Fabian
Well-Known Member
I've made this modification to the clutch camshaft and clutch lever tension has dropped significantly.
This was not the reason for the modification though.
I was seeking much better clutch modulation as in standard form it was almost impossible to get a good range of clutch lever movement from the point of disengagement to fully engaged.
The clutch was either "ENGAGED" or "DISENGAGED"
I wanted a progressive spread of engagement over at least half the clutch lever movement, allowing me to feed in the clutch at much higher rpm for faster getaway's from a standing start.
Over a period of time grinding away the clutch camshaft, i realised that the engagement point on the camshaft needed to be moved closer to the centreline allowing more lever travel for less overall clutch throw.
With these Happy Time style engines there is only about 2mm of throw at the clutch plate from fully engaged to fully disengaged, yet there's about 8mm of throw available on the clutch of which 6mm is doing nothing at all.
All the modulation needs to take place in such a small window of about 2mm - a very bad design.
I've achieved much better modulation with this modification, moving the contact point of the camshaft inwards by approx 2mm.
Now i can feed in a reasonable amount of revs and have a nice progressive take-up over a reasonable range of clutch lever travel.
It's taken me 3000 kilometers of being seriously irritated by such a useless clutch to do something about it.
The image on the right needs to be flipped over 180 degrees as it's the right hand side that needs to be ground away.
Fabian
This was not the reason for the modification though.
I was seeking much better clutch modulation as in standard form it was almost impossible to get a good range of clutch lever movement from the point of disengagement to fully engaged.
The clutch was either "ENGAGED" or "DISENGAGED"
I wanted a progressive spread of engagement over at least half the clutch lever movement, allowing me to feed in the clutch at much higher rpm for faster getaway's from a standing start.
Over a period of time grinding away the clutch camshaft, i realised that the engagement point on the camshaft needed to be moved closer to the centreline allowing more lever travel for less overall clutch throw.
With these Happy Time style engines there is only about 2mm of throw at the clutch plate from fully engaged to fully disengaged, yet there's about 8mm of throw available on the clutch of which 6mm is doing nothing at all.
All the modulation needs to take place in such a small window of about 2mm - a very bad design.
I've achieved much better modulation with this modification, moving the contact point of the camshaft inwards by approx 2mm.
Now i can feed in a reasonable amount of revs and have a nice progressive take-up over a reasonable range of clutch lever travel.
It's taken me 3000 kilometers of being seriously irritated by such a useless clutch to do something about it.
The image on the right needs to be flipped over 180 degrees as it's the right hand side that needs to be ground away.
Fabian
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