Extreme Wear on Friction Plate Tabs

Paul W. · Jan 7, 2019

I removed the primary to time my engine. I noticed extreme wear on the friction plates where the seat against the clutch basket. I will be ordering some new clutches from Barnett. Any idea as to what the cause may be?

She looks a bit dry, because all the oil dripped out, and needs the primary tightened. I thought I sealed it when I re-installed it last August.. I will spend extra time making sure I do a better job.

mdt-son · Jan 7, 2019

I think the tangs deform due to continuous clutch slip. It is noticed the defomation increases towardrs the chain wheel, which supports this theory. At every sudden increase in torque, the steel plates will start hammering against the chainwheel slots as the clutch grips, releases, grips again asf.
So, how do we eliminate clutch slip? By increasing friction (friction plates, ensuring perfectly plain steel plates; avoid use of certain oils), and/or by increasing spring pressure.

Fitting a mainshaft sealing nut as offered by Dynodave is recommended.

-Knut

Bodger · Jan 7, 2019

Paul W. said:
I removed the primary to time my engine. I noticed extreme wear on the friction plates where the seat against the clutch basket. I will be ordering some new clutches from Barnett. Any idea as to what the cause may be?

She looks a bit dry, because all the oil dripped out, and needs the primary tightened. I thought I sealed it when I re-installed it last August.. I will spend extra time making sure I do a better job.

I would be concerned about the condition of the primary chain. IMHO it's likely to be knackered. There doesn't seem to be any lubricant on it. I do a crude check of the oil or ATF level in the primary by using a piece of stiff electrical wire inserted in the inspection cover - the top central opening used to check the chain tension. You have to fiddle the wire a bit to get it past the bottom run of the primary chain and it's not very exact, but at least it let's you know if there's anything in there. Can also get some idea by opening the inspection cover and running a finger on the chain.

Paul W. · Jan 7, 2019

Bodger said:
I would be concerned about the condition of the primary chain. IMHO it's likely to be knackered. There doesn't seem to be any lubricant on it. I do a crude check of the oil or ATF level in the primary by using a piece of stiff electrical wire inserted in the inspection cover - the top central opening used to check the chain tension. You have to fiddle the wire a bit to get it past the bottom run of the primary chain and it's not very exact, but at least it let's you know if there's anything in there. Can also get some idea by opening the inspection cover and running a finger on the chain.

I’m concerned about the chain, too. I really haven’t put many miles on it since I did all that in late August, it went together with ATF in the primary. I may just install an O-ring chain an forget about the lake lubricant. Also, the plates did not look like that when it went back together. I’ll be pulling the clutch off this week and gathering all the replacement parts for re-assembly.

Bodger · Jan 7, 2019

I kn

Paul W. said:
I’m concerned about the chain, too. I really haven’t put many miles on it since I did all that in late August, it went together with ATF in the primary. I may just install an O-ring chain an forget about the lake lubricant. Also, the plates did not look like that when it went back together. I’ll be pulling the clutch off this week and gathering all the replacement parts for re-assembly.

I know I shouldn't have to say this, but you should not check primary chain lubrication, especially with a finger, while the bike is running. Of course most twins have an automatic safety - they stall if you leave them idling too long. Unfortunately the safety works best at intersections when there's a lot of traffic.

Hortons Norton · Jan 7, 2019

Looks like you do some wheelies once in awhile? Burnouts maybe? But really it looks also like you have been low on oil in the primary, was it leaking?

Paul W. · Jan 7, 2019

Hortons Norton said:
Looks like you do some wheelies once in awhile? Burnouts maybe? But really it looks also like you have been low on oil in the primary, was it leaking?

Ha! I wish! Low fluid, but honestly it looked better before I took it apart and filled it up. And it was bone dry then. PO said he just oiled the chain on occasion.

norton bob · Jan 8, 2019

NO OIL, = bad wear and rust. That looks like a decent chaincase too ,no excuses accepted. I run 2 Nortons with the leaky tin cases ,never seen anything that bad in 50 years . Atf will work while its there, but once its gone it don't leave anything behind. A sexy brit bike is like a sexy date ,lots of attention needed.

N0rt0nelectr@ · Jan 8, 2019

Paul W. said:
I removed the primary to time my engine. I noticed extreme wear on the friction plates where the seat against the clutch basket. I will be ordering some new clutches from Barnett. Any idea as to what the cause may be?

She looks a bit dry, because all the oil dripped out, and needs the primary tightened. I thought I sealed it when I re-installed it last August.. I will spend extra time making sure I do a better job.

Did you make the gasket yourself? I have looked at RGM's site and they list nothing for the Hybreds. I built a pointer out of aluminum that I could bolt to the inner primary, I think it works better than a piece of wire.
John in Texas

Paul W. · Jan 8, 2019

N0rt0nelectr@ said:
Did you make the gasket yourself? I have looked at RGM's site and they list nothing for the Hybreds. I built a pointer out of aluminum that I could bolt to the inner primary, I think it works better than a piece of wire.
John in Texas

No, I purchased from Steadfast Cycles on eBay or his website Steadfast. As for the pointer, being an electrician, I have more than enough solid copper wire on hand.

Paul W. · Jan 8, 2019

I tore apart the clutch today. I found more fun that the PO left behind. The clutch center body looks like it's been filed and/or emery clothed. The center rubbers seem to be RTV and not rubber. I've put lots of motors together with a LoveJoy coupling, and the rubber is hard. These particular pieces are very lightweight and soft. Either way, I'll add a new center and center rubbers to my list of items to purchase.

You can that the wear marks have been filed/emery clothed.

Different angle. Some rubber in the spring hole.

Center cover off exposing the rubber. This looks like it was filled up and covered to let dry.

Close-up of 4-oclock position where the rubber is joined.

texasSlick · Jan 8, 2019

Ugh!!

Slick

Paul W. · Jan 8, 2019

I remember that he told me he rebuilt the oil pump when I was first looking at it. He said something about having to emery cloth it, too. I 'spose I should remove it before I put things back together.

norton bob · Jan 8, 2019

My experience of new clutch centers is that they are not hard enough, I would also check (with a feeler gauge) the clearance between rollers and drum track, if 3 thou or bigger consider fitting oversize rollers.

Triton Thrasher · Jan 9, 2019

Looks like the wear on the splines has caused hammering of the tabs. Bad cush drive rubber has probably aggravated both conditions.

You have badly and dangerously neglected servicing, by letting the chain run dry. The chain can break and throw you off the bike and/or destroy the crankcase.

When oil leaks out, you have to put more oil in. That’s quite basic, isn’t it?

Bodger · Jan 9, 2019

Triton Thrasher said:
Looks like the wear on the splines has caused hammering of the tabs. Bad cush drive rubber has probably aggravated both conditions.

You have badly and dangerously neglected servicing, by letting the chain run dry. The chain can break and throw you off the bike and/or destroy the crankcase.

When oil leaks out, you have to put more oil in. That’s quite basic, isn’t it?

Wonder if those improvised rubbers ever worked? I mean that's a world class piece of bodgery. FWIW, upon further review of the photos of the chsincase, it's hard to believe there ever was any oil or lubricant in there. Maybe the PO who created the clutch rubber system thought the primary chain needed no more [occasional] lubrication than a final drive chain. While it's beyond my pay grade, hasn't this discussion drifted off topic?

Paul W. · Jan 9, 2019

Triton Thrasher said:
Looks like the wear on the splines has caused hammering of the tabs. Bad cush drive rubber has probably aggravated both conditions.

You have badly and dangerously neglected servicing, by letting the chain run dry. The chain can break and throw you off the bike and/or destroy the crankcase.

When oil leaks out, you have to put more oil in. That’s quite basic, isn’t it?

You’d think. I haven’t neglected any servicing. I’ve got less than thirty miles on the bike since I purchased it in May. I’m trying to fix it properly.

Paul W. · Jan 9, 2019

Bodger said:
Wonder if those improvised rubbers ever worked? I mean that's a world class piece of bodgery. FWIW, upon further review of the photos of the chsincase, it's hard to believe there ever was any oil or lubricant in there. Maybe the PO who created the clutch rubber system thought the primary chain needed no more [occasional] lubrication than a final drive chain. While it's beyond my pay grade, hasn't this discussion drifted off topic?

I think we’re still on topic. It seems to be agreed upon by a couple people that the improvised rubbers could very likely have contributed to the were on the plates. Compounded with the lack of oil. Now it’s time to order a plethora of parts and pay special attention to sealing it up properly.

Paul W. · Jan 9, 2019

norton bob said:
My experience of new clutch centers is that they are not hard enough, I would also check (with a feeler gauge) the clearance between rollers and drum track, if 3 thou or bigger consider fitting oversize rollers.

Where would be the best place to get new quality rubbers and a center?

Paul W. · Jan 10, 2019

Dropped a few bills at Walridge today to replace the ailing parts. Sad part is that with back orders it will be 4 weeks before I see them. I also ordered a new oil pump after removing it today and dissecting it. Too much wear to trust it with proper lubrication. A 55 year old machine deserves some proper new parts. I also ordered a new Venhill clutch cable per TexasSlick's advice. Hopefully I'll have a decent riding machine by February.