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Post by jeff84 on Jul 13, 2017 0:16:52 GMT -5
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Post by dan50 on Jul 13, 2017 0:18:05 GMT -5
Agreed about aerodynamics. Look what bicycle racers do in that area, tucking (don't tuck your arms to the side of your chest it increases the area of the chest, let them out a bit to let air through between your chest and arms. I saw that trick on a tv program about a bicycle racer testing in a wind tunnel), tight clothes, even the shape of the helmet, all adds up.
Have you done any CVT tuning? Tuning the CVT should be the next step. When my motor was stock 50cc,I tuned the CVT and got a top end of 42mph without over-revving. My CVT has a drive ratio of 11.1:1. Tuning the CVT got me mph as well as more drive-ability and cost about $50 to do.
I just installed a 47mm BBK, 47mm head and A-9 cam. This got me 4mph without re-tuning the CVT and the ability to fight wind and hills. I cruise at 37 to 38mph and in a strong 20mph wind I can still go 37mph at WOT, That wind speed used to slow me down to less that 20mph before the CVT tuning.
Also, make sure you do a plug chop to make sure your carb is jetted right. The color of the plug should be a caramel brown color meaning it's running slightly rich which is where a scoot engine runs best. If it's black - too rich. If it's white - too lean (lean makes more heat in the engine, the fuel helps cool the cylinder a bit).
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Post by dan50 on Jul 13, 2017 0:21:00 GMT -5
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Post by lostforawhile on Jul 13, 2017 0:21:39 GMT -5
the less power you have on tap, the more aerodynamics play a role. with more power you can easily overcome lack of good aerodynamics to a point. an you have to pretty fast before you reach the that point. right, and with these small engines, it becomes even more important as we don't have power to spare, one big advantage of not pedaling, is we can wear a full face helmet with a shield, which is probably more aerodynamic then even the best bicycle racing helmet and goggles. We don't have to worry about sweating inside the helmet from heavy exertion, or the weight penalty, as the engine is doing all the work
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Post by lostforawhile on Jul 13, 2017 0:26:44 GMT -5
Agreed about aerodynamics. Look what bicycle racers do in that area, tucking (don't tuck your arms to the side of your chest it increases the area of the chest, let them out a bit to let air through between your chest and arms. I saw that trick on a tv program about a bicycle racer testing in a wind tunnel), tight clothes, even the shape of the helmet, all adds up. Have you done any CVT tuning? Tuning the CVT should be the next step. When my motor was stock 50cc,I tuned the CVT and got a top end of 42mph without over-revving. My CVT has a drive ratio of 11.1:1. Tuning the CVT got me mph as well as more drive-ability and cost about $50 to do. I just installed a 47mm BBK, 47mm head and A-9 cam. This got me 4mph without re-tuning the CVT and the ability to fight wind and hills. I cruise at 37 to 38mph and in a strong 20mph wind I can still go 37mph at WOT, That wind speed used to slow me down to less that 20mph before the CVT tuning. Also, make sure you do a plug chop to make sure your carb is jetted right. The color of the plug should be a caramel brown color meaning it's running slightly rich which is where a scoot engine runs best. If it's black - too rich. If it's white - too lean (lean makes more heat in the engine, the fuel helps cool the cylinder a bit). the CVT tuning and contra spring as well as a belt change, is next on my list, the carb that was on my scooter is a genuine Keihin, but I ordered a complete one, just like it, since my diaphragm has a hole in it, and i'm having trouble tracking down the genuine parts. Then I can take my time repairing this one, they come with 85 jets factory installed
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Post by dan50 on Jul 13, 2017 0:47:18 GMT -5
#85 main jet should be good in a stock engine. #78 was just a tad small so I ran a #80 with the stock 18mm carb.
Check your drive ratio by removing the CVT cover, Then marking a spot on the tire and turning the clutch bell and counting how many times the clutch goes around for 1 revolution of the tire. That is the ratio of the drive gears. Knowing that ratio helps in considering what mods will work. Some scoots have 13:1 ratios and 2t's have even 15:1 in some scoots. My 2t Jog90 that I'm installing in my Kalibur came with a 10.25:1 gear ratio.
The Keihin carb is a great choice. I've heard only good about them.
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Post by lostforawhile on Jul 13, 2017 1:11:09 GMT -5
#85 main jet should be good in a stock engine. #78 was just a tad small so I ran a #80 with the stock 18mm carb. Check your drive ratio by removing the CVT cover, Then marking a spot on the tire and turning the clutch bell and counting how many times the clutch goes around for 1 revolution of the tire. That is the ratio of the drive gears. Knowing that ratio helps in considering what mods will work. Some scoots have 13:1 ratios and 2t's have even 15:1 in some scoots. My 2t Jog90 that I'm installing in my Kalibur came with a 10.25:1 gear ratio. The Keihin carb is a great choice. I've heard only good about them. just don't work on the 80's emissions nightmare ones on Honda cars, especially the dual prelude Keihin, I can take apart all of them and repair them, but my therapist said I shouldn't talk about them, and only think happy thoughts, not the nasty bad carburetor thoughts
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Post by lostforawhile on Jul 13, 2017 19:46:01 GMT -5
The Keihin finally made it here, and it's a real one, so 20 bucks plus shipping for a brand new carb, from working on many Japanese made keihin carbs for cars, the casting appears to be Japanese, the casting finish is too good to be the Chinese cast one, the aluminum used in Japanese cast Keihins is also a darker color, vs the somewhat shiny cast of the others. I need to order another for a backup, he only had a couple left, luck of the draw I guess
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Post by greggkinney on Jul 13, 2017 21:50:04 GMT -5
#85 main jet should be good in a stock engine. #78 was just a tad small so I ran a #80 with the stock 18mm carb. Check your drive ratio by removing the CVT cover, Then marking a spot on the tire and turning the clutch bell and counting how many times the clutch goes around for 1 revolution of the tire. That is the ratio of the drive gears. Knowing that ratio helps in considering what mods will work. Some scoots have 13:1 ratios and 2t's have even 15:1 in some scoots. My 2t Jog90 that I'm installing in my Kalibur came with a 10.25:1 gear ratio. The Keihin carb is a great choice. I've heard only good about them. just don't work on the 80's emissions nightmare ones on Honda cars, especially the dual prelude Keihin, I can take apart all of them and repair them, but my therapist said I shouldn't talk about them, and only think happy thoughts, not the nasty bad carburetor thoughts preludes kick ass! 😂
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Post by lostforawhile on Jul 13, 2017 22:06:50 GMT -5
just don't work on the 80's emissions nightmare ones on Honda cars, especially the dual prelude Keihin, I can take apart all of them and repair them, but my therapist said I shouldn't talk about them, and only think happy thoughts, not the nasty bad carburetor thoughts preludes kick ass! 😂 this was the worst Keihin nightmare Honda ever created, it's advertised as twin carb, when in reality, it's a single carb split into two, one barrel is the primary and one the secondary, if the primary goes bad you have to chuck both, as they are matched, the best repair for these is to rip off all this crap, and install a nice set of side drafts, at this time it's the only repair as most parts are no longer made, also many of these carbs have the power valve sealed into the carb top, which means you have to replace the top or machine it to split it.
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Post by greggkinney on Jul 14, 2017 7:51:37 GMT -5
^^^^ 😱 ouch!!! ^^^^ looks like maybe you should remove the p.a.i.r system on that lude! (jk) wow that does look like a p.i.a
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Post by jeff84 on Jul 14, 2017 9:29:21 GMT -5
that does look like a nightmare
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Post by humanshield on Jul 14, 2017 10:10:54 GMT -5
the less power you have on tap, the more aerodynamics play a role. with more power you can easily overcome lack of good aerodynamics to a point. an you have to pretty fast before you reach the that point. lol. Yeah...when my 83cc scoot is struggling against a head wind I know for sure aerodynamics is at play (or lack of). I keep thinking.....man, if I could get get a nice, teardrop shaped clear, super lightweight bubble to put around my scooter it'd probably be able to cruise along at 50mph. I know when I have a strong tailwind of 25-30mph I can do 50 or better. Maybe I should invent Sails for scooters At the very worst...backup power for getting you home after an engine failure?
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