Miss November XS2 tribute

Indeed - good for you for sticking at it, being systematic and thorough Raymond.

On the indexing of that "dot & hole" marking - and I am just guessing here - there are a lot of geometric features and a number of components that need to line up for the clutch to work properly and my guess is that rather than try to hold tight tolerances on everything, Yamaha simply machined the assembly together and then marked it to make sure that it would be assembled after service with the mating features ...."mated". If they hadn't done that - they would have needed to make all of the parts much more accurately to be able to assemble everything - and that would have driven costs up without actually providing a real benefit in operation.

The mismatch perpetrated by your P/O could account for your difficulty in removing some of the springs and that last clutch screw. As you said in an earlier post (I think about the timing chain length) ...I wonder what else he left behind? :yikes:

As for re-assembly, I would suggest measuring the "free" length of the springs to ensure that they are within spec. and also, many folks lap the rust and burrs off the edges of the steel plates by simply giving them a good rub on a piece of emery cloth on a sheet of glass or a steel plate (for flatness).

Pete
 
Last edited:
View attachment 147843

The shoulders of the baskets show light scuffing from the plates. But my thumbnail cannot detect any wear ridges, so in terms of wear I'd say the clutch is AOK. Perhaps I'll check the thickness of the friction plates.

Should make it clear, meant thumbnail literally, not a mini-photo . . .

Pete, interesting theory on the marker hole & dot. If correct, sounds like a subtle problem at worst and probably not account for clutch not working?

It's only light rust on the steel plates - should be possible to wipe or rub it off. Will check the edges are not burred and clean with wet & dry paper if needed.

Will measure the thickness of the friction plates to confirm they aren't worn out.

Will measure the spring lengths, see if they are all the same, and compare to the spec.

Might decide to buy new set of springs and screws anyway because the screw heads are a bit chewed up. Gonna look and see what they cost.
 
Last edited:
to buy new set of springs and screws anyway because the screw heads are a bit chewed up

Many folks have gone to a set of socket head cap screws (SHCS) with shoulders to replace the big #3 JIS clutch retaining screws that Yamaha installed at the factory. While most people don't have to get into the XS650 clutch too often, the large number of these stock JIS screws with ruined heads (likely due to people who don't use JIS drivers.....:p ) means that they can be challenging to remove - particularly without an impact driver. When I dug into one of my bikes, three of the six screws had badly damaged heads. When I first saw them, I thought....oh gawd...I hate drilling out screws...

In fact, the heads were in much better shape AFTER I had removed them with the Vessel #3 Impacta driver than they were before. Anyhow, the Allen head SHCS replacements from XS Performance are available from most of the main parts vendors. They fit perfectly and are a treat to use.

The other thing to check is all of the myriad spacers and washers in the clutch assembly. People have found that if any of them are omitted or in the wrong order, the darned clutch doesn't function properly. I would suggest taking a very careful look at the exploded view in the manual and making sure that your bike has all of those components in place as you reassemble it.

As for the "hole & dot" alignment thing - it is just a theory, but I have seen manufacturing schemes like that in vehicle transmission assemblies before and no manufacturer does things like that just for fun. Personally, I think that it very well could be the cause of your clutch assembly difficulties.

Cheers,

Pete
 
Raymond,
New springs are relatively inexpensive and for me anyways a worthwhile investment. I’ve had good luck with EBC brand springs. Something else I did to both of my bikes was to upgrade the clutch screws to an Allen head kit.
Not absolutely necessary , but I never liked those easy to mangle Phillips head screws. I bought my kit through Mikes XS, here in the states. On your side of the pond , they are also available from Heiden Tuning, might ship for less? Just something to consider.
https://www.heidentuning.com/xs650-...nsmission/clutch-spring-screw-set-detail.html
 
...Clearly, the clutch has been assembled incorrectly. Both the Haynes manual and this site stress the need to align dot and hole - I would be very interested if anybody knows why or what the effect of not aligning might be?

Yeah, that's your whole problem right there.

There's 29 splines on the clutch hub, and mating pressure plate.
A prime number.
There's only one orientation that'll let the 29 splines and 6 springs line up.

Misaligned like yours, the pressure plate will bind on the mating hub splines, and the 6 spring pockets will be pressed to one side, binding the springs.

Yours is the first that I've heard of that actually almost worked...
 
Prime Numbers: When most of us went to school 1 was probably a prime number. It certainly was at my school. Then in the very early 60s 1 was removed because of something called units. Now we start at 2. Thank goodness 29 was not renamed or messed with and is hopeful respected by all!

Nice to get the reason from 2M. But why was 29 chosen? Is it back to what MaxPete said about limiting assembly possibilities and tolerance?
 
Prime Numbers: When most of us went to school 1 was probably a prime number. It certainly was at my school. Then in the very early 60s 1 was removed because of something called units. Now we start at 2. Thank goodness 29 was not renamed or messed with and is hopeful respected by all!

Nice to get the reason from 2M. But why was 29 chosen? Is it back to what MaxPete said about limiting assembly possibilities and tolerance?

I apologize.

Prior to 2M's note, I hadn't realized that they had used a prime number of spline "teeth" but as 2M said, the use of a prime number means that the assembly can only work in one particular position. That must be the reason for the "dot & hole" alignment marks.

Perhaps that was desired because of machining / tolerancing issues or because they balanced the clutch as an assembly and didn't want anyone to mess that up by putting the inner and outer hubs together after rotating them relative to each other.

What is a bit puzzling is that they chose an odd number of teeth (which clearly, any prime number would be). This makes machining the male and female parts of the spline somewhat more complex and even measuring them is more challenging because many of the measurement methods require two diametrically opposed teeth.

Hmmmm....lots to learn here. Thanks for the insights 2M!

Pete
 
Yeah, that's your whole problem right there.

There's 29 splines on the clutch hub, and mating pressure plate.
A prime number.
There's only one orientation that'll let the 29 splines and 6 springs line up.

Misaligned like yours, the pressure plate will bind on the mating hub splines, and the 6 spring pockets will be pressed to one side, binding the springs.

Yours is the first that I've heard of that actually almost worked...

Well, thank you Sir! I kinda felt there had to be reason for the necessity to line up hole & dot.

Seem to remember the crank sprocket, cam sprockets and intermediate sprockets on the Triumph used prime numbers and it was all figured out (clever man, Edward Turner) so that two particular teeth on adjacent sprockets only met once every few thousand engine revolutions. Love that word you made up, very succinct.

Pete, most prime numbers are odd, but 2 is an exception. Unless the maths Powers-that-Be have decided 2 is no longer Prime. Or no longer Even. Hell when I was a school, Pluto was a planet.

Looks like new set of springs, new screws, reassemble and the clutch should be fine.
 
Last edited:
Further to the issues of clutches and correct assembly thereof....2M just posted an excellent array of schematics and photos on this very topic in another thread.

Yes, that looks correct.
One trick is to dab some grease behind the new needle bearing. Helps to keep it in place during hub install. It has been known to slip down and get caught off-center.

Some clutch assembly pics...

View attachment 147909 View attachment 147910
View attachment 147911 View attachment 147912 View attachment 147913 View attachment 147914
 
Today, I have mainly been servicing the clutch.

Measured thickness of friction plates. Spec is 3.0 mm but mine are all more than that. According to a confoundedly cheap Aldi digital micrometer they are about 3.1 to 3.25 mm - might have swelled up with oil or the petrol I soaked them with? Anyhow, seems little point in replacing them.

The light surface rust proved to be a bit deeper on the inner steel plates, so I resorted to steel wool.


PICT1944.JPG


You can see surface marking but rust gone and plates nice and smooth now. And since I'm not replacing the friction plates, no point replacing these.

Measured spring length and they too exceed spec length. Only very slightly, and it might be the cheap tool but - well, I'm sure you can see where this is going.

So, nailed it all back together again. Plenty of oil slathered on the plates of course. Marker hole & dot lined up correctly this time . . .

It'll be fine. The misalignment is ample to explain the clutch misbehavin'. And if I'm wrong, it's not a big deal to get at.

When I adjusted the clutch, perfect at the handlebar (perch?) end. Which I take as a good sign.

Looking forward to getting her going again.
 
Yup - it sounds like you will be back in business in a jiffy Raymond!

Now, just wait for a bright sunny day on the Scottish Borders and frappe la rue! :cool:

....oh, yeah...well maybe just pick a day without TOO much rain and go cautiously on a nice sedate ride while wearing your Barbour suit.
 
It doesn’t rain ALL the time in Scotland. Only when I’m there.

Yup? It can seem that way . . .

Actually, it would seem - not to tempt fate - that we're in for a weekend of excellent weather.

And with the XS out of action over the next couple of days, I guess Polly (W800) will get some of the attention and miles she's been missing out on this summer.
 
Regarding the removal of rust from clutch plates: I have seen two different methods mentioned on this forum. One method leaves the plates polished and the other leaves them with a sanded finish. Which is correct?
 
Regarding the removal of rust from clutch plates: I have seen two different methods mentioned on this forum. One method leaves the plates polished and the other leaves them with a sanded finish. Which is correct?
I have no idea!

But I was looking at 2M's thread on clutches - sorry, don't have the link to hand - where it is mentioned by Mailman that a lot of clutches such as Hondas have steel plates with a dimpled finish. This is supposed to improve the clutch action by breaking the suction that can, it is said, hold plates together. Hmm, that would kinda make sense if we were talking two smooth steel plates together. But plain plates and friction plates are always interleaved.

Any hoo, after I've dealt with them, the steel plates are free of rust and roughness. But the surface has very light pitting. Which might help them, like a dimpled finish? Who knows, but I expect the clutch to work a helluva lot better than it has been.

If not, will have to have another look inside.
 
Back
Top