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Old 08-09-2011, 07:40 PM
dtj6ppc dtj6ppc is offline
Motorized Bicycle Senior Member
Join Date: Feb 2011
Location: redondo
Posts: 61
Default Re: Centrifigal clutch modification.

Originally Posted by Erich_870 View Post
That's an intriguing question! If you have an accurate way to measure RPM, the weight of the clutch and the spring tensions, you should be able to work up an equation to get close to your 3000 rpm goal.

What are you capabilities to measure those three variables?

I think I have reasonable measurements of the three variables;

RPM= Engagement rpm= 3,000 Idle rpm=2,400

Clutch half weights= 100 grams (3.5 oz) per side or 200 grams (7.0 oz) total

Spring tension= 15 pounds force retracted and 21.5 pounds of force at .125"
or 1/8" extended about the engagement distance of the
clutch shoes when contacting clutch drum as measured
using a postal scale

My gut feeling is that it is going to take about 20-30 grams of weight removal per side or 40-60 grams total to achieve the 1,000 rpm engagement delay that I am looking for. If I cannot come up with a ballpark estimate I will just have to start out conservative at say 15 grams removal per side, re-assemble, test, and re-drill. Problem with this trial and error method is that dis-assembly of the engine, gearbox, and clutch is a long drawn out procedure that I dont want to have to repeat too often...............Don
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