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Hello everyone, new to the forum, as well as bikes. Was given an old yds3 to fix up and use for the summer. I’ve got it all together and running (with a pop start) and took it for a spin...this things is gonna be a ton of fun.

Hoping someone can help me with the clutch repair as it was slipping badly. Replaced friction plates with new Barnett set. Went together smoothly but now I have no tension at the clutch lever at all. Had it tight before replacing a plates so it seems I’ll need to adjust at the clutch lever at the case.

Anyone have experience with these in particular that can help out a noob? I have general mechanical experience but this clutch is very strange being on the left side of the case
 

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Cable pull mechanisms are notorious for doing that on a lot of different bike models. They look just like the one in that picture.

Just by memory wasn't that a model that had a primary mounted clutch? Cool that will be a fun bike.

Where does the clutch get its oil from and what are you using? Transmission, right?
 

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Cable pull mechanisms are notorious for doing that on a lot of different bike models. They look just like the one in that picture.

Just by memory wasn't that a model that had a primary mounted clutch? Cool that will be a fun bike.

Where does the clutch get its oil from and what are you using? Transmission, right?
manual calls for sae30 or 10w-30 motor oil. I did some adjusting and the clutch will not fully disengage.

seeing some conflicting statements about clutch stack height and friction plate thickness as well as quantity. I see 4/4 for clutch plates. Dissasembly led to 5/5 with badly warn friction plates. Today I plan to remove one friction and one steel and readjust from there
 

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Hi, my printer wont scan documents so I tried to photo the pages in my service manual maybe you can read them? It says the 1965 YDS3 has 4 friction plates and 3 clutch plates ( the diagram shows 5&4 ? It looks like they made some changes to the clutch from YDS2 to YDS3 and to YDS3c so have fun?
102902
102903
102904
 

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How come I count 4 and 4 ?

Pages will show better with tons of light and the camera aimed perpendicular to the page surface.
 

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The end plate counts as the 5th plate. Also, just a thought, if the thrust bearings are worn it might be a possible cause for the original slipping issue?
 

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The end plate counts as the 5th plate. Also, just a thought, if the thrust bearings are worn it might be a possible cause for the original slipping issue?
I just found a pdf slide thing on rebuilding that engine, I was right it's a primary drive clutch, which means you can't start it if you pull the clutch in and the clutch can be lighter duty because it has less actual power to deal with, the one on that bike is kind of a crap one because the clutch is hanging way out on the outside of the primary gears.

All your bearings are going to need to be perfect, but the clutch itself should not slip if the rubberized cork plates are in decent shape and collectively fill the space they need to. It's Old tech you should be using oil that does not contain modern friction modifiers, doesn't even need to be multi-grade, same oil you would use in a farm tractor transmission and hydraulics is perfect and super cheap by comparison, change it frequently. If your clutch ever makes noise or slips, you likely have fuel or water polluting your oil or your clutch plates are disintegrating.

On a Montesa clutch there are 3 cork plates and 2 paper plates
;) I bet most did't even know plates come in two flavours.


PS: Cork swells in the presence of fuel or water, I have heard that if you wash the old corks off with gasoline (which sounds like a horrendously dangerous process) and then assemble it and run it, they will never grab any better then that.
 

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Discussion Starter #9
Thanks for the input everyone, here’s where I’m at. Lots of mixed info on friction plates and their thickness. As of now I substituted 1 old friction with 1 new and the clutch is functioning properly. Took her for a spin and feels like some adjusting is needed but generally works and feels good. Old plates were quite worn between 2.6-2.9mm. No other orientation of new and old plates seemed to work once filled with oil everything became way to tight (beyond needing to break in. As of now I’ll just keep an eye on it and replace plates as needed.

On to the carbs now. Seem to be dialed in nicely but I have a high idle issue with an occasional hanging idle. Throttle cables are not in good shape + unsure of cable routing so next step is to source or make all new cables.

in other new this thing is a blast on the road!
 

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Replace your clutch cable and service that clutch actuator too, it will make a major difference in the feel of the clutch.

Carb slides wore out in the olden days, that can certainly cause them to hang up if there are rough spots on the slide or the bore it slides in. Or even just grit that gets past the filter over the decades.
 
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