XS1 Clutch Recommendations

[patentgeek]

Clutch questions directed to the resurrection of a crusty 1970 XS1/XS650. . . .

The (6) fiber clutch plates measure 3.5mm thick and the (5) metal plates measure 1.56mm thick, which seems to be in spec.

On the downside, the left engine cover has a long crack at the rear on the top side and the clutch cable hole has a big chip . Additionally, the clutch actuation mechanism is very rusty, and the plastic worm gear is cracked. So some new parts are in order.

Will a later left engine cover and actuation mechanism fit? And if so, which years would provide the best clutch actuation?

I'll be fitting a TX500 rear hub to my bike, which features a rubber cush drive. Would there be additional benefit to using a 1980 or later inner clutch hub that features a dampener?

The clutch spring retainer Phillips heads are showing some wear and tear. Is there an upgrade to a socket head type setup?

Any other recommendations? For example, newer design clutch plates, springs, etc.

This will mostly be my girlfriend's bike with a very mellow engine build, so ease of clutch pull and actuation are the most important factors.

 

[Jim]

Check out the Tech section. There's tons of info there on clutches...

 

[gggGary]

Some of the LH cover mount holes changed in 72, the good news is that the newer covers still have the bosses where the bolts used to go, so drilling and fitting a new style cover to an old bike is a bit involved but not impossible. I'd be cleaning real well under that cover and inspecting around the shift drum boss in the upper case for cracks.

 

[5twins]

Besides a screw location change, a dowel location was changed too. This pic of the 2 different gaskets used illustrates that quite well .....

So, for a perfectly fitting swap, you would need to find an XS1 or 1B cover. Something else to keep in mind is that the very early XS1's used a different worm gear than any of the later models. The mounting hole spacing was different. These old worms are nearly impossible to find and were flawed anyway. Best option would be the later early cover that uses the later style worm gear. Then you could use a worm assembly from any of the later models as well as a few others like the XS500 and 400. Any of these later worms (except the XS500 one) would give an easier lever pull because the arms are longer. Here's a very in depth write-up on the worms by 2M. He did extensive mods to them to try and improve their function. It's quite long but if you go through just the first couple and last couple of pages, you'll glean most of the important info .....

http://www.xs650.com/threads/xs650-clutch-worm-actuator-experiment-tidbits.31554/

Some of that being that the 1L9 worm assembly from an XS400 is a viable swap that is already made with many of the mods 2M implemented. The arm is pretty much the ideal length and it already steps down (originals step up). The stepped down arm should rotate the worm more efficiently without binding. These are readily available on eBay, maybe even more so than 650 ones, and reasonably priced. In fact, I just scored one a few weeks back for $12.

To use the 1L9 worm, you have to mod it's female part slightly, but it's easy and simple, and outlined in the thread linked to above.

 

[5twins]

Yes, I think a 1980 or later inner hub with the dampener plate would be beneficial. Anything you can do to reduce the strain on the cush springs mounted in the back of the outer hub is a good thing, and this is one of the things you can do. You're already doing the other, a different rear wheel with a rubber cush drive sprocket mount.

MikesXS sells an Allen bolt and spacer clutch spring screw kit but it costs about $35. You can do the same by modding your original screws for $5 or $6. Turn the screws into spacers by cutting the threaded portions off and drilling 1/4" holes through them, then add 40mm long Allen bolts. You will also want to grind the domed screw tops flat .....

Pretty much all of these bikes can benefit from new clutch springs. The originals are pretty wimped out by now. You can still buy new originals from Yamaha but they're pretty expensive, nearly $5 each (and you need 6). Slightly stiffer aftermarket replacements are readily available at half or less than half of that.

https://www.amazon.com/EBC-Brakes-C...3227&sr=1-1&keywords=ebc+xs650+clutch+springs

 

[patentgeek]

Thanks for the input. I found this helpful thread on left side cover differences:
http://www.xs650.com/threads/left-hand-engine-covers.32250/
http://www.xs650.com/threads/left-hand-engine-covers.32250/

The XS1 and XS1B left side cover is 256-15411-09-00 and the XS2 left side cover is 306-15411-04-00.

Here you say, "For a perfectly fitting swap, you would need to find an XS1 or 1B cover. Something else to keep in mind is that the very early XS1's used a different worm gear than any of the later models. The mounting hole spacing was different. These old worms are nearly impossible to find and were flawed anyway. Best option would be the later early cover that uses the later style worm gear." By "the later early cover" do you mean the XS1/XS1B cover or the XS2 cover? Drilling a hole through an XS2 cover boss to match the XS1/XS1B bolt pattern wouldn't be a big deal, and lack of a locating dowel pin shouldn't cause any problems.

 

[TwoManyXS1Bs]

You can view the clutches as being 3 different designs.

70-73, The '256' clutch. 6 friction plates, thicker, with thicker steel discs.
74-79, The '447' clutch. 7 friction plates, thinner, with thinner steel discs.
80-on, The '1T3' clutch. 6 friction plates, has the additional spring disc.

I consider the '447' clutch as better than the '256' clutch for several reasons.
- More plates, that have better availability, used on other bikes.
- The '256' pressure plate delivers its torque thru the spring posts.
- The '447' pressure plate delivers its torque thru the indexed hub splines.
- The '256' clutch relies on external oiling.
- The '447' clutch has internal oiling holes in the pressure plate and hub/boss.
- Complete '447' clutches are abundant on eBay.

The '1T3' clutch includes all the '447' improvements.

Pay close attention to friction and steel disc thicknesses, careful of intermixing.
Try a forum search on "stackup thickness"...

 

[TwoManyXS1Bs]

Couple threads on the early left case cover.

http://www.xs650.com/threads/i-have-a-question-about-lh-engine-cover-early-late.35500/

http://www.xs650.com/threads/left-hand-engine-cover-for-1971-xs1b.41672/

Also, there's an early 70 left cover on eBay, right now.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/232660274314

This one has the early clutch worm, with the wider mount screws. Member wrenchjohns converted his early to use the later worm parts...

http://www.xs650.com/threads/3-screw-worm.41914/

 

[5twins]

I have the parts drawing you got your numbers from but I also have another that lists 2 for the XS1 and 1B. It has a 256-15411-00 part number for the very early XS1 cover up to engine #1124, then a 256-15411-01 for later XS1's and 1B(F)'s. What you'll want is one with the worm mount hole spacing that matches the later worms so you can use them. I don't know offhand what that hole spacing measures but could check it if no one else chimes in with it.

 

[TwoManyXS1Bs]

This thread has the worm hole spacing dims.
Early XS1 worm = 55mm, all afterward = 40mm.

Posts #10 and #11.
http://www.xs650.com/threads/71-xs1-clutch-worm-gear-help.37385/

 

[Marlin72xs]

Clutch questions directed to the resurrection of a crusty 1970 XS1/XS650. . . .

The (6) fiber clutch plates measure 3.5mm thick and the (5) metal plates measure 1.56mm thick, which seems to be in spec.

On the downside, the left engine cover has a long crack at the rear on the top side and the clutch cable hole has a big chip . Additionally, the clutch actuation mechanism is very rusty, and the plastic worm gear is cracked. So some new parts are in order.

Will a later left engine cover and actuation mechanism fit? And if so, which years would provide the best clutch actuation?

I'll be fitting a TX500 rear hub to my bike, which features a rubber cush drive. Would there be additional benefit to using a 1980 or later inner clutch hub that features a dampener?

The clutch spring retainer Phillips heads are showing some wear and tear. Is there an upgrade to a socket head type setup?

Any other recommendations? For example, newer design clutch plates, springs, etc.

This will mostly be my girlfriend's bike with a very mellow engine build, so ease of clutch pull and actuation are the most important factors.

Hey Pat,
Some guys may stone me for this, but I bought Mikes clutch plates and discs, basically the 447 clutch stuff, and Mikes springs. My clutch has never been better. It works great. Smooth as butter. I'm using my original 72 clutch hub. Throw away the old plates or save them in your old parts museum. About the phillips spring holders, get a good manual impact driver and some strong bits. If you have never used one, read the instructions. I find that my cordless impact driver on tough phillips head bolts can sometimes really bugger them up.
Good luck!

 

[Marlin72xs]

This thread has the worm hole spacing dims.
Early XS1 worm = 55mm, all afterward = 40mm.

Posts #10 and #11.
http://www.xs650.com/threads/71-xs1-clutch-worm-gear-help.37385/

Hi 2M. I can't believe that someone thinks that your novels are too lengthy.

 

[joebgd]

The '256' pressure plate delivers its torque thru the spring posts.
- The '447' pressure plate delivers its torque thru the indexed hub splines.

Can you explain this a little bit. I am going to look at other threads and see if I can figure it out. That sounds like the clutch works very different.

 

[5twins]

They really don't work any differently, it has to do with how the parts lock together. The early "256" pressure plate is attached to the inner hub with only the 6 screws. The later "447" design has teeth that lock into the inner hub as well. Much better, stronger way to lock the 2 parts together .....