C: Clutch Comet Clutch Lifting Mechanism

bodlan

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My Comet has the divided push-rods and 1/4" roller fitted but what should be the orientation of the roller? Flat ends in contact with the rod ends or the circumference of the roller? When I took the clutch side rod out the roller came out with it but it fell off before I could see how it was assembled previously.
 

stumpy lord

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My Comet has the divided push-rods and 1/4" roller fitted but what should be the orientation of the roller? Flat ends in contact with the rod ends or the circumference of the roller? When I took the clutch side rod out the roller came out with it but it fell off before I could see how it was assembled previously.
end to end
 

davidd

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Think of the roller as a part of a segmented clutch push rod. On the clutch side of the segmented push rod, the push rod may continue turning with the clutch, but if it does, the rotation will stop at the roller. This means that the gearbox side of the pushrod won't be turning and wearing away at the gearbox clutch lever.

David
 

oexing

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You mean a cylindrical roller ? Why would one take a roller at this place ? Standard on many clutch rods is a ball bearing ball between segments of pushrods for mimicking a thrust bearing. The ends of the pushrod have to be hardened anyway !

Vic
 

A_HRD

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I'm guessing Tim is getting mixed up with the multiple loose Burman clutch rollers (PR50-35X?) used in certain models as the clutch bearing - they are 1/4 dia but a little shorter than a std 1/4 x 1/4 roller - which if fitted to the clutch bearing would indeed cause heartache. For the pushrod - take your pick of any suitable length - or a ball.

Peter B
 

davidd

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I use the ones that Coventry sells: 57-0394. I last ordered some over a decade ago, but I bought a lifetime supply. They measure .250" in diameter by .234" in length.

David
 

bodlan

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I am referring to the modification mentioned in KTB when splitting the actuating rod in two. It specifically says to use a roller in the centre but of course there are balls at each end so why a roller in the centre? I think DavidD's logic is the same either way?
 

timetraveller

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Vic, people who use ball bearings as spacers years ago found that they distorted and become non-spherical. The answer was to use rollers and they have been shown to last in Vincents for decades. If one uses the needle roller thrust race modification which I developed years ago then there is no need to split the push rod at all.
 

oexing

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You don´t mean balls at each end but domed rod ends ?? Nevertheless I´d use ball bearing balls between any number of split rod ends - unless the "roller" has very domed ends. We don´t have that type on rollers here, just on needle rollers if one likes these types. Balls are widely used there in all kind of bikes, no problem when rod ends are hardened. There is only around 300 pounds thrust on them - or even a lot less with the servo clutch.

Vic
 
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