Clutch in the small-block models.

[audiomick]

I don't expect there will be many takers for this here, but I've just written something on the subject somewhere else, and I thought I might as well put it here too.

 

As I have mentioned elsewhere, I have a V35 Imola. About the only thing that annoyed me about it was that the clutch was so heavy.

In the German forum that I am active in, a couple of bright sparks figured out that the clutch from a V85 will fit in any of the small block models. The only restriction is that the V35 and V50 have a different input shaft on the gearbox to the V65 and later models, including the V85. This means that the clutch plate for the V85 clutch wont fit on those early models. However, the V85 produces close to 80 PS, the V50 only 49, and the V35 a bit more than 30, maybe. So it is a safe bet to just use the smaller clutch plate in the newer clutch.

Long story short: I bought a brand new clutch in e-Bay for about 150 Euros (price for a new V85 clutch from a dealer about 250 Euro). It turned out to be a V9 clutch, but is obviously effectively the same as the one in the V85. The original clutch in the V35 required a full hand, and a lot of effort. Now I can operate it with one finger. Need I say more?

And....

the newer clutch is lighter than the old one, so blipping the throttle at the traffic light is much more effective.

So...

if anyone has a small-block Guzzi and a bit of spare cash, and a bit of time, think seriously about doing the mod. It is worth the effort.

 

If anyone is interested and needs more details, let me know and I will elaborate.

Edited March 28 by audiomick

[gstallons]

IDK anything about these bikes . Are these hydraulic or cable operated clutches ?

[Chuck]

1 hour ago, gstallons said:

IDK anything about these bikes . Are these hydraulic or cable operated clutches ?

Cable. Entirely different (better)  clutch than the big block. 

[bmc5733946]

I am interested! Both of my Breva clutches are hard pull. What's it take?

Brian

 

[audiomick]

5 hours ago, bmc5733946 said:

I am interested! 

Brian

 

Brian has a hopefully recieved a PM from me.

In answer to his question, for the rest of the world, "what's it take?" : buy one, and bolt it in. 

EDIT: the V35 and V50 models had a smaller diameter input shaft to the gearbox, and a smaller diameter clutch plate. The older clutch plate was 160mm, the newer 170 mm, the older input shaft 17mm, I believe, the newer 20 mm or so.

On the advice of a very experienced member of the German forum, I used the V35 flywheel and clutch plate with the new clutch. The new clutch is designed for the "about" 80 hp that the V85 generates. The V35 makes (maybe) 30 hp, the V50 (maybe) 48. The assumption was that the new clutch can handle that even with the smaller clutch plate from the older, "weaker" models. With my V35 Imola, even determined attempts to induce a slipping clutch confirmed that the new clutch can deal with the power. 

Edited November 20 by audiomick

[guzzi323]

This is incredibly helpful me. I have a hot-rodded V50 that even with a new pressure plate and friction plate easily overpowers it. I think your solution might be mine as well.

 

Thanks!

[audiomick]

2 hours ago, guzzi323 said:

...I have a hot-rodded V50 that even with a new pressure plate and friction plate easily overpowers it. ...

How the hell did you manage to get that much power out of a V50?  

 

Whatever, be aware that the later models had a larger friction plate, and input shaft to the gearbox. As of the V65 and later, as far as I know. The V35 /V50 had a 17 mm input shaft, and a 160 mm friction plate. The later version was a 20 mm input shaft and a 170 mm  friction plate.

Given that the clutch is intended for a bike with close to 80 hp and my V35 Imola barely makes 30 hp, I just stayed with the old 160 mm friction plate. Serious attempts to make it slip have indicated that it wont. I'd be prepared to go that way with a V50 too, even with a hot motor. I can't imagine you're much over 60 hp or so, more like 55 at a guess. The motor just isn't capable of producing much more than that. I'm guessing, but I would expect that even with the smaller friction plate you should be ok.

If you want to use the larger friction plate, you will have to swap at least the primary drive, or the whole gearbox. The larger friction plate wont fit on the input shaft of the V50 gearbox. Also, if using the old flywheel from the 160 mm friction plate with the new 170 mm friction plate, the contact area on the flywheel has to be enlarged to accomodate the larger friction plate.

The kit I bought came with everything. I sold the 170 mm friction plate on to someone who could use it. 

Edited November 20 by audiomick

[Chuck]

FWIW, the 750cc Aero engine with the big valves makes right at 50 hp on the dyno. 

[guzzi323]

21 hours ago, audiomick said:

 

Given that the clutch is intended for a bike with close to 80 hp and my V35 Imola barely makes 30 hp, I just stayed with the old 160 mm friction plate. Serious attempts to make it slip have indicated that it wont. I'd be prepared to go that way with a V50 too, even with a hot motor.

My seat of the pants estimate is 50 'ish, maybe a little more. It's  a 573cc with a cam, fancy rods, polished crank, porting, carbs...all the normal stuff. 

Of course I've been busy on other things for years, who knows when I'll get to doing this.

 

[bmc5733946]

I found a decent V9 clutch on the bay of fleas for short money. Next comes install. My shop is a total wreck right now with too much crap and too many projects left undone, mainly a 1976 Convert that needs everything. I must get busy and clear space for this clutch job!!!

Brian