305 Clutch Rebuild and History

[rzgkane]

I ordered the springs you used from Honda and they just came in. Out of curiosity, why did you not use the stock springs that still seem to be available from Honda? Are these heavier duty?

I have the new 020 discs in my hand and they look correct, complete with aluminum core. Just need to measure their thickness. I also ordered what the Honda parts fiche said was the first metal plate in the pic (#8 in the online image) that the site, for some reason, calls both an A and a B plate. It seems thick, but without the others in my hand to compare it to I'm just going off memory of what the other plates felt like the other day when I held them. Also, I ordered an "A" plate part # 22321-MT3-000 but the dealer handed me 22321-GHB-811 because they said my number had been superceded. FYI.

I'll post pics later tonight after soccer, baseball and all the other things that occupy my time.

Here are the parts I used in my 65 Dream: Testing still underway! These parts are in no way the only possible solution. It is just what I had and should be a good fit in my Dream project given the numbers generated on paper. As I said, testing still in progress. Please add other options that you find that might work in these engines in the following posts. It would be great to find a modern replacement for the 020 friction plates. They are out there, they just take time to find.

Friction Plate – K&L (17-1598)
Steel Plate – Honda (22321-KA4-700)
Springs – Honda (22401-KTO-000)

[rzgkane]

Update:

Today, I received the parts I ordered from HONDA last week and have what I think is good news for everyone with a CA77 or similar clutch. Pics are below.

First, I ordered the 020 friction discs many thought were no longer being produced and I'm happy to report they seem to be back in production by HONDA. They are aluminum core with what appears to be a cork-based friction material. The thickness new is 3.7mm give or take a tenth of a mm or so. I was hoping they'd be above the 4mm thickness as called for by the spec sheet in the Bill Silver materials but I suspect those specs refer to a 4 friction disc setup? The friction area of the new 020 disc is also larger than that of the discs of the spare motor I have to the tune of 9.5mm v. 13.0mm, measured from innermost edge to outermost edge, as you can see in the pics.

What the Honda parts fiche represented to be the first plate in the setup or "A" plate is indeed thicker than the metal plates in this clutch by a full .5mm, 1.6 to 2.1. Not double the thickness, mind you, but thicker for sure. The part number of this new steel plate is 22321-GHB-811 as a supercession to the 22321-MT3-000 plate I ordered. The plate fits right into the clutch pack, has no relief cut and is perfectly flat with no bevel.


IMG_0715 by rzgkane, on Flickr






IMG_0713 by rzgkane, on Flickr


IMG_0712 by rzgkane, on Flickr

I don't have the tape measure lined up perfectly in the pic below but the contact area of the new disc is maybe a hair short of a full 13.0mm as compared to the 9.5mm of the old disc. Definitely more bite I would have to think.


IMG_0716 by rzgkane, on Flickr


I ordered the HONDA springs NBD used in his clutch replacement instead of the ones the HONDA fiche called for and they are a full 5mm longer than the ones in the spare motor, although some of that may be attributable to the fact that the old springs have been compressed for a long time and the replacements are new.



IMG_0709 by rzgkane, on Flickr

The new "A" plate I got from HONDA. 2.1mm thick, no relief cut and no bevel.


IMG_0708 by rzgkane, on Flickr


IMG_0707 by rzgkane, on Flickr

When I get my bike's clutch apart I will take measurements and pass them along for the group's information.

I ordered the springs you used from Honda and they just came in. Out of curiosity, why did you not use the stock springs that still seem to be available from Honda? Are these heavier duty?

I have the new 020 discs in my hand and they look correct, complete with aluminum core. Just need to measure their thickness. I also ordered what the Honda parts fiche said was the first metal plate in the pic (#8 in the online image) that the site, for some reason, calls both an A and a B plate. It seems thick, but without the others in my hand to compare it to I'm just going off memory of what the other plates felt like the other day when I held them. Also, I ordered an "A" plate part # 22321-MT3-000 but the dealer handed me 22321-GHB-811 because they said my number had been superceded. FYI.

I'll post pics later tonight after soccer, baseball and all the other things that occupy my time.

Here are the parts I used in my 65 Dream: Testing still underway! These parts are in no way the only possible solution. It is just what I had and should be a good fit in my Dream project given the numbers generated on paper. As I said, testing still in progress. Please add other options that you find that might work in these engines in the following posts. It would be great to find a modern replacement for the 020 friction plates. They are out there, they just take time to find.

Friction Plate – K&L (17-1598)
Steel Plate – Honda (22321-KA4-700)
Springs – Honda (22401-KTO-000)

[rzgkane]

What I found inside when I finally took apart my bike's clutch was a 4 friction disc clutch with each disc being the plastic-type core and measuring over 5mm thickness per disc. No retaining wires were present. The thicker metal plate was 2.1mm, just like the new one I just got from HONDA, but it was installed as the second plate working from the interior outward, with a regular 1.6mm metal plate as the "A" plate. Pics are below.

I measured the height of all the discs and plates stacked up together and it came to about 26mm. The new 5 disc setup I'm installing using the again-available 020 discs measured 28mm in height. What will be the functional affect of a thicker clutch pack? Who knows.

An observation and a question; First, if I stacked two "B" plates together and tried to use them as an "A" plate, they would be too thick to reinstall the retaining wire. There simply is not room from what I can see. I will use the 2.1mm plate as an "A" plate.

The question I have is, since I am using thinner friction discs (3.7 compared to the 5mm discs that were in there) but more of them (5 v 4) should I use a second 2.1mm plate in the slot between the two retaining wires currently occupied by a 1.6mm metal plate and a 5mm friction disc? If I dont, the disc and metal plate between the retaining wires will measure 5.3mm total instead of the 6.6mm of stuff currently in there. What about the thought of keeping an old (looks almost new) 5mm plate in between the wires just to maintain the thickness of the parts there? If I don't have enough material between the wires is there a chance the wire will be broken by an adjacent disc invading its space?

Old clutch basket Ed Moore says to replace with the cush drive I have in my parts motor.


IMG_0729 by rzgkane, on Flickr

The discs as they were situated in the motor. As you can see, the "A" plate is second and a standard 1.6mm plate with relief cuts is acting as the "A" plate.


IMG_0725 by rzgkane, on Flickr

The clutch I removed from the bike. Very clean, as you can see.


IMG_0726 by rzgkane, on Flickr

[NBD925]

Wow this is great info rzgkane! Thanks for the post. The new 020 disks look great and appear to be the correct measurements.

Here is what I got for the measurements on the stock used 020 plate from ED Moore:
3.683mm Thick 13mm wide They seem to be the same. Thats Great!

Here are my A plate measurements:
.21mm Thick

The taller springs should give more clamping force on the plates and give about the same or a little less lever pull force on the clutch lever. I couldn’t tell if they were tapered springs but man the pull at the lever is easy. Something is better about them. The springs I have installed are working great. Like I said, Easy lever pull force and they seem to lock up nicely.

rzgkane: Put the 2.1mm thick A plate in first bevel side toward the inside facing the engine. Then alternate Fiber and Metal until your left with a fiber on top. Leave out the wires because your old 4 plate setup that now has 5 plates in it will tear up the wires. Make sure to soak the fiber plates in oil (a large baggy works) for a few hours before you install them in the basket.

Throw the new springs in the setup and you should have a great clutch. More friction area, heavier clamping force, and an easier lever pull. As good as you can get on these bikes at the moment.

Make sure to share your findings with everyone here on how it works and what your experiences are. Also let us know about the lever pull? I don't think it was just in my mind. It would be great for someone else to make the same conclusion.

[rzgkane]

rzgkane: Put the 2.1mm thick A plate in first bevel side toward the inside facing the engine. Then alternate Fiber and Metal until your left with a fiber on top. Leave out the wires because your old 4 plate setup that now has 5 plates in it will tear up the wires. Make sure to soak the fiber plates in oil (a large baggy works) for a few hours before you install them in the basket.

First, I don't see what I would call a bevel on any of the "A" plates. Is this bevel of which you speak simply a rounding of the edges of the disc or an unmistakeable bow in the plate?

Second, remember, I am not using the clutch parts (basket, pressure plate and center) from the 4 friction disc setup that's currently on my bike. I'm changing it over and using the Cush setup from the garage motor that had 5 friction discs in it and the retaining wires intact.

As a point of note, as far as I can tell the depth of the areas on the clutch centers in which the "A" plate and the next-in-line friction and steel plate reside (these are the two areas cordoned off by the retaining wires) is the same when comparing the current center to the Cush center. For discussion purposes I'll call them Slot A and Slot B respectively, with the remaining plates and discs occupying Slot C. That's why I'm wondering if having the thinner 020 disc (3.7 of the 020 disc v. 5.0mm of the plastic friction disc) and metal plate occupying Slot B would be an issue that might be made better by replacing the thinner metal plate in Slot B (1.6mm) with an additional "A" plate that measures 2.1mm? In effect, the combined thickness of the parts in Slot B could be made to be 5.8mm (3.7mm + 2.1mm) instead of 5.3mm (3.7 + 1.6).

The real question is if Slot B has less thick parts in it, would that allow the first friction disc of Slot C to invade the area of Slot B such that the wire would be broken?

[brewsky]

The taller springs should give more clamping force on the plates and give about the same or a little less lever pull force on the clutch lever. I couldn’t tell if they were tapered springs but man the pull at the lever is easy. Something is better about them. The springs I have installed are working great. Like I said, Easy lever pull force and they seem to lock up nicely.

Taller springs do not necessarily mean more clamping force, see this thread for example:
http://www.honda305.com/forums/clutch-s ... ht=springs
If you test them at the installed length you can tell the difference.

[NBD925]

Brewsky the springs were tested and do indeed give more clamping force compared to the original springs.