Talk Morgan Forums Thread Like Summary - Drive belt

Good evening everyone,

Had my M3W MOT'd the other day, which it passed with no advisories. They did mention the drive belt needs adjusting and possibly a new belt. I'm not too bad with a spanner, is this something dealer only or would I be able to adjust or fit a new belt?

Cheers,
Martin

I acquired an older-model rear hub, modified it on a lathe (removing 5 mm), and machined the exact 85.8 mm centering bore for the wheel; I then installed studs and used acorn nuts to secure the wheel. I also applied this stud modification to my original black hub.

How would an MOT inspector know anything about belt tension or condition on a M3W which is a very unique application? Unless you are at very high mileage the belt is likely fine as is. The belts are very durable and long lasting as long as the tension and alignment are both in a reasonable range. The original alloy rear sprockets were a different story and wore fairly quickly and were later replaced with steel. It is possible that a very worn alloy sprocket can do damage to the belt teeth, so look for that if you have or had an alloy rear sprocket fitted.

To answer the replacement question, if you have a jack and a couple of stands you can do a belt R&R yourself (search this forum for details). It does require removing the rear wheel and swing arm, so it's a bit involved, but can be done in a few hours. Belt alignment takes some nuance, but again not too difficult. You might wait and evaluate all things belt related until the rear tire needs replaced, unless the belt is manifesting problems at present.

Also see:
https://www.mtwc.co.uk/wp-content/uploads/2018/01/M3W-Rear-Hub-and-Sprocket.compressed.pdf

which will give you an indication of the amount and type of work to be done.

Maybe they were interested in the way the belt probably overhangs the edge of the drive sprocket by about 4mm...this is the approved configuration.

My personal method for centering the belt is to lift the rear of the trike with a jack while the engine is running and second gear is engaged, then adjust the tensioners to position the belt in the middle of the rear sprocket.

Just for clarity, the only difference between early 'silver' hubs and the later 'black' ones is the position of the wheel mounting flange - with the later one (theoretically) giving 5mm additional clearance between the belt and tyre. The sprocket mounting flange is identical between the two.

On my early 2012 car, I run a 1/4" spacer between the sprocket and the hub flange and my belt tracks quite nicely. This is with a black hub and Fabian sprocket. The inner diameter of the spacer does need to be machined out slightly for fitment to the Morgan hub. This isn't necessarily a recommendation by the way because we all know that each car is different!

Hi Martin W
I read your comment that you do not have a NVH kit.
Question : How is your bevel-box then attached to the frame?

When you use a PB-bevel-box-mount, than I would advice to read the article about alignment in Bruces his m3wbevelbox.work website.
It is an article valuable for all M3W belt-drives
Possibly the article will give a solution to your problem

link : Being good aligned is an issue to consider