Centrifugal Clutch Spring, Lower RPM Engage

[MotorizedBikeRider]

I have a motorized bicycle, has a 33cc 2 stroke motor. The front sprocket has 1en teeth, rear sprocket has 40, and wheel size is 27.5". It is a bit difficult to go much below 15mph, top speed is around 30-32mph. Geared a bit higher than I wanted, but cruises nice around 20mph or so. I want to put a lower tension spring into the clutch so it engages at a lower RPM. I looked for a thread on this subject, if there is one I could not find it. Does anyone know of a source for springs? What special tools might be needed?

 

[Venice Motor Bikes]

There are thousands of clutches out there.... It would really help if we knew which one you have

 

[MotorizedBikeRider]

There are thousands of clutches out there.... It would really help if we knew which one you have

Oops, okay. Has single large spring in center

 

[Venice Motor Bikes]

That looks like a engine that would be used on a 'Go-Ped'.... Google go-peds & go down the line of sellers & see what they have!!

Another option would be to slowly stretch the spring a little at a time until it engages at the RPMs you're looking for.

 

[MotorizedBikeRider]

That looks like a engine that would be used on a 'Go-Ped'.... Google go-peds & go down the line of sellers & see what they have!!

Another option would be to slowly stretch the spring a little at a time until it engages at the RPMs you're looking for.

Yes, I suppose they use them on Go-Peds, etc. Basically it's a weed wacker motor.

 

[Mossy]

There's many different springs for other things... I would measure the length / size of the coils / thickness of the wire and get a few to try and a direct replacement to mess with... Eventually through trial and error the magic one will emerge... A place that repairs scooters might have done this or scooter forum could have past threads about it... When stretching it I would rig it up so I could measure or have reference... Like hanging a bucket from it and adding weight... So you know about how much got you there... You can never unstrech it if you go to far... A smaller wire diameter everything else being the same is going to be the best reliable way around it...

 

[Mossy]

There's another way by adding weight to the shoes to overcome the spring sooner... I just thought about... The weight needs to be the same for each shoe... The worst way to do it would be to heat the spring and loose the temper because it won't rebound back as many times and break... Or slowly engage at a lower and lower Rpm as it lost it's springy... That's my take on it like everything else there's many ways and it's good to know a few of them because it's usually a combination of things... Mechanical advance points distributor is where I would work some magic and the comet clutches on snowmobiles in the 70's...

 

[MotorizedBikeRider]

There's another way by adding weight to the shoes to overcome the spring sooner... I just thought about... The weight needs to be the same for each shoe... The worst way to do it would be to heat the spring and loose the temper because it won't rebound back as many times and break... Or slowly engage at a lower and lower Rpm as it lost it's springy... That's my take on it like everything else there's many ways and it's good to know a few of them because it's usually a combination of things... Mechanical advance points distributor is where I would work some magic and the comet clutches on snowmobiles in the 70's...

Adding weight may be a way. Added weight would need to be exact on each side. Possible drill and tap a hole and put a bolt in (using thread lock so it does not come loose) ?

 

[Mossy]

Adding weight may be a way. Added weight would need to be exact on each side. Possible drill and tap a hole and put a bolt in (using thread lock so it does not come loose) ?

Right ! a line of Allen heads and high temp red lock tight.. the farther out the more effect... if one is too much carefully grind down a little on each one equal...