Converting PA50-I engine to 30mph

I have read the web page ( titled:

"Modding a Honda PA50-I Variator to a PA50-II"

I happen to have the 30mph ramp plate from the original II engine. The carb and reed valve are also from the II engine.

Question: The instructions are to

"Mill off the side of the PA50-I drive face threads to accept the 30 mph ramp plate."

Is this all I need to convert the variator to 30mph? When I bought the engine via eBay I wasn't informed that it had come from a PA-I.

I had been wondering why the beast ran so slowly in spite of the engine running well.

Until I installed a replacement motor I had never had the bike on the street, so I didn't know what performance to expect.

Any input will be appreciated.

Re: Converting PA50-I engine to 30mph

I solved the problem by swapping the facing plate hub from the old engine. I can see how valuable would be the above proceedure if one didn't have the old parts.

Re: Converting PA50-I engine to 30mph

there are other differences between the two bikes. Cylinder porting is milder in the PA50I .. aimed at more power at lower RPM range. Compression ratio is also higher in the slower bike for the same reason.. I now have doubts about the rear gear box ratio being different although i was convinced of it in the past.

But, if you just switch variators you should pick up a few miles per hour..

Aside from the more severe curve on the PA50II steel ramp plate there may be other differences in that outer pulley body... specifically, exactly how far the rollers can travel outward before they contact the wall. If you have one of each unit to compare, a close look should reveal any diffferences.

Honda was forced to limit the speed of both bikes and they were pretty sneaky about how they went about it.. and, imo, modifying top speed of either bike was made purposely difficult.

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