Post by rocketdogiv on Jun 22, 2020 20:46:22 GMT -5
On and off I've been working on an old 150cc gy6 Racer style scoot. It has always run pretty well and kept up with 50-55mph traffic well. However, being a speed junkie I wanted more HP and top speed. I finally got it where it suites me. Here's what I did.
Brand new Chinese stock long case. I've had it for a few years.
61mm bore and bigger port head with better valve springs-bought it on Ebay from PR shop-made in taiwan. Nice looking parts at a reasonable price. If you'd like the company name I'll look it up. Fits right in a stock A Case.
Stock stroke
A9 Cam from somewhere, I forget. Had it awhile.
NCY long intake. They make a shorter one. Any of ya'll that have experimented with different carbs and different intakes know how hard it is to find a combination that will fit the stock 150cc frame. Ever notice how the Ruckus folks just run their carbs forward? I made sure that the ports on the intake and the head were well lined up with one another. As in the ports matched well. Ditch the spacer, you don't need it. I used a gasket however.
A 24mm Nibbi slide carb. No powerjet. These are well made carbs and much better than an Oko for the same price. My opinion, but I can show you the difference. I live in TN at 500ft above sea lvl and it can get hot and humid here. I'm running a 35 pilot, a 108 main and I lowered the needle, raised the clip, one notch from the 5 slot center so it would run a little leaner.
I have an after market exhaust pipe. It's a little loud, but not as loud as the Harley guys run. I can say that because I used to be one. Tattoo to prove it.
Cooling-You'll notice that I cut the shroud. I did this so that I could easily change out different manifold carb setups. It still cools the engine from the stator side. Honestly? I can't tell a lick of difference in cooling. What may attribute to that is I no longer have the storage under the seat. That compartment is gone. Hence the milk crate bolted to the back. LOL
Transmission-I like the stock clutch springs and the stock contra spring. The stock clutch, because I don't want to have to rev the snot out of my engine to tool around a parking lot. My clutch engages at 2500 rpm and it has the torque to move out. If you'll change your roller weights so that your scoot accelerates, between 6500 and 7500 rpm, it won't be a problem. Wanna race it? Sure change them out, but don't go overboard.
Rear gear- 13 inch tire 150cc scoots come with a 40 tooth rear output gear. I put a 38 in mine.
I don't trust the Chinese speedo but she will move out. I'm installing a gps speedo so bare with me. I know she'll do 65 mph and probably more but that awaits confirmation.