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Old 01-05-2015, 05:07 PM
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cannonball2 cannonball2 is offline
Motorized Bicycle Elite Member
Join Date: Oct 2010
Location: Colonial Coast USA.
Posts: 3,286
Default Re: 50cc GY6 on a Bicycle??

Hooking up the CDI is not a big deal it pretty simple. There are two versions an AC and a DC The DC is fed by the battery while the AC is fed by the alternator. Just have to know which one the engine is supplied with.

As far as variator tuning, a DR Pulley is about the best. It has a bigger driven face allowing higher ratios as the belt can climb higher. Also adding a few mm to the drive belt size will allow the belt to travel there as the rear driven sheave stops it short with a stock belt. I guess you all realize the clutch is in the rear sheave and not on the engine. Clutch springs come on various rpm ranges, and there are several main springs for the rear sheave to tune how it responds to the variator. I like my CVT to get to the upper ratios pretty quick. The big bore engine has the power/torque to handle faster travel to high ranges. Therefore I run fairly heavy weights. A typical take off for me is WOT and hold it there until the speed I want is reached(pretty quickly too). I have carefully tuned the variator to allow the engine to get to its max torque range. The engine immediately jumps to around 6500rpm and just stays there while the variator makes the speed happen. Once the engine unloads at around 65mph then it will rev on to around 7500 which allows the variator to finally push the belt to the full extent of the drive face and topping just north of 70mph. The design of this little power unit is pure genius!
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