Explaining a Nomad clutch

[cyclecat]

Very few people seem to know how a Nomad clutch works so I am going to explain it. The following picture is 6 of the 7 clutch springs Brian has changed on his 2001 1500 Nomad. My Ruby, on the other hand, a 2003 1500 Nomad has not needed the spring changed, with over 55,000 miles on her. The 2 gold springs on the left are both Barnett springs and are also worn out and they too will wear out when you have a bad clutch. Brian finally got tired of wasting time and money, after changing his spring 3 times in one summer, so he changed out the clutch for a Gorrilla clutch and has not problems since. He does not, however, have the ‘slipper clutch’ feature that we all have gotten used to and like, so he has to be a bit careful shifting down so he doesn’t lock up the rear wheel.



The following picture is the parts that go into a Nomad clutch. They are a lot of parts but the following list are the ones that we all need to be concerned with.

92015 NUT,20MM
92033 RING-SNAP
13187 PLATE-CLUTCH OPERATING
13091 HOLDER,CLUTCH SPRING
92144A SPRING,CLUTCH
92144 SPRING,LIMITER (3)
13187A PLATE-CLUTCH OPERATING
13089 PLATE-CLUTCH, FIBER (8)
13089A/B PLATE-CLUTCH, METAL (8)

13116 ROD-PUSH,CLUTCH
13116A ROD-PUSH



Here’s how the whole thing works: #92015 is the outer nut that you see when you take off the side cover. This nut will have to be removed with an impact since it is really tight. When putting the nut back on, DO NOT use the impact or you will not be able to remove the nut a second time. Brian found this out the hard way when he had to cut the nut off the second time and it cost us $8 for a new nut (only in Canada does a nut cost $8) and a weeks waiting time to get the new nut. Torque the nut with a torque wrench to the specs in the service manual.

#92033 is the snap ring that holds everything else in place once the nut is removed. #13187 pushes #13091, which pushes against #92144A (the dreaded clutch spring), which pushes against #92144, which pushes against 13187A, which pushes against #13089 and #13089A/B. When I say ‘pushes against’ that is an easy explanation when in actuality it is an exact pressure that is applied by each working part to make the clutch work smoothly.

#13166 and #13116A is the push rod that is on the very inside end of the whole clutch assembly. When you pull in the clutch lever, this push rod is what makes shifting possible. The clutch spring is concave and the when the clutch lever is pulled in, the push rod pushes the clutch plate flatter so the pressure is released off of the plates and allows us to shift up or down. Let go of the clutch lever, and the spring again goes concave and applies pressure on the plates to make us keep moving

What is happening with the spring is that we have metal on metal and the metal parts are constantly turning and wearing against each other. #13091, the damper spring holder, is sitting against the clutch spring and turning on the ‘inner teeth’ of the clutch spring. Even though we have a wet clutch, we still have metal on metal and the ‘teeth’ eventually wear down to the point where there is not enough metal left to apply the right amount of pressure on the plates and the plates begin to slip when we roll on the throttle. If you look closely at the following picture, you can see the shiny ring on the ‘inner teeth’ where the metal has been worn away. The ring is actually only half as thick as it should be so it does not create nearly enough pressure on the plates.



If you suspect you have more wrong than a slipping clutch spring, take the time to take the clutch apart to the plates and measure the plates with a good set of calipers. Get the plate thickness specs from Barnetts since I doubt any stealer will either know or tell you but Barnetts probably will. Brian's plates were actually worn down enough that his whole clutch was bad.

[BudMan]

Thanks for the info. I don't have a good understanding of a Nomad clutch, but I now know more than I did. :)

[MAS Tequila]

http://www.turbotecusa.com/VULCAN.html

The link shows my next spring. They developed this to stay together behin a 140 hp turbo'd 1500, it should do just fine on my lightly modified 1600.

MT

[cyclecat]

If it works like it should, that type of setup, instead of the crappy spring we have, will eliminate changing the springs. That's the type of clutch spring used on Kawi quads and they can take a beating and not wear out.

[ringadingh]

I really like that billet motor mount that they have available as well. That should help the bike from wallowing through corners and feeling like a bowl of Jello.

[billmac]

Some smart members in Kawanow. Thanks for the explanation and great photos Cyclecat.

[blowndodge]

I wonder about converting to a six spring design and what parts are no longer used. What does the pushrod push against to disengage the plates? Just wondering... At $199 seems like a very reasonable conversion.

[cyclecat]

The push rod would first push against part #92143 which in turn pushes against the parts that follow through to the clutch spring. The push rod flattens out the spring so the pressure is released off of the plates.

[blowndodge]

I was talking about the 6 spring design CC..

[cyclecat]

Yeah, I realized that after I posted, major brain fart. You'll forgive me since I did make the comments about your nice ass in another post awhile ago. LOL

Brian says the clutches he's seen with that type of clutch spring work pretty much the same way as ours do. The plate that holds the 6 springs has flex and the push rod pushes it just enough to take the pressure off the plates.

I just tried to upload a picture of the type of clutch with the 6 spring clutch spring and can't get it to work but needless to say, the clutch has a lot less parts to it and is easier to work on.

[AlabamaNomadRider]

Thanks for all the good information and the pictures. That gives a person a lot better perspective of how it works.

[macmac]

6 spring clutches can fail for the same reasons SORT OF, but no cutting on the star spring would be possible since there isn't one.

I agree CC, that under cutting is 95% of the problem, but even heat and long term pressure can effect 6 spring clutches. It takes a lot longer.

My OLD 1981 xs850sh needed new coil springs. Not understanding that I replace the clutch pack as well as all the springs, but it was just all 6 springs out of spec.

Since I got that bike off a scrap yard junk heap in the metals pile, I had no idea on the history, but i did know I over heated the engine 2 times at Laconia, in a parade like traffic jam.

No spring I took out matched the spring height spec. The combined use, crushing and relief, like in a magazine for guns, the heating at over 375 degrees F, and long term pressure caused these springs to fatigue.

But that 6 spring pack will be much better than the star spring.

What kills springs is using them. In a magazine for a gun you can load it and compress that spring to max and that won't bother the spring a bit. It will not take a set.

But use that spring, and it becomes weaker and weaker untill it won't feed ammo to the last casing. This takes a long time, but it happens.

Add heat to 375' F as in oil much hotter than that, and temper is lost, little by little.

I make V springs for flintlocks and go from dead soft to make the shape to glass hard in heat treatment, so hard that a compressed spring would break like glass.

In order to make the part a spring then tempering has to take place and that heat is well over 375, closer to 625' to soften the the steel so it will flex and not break, but not be dead soft and too weak to be a spring. In flintlocks there is 3 V springs.

A slipping clutch will generate a lot of heat, just for the friction of slipping. This can bend and warp the plates, both the fiber and the steel. When that happens the warped plates make a grabby condition, which can show up trying to get moving from stopped.

Feathering in a parade or like instance will indeed raise cluth temps to well over 600 degrees.

Any time a clutch is slipping it raies the temps, and that counts for a dry clutch as well.

I have seen many types of clutches both wet and dry and seen the blueing result from over heated pressure plates many times. Some dry clutches have a similar much bigger star spring, while others have levers and coil springs, but both can turn peacock blue from being in a slipped condition, where there is no oil at all.

Since engine and tranny oil are shared and hot, all wet clutches are heated to temper loss just by the envrioment they are subject too.

If no undercutting occured, still a point in time, which would vary widely, these star springs would still fail just from flexing and heat alone. It's what springs do.

Flexing alone has ruined the ft suspention on my 83 chevy truck suspention and they were replaced. If I had wanted to bad enough, I could have saved them and hammer forged them back to be what they should be, since they were not broken, but the labor would have take me a life time. No heat there, just flexing. (leaf spring type)

Once I did brutal working to build truck spring packs from scratch in a spring shop. I cut raw stock on a gillotine press, that sheared 1/2" x 4" spring steel, then rolled the eyes with a real big torch, and the press made to roll eyes, added more leaves, and clipped the pack to be a set of leaf springs, for big trucks, fire engine, and road graders. Then I installed them.

No Fun at all...... Men made these spring packs and installed them by hand. There were no robots to lift and move a built up spring pack around. Men did it all.

[ponch]

3 springs in a summer is ridiculous. I have to wonder if the user was responsible for the premature wear, either through improper use or improper maintenance. Just wondering.

[ringadingh]

Originally Posted by ponch

3 springs in a summer is ridiculous. I have to wonder if the user was responsible for the premature wear, either through improper use or improper maintenance. Just wondering.

I was wondering something like that myself Bill, or if something wasn't installed properly. It just seems very odd to use three springs that fast.

[MAS Tequila]

The original post states that the steels were worn. Sometimes we assume that our problem is the normal one. In this case he didn't check to see if anything besides the spring was bad. If the basket is out of spec it will cause the spring to wear quite rapidly.

So yes something else was wrong, but most of us would've done it similarly figuring that the first replacement was defective then the second one would have raised suspicions. But I would've put it in and killed it also.

MT