XS650 Clutch Pushrod experiment & tidbits

[bighairyralph]

I'd thought of doing this but I don't ride my XS enough for the Mikes one piece pushrod to drive me nuts. I appreciate you posting all the information - although I find it hard to imagine a better alloy than 7075 If you decide to make these, consider me standing in line.

 

[OakBehringer]

Hey, Ralph. So far, I guess 'No news is good news'. During the hotter 102° days, I was able to (easily) overheat my engine in stop-and-go traffic, and experienced some clutch slackness. Again, it quickly and mysteriously disappeared as soon as I was able to get up to around 15-20 mph.

I'm just finishing some mods to my lathe, including a precision collet chuck, so I can make some more pushrods. I found another alloy with better expansion and wear properties than 7075AL, just having problems sourcing sample stock.

Later this year, I plan to pull the left cover, and examine the experimental bi-metal rod, adjuster screw and cable sheath to see what's happening in there. It's hard to justify more experiments since it's working so easily now. I think I'm getting spoilt...

I haven't been riding nearly as much as I'd like, but living in the middle of the desert where it's over 100 deg every day I do ride, the bi-metal pushrod is working great!

 

[56nomad]

I'm just finishing some mods to my lathe, including a precision collet chuck, so I can make some more pushrods. I found another alloy with better expansion and wear properties than 7075AL, just having problems sourcing sample stock.

Hi TwoMany,

Well that was a monumental read which has served to consolidate my own thoughts on the OEM 2 piece and ball rod assembly.

Now, your quote. When you say 'another alloy with better expansion properties' you're meaning an alloy that will expand more than the alloy you're currently using, right? If so, then based on yours and others findings of your bi-metal rod, I'm with you there.

You must be so close, TwoMany, so close.

 

[TwoManyXS1Bs]

Hey, 56nomad. Glad you enjoyed this, thanx for the support.

The mystery alloy is ZAMAK.

http://www.dynacast.com/zamak-3

The alloy-3 has an expansion rate greater than aluminum, at 15.2 microinch per inch per degree fahrenheit. Also has high strength properties, and has been used successfully in many machine/stress environments, like many parts of my antique Atlas lathe. Unfortunately, it's mostly available as a casting alloy. I haven't found any in 5/16" (8mm) rod of at least 10"...

 

[56nomad]

Hi TwoMany,

I had a search for 8mm round bar/rod in Zamak 5 which is more common over this side of the pond and came up with a big fat zero. I also tried Zamak 3, ZP3, ZL3, ZP5 and ZL5 but had no luck. I'm informed that ZP and ZL are Euro and UK equivalents. Would these equivalents be of use to your stockist?

Have you had any progress reports from the guys running your bi-metal push rod?

 

[TwoManyXS1Bs]

...I had a search for 8mm round bar/rod in Zamak 5 which is more common over this side of the pond and came up with a big fat zero...

Hey, 56nomad! Yeah, same here. So, our score is tied.

I also tried Zamak 3, ZP3, ZL3, ZP5 and ZL5 but had no luck. I'm informed that ZP and ZL are Euro and UK equivalents. Would these equivalents be of use to your stockist?

Some of those have features that don't make them sufficiently competitive to AL7075.
The main material properties I'm focused on are:
Coefficient of Thermal Expansion - We're trying for better than aluminum's 13.1 uInch/Inch/°F
Young's Modulus (of elasticity) - Highest possible value, better than 15M (brass), reduces compression losses.
And, of course, economically available.

The biggest problem I'm running into with the current crop of 5/16" rods is straightness. I roll them on a reference surface and get at least 0.020" (0.5mm) of wobbling. Takes me forever to get them down to less than 0.002" (0.05mm). I need to make a rod straightening station, similar to the contrivance used for straightening arrow shafts.

Have you had any progress reports from the guys running your bi-metal push rod?

No. I guess it's still in the category of "No news is good news".

Generally, things that irritate us percolate to the top of our attention list. Otherwise, they're ignored, and taken for granted. I've gotten to the point where the clutch action is no longer on my radar. Kinda like after mounting new tires, becoming accustomed to them, then other things get your attention, like... top end clatter..., ....and soccer mom drivers...

 

[5twins]

TwoMany, have you compared (or can you even) the expansion properties and functionality of a Mike's "generic" long rod to an original? I see originals on eBay (in fact I bought one) for pretty much the same price, sometimes less, than Mike's replacement. I'm inclined to think an original is better, even if the expansion properties don't differ. Machining and manufacture is probably more precise.

 

[TwoManyXS1Bs]

TwoMany, have you compared (or can you even) the expansion properties and functionality of a Mike's "generic" long rod to an original? I see originals on eBay (in fact I bought one) for pretty much the same price, sometimes less, than Mike's replacement.

Hey, 5twins! Yes, there's an expansion comparison pic in post #52, showing the MikesXS rod with a stock rod and the other candidates.
But, it's based on theoretical material properties, not on laboratory quality testing.

... I'm inclined to think an original is better, even if the expansion properties don't differ. Machining and manufacture is probably more precise.

I had the same suspicions, and touch on the differences in posts #2, #23, #105.
(Gads, this thread has gotten long!)

My original XS1B rod has an interestingly polished/hardened zone at the last 1/2" of the rod, at the end closest to the clutch. There's a section of the mainshaft bore at that end that seems to be finish-reamed to support that end, where it rides the ball bearing against the mushroom pushrod.

There's also an oil hole in the mainshaft at that zone. I've found a very tiny score line in my factory rod (about 1/4" from the end) that aligns with that oil hole, perhaps caused by a burr on the hole edge, or crud in the oil.

The 2-piece rod that DogBunny sent me has the same score line, but in the aluminum part, near the steel 'button end'.

Top to bottom: XS1B pushrod, stainless rod, 2-piece rod



I don't know if later 1-piece factory pushrods have that hardened/polished end.

Probably not important, but the next time you have your pushrod out, might want to inspect that last 1/2" for wear/score lines...

 

[TwoManyXS1Bs]

Received an interesting 'status update' from DogBunny on his version-1 bimetal pushrod.

From DogBunny:

It's been approx. 14 months since I put push rod # 2M002 on my bike.* It gets ridden daily, but usually for very short trips to the post office or store.* It gets 20 miles on it in a day fairly commonly.* Over 30 miles a day is pretty rare.* 60 to 100 miles in a day maybe 6 times a year.* Riding it to Luchenbach from Austin once a year.
*
I'd really like for you to see the rod in person, it's sort of interesting.* The dimples on the ends, the "coupling"and rod straightness are all like new.* However, the steel part of the rod has corrosion – isn't it made from SS?* Doesn't make sense to me – the "air"side of the rod is covered with chain lube, and the engine side is covered with oil.* Maybe the flung-off chain oil on the rod is adulterated with water?* Maybe the (stainless ?) steel used is susceptible to corrosion?* To make sure I'm not crazy, I compared it to rod # 2M005 which is still un-used.* The steel part on it looks nice and shiny in comparison.
*
Should mention that bike is kept outdoors, covered, but very susceptible to condensation.* I try to avoid wet roads, but I get caught in the rain occasionally.
*
For reference, I have circled the same pit on the rod in each picture.* This is the worst mark on the rod, very easily detected with a fingernail.* The arrow is where the rod contacts the oil seal.* The seal mark has to be the "rest"position.* I find this mark curious – does the rod rotate while at rest?



*************
Reply:

Hey, William. Thanx for the pushrod pics. Been studying them up close, and re-researching 304 stainless properties.

I ordered the rods from an eBay metals supplier back then, and they had some surface blemishes (and slight bending) when received. I figured that was from supplier storage and neglect, and the usual eBay product 'dumping' on the gullible (me) public.

I straightened the rods, and polished-out the blemishes best I could. But, your pics show that those blemishes may have been more than skin deep, and are again revealing themselves.

This is a good catch. 304 stainless isn't supposed to blemish like that, as in your pics. The only cautions I could find for 304 stainless is to avoid strong sulphuric and hydrochloric acics. If those existed on that sidecover area, there would be much more serious problems down there.

I probably should find a different supplier, as in non-eBay.

I don't see the blemishes as detrimental to the structural integrity of the pushrod, but I do have a concern if they accelerate the seal wear.

The pushrod rides inside the mainshaft, and will spin with the mainshaft if sufficient contact and friction is made, especially in compression against the ball and mushroom rod, like when the clutch lever is pulled. With clutch lever released, the rod may or may not spin with the mainshaft. Depends on how much inner drag/contact is made with the mainshaft bore, versus the holding friction of the seal.

The only time that the mainshaft isn't spinning is when you're stopped, in gear, with the clutch pulled.

I'll take your pics and update the 'pushrod' thread. And try to figure out how to avoid this quality-control issue, without spending $100 for precision ground laboratory grade shafting...

 

[Marlin72xs]

FYI, that's redundant, anyway, someone once mentioned the roughness of the mikes clutch shaft. Well I bought one and it's rough. I put it on a drill press and polished the area where it contacts the seal, with 400, then 800 paper. Otherwise, the seal would have gone south very quickly.

 

[TwoManyXS1Bs]

Hey, Keith! Check the ends of that new rod. Mine were rough and out-of-square. Dimpling ensured that the ends would remain centered...

 

[Marlin72xs]

Well, they were slightly con caved, but rough. I have an unlimited supply of ball bearings, so I thought I would just check the ends and the balls occasionally.

I'm also lazy, well, I still work somewhat full time, but of the 2 lathes that my father owned, my brother got the one that was set up. Mine is still not usable, yet. Had a milling machine in Jersey, my brother sold it. It was from the 40's and heavy as a tank.

Yes, the ends could have been machined better.

 

[TwoManyXS1Bs]

Status update.
About a year and few months ago, I swapped-out my bimetal pushrod for a 1-piece 7075AL pushrod. The bimetal rod worked fine, and showed no wear. But, now it's time to examine this 7075AL pushrod, and see if there's any significant wear at the seal/bushing area, and if the ends are handling the pressure from the ball bearings. So, here's a couple of pics of the 7075AL pushrod.



First pic is of the worm/actuator end. The seal/bushing wear area can be seen, but I can't feel any wear there, just contact blemish. The dimpled end that goes into the worm/actuator only shows settling and polishing from the ball bearing, no signs of distortion or stress.

Second pic is of the clutchpack end. Again, no distortion or stress, just polishing from the ball.

This pushrod has been working great. After an initial settling-in, with minor readjustment, it needed no more adjustments, and displayed minimal heat slack.

 

[kevski]

I have just replaced the push rod in mine along with the needle roller bearing the guide and oil seal, all these i got from Heiden tuning in Holland, i also got the clutch holding tool, all done in under an hour and working beautifully

 

[ihaxs650]

I am new to this site. I have been an observer for months maybe years. I purchased the hydraulic clutch kit from Heiden tuning and have it installed on my 1980 XS650 with little difficulty. A trip to the machine shop and it buttons up. This Heiden kit works much better than the Yamaha worm gear but it is not optimal. The release point is good and the pull is similar to the 650 Central "easy pull clutch". Like the worm gear, finding neutral when cold is not a problem but when warmed up, the neutral at a stop is doable but not easy. I would like to improve the ability of this hydraulic clutch to find neutral when hot.

The Heiden push rod is close to 106 mm compared to the stock rod of 85 mm. I have determined that there is around 6 mm of slave cylinder distance remaining before the side case cannot be buttoned up. I have ordered 5/16 inch rod and will make a clutch push rod of 108 mm. I do not see why this will not give me more clutch separation when hot. What bothers me about this approach, if this allows finding neutral finding when hot. Why did not Heiden tuning shipa longer clutch push rod?

 

[ihaxs650]

Well I thought I would give an update. I received a long clutch push-rod from Mikes XS. Cut one to 108 mm and the other to 110 mm. Tried the 108 mm clutch push rod in the XS650 and it made a little bit of a difference but it is still not optimal. I am still having problems finding neutral when the bike is hot. Tomorrow I will swap in the 110 mm clutch push-rod and see if the case will button up. I do not believe that I can go over 110 mm as this will leave me with 2 mm slave cylinder capacity and I believe I need some room for expansion. I suppose if the 110 mm clutch push-rod is a no go, I will try a one piece of AL 7075 rod.

 

[TwoManyXS1Bs]

Great, another experimenter! From the hydraulic side of the fence.
Welcome to the forum, ihaxs650.

You may want to observe and measure the pressure plate travel, at the clutch side, since you may not be able to get reliable pushrod travel measurements from the slave cylinder end.

I've been working on an experimental clutch pack that may shed new light on this pressure plate displacement...

 

[ihaxs650]

TooManyXS1bs, Thank you for the welcome to this site!

I tried installing the 110 mm clutch push-rod and was not able to button up the side case. I am finding very little difference in clutch action finding neutral when hot with the stock Heiden clutch rod of 106 MM or the custom 108 mm rod. I am thinking that there is more to this hot neutral issue than clutch separation. I will not go back to the worm gear because the Heiden Hydraulic clutch is self adjusting and the clutch action is much better hot or cold. I am not convinced that a one piece aluminum 7075 rod will solve the hot neutral issue.

 

[ihaxs650]

Read more posts about the benefits of the one piece clutch rod. So, I decided to give it a go. Here is a shot of the Heiden slave cylinder. Not sure how to post the image files and narrate at the same time. This shows the tools of the trade. Got the suckers out. I surprised my self needing only one bushing and clutch push-rod.seal. Ready to button up. Ready to test ride. I used an AL7075 rod of 266 mm to match the Heiden slave cylinder. Thank you TooMany for testing this rod. The first thing I notice is most all the side play is gone compared to the 2 piece rod setup. On the ride the shifting is much easier and crisper, definitely a major improvement. These hydraulic clutch setups are so nice. Finding neutral when hot is greatly improved but it is not nearly as smooth as my FT500 Ascot. I can find neutral when hot from first by going into second and then down to first. I notice that when hot I have the clutch lever pulled in and I can hear a very slight drag on my clutch in first. The bike rocks back and forth very easy, Yet I have to let the clutch out another 70% of lever travel before the clutch engages. Very strange! How can you have clutch drag and still have to let the clutch out tremendously to start moving?? I suppose I will have to look at the clutch side. Very strange!

 

[TwoManyXS1Bs]

... Thank you TooMany for testing this rod. The first thing I notice is most all the side play is gone compared to the 2 piece rod setup. On the ride the shifting is much easier and crisper, definitely a major improvement. These hydraulic clutch setups are so nice. Finding neutral when hot is greatly improved but it is not nearly as smooth as my FT500 Ascot.

Hey, ihaxs650, thanx for your feedback.

... I can find neutral when hot from first by going into second and then down to first. I notice that when hot I have the clutch lever pulled in and I can hear a very slight drag on my clutch in first. The bike rocks back and forth very easy, Yet I have to let the clutch out another 70% of lever travel before the clutch engages. Very strange! How can you have clutch drag and still have to let the clutch out tremendously to start moving?? I suppose I will have to look at the clutch side. Very strange!

One trick the members here have is to 'blip' the throttle when trying to get into neutral. I suspect that this momentarily uncouples the sticky discs & plates, which is the basis of my next experiment.

Having clutch engagement occur at the last 30% of lever release is the proper zone for '70s bikes.

And, yes, the slight clutch drag is indeed a problem when fully disengaged.
Some tricks that have been done to address this (with varying degrees of success):
- Smoothing and/or removal of plate/disc tab gouges in the basket and boss (hub).
- Deburring the sharp edges of the steel disc tabs.
- Employing the later '80-on spring-damped style clutch hub.
- Replacing organic/cork composition friction plates with modern materials, like Kevlar (Barnett).
- Simply cleaning and surface sanding the plates and discs.
- Increase pressure plate travel.
- Changing oil to a JASO certified type (safe for wet clutches).
- Yamaha employed plate separator o-rings on the early 256 model 6-plate clutches.