The Hodaka Club Forum

I took clutch apart because I had way too much free play at clutch arm. There were 3 .5 shims, which seemed excessive,? not sure.
It has 4 fibers and 3 steels. Fiber plates measure average 2.36-2.40, which is more than new.
Book says 2mm new. I didn’t think clutch surfaces was that bad. (Not perfect) Cage wasn’t grooved up.
Outer spring measures 16.78ish, which is not too good. New is 20mm.
Inner springs are 16.95.
So after all that my question is...what is the recommendation to get clutch up to par?
And what’s an average shim stack...better yet what’s too many shims?
Thanks, Brian

New (thick) friction disks "move" the clutch "in" (toward the engine) so more adjuster shims are needed. As the friction disks wear, the clutch will "move" "out" (away from the engine), clutch lever freeplay will be reduced and you'll have to remove adjuster shims. I didn't read anything negative in your post about actual problems with clutch operation . . . so I'm thinking everything is OK.
Ed

So I have add even more shims to get the desired 3/32” free play??

Just for reference, my recently acquired and nearly brand spanking new 01 Dirt Squirt has about a 3 mm shim stack for proper free play on the clutch actuating arm. Intuition suggests as the plates wear, shims must be added to make up for the diminishing disk thickness. Wrong! Keep in mind the fixed vs moveable part of the clutch pack and it becomes apparent that as the disks wear down, the clutch pack moves outboard thus taking up free play. Removal of shims becomes necessary to restore correct free play. There are a few ways to adjust the free play. Cable adjustment, shimming, and rebuilding the clutch pack, specifically. In the case you are describing, my suspicion is that you will need to add shims to the stack. Clutch slippage is the predictable outcome with inadequate free play as the clutch is always in a partial state of disengagement. Your clutch springs are beyond their service limits so inadequate compression of the plates together as the clutch is engaged would likely further exacerbate slippage. Replacement of all springs - good. Also, you might want to inspect the steels. They are a stamped part so one side of the teeth will feel smooth while the other side will feel sharp. Its a good idea to give the sharp edges a light deburring. There are numerous threads on the forum which discuss clutch maintenance and blueprinting. There are also many really smart people on this forum (myself NOT included) that will take you step be step on the road to the perfect clutch.

Matt, I was fully on-board with your post until I got to this part:

"Clutch slippage is the predictable outcome with inadequate free play as the clutch is always in a partial state of disengagement. Your clutch springs are beyond their service limits so inadequate compression of the plates together as the clutch is engaged would likely further exacerbate slippage."

While the two sentences are perfectly correct - they are in the middle of a discussion about a machine which is exhibiting too much clutch lever freeplay.

With too much freeplay, the likely problem is never achieving full clutch disengagement. If you use up a bunch of the hand lever travel just taking up freeplay - there isn't much movement left to actually disengage the clutch.

I did forget to comment earlier that the short springs could be an issue . . . buuuuut, I still haven't heard anything negative about how the clutch is actually working on the bike. I've only heard about a desire to get the clutch lever freeplay dialed in. (and I'm still thinking everything is going to work OK when the freeplay is brought into line)

NOTE: Some VERY fast guys I know adjust for 1/4" to 3/8" freeplay - cuz they don't want to be out on the track fanning and slipping the clutch like crazy and find that enough has worn off the friction disks that it starts slipping ALL the time. This gives a bit of "frame of reference" to the factory freeplay specification - which tends to assure maximum clutch disengagement for safety and comfort of regular riders . . . and sort of assumes that a bit of slippage developing with wear can be tuned out when needed.

Ed

Sorry Captain and Michigan. I derailed myself while taking a poke at the last part of Michigan's post looking to optimize clutch function. The index problem is too much free play. Let me try this again: Too much free play? Add shims. Too little? remove shims. Dial function with cable adjustment. Aah...all better. The springs have me a bit worried though. The goal is best clutch function. Steadily worsening slippage as the plates wear will likely occur if the springs are weak. Now I shall repair to my naughty chair for some thumb sucking (Left hand)and a little Dremel-ing (right hand) .

PS- The title of the original post is "Clutch Confusion" . Clearly, that's a topic right up my alley. Unfortunately, I misinterpreted that to mean "please add to my clutch confusion". Hmm...

I don't think there is need for a "naughty chair" (you crack me up). Between us all, this has been a sort of "92B Clutch 101" discussion - and that is a good thing.
Ed

Agreed, Captain. I'm a firm believer in the old saw "one can never have too much clutch discussion". That was one of my grand mother's favorites.

Yore grandma must have ben a speshul lady!
Ed

mm hmm

Clutch was acting like it wasn’t engaging all the way, which makes sense with the amount of free play I have.
After seeing there were already 3 shims, at .5 each in there, I expected the clutch discs to be totally wore out. I assumed PO was milking the clutch out. So I was surprised and a little confused to see how good it was in there.
I will order new inner and outer springs, clean everything up good, and shim it to where I need it and see how that works.
Does that sound like a solid plan??

Perfect! You might want to look at the clutch blueprinting method while you have it off the bike. I've blueprinted all my clutches and it really takes a good clutch system to an awesome clutch system.

MichiganBrian, your plan is solid. Now that you have reported a symptom - feels like the clutch is not fully engaging - you can go after a solution. The shorter than specification springs are very good suspects for causing that symptom.

However, you've got the clutch lever freeplay issue reversed. (clutch lever at the engine)

- If you have TOO MUCH freeplay (what you reported) - the clutch would tend to drag (not fully dis-engage) when the handlebar lever is pulled in.

- If you have NO freeplay (not the issue you reported) - the clutch would tend to slip (not fully engage).

As Matt mentioned, if you are a member of the Hodaka Club, you have access to the full library of techinical articles in the "Resonator Revisited" (the club newsletter). Clutches are pretty well covered.

Ed

Thanks for info, I am a club member so I’ll take a look at blueprinting clutch.

I decided not to do a full restoration on this bike. I’m polishing what’s there, try to make it look as good as it can. But I want a mechanically sound bike, what ever it takes to make it right.

The clutch blueprint is in Volume 1 issue 4! Victor

Good call. All my bikes are that way. No trailer queens in the lot. Like you, I work toward ideal mechanical function. Depending on the overall shape of the bike, you may need to strip and repaint the frame and swinging arm to assess the health of the metal and welds.

Metal health is important, especially if you're far enough gone to ride Hodakas.

Just to throw the proverbial wrench into this discussion, here are some specifications from the Official Hodaka Workshop Manual that don’t add up.

On the Ace 100 (Model 92) it lists new clutch plate thickness as 2.54 mm, outer springs as 17.27 mm and inner springs as 17.65 mm.
On the Super Rat (Model 93) it lists new clutch plate thickness as 2.00 mm, outer springs as 20 mm and inner springs as 17 mm.
On the Wombat (Model 94) it lists new clutch plate thickness as 2.5 mm, outer springs as 16.9 mm and inner springs as 17.4 mm.
On the Combat Wombat (Model 95) it lists new clutch plate thickness as 2.5 mm, outer springs as 16.9 mm and inner springs as 17.4 mm. (Same as the Wombat)

All of the above parts referenced should be the same specs as they are all the same part numbers – (clutch plates – 934006, outer springs – 934011, inner springs – 934017).

It also lists wear limits on clutch plates. In one section it lists wear limits of 2.2 mm and then in other sections it lists wear limits of 1.7 mm.

So, the question is – what are the official wear limits on clutch plates part# 934006?

What are the actual spring sizes for the outer springs part# 934011 (20mm or 17.27mm or 16.9mm) and inner springs part#934017 (17mm or 17.65mm or 17.4mm)?

Let the discussions begin!

Troublemaker. Maybe after this we can discuss gear and/or premix oil,

. . . and you forgot something. There are two different thicknessess of steel clutch plates.

Ed

After replacing all the plates, friction discs and inner and outer springs I found that the kick starter would not turn the engine over. The replacement outer springs measured approximately .670 inches. My manual says they should be .790 inches. What is the correct dimension of those springs and would "short" springs cause a kick start that fails fully engage?

56lowrider wrote: ↑Thu Jul 09, 2020 11:41 am After replacing all the plates, friction discs and inner and outer springs I found that the kick starter would not turn the engine over. The replacement outer springs measured approximately .670 inches. My manual says they should be .790 inches. What is the correct dimension of those springs and would "short" springs cause a kick start that fails fully engage?

.670 would be the correct length. Some manuals and some spec sheets list them as .790 while others list .670 for the same spring part number.

I don't think the springs are contributing to your kick starter issue...

99.99% of the time this means your kick roller retainer is sacked out. There are bulletproof replacements available at a pretty good price.

If you put i a longer clutch screw the engine cannot turn over with the clutch cover on. Sounds like you are saying the engine is like locked up or is the kick start slipping. -------- Clarence

The kick start is slipping. It does not engage to turn it over at all. Thanks for all your info, this is a great spot to turn to.