facebook1 youtube1 twitter1 instagram linkedin1 pinterest1

NOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community! REGISTER AND MAKE THIS BOX DISAPPEAR!

×

Pictures Posting Not Working (12 Jun 2023)

Picture uploads is again unavailable. We are working on the problem. Thanks for your patience.

Makotosun

Good clutch plates

  • willlgord
  • willlgord's Avatar Topic Author
  • Offline
  • Junior Member
  • Junior Member
  • Posts: 28
  • Likes received: 31

Replied by willlgord on topic Good clutch plates

Thanks!
12 Dec 2020 18:18 #11

Please Log in or Create an account to join the conversation.

  • Posts: 349
  • Likes received: 313

Replied by JayB on topic Good clutch plates

I don’t know if you solved you problem yet, but here are some possible choices:
1. For an AT1, install Barnett springs 501-25-05043 (from page 114 of www.barnettclutches.com/media/BarnettCatalog.pdf) with your stock clutch plates. Stock friction area is 289cm^2. If this solves your problem then you are done. Otherwise you have some choices.
2. Get 5 of Barnett 301-90-10902 friction plates. I believe these should be 4mm thick plates, but I have no dimensions for this part so I can’t comment on total friction area. If these are tall and get rid of the rubber rings, this is a very good option.
3. Get 5 Yamaha part number 401-16321-00 friction plates. These are 4mm thick and have no room for the rubber cushions. The space where the rubber cushions were would now be replaced with friction material. This will give you 403cm^2 friction area, an improvement of 39 percent. This is basically a 74/75 MX125 clutch pack. The 401-16321-00 are no longer available, and the prices seem high.
4. The following options are not without risk, but I believe would work with any 1969-1975 125 or 175 Yamaha enduro. This particular option gives you a clutch pack similar to a 1976 YZ175 or a 77-83 IT175. Get 6 of Yamaha part number 537-16321-00 3mm thick friction plates and an extra Yamaha 336-16324-00 clutch plate. Assemble with a friction plate first and then alternate adding clutch plates/friction plates with a metal clutch plate last before the pressure plate goes on. The AT1 stock clutch pack is 5 friction plates x 4mm + 5 clutch plates x 1.6mm = 28mm thick. Minimum worn stock clutch pack is 5 friction plates x 3.6mm + 5 clutch plates x 1.6mm = 26mm thick. This option would be 6 friction plates x 3mm + 6 clutch plates x 1.6mm = 27.6mm thick. I bought and checked that the 537-16321-00 fit perfectly in a 1975 DT125 clutch, which uses the same friction plates, clutch plates, inner hub, pressure plate and a similar outer hub as the AT1. This will give you 483cm^2 friction area, an improvement of about 67 percent over stock.
5. Do option 4 but use six Barnett 301-90-10006 instead of the Yamaha 537-16321-00 plates.
6. Copy the clutch plate pack from an XT225, TTR225 or TTR230. Similar to option 4 but has one short plate with a spring to help the clutch disengage.
I haven’t actually done any of this. The math works out, I fit checked the 537-16321-00, and I have parts on order to check 4 and 6. I will report back after I try 4 and 6 on a stock 75 DT175. I don't have the power to slip a stock clutch.
The following user(s) Liked this Post: MarkT, 2fishkev
Last edit: 22 Dec 2020 13:56 by JayB. Reason: Corrected that a friction plate first and a metal clutch plate should go last for early (69-75) 125 and 175 enduros.
22 Dec 2020 07:25 #12

Please Log in or Create an account to join the conversation.

  • Posts: 349
  • Likes received: 313

Replied by JayB on topic Good clutch plates

I have also used CSK42 clutch springs in 74/75 DT100/175 with good luck. They are 34mm long and claim to be 15% stronger than stock. I am not sure of the stock length for AT1 springs.
The following user(s) Liked this Post: MarkT
Last edit: 22 Dec 2020 09:56 by JayB. Reason: Added a sentence.
22 Dec 2020 09:55 #13

This message has an attachment image.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 13392
  • Likes received: 9258

Replied by MarkT on topic Good clutch plates


Great information here!

One thing is the the early pressure plates were not splined to lock to the inner clutch hub so the stack must end with a steel, not a friction.

Later splined pressure plate, stack can end with a friction:



Early smooth pressure plate, stack must end with a steel:






.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
The following user(s) Liked this Post: Dirtboy, JayB
22 Dec 2020 10:16 #14

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 349
  • Likes received: 313

Replied by JayB on topic Good clutch plates


Oh, wow, I see what you mean! And I think some of the parts diagrams could be wrong? The 1975 DT125 clutch I have on the bench shows wear like the steel was the last one on the outside and the friction was the first one on the inside. It could have been taken apart sometime before I got it.


But the parts diagram shows a steel on the inside and a friction on the outside.


Now my head is spinning.
22 Dec 2020 11:28 #15

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 13392
  • Likes received: 9258

Replied by MarkT on topic Good clutch plates

Yours was assembled correctly with steel on last.

Diagrams can't be trusted.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
The following user(s) Liked this Post: JayB
22 Dec 2020 11:43 #16

Please Log in or Create an account to join the conversation.

  • Posts: 13392
  • Likes received: 9258

Replied by MarkT on topic Good clutch plates

FYI, the US 74-76 DT125 is the early AT/CT design. The exploded parts diagrams are wrong for those too I think.

Here's the engineering drawing out of the CT manual. I have marked the friction plates with a blue dot and the steels with a red dot. You can also see the v-shaped rubbers inside the frictions.

Stack starts with friction and ends with steel.






.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
The following user(s) Liked this Post: JayB
22 Dec 2020 12:02 #17

This message has an attachment image.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 349
  • Likes received: 313

Replied by JayB on topic Good clutch plates

MarkT, Thank you for clearing this up. Should I go back and edit my option 4 to correct it, so no one in the future puts the plates on in the wrong order? Including me?
Last edit: 22 Dec 2020 12:51 by JayB. Reason: Added a sentence.
22 Dec 2020 12:50 #18

Please Log in or Create an account to join the conversation.

  • Posts: 349
  • Likes received: 313

Replied by JayB on topic Good clutch plates

I went back and corrected the post with the wrong clutch plate order. Thank you Mark!
22 Dec 2020 14:01 #19

Please Log in or Create an account to join the conversation.

  • Posts: 13392
  • Likes received: 9258

Replied by MarkT on topic Good clutch plates

I think a lot of these clutches have been put together "wrong". I'm not sure it's a disaster or anything if you do... probably better if you don't though.

Come to think of it... I wonder if maybe the correct disk order has something to with slipping sometimes? A lot of people seem to complain of slipping after installing new parts. With the exploded views wrong I'm sure a lot get put together with a steel first and friction last.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
The following user(s) Liked this Post: JayB
22 Dec 2020 15:04 #20

Please Log in or Create an account to join the conversation.

Moderators: yamadminMakotosunDEETVinnieJames Hart