bike with a BBK or stroker.

I'm thinking when you first got the bike, the weights might of been too light. Your belt might not of made it to the top of the pulley, costing you top end speed. It was probably pretty peppy on the bottom end tho. Before I changed my variator, I had 14 gram rollers and it would do 55 on the top at WOT. and remember, I'm a 300lbs rider.

Sorry for such a long post, but these are the things I've tried and what has worked out well for me.

All those upgrades on a stock motor and stock head will make it slower or the same speed. Bigger carbs and performance pipes need more cc put a big bore kit performance cam and a ported head on it and it will come to life with your mods you already have.

What size wheels are on your scooter ?

The best upgrade is always a bigger motor alot of the upgrades need a bigger motor or you bottleneck.

This is his current problem, , that scoot should have no problems hitting 55+. You guys should know this by now, he is trying to feed fuel as if he had a 250-300cc motor to a 150cc STOCK MOTOR.
Alleyoop

Don't need no turbo and or EFI for the speed he wants, unless of course he wants a 65+ runner.
Alleyoop