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Lineslinger · Aug 4, 2023

Britstuff said:
I'm currently installing a belt drive on my 850. Mine seems to run straight and true with the original single sided adjuster. However, it seems like mine is the exception to the rule. Apparently the condition of the lower mounting bolt on the gearbox - the one that acts as a fulcrum for chain / belt adjustment, is critical. In my case it appears to be one of the few components on my bike that was not totally knackered!

My plan B is definitely to buy a two sided adjuster.

I don't know that your scenario is an exception, maybe just different?
My belt drive upgrade on a 74' is one adjuster. Still aligned and behaving over a year after installation. I finally gained confidence in it after checking it every ride for a month after installing.
Methinks so many bikes just have past usage/riding influences in them that dictate various results when improvements of upgrades are introduced.

baz · Aug 4, 2023

Lineslinger said:
I don't know that your scenario is an exception, maybe just different?
My belt drive upgrade on a 74' is one adjuster. Still aligned and behaving over a year after installation. I finally gained confidence in it after checking it every ride for a month after installing.
Methinks so many bikes just have past usage/riding influences in them that dictate various results when improvements of upgrades are introduced.

Also we are dealing with manufacturing tolerances from back in the day when these bikes were being built

swooshdave · Aug 4, 2023

baz said:
Also we are dealing with manufacturing tolerances from back in the day when these bikes were being built

Tolerances measured with a yardstick.

swooshdave · Aug 5, 2023

cliffa said:
Dave, are you sure it's not just an illusion? As you pull on the belt it makes the clutch rotate slightly as it takes up the slack, but is it actually moving closer to the centre stud boss? In the film of the bike running the clutch body appears to run true, but the centre does not (not sure if that's an issue really).

.020-.025” deflection at the center.

swooshdave · Aug 5, 2023

I need to fire my mechanic. Took the primary apart (is it sad how fast I can strip a primary?) and discovered a missing circlip on the clutch basket bearing. Clutch gasket don’t wobble so much now.

I’m still concerned about two things. The clutch hub is a sliding fit on the bearing. No perceivable play but not an interference fit.

And the main shaft has some play. I don't know the last time the gearbox was rebuilt but I should probably put that on the list.

Oregon Vintage Motorcyclists have their second show of the year tomorrow. Or as I’m calling it… a test ride for the belt.

swooshdave · Aug 6, 2023

Work flawlessly today. As soon as I got home I popped off the cover and the belt still had some play. Preformed flawlessly.

Schwany · Aug 6, 2023

swooshdave said:
Work flawlessly today. As soon as I got home I popped off the cover and the belt still had some play. Preformed flawlessly.

How much play? Curious mostly, I am not lining up a cheap shot.

swooshdave · Aug 6, 2023

Schwany said:
How much play? Curious mostly, I am not lining up a cheap shot.

This much.

ashman · Aug 6, 2023

If the GB is changing smoothly and all working good I leave it alone, most problems with GBs is primary, clutch and rear chain not adjusted right, if all adjusted right the Norton gear box is pretty reliable, after 47 years of ownership mine is still one of the best gear changes around, even smoother than my modern Triumph and all my left hand gear change bikes.
My right hand change and light clutch just clicks in gear no clunk like all my left hand change bikes do and gear levers with linkages seem to clunk more when putting in gear, Harley's with forward controls seem the be the loudest clunk of all bikes.
No matter what you run in your primary, belt or chain, I love how good my right hand gear change is even after 47 years.

Ashley

Schwany · Aug 7, 2023

swooshdave said:
This much.

Thanks
Very kind of you to take a picture. Appreciate it.

swooshdave · Aug 7, 2023

Schwany said:
Thanks
Very kind of you to take a picture. Appreciate it.

I took it before you asked as I wanted to record the tension while it was still hot from the ride.

Schwany · Aug 7, 2023

swooshdave said:
I took it before you asked as I wanted to record the tension while it was still hot from the ride.

Figured that was probably the case about an hour later. You are a pictorial and video documenter of the highest order. Thanks are still due.

swooshdave · Aug 7, 2023

Schwany said:
Figured that was probably the case about an hour later. You are a pictorial and video documenter of the highest order. Thanks are still due.

If I don't document I may forget what I did. Even if I do document I may forget what I did...

ringydodds · Aug 8, 2023

swooshdave said:
If I don't document I may forget what I did. Even if I do document I may forget what I did...

My experience with the primary belt. Even a tiny bit tight and it will not track. I have found - adjust until you can slide the belt off and on the pullies by hand. Any tighter -it will run off.Loose is good.

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