Neo_Epoch
Member
- Local time
- 4:49 AM
- Joined
- Aug 14, 2017
- Messages
- 61
You’ll just have to experiment! Start at about 4 1/2” and work up. You’ll hit a point of diminishing returns when your intake gets too long.
Gotcha, that makes sense
You’ll just have to experiment! Start at about 4 1/2” and work up. You’ll hit a point of diminishing returns when your intake gets too long.
I want to make my engine to work at low RPM, I'm using a 32T sprocket and 28" wheels and a sleeved cylinder. The timing is the same as stock, but I have a 44 mm stroke and 47 mm diameter piston which equals 76cc. The sleeved cylinder and the longer stroke gave me more low end powed and I want to boost it more, because when I reach 60km/h (~6500RPM) my seat starts to shake like crazy and the engine gets louder too. I also have a 27 T sprocket, the 60km/h speed was fine, but I had to pedal more. So I want to make my engine work in a 2000 - 5000RPM range. The last time I used my 27T sprocket, the engine holding bolts broke, one on each side, so now I have M8 bolts holding the engine. I also put rubber between the frame and the engine, and the crank is trued, so the stock cdi might cause the vibration. I will try out the intake extension, because I've never tried it before. And a larger sprocket doesn't give you low end power, you just run your engine on a higher RPM try to cruise within the 2000 RPM range, I did that on this video.
The crankshaft isn't balanced, that might cause the problem. I found out today, that I need a larger main jet, because above 50 km/h the engine loses it's power, but when I pull the choke throttle (Yeah, I have a throttle for the choke too on the handlebar it opens another jet so the mixture will be richer) it accelerates like crazy. Once I was brave and with the choke on I accelerated to 70 km/h, but I think it could go faster. I'm not a fan of the big RPM, this engine is not designed for crazy high RPMs, the RPM was 70 km/h was 7500, with stock CDI. The bearings are too small, the wrist pin is too small and crankshaft is not balanced well, if I could do that I could be braver to make it go faster. I'll try to make a shift kit, so I could test is I can go faster if I lower the RPM, because with the 27T sprocket, it still got up to 60km/h but it was better to hear the engine running. I'm not a fan of the high RPM, there are motorcycles around here they have annoying noise, goes around 40km/h but already in the 5th gear. That's just ridiculous. I know it's only 50cc, but that buzzing sound is annoying. I love this engine's sound in the low RPM range, but there are other noises too, but there aren't much I can do about it, the clutch plate amplifies the clutch's noise, if there would be enough place I could put some sponge into the clutch plate to reduce the noise. It revs up nice, there's a range around 4000 - 5000 RPM when it accelerates like crazy, but after that the main jet seems to be small, because I can feel the mixture is too lean. Here's another video showing how it accelerates, even though the clutch was slipping, I solved that problem, but now it does a whine noise now.
The camera stand was sh*t, I mounted on the handlebar and the screen shakes like crazy at certain RPM, the crankshaft wan't trued when I took the video, it's a little better now. I forget to mention it revs up like crazy, because the bike weights 25 kg, and I weight around 60 kg.