Sealed clutch bearing experiment

Trying this out as a wee experiment.

My T140 belt conversion has worked out well, but as with most triumph belt conversions, running the primary dry with an open bearing is concerning, so I located this sealed bearing that's a close fit to the clutch basket open roller dimensions:


First step was to press out the old outer race and machine a new race with a -.002 ID for an interference fit, here's the old and new races plus the bearing



New race pressed into hub, I made up this two sided plug to press in and out the races



bearing on hub prior to installtion



Clutch was reassembled with standard thrust washer in place, I felt this was necessary to prevent the output shaft hub's bearing race from grinding into the back of the clutch basket. The difference in centre-basket play between this and the standard set up is significant, it took only a minute to dial in the plate run-out to within .005. I've had the bike out twice so far with this set up and no ill effects. After the first run I disassembled to check for any problems and the clutch centre had no increased play.

Looks good
But what's the reason?

baz said:

Looks good
But what's the reason?

Click to expand...

Running a dry primary, so the open, non lubed rollers are concerning... that, and I can't afford a Newby kit with the sealed bearing

acadian said:

Running a dry primary, so the open, non lubed rollers are concerning... that, and I can't afford a Newby kit with the sealed bearing

Click to expand...

Your conversion does look very good
But I wouldn't worry too much about the clutch rollers running dry
I have run open primarys on triumphs and BSAs without issue
And when stripped the grease is still there
I'm guessing if you ride in heavy traffic/traffic lights etc etc with heavy clutch use then a sealed bearing would be great as the only time the bearing does anything is when you have it pulled in and in gear

baz said:

I'm guessing if you ride in heavy traffic/traffic lights etc etc with heavy clutch use then a sealed bearing would be great as the only time the bearing does anything is when you have it pulled in and in gear

Click to expand...

Yup, this is exactly my concern, cant go 1 block without hitting a light or traffic, and yes, I do flip it into neutral at long reds, but the clutch use in the city is still quite heavy

Looks like a good improvement even for engines still using wet primaries. Good research, finding a sealed bearing that can be made to fit.