Ordering New Friction Plates

I plan to replace my friction plates per my Service Manual. All of my friction plates are <3.1 mm as measured at 3 different locations per plate with a digital caliper.

I have yet to check my steel clutch plates on a surface plate with a feeler gauge. I've seen suggestions (retired gentleman) not to run out to replace clutch plates since they don't wear much. If they're not warped, I'll just reuse them.

I have 7 friction plates and 6 clutch plates.

My inclination is to go with OEM friction plates (if I can find them online). My local Yamaha Shop says they are on BO and that it will be September before they have stock.

Looking @ MikesXS offerings, they have 3 choices, their $12 Kevlar made in Japan, $11 "High Performance" and $8 plates.

Any strong feelings either pro or con on these 3 choices?

Friction Plate & Clutch Plate Installation: On page 79 of Clymer (12) it states "Note that the friction plates are alternated with metal clutch plates but that the friction plates are not identical. There are 4 fiber-backed plates and 2 aluminum-backed plates. Two fiber-backed plates are installed first, followed by the 2 aluminum-backed plates". I'm confused about these statements.

Here is another Thread I came across discussing the fiber and aluminum backed plates on earlier models:
http://www.xs650.com/forum/showthread.php?t=8840

I've looked each of my 7 friction plates over and they appear to be identical. Comments?

I used Forodo Plates in my 75. That and Kibble White 70 lbs springs. Work well no slip. and with a well lubed worm and cable I can still pull the lever with two fingers.
I can't say anything about different plates on the stock plates, mine all loked the same. Two of the Forodo plates looked different so I put them in the middle.
Leo

Thanks, Leo. I'll definitely look into these. I tend to be conditioned to either consider OEM or MikesXS products for whatever reason.

Personally, I'd buy a Vesrah or EBC set and be done with it. You can get name brand parts for all but the cheapest of prices on those plates, and you can get them with a great return policy, and free shipping.

Wasn't aware that Forodo made plates for it. That would be an option as well.

I do love free shipping.

My horizons are being broadened.

Your Clymer is referring to the very early clutch plates used up until about '73. On your bike, the friction plates are all the same. Don't throw your old plates out, they're still good. I've never replaced any because they weren't worn. Springs yes, I always replace them. They're always weak.

YamaLovin76 said:

I plan to replace my friction plates per my Service Manual. All of my friction plates are <3.1 mm as measured at 3 different locations per plate with a digital caliper.

I have yet to check my steel clutch plates on a surface plate with a feeler gauge. I've seen suggestions (retired gentleman) not to run out to replace clutch plates since they don't wear much. If they're not warped, I'll just reuse them.

I have 7 friction plates and 6 clutch plates.

My inclination is to go with OEM friction plates (if I can find them online). My local Yamaha Shop says they are on BO and that it will be September before they have stock.

Looking @ MikesXS offerings, they have 3 choices, their $12 Kevlar made in Japan, $11 "High Performance" and $8 plates.

Any strong feelings either pro or con on these 3 choices?

Friction Plate & Clutch Plate Installation: On page 79 of Clymer (12) it states "Note that the friction plates are alternated with metal clutch plates but that the friction plates are not identical. There are 4 fiber-backed plates and 2 aluminum-backed plates. Two fiber-backed plates are installed first, followed by the 2 aluminum-backed plates". I'm confused about these statements.

I've looked each of my 7 friction plates over and they appear to be identical. Comments?

Click to expand...

Unless the specs for the 1976 are different from my 1978, your friction plates are in spec and don't need to be replaced.

For my clutch, normal = 3.00 mm (0.118") wear limit = 2.69 mm (0.106")

Cool. I've got a new set of springs, so I can get my clutch re-assembled. Will be nice to get closure on something. I had seen different values in the various references as to when to replace friction plates, and was therefore confused.

Is it correct to say that the early 650's (70-73) had THICKER Friction plates than the later models??

I've got one of MikesXS new bearings, so I'll need to ensure that I correctly install that as well as the washers, etc.

I took absolutely no note of existing alignment when I took everything apart, although I may have inadvertently picked it up on video or with a still shot. I'll have to scrutinize my footage like its the Zapruder Film.

Do I simply need to line up the hole on the pressure plate with the dimple on the clutch boss?

Thanks.

Stock 30 year old clutch plates should be replaced my opinion. If you didn't buy the bike new and the wrong oil was used they are still old junk clutches. The Forodo is the best. The other brands like EBC I have read of clutch slippage with heavier springs. Been there done that with old shit trying to save a buck. I use the Forodo springs

I appreciate your feedback, scabber. I'll research the Forodo products that Leo also referenced.

I assume you're referring to Ferodo, right?

YamaLovin76, just to recap, isn't this for fixing a perceived 'clutch slippage' problem?

Hi, TwoManyXS1Bs.

Well, that's part of it. I'm in the midst of my first ever top-end rebuild. In an nutshell, I had 0 compression on Left and found a bent Left Intake Valve not to mention significant carbon buildup. In general, I'm learning how to measure various parts (buying new tools as you recall) for wear and replacing as necessary and/or if I have the cash and want to replace parts.

I had measured my friction plates and concluded that they needed replacing, but I believe that I was basing that upon specs applicable to early 650's that had thicker plates. So, at this point I'm on the fence about replacing them whether it be for low-end, high-end, etc. I'll probably focus on getting top-end dealt with & back together, reassemble clutch, then deal with clutch down the road as necessary. I had not intended to touch the clutch, but it was a mystery area to me, so I tore into it....to get to the other side...

As to specific clutch issues, I had an issue last year where bike was creeping forward even when I was in neutral and/or had the clutch lever depressed. I followed some 5twins advice and tightened an adjustment screw accessible at the left cover while adjusting at the clutch lever. That helped that particular issue. Also had some shifting issues finding neutral and first when riding and when engine running.

A few mods will include: 1) install of long clutch pushrod to replace a bearing & the inner & outer push rods, 2) install of MikesXS clutch bearing (which I've learned may not help at all) and 3) new clutch springs, MikesXS), new OEM clutch screws and 4) new clutch pushrod seal (after beveling sharp engine case with brand spankin' new Shiviv deburring tool.

Sorry for the lengthy answer to short question.

The simpler the question, the longer the answer.

I'm sure ANLAF will read this as well, so here's a couple tidbits on the XS clutch:

The early friction plates were about .140" (3.5mm) thick, later are about .120" (3.0mm).
The reason I say 'about' is because I've seen them with small variances in thickness, something to watch, for total stack-up thickness.
The clutch 'steel' plates came in different thicknesses, including a sprung 'cushioning' plate. Research the forum threads for details on this.
I have measured clutch action/movement and forces on my early XS1B, later models will be somewhat different, largely due to different worm-screw arm length.
XS1 clutch lever - 2.5" travel max - 30-35 lbs pull
XS1 clutch cable - .65" travel max - 4:1 leverage ratio = 120-140 lbs cable tension
XS1 clutch worm - .080" travel max - 8:1 leverage ratio, 32:1 total = 960-1120 lbs pushrod pressure
The actual values for force will be somewhat less because some of the actuating force is from friction.
The XS1 worm screw arm is shorter than the later models, giving different travel and leverage values.

Edit: The pushrod pressure is actually less than half that, due to significant friction in the whole clutch actuation assembly...

So, for this little exercise, let's assume that later XS pushrod max travel is .060" (1.5 mm)
That .060" must be distributed over all the clutch friction faces to allow clutch disengagement. If you have 7 fibre discs, that's 14 interfaces, divided into .060" pressure plate travel, gives about .004" individual face clearance, assuming everything is dead square/flat and evenly distributed.

Suppose, in the real world, that a slight warpage of about .001" exists in the plates. Totaling-up that warpage over that many plates, you can see how the clutch disengament travel is reduced, significantly. (Think tolerance stack-up) Add to that any out-of-true runout of the pressure plate, and you could find yourself in a condition where the clutch barely disengages at all. Non-equal, uneven pressure plate springs can cause slight runout/wobble of the pressure plate. Some folks would measure and sort their clutch springs, mounting equal springs across from each other.

To check pressure plate runout, with the right cover off, clutch lever pulled-in, have someont spin the rear wheel, and observe pressure plate spin, looking for runout. With good, straight, flat plates, and a non-wobbling pressure plate, chances are good that your clutch won't try to prevent you from finding that elusive neutral.

In the old days, you could toss-in new factory parts just as mindlessly as putting gas in the tank, and things would work. Nowadays, with questionable budget parts quality, and a history of rough transport and storage, it may be prudent to measure/check all replacement parts...

Wow, that's a wealth of great information. Thank you. Going to have to read it a few times.

Any need to use a dial indicator on checking the pressure plate runout or does visual observation of any wobble suffice?

A lot depends on the calibration of yer eyeballs, and if this is one of your visual skillsets. I can chuck-up a bar in my lathe and eyeball true it to +/- .002", good enuff for making sledgehammers, but if it's important, I use a dial indicator (like 'last word') to reduce runout to +/- .0002".

When I would go target shooting, I always gathered the brass. Then, I got involved with a bunch of flintknappers, learning knapping, how to find/id flint and arrowheads in the field. Now, when I go target shooting, I can't find my brass.

I needed to cut a long/narrow sheet of plywood in my bandsaw, asked my cousin to hold the other side, perfectly flat. He torqued it over almost 30°, then argued that it was flat. Concerned, I later had him power-drill a vertical hole in a board, again, almost 30° off. He has since gone to an eye doctor.

So, the answer to your question, "can you visually see the runout?", is: I dunno...

No matter how I'll do it, I'll check for run-out after I get my engine re-assembled and back in bike. Will be awhile...

I pulled my shift shaft this morning. A piece of cake. Referring back to polishing up the shift shaft (covered in other thread with Anlaf), I've got a basic Dremel tool and some polishing/buffing wheel attachments. Will using this system along with some Autosol metal polish do the trick?

Looks like I also need to replace the shift shaft seal and will replace those 2 little springs.

While you are in there, YamLovin, and before you go ordering clutch plates, check that no-one has been in before and swapped your seven friction plate clutch for a sixer. My friction plates were worn to 2mm oblivion, so I had to replace - your 3mm seems fine to me (and TwoMany and Retired Gentleman). If is isn't broken (worn, bent etc) don't mend it. Keep cost down to replacing the shifter-shaft springs and oil (try and preserve your gasket unless torn).

If you are thinking replacement will solve another problem with the clutch and your plates are 3mm chack the indexer marks are aligned.

Anlaf

The thing with the clutch is you can go in there any time and fix it if need be, even with the motor back in the frame. I would save the $70 to $80 cost for new plates now until you see whether or not you really need them. I think with new, stronger springs, you're going to find your originals are just fine.

As I mentioned earlier, original springs are crap. The stock springs in every Jap wet clutch I've owned over the past 40 years have been crap. They all needed replacing.

I'm with 5twins on that. I put new springs in - and would have done so even if the friction plates in mine didn't need replacing.

Anlaf