BOB & BILL show us your new and improve ural clutch plate.

Are ya having a problem with your rig? We'll try to help. Share your tech tips and experiences here. Dr. Billy Glaser, author of the "Unofficial 750 Ural Service Manual" site myural.com, is moderating this section.
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tonered
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by tonered » Fri Jul 07, 2017 1:11 pm

I don't exactly know. The only guess is that the web page notes K750. This is the one that I am asking them about:
https://www.ural-zentrale.de/en/motors/ ... -gear-ring

With this kind of wear, I am very much against using an IMZ flywheel:
Capture 1.jpg
Have a good one.
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by gobium » Fri Jul 07, 2017 1:39 pm

tonered wrote:I don't exactly know. The only guess is that the web page notes K750. This is the one that I am asking them about:
https://www.ural-zentrale.de/en/motors/ ... -gear-ring

With this kind of wear, I am very much against using an IMZ flywheel:
Capture 1.jpg
Have a good one.
That is 650 fly

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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by GregAus » Fri Jul 07, 2017 6:08 pm

Early 750/825 Ural engines used a 6 pin flywheel with the starter ring gear being machined on the outer cover plate. If a flywheel is compatible with SV or CJ it will only fit a Ural 650 NOT a 750. SV, CJ and Ural 650 have the same taper. Dnepr OHV and Ural 750 both have different tapers.

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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by tonered » Fri Jul 07, 2017 8:20 pm

GregAus wrote:Early 750/825 Ural engines used a 6 pin flywheel with the starter ring gear being machined on the outer cover plate. If a flywheel is compatible with SV or CJ it will only fit a Ural 650 NOT a 750. SV, CJ and Ural 650 have the same taper. Dnepr OHV and Ural 750 both have different tapers.
Thanks for the confirmation.

Oh well. It looks like I will be stuck with weak IMZ parts and will be chugging around like a granny peeking between the steering wheel and dash. I'm sure the engine will love that lugging.

Have a good one.
tony b
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by GregAus » Sat Jul 08, 2017 12:01 am

tonered wrote:Oh well. It looks like I will be stuck with weak IMZ parts and will be chugging around like a granny peeking between the steering wheel and dash. I'm sure the engine will love that lugging.
Maybe not. There's a bloke in Brisbane building a hot rod Ural out of a 650 motor and he's designed a clutch for it. I had an idea who it might be and found his mobile number and gave him a call. Had a good long chat about the project He asked me not to give out any details as if turns out a failure he doesn't want to lead anyone up the garden path. If it works well then everyone can know.

One thing that I can say is that this clutch might just fit into a Ural 750 flywheel with a little machining. Anyone in Australia who wants to donate a worn-out flywheel will be re-imbursed postage and get first dibs on a proper clutch.

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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by tonered » Fri Jul 14, 2017 5:16 pm

Thanks, Greg.

I am close to ordering parts. So any progress would be appreciated.

Have a good one.
tony b
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by tonered » Tue Jul 18, 2017 10:24 am

Sorry for the premature thought there. I think I am going a different route, which will give the 650 flywheel mod from the guys down under some time to gestate.

I keep looking back at the original friction plates and wonder to myself about wasting money right now. I am going to install the old plates and get a few klicks in while I slowly gather up the proper parts for a swap.

So please keep the idea alive for getting away from the IMZ flywheel and drive plates. The question about timing marks still stands: would a 650 flywheel come with marks or would that be on me?

I'm going to have to change the RPOS's name to Grannie's Cruizer. I thought that I was on Ural time before . . .

Have a good one.
tony b
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by GregAus » Tue Jul 18, 2017 8:04 pm

tonered wrote:Sorry for the premature thought there. I think I am going a different route, which will give the 650 flywheel mod from the guys down under some time to gestate.
If the 750 flywheel can be turned out to a 212 mm internal diameter and keep a thick enough wall thickness to hold the ring gear, it will fit. Looking at a photo of a 750 flywheel and comparing it to a 650 flywheel that should be about 3mm past the six clutch screw holes. The clutch parts my friend is using are quite expensive but he says he's found some European car parts that should help bring the cost down a lot. I'll keep you informed.

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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by Michal » Wed Jul 19, 2017 7:23 pm

Ural clutch will never work in the long run neither over offroad abuse. It's a bad design with heat damage prone thin plates and wear prone thin splines. IMZ should dump this design and use as much car clutch design as possible instead. Also using reliable and cheap car clutch parts is advisable.

Clutch design that works fine has been listed on this board, i.e. http://www.sovietsteeds.com/forums/view ... 0&start=45 and http://www.sovietsteeds.com/forums/view ... 11&t=46479
It could be even better and cheaper if a starter ring and cover disc was made a single piece. If all parts were made from scratch, it would be cheaper than Ural clutch an flywheel with 105 precise fine splines machined.
Also a common small car clutch disc could be used as is if more common gearbox shaft splines were used. A common car clutch disc with spring loaded cush drive costs much less than simple but small batch made Ural disc.
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by GregAus » Wed Jul 19, 2017 8:36 pm

Michal wrote:Ural clutch will never work in the long run neither over offroad abuse. It's a bad design with heat damage prone narrow plates and wear prone narrow splines. IMZ should dump this design and use as much car clutch design as possible instead. Also using reliable and cheap car clutch parts is advisable.

Clutch design that works fine has been listed on this board, i.e. http://www.sovietsteeds.com/forums/view ... 0&start=45 and http://www.sovietsteeds.com/forums/view ... 11&t=46479
It could be even better and cheaper if a starter ring and cover disc was made a single piece. If all parts were made from scratch, it would be cheaper than Ural clutch an flywheel with 105 precise fine splines machined.
Also a common small car clutch disc could be used as is if more common gearbox shaft splines were used. A common car clutch disc with spring loaded cush drive costs much less than simple but small batch made Ural disc.
No secret where the idea came from, but look at the difference in teeth.
DSC_0100_zps5deo1q6s.jpg
Moto Guzzi Clutch

Another half-arsed Ural improvement.
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Re: BOB & BILL show us your new and improve ural clutch plate.

Post by tonered » Fri Jul 28, 2017 10:35 am

GregAus wrote:
tonered wrote:Sorry for the premature thought there. I think I am going a different route, which will give the 650 flywheel mod from the guys down under some time to gestate.
If the 750 flywheel can be turned out to a 212 mm internal diameter and keep a thick enough wall thickness to hold the ring gear, it will fit. Looking at a photo of a 750 flywheel and comparing it to a 650 flywheel that should be about 3mm past the six clutch screw holes. The clutch parts my friend is using are quite expensive but he says he's found some European car parts that should help bring the cost down a lot. I'll keep you informed.
Thanks, Greg!

I got the old, original pack in and the Grannie Mobile is back on the road. Every shift or lurch while engaging the clutch is giving me a worrying feeling.

I'll keep an eye out. I'm thinking that the swap will happen when I hit the next 5k service. So, I have some time. Maybe December - January?
Michal wrote:Ural clutch will never work in the long run neither over offroad abuse. It's a bad design with heat damage prone thin plates and wear prone thin splines. IMZ should dump this design and use as much car clutch design as possible instead. Also using reliable and cheap car clutch parts is advisable.

Clutch design that works fine has been listed on this board, i.e. http://www.sovietsteeds.com/forums/view ... 0&start=45 and http://www.sovietsteeds.com/forums/view ... 11&t=46479
It could be even better and cheaper if a starter ring and cover disc was made a single piece. If all parts were made from scratch, it would be cheaper than Ural clutch an flywheel with 105 precise fine splines machined.
Also a common small car clutch disc could be used as is if more common gearbox shaft splines were used. A common car clutch disc with spring loaded cush drive costs much less than simple but small batch made Ural disc.
Michal,

This is not really coming from offroad abuse. Just road riding and expecting to keep up with traffic while commuting, joy riding, and fetching groceries. Basically, if the motor can do it with about 40 hp / tq, the clutch should not be this weak. I was offroad for a handful of miles on the pack that failed.

Anyway, I really like your work. I have no machine tools and only know one shop in the areas that works on fab like this. Are you willing to fab up one for a schlub like me? What would the cost look like?

Again, beautiful work!
GregAus wrote:
Michal wrote:Ural clutch will never work in the long run neither over offroad abuse. It's a bad design with heat damage prone narrow plates and wear prone narrow splines. IMZ should dump this design and use as much car clutch design as possible instead. Also using reliable and cheap car clutch parts is advisable.

Clutch design that works fine has been listed on this board, i.e. http://www.sovietsteeds.com/forums/view ... 0&start=45 and http://www.sovietsteeds.com/forums/view ... 11&t=46479
It could be even better and cheaper if a starter ring and cover disc was made a single piece. If all parts were made from scratch, it would be cheaper than Ural clutch an flywheel with 105 precise fine splines machined.
Also a common small car clutch disc could be used as is if more common gearbox shaft splines were used. A common car clutch disc with spring loaded cush drive costs much less than simple but small batch made Ural disc.
No secret where the idea came from, but look at the difference in teeth.
DSC_0100_zps5deo1q6s.jpg
Moto Guzzi Clutch

Another half-arsed Ural improvement.
Wow. Yeah. I am not very familiar with MGs. Do they have a primary reduction? Either way, they are kicking out much more torque that ours, moving about the same mass a whole lot faster.

Those teeth do look stellar, esp the friction plates.

I suppose my big question would be about how that adapts and transfers twist to the GB input shaft? I could see a small drum there, but there is nothing to fasten to? I don't think welding is an option since the Ural shift forks seem to be damn wear item also.

Have a good one.
tony b
Lynnwood, WA
2013 GearUp (Taildragger)
2001 Duc ST4 (Thumper)

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