Friday, 4 March 2016

How to build a nine disk performance clutch for a TR1 or Virago

I have mentioned it before, one of the biggest features of the Yamaha XV750, 920, 981, 1000 and 1100 family is continuity. Which in other terms means, there's lots of parts mixing and matching to be done.

Now the stock clutch on a early XV750 or TR1 is fine as long as you don't get freaky with power addons. Luckily it is relatively easy to build a very nice clutch from a mix of Virago 1100 (or late Virago 750 - I'll just refer to the from here on as "Virago", even though I know that even the early XV models were called Virago in some countries) clutch hubs, TR1 clutch steel disks and pressure plate.

First we need a Virago clutch basket.
A low mileage Virago 1100 clutch in all its glory
Unlike the TR1 clutch it doesn't use six coil springs but one giant plate spring. 

The wire is hardly visible in this picture, but trust me, it's there
 In order to make the basket usable, one has to remove the retaining wire and the thick steel plate on the bottom of the clutch hub and replace it with a normal one out of a TR1. This mod and the fact that the basket is slightly taller are the main reason, why a ninth friction plate can be fitted.
Here you can see the difference in thickness
And here you can see the height difference (Virago on the left)
Next let's fill the clutch hub up with friction plates.

As you can see the posts for the springs are protruding through the pressure plate and as such rendering the clutch useless, unless you trim them on a lathe or mill. (Very brave people might get away with hacksawing these off, but I am a strong believer in equal length studs...)

Unfortunately I don't have a picture, but it's quite simple really, just like on the TR1 basket, you want the posts to be the same height as the inner part of the clutch.

... and it still wouldn't work this way

At this point you have to bear in mind, that the Virago 1100 clutch cover is a bit more spacious. Unfortunately the one I had was cracked and I wanted to keep things stealthy after all... So it was lathe time once more and I turned down the ribs on the pressure plate.
Thing o' beauty
... and now say bye-bye to clutch slip on your TR1. If it still slips, check the adjustment of the lower clutch lever. There's supposed to be about an eighth of a turn play before the rod bottoms out.

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