XS650 Clutch Worm Actuator experiment & tidbits

[5twins]

So, the results are??? Well, at first I didn't notice much change. Lever pull seemed about the same as before. Shifting and neutral finding were maybe a little better/easier. But, I did this a couple days ago and it was rather cool out, mid 50s probably. I didn't take much of a test ride, maybe 10 miles or so. The bike didn't get really hot. Yesterday was warmer so I took a longer, maybe 50 mile ride. About half way into it, the clutch pull suddenly got easier, quite noticeably easier. I have no idea why this happened, maybe because everything finally got good and hot. But also, neutral finding at a stop remained easy too, so that's a definite improvement.

Something else I changed while in there was the pushrod. I've been running the long rod from Mike's for several years and about 10K miles. I like it's benefits. I've acquired some original rods now and wanted to try one. I got a used one from an XS1 motor and a N.O.S. one off eBay. I was disappointed with the amount of wear I found on the MikesXS rod. It looks to be at the point of shedding metal bits, especially on the inner end. The used original has only a small dimple .....

The outer worm gear end wasn't worn as bad, but still more than the Yamaha rod. Also, it appears the Yamaha rods are pre-dimpled on the outer end .....

Now, I was hoping the Yamaha rod might be a different steel and expand differently than the Mike's rod, possibly not adding the extra lever freeplay when hot. No such luck I'm afraid. I still get increased lever play when hot, but I think the Yamaha rod is better. Even with that increased play, I can still find neutral pretty easily now when hot.

I will be playing with worm screw adjustments for a while to see if even better results can be had. What I did notice while doing my initial setting was that I can adjust all the freeplay out of the hand lever with the worm adjuster screw. I couldn't do that with the 650 worm. I could get most of the cable freeplay out but had to add some adjusting up at the perch to get it all.

What I may try next is a flattened XS500 worm, with the cable arm sticking straight out the side, not stepped up or down.

 

[TwoManyXS1Bs]

Excellent writeup and pics there, 5twins!

I'm glad you found and confirmed that ring of casting flash around the sidecover's opening for the nylon worm body. For a while, I thought I was the only one with that issue. Nice trick leveling that down with the Roloc disc. From your and gggGary's previous recommendations, I've recently acquired a variety of those, and will soon be destroying things learning the tricks.

Excellent job fitting that 1L9 clutch worm. Looks like you've got it 'clocked' just right.

The fact that you noticed no immediate improvement to the clutch actuation also confirms what DogBunny and I discovered in the test thread:

Clutch worm mod testing

Although this mod to the worm's actuating lever makes sense and sounds good on paper, it doesn't seem to provide any significant benefits on its own merits, especially on a properly serviced and tuned clutch system like yours.

So, it would seem that this mod may only have significance if implemented as part of an overall plan of cleaning, servicing, and doing the ancillary mods, like the selection of a good cable, elbow bend, entry angle into the sidecover, cable routing, clutch lever pivot, ...etc., as mentioned in these other threads:

Clutch pushrod experiment and tidbits
Clutch cable experiment and tidbits

Your reporting of your clutch actuation suddenly 'freeing up' is a welcome surprise, and a mystery. I wonder what happened there?

It also seems that you've confirmed the non-hardening of the aftermarket clutch pushrod ends. You'd think that the dimpling of the ends would reduce any wear there, by distributing the load (about 400 lbs) over a larger area. But, what you've found reveals some pretty soft stuff. My bi-metal rods didn't show wear like that, and I'll be pulling my 1-piece 7075al rod to closely examine the ends.

 

[5twins]

Well, I'm happy with the results. Maybe all the new parts just needed to "settle in". They were pulled from a boneyard bike that was sitting outside for probably years. They were in pretty good shape though thanks to the P.O.'s lack of cleaning under that left cover. Everything was covered with grease build-up, lol. Like I said, I will be fooling with worm adjustment settings to see if it makes any difference.

I spied another XS400 in the boneyard, one I missed previously because it's way off to one side. It looks mostly intact so I'm hoping to score another "1L9" worm off it. It's a little later model, maybe an '80 or '81, judging from the tin top BS34s it sports, so maybe it will have that illusive "12R" long arm version you pictured a couple posts ago.

What I like most so far is the easy-to-find-neutral-when-hot factor. I've been trying to solve that little problem for years. I don't know if it's the different worm or the original pushrod that's doing it but I kinda think it may be a combination of both. Sometimes that's how these nagging problems get solved - not one major change but several little ones add up to resolve the issue.

 

[theDQG]

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[5twins]

So, I've put maybe a hundred miles or so on the "1L9" install and the parts seem to have done some "settling in". Time for a look-see under the cover again and some worm gear re-adjusting. My original adjustment settings had the worm sitting at very slightly less than a 90° angle to the cable. Distance from the cable entrance to the center of clevis was about 3 15/16". When the clutch lever is pulled, the worm arm would sweep through the best leverage point of 90° but most of the arm's movement would be beyond that. With some re-adjusting, I should be able to do better .....

Backing the perch adjuster off fully returned the cable distance to 4 1/8", the fully retracted worm distance as measured during the install with no cable connected .....

Now, to try and keep it that way, lol. I checked the worm screw setting and probably because of the parts settling, it was loose. I re-set it and did pretty much all my freeplay adjusting with it. Up at the perch, I finished with barely a turn out on that adjuster.

For many years, as far back as the Minton Mods, this has been the preferred and recommended method for adjusting the 650 clutch. To quote the Minton Mods - "... you will have put the clutch pushrod actuator in the best position to assure maximum clutch plate separation ...". Translated, what that means for us is that you stand the best chance of getting the worm arm working through that ideal 90° range using this adjusting procedure. When you adjust the freeplay out using the worm screw, you don't alter the cable to worm arm angle at all. When you adjust the freeplay out using the perch adjuster, you do. The perch adjuster shortens the inner cable length in relation to the cable sheath. Basically, it makes the sheath longer. This pulls the cable up down inside the cover and lifts the worm arm, changing it's angle to the cable. Do enough, or too much cable adjusting at the perch and you can move the worm arm through and past that ideal 90° leverage range.

 

[TwoManyXS1Bs]

... When you adjust the freeplay out using the worm screw, you don't alter the cable to worm arm angle at all...

I wonder how many folks have picked up on that?

 

[5twins]

If most of the 650s I work on in my area are any indication, not many, lol. Their clutch adjustment setting consists of pretty much ALL perch adjustment. The adjuster is run out pretty close to the max many times. Chances are, they aren't even aware there is a lower adjustment.

 

[wrenchjohns]

Put the il9 worm on, geometry looks better and clutch pull feels good. Going to ride today.

 

[5twins]

If your XS1 still had it's original short arm worm then you should definitely see an improvement with the "1L9".

 

[peanut]

I have always advocated setting up the clutch lever first to the individuals finger reach , before adjusting the cable tension because of simple physics....mechanical advantage at the clutch lever. I say this in one of my videos that this contravenes Yamahas and other workshop practices recommendation but what the heck.

If you have to over-extend your fingers to get sufficient purchase on the lever then the resultant loss of 'pull ' power would I reasoned negate much of any smoothness obtained in the mechanical components of the entire clutch train /assembly.

My feeling is a lot of owners don't consider the ergonomics of finger-clutch lever operation when setting their clutch up.

Regarding the initial take up position of the clutch worm lever and the travel arc (degrees) of the arm in operation.

It might be interesting to determine the length of travel of the worm arm with the clevis at various lengths along the worm arm and also measure the weight of the clutch pull at the clutch lever at various degrees of the clutch worm arm lever range.

The results might suggest an advantageous starting position of the worm lever arc and also the best fixing point of the applied force (clevis ) around the centre of moment of the arm.....
The magnitude of the moment of a force acting about a point or axis is directly proportional to the distance of the force from the point or axis M = (F)(d) etc etc. Pay attention at the back there
ie

Every advantage gained is usually at the cost of something else and the best solution is often a compromise of trade offs

 

[wrenchjohns]

Il9 worm makes all the issues of the 3 to 4 start worm interchange seem to disolve, thanks

 

[TwoManyXS1Bs]

Thread update.

I did a complete swap-out, upgrade, of my old 256-type 6-plate clutch to the better 447-type 7-plate clutch, with new clutch springs and OEM clutch plates. Numerous little tweaks and mods went into this upgrade, which will be covered in another thread. Ran the Travel and Pull tests on this new clutch, entered below as configuration #D. As expected, the travel and score value dropped, due to the stronger springs, and the fact that I had also replaced my grips with thicker "palmswell" Renegades, reducing the clutch lever pull distance.

# Score Travel Pull - Description
#9: 4.1 0.058" 14.0 - Ultimate XS worm, 1.65" clevis hole distance, mod cable entry angle.
#A: 5.1 0.054" 10.5 - Configuration #9, New/modified Motion Pro cable, settling-in.
#B: 5.5 0.058" 10.5 - Configuration #A, over 2 years later, 7075AL pushrod
#C: 5.8 0.058" 10.0 - Configuration #B, complete clean and servicing

#D: 4.5 0.050" 11.0 - Configuration #C, Complete clutch upgrade, "256" 6-disc to "447" 7-disc, new springs, thicker grips.

The score value went down to 4.5, because of those new clutch springs and thicker handgrips.


For the sake of interest, I attached the worm travel depthgauge to the left cover, and attached another dialgauge to the right side, measuring the pressure plate displacement. This video shows the new clutch actuator travel of 0.050" (1.3mm) and pressure plate displacement of 0.040" (1mm):

Note that the pressure plate doesn't move as much as the worm mechanism (on my clutch), with a loss of about 0.010" (0.25mm).

 

[Jim]

Now, when I mount the nylon worm and tighten down the 2 mount screws, the metal worm fits right in, WITH NO BINDING!!!

Good to know 2M. Thanks for the heads up. I'll let you know what I find as my motor goes back together.

 

[G_YamTech_314]

Thanx, Mharrington! And that is EXACTLY the direction of this thread! The clutch/neutral issue has been ongoing for 40 years, and hopefully we can lick this thing. Other bikes of similar design don't have this problem, so there is hope that the XS's problem can be solved.

I believe that the solution is NOT found in a singular fix, but in a combination. The first area to address is the worm-actuator, followed by the clutch (inner oiling and side load management), then the shiftdrum design (possible binding on the fork guidebar?).

Yamaha has implemented various tweaks over the years, attempting to resolve the 'neutral/clutch' issue. I've seen Honda implemented tweaks as well, which were different but successful.

But, that's for a future thread...

Not sure if anyone has ever mentioned this, but Kawasaki in their later 90's models solved the neutral finding issue in a very unique way. They used ball bearings (in I believe 2nd gear)

The idea is that when you downshift to come to a stop, the speed of the gear box would slow, and when you hit first gear the ball bearings would fall halfway between the shaft and second gear, preventing it from sliding on the splines. This means you can yank up as hard as you want from first gear at idle and not hit 2nd gear. When you rode off into the night from first gear the shaft would spin fast enough to cause centrifugal force to pull the ball bearings away from the shaft, allowing 2nd gear to move freely on the splined slider. I worked on them in school. Getting 2nd gear off the shaft required special techniques because of the three ball bearings needing to he ulled away from the shaft. It was a kind of "push and pull at the same time" kind of shaking motion I used to release the gear from the shaft. And my God... Watch where the bearings go... Better not drop them.

 

[TwoManyXS1Bs]

I guess we're not alone...

 

[G_YamTech_314]

I guess we're not alone...

Just been doing a lot of reading while I'm bored at my 9-5. Just ordered a clutch cable from partzilla... I see now that may not be the best bet. But if I'm gonna have trouble getting into neutral, I wanna know. Not sure I'll be able to get my hands on any of the tech from the Kawi's to show off, but I'll check online. Sorry if I'm digging up old news, just really trying to be thorough in my build and do what's truly best. I admire all of your guy's research and care. True definition of enthusiast/technician/engineer. Although, I feel if you were the engineer for Yamaha back in the 70's they'd be even more beastly... Thanks for all of your contributions. You, and everyone else.

 

[MaxPete]

 

[G_YamTech_314]

 

[TwoManyXS1Bs]

... if I'm gonna have trouble getting into neutral, I wanna know...

You may want to look in here.

http://www.xs650.com/threads/finding-neutral-while-stopped-and-in-gear.47568/

 

[Mailman]

Just been doing a lot of reading while I'm bored at my 9-5. Just ordered a clutch cable from partzilla... I see now that may not be the best bet. But if I'm gonna have trouble getting into neutral, I wanna know. Not sure I'll be able to get my hands on any of the tech from the Kawi's to show off, but I'll check online. Sorry if I'm digging up old news, just really trying to be thorough in my build and do what's truly best. I admire all of your guy's research and care. True definition of enthusiast/technician/engineer. Although, I feel if you were the engineer for Yamaha back in the 70's they'd be even more beastly... Thanks for all of your contributions. You, and everyone else.

I’m glad you opened this up again. I had actually forgotten about it. It is particularly timely for me right about now.
Like Steve, I have a 256 motor that I have swapped in a later model 447 clutch pack along with the newer worm gear and actuating arm. Until I get my bike running I won’t know how well it all works, but as for now, I know that my clutch pull is significantly harder than my ‘77 clutch. So I’ve bookmarked this thread and I will be going through it to see what nuggets I can un earth! 2M writes marvelous technical pieces that always make you think!