Hi All. I'm new here. I found this post because I'm having a similar problem with my 87 TRX350D except it's not the oil. The clutch slips while cold. (It's not an oil problem. I run the same Rotella T4 in this quad that I run in another quad and two other bikes that have wet clutches. I've never had a clutch issue.) I adjusted the clutch free play but it did not help. I finally tore it down to figure it out. While cold, I could slip the change clutch with my hands. So I thought, no big deal I just need a new clutch kit. But once I got the clutch apart the friction discs looked nearly brand new. I measured the thickness and found them to be well above the min thickness in my Honda service manual. I checked that all 6 friction discs and 5 plates were there and in the correct order per the service manual. The springs are fine. It didn't make sense so I ordered a new EBC kit (CK1196) anyways.
I put the new friction discs in today and had the same problem. So I did more investigation. When I stack all the friction discs and plates together they are 23.30mm (measured with digital calipers). Then I took the clutch center and assembled it with the pressure plate (without the discs & plates installed). So the clutch center and pressure plate are squeezed together as tight as they can be, aluminum against aluminum. I measured a 23.20mm spacing. See pictures. So the stack of plates and the minimum gap between the clutch center and pressure plate are the same. This doesn't make sense. What am I missing? Certainly the clutch is not going to work well if I put it back on like this.
The service manual says each friction disc is allowed to be as thin as 2.3mm. New is 2.7mm thick. So each disc can wear 0.4mm. Since there are 6 discs, thats a total of 2.4mm of wear that the assembly should allow. My assembly will only allow 0.1mm of wear before pressure can no longer be applied to the plates.
I've checked part numbers for all the years (87-89) of this quad and all have the same clutch center, pressure plate and same number of friction discs and plates. The service manual doesn't list any wear measurements for either the center or pressure plate and they don't look worn. I can't find any dimensions for what the clutch center and pressure plate gap is supposed to be. Is it possible that the clutch center I have is from another model Honda or something and is slightly wider than it's supposed to be?
I need a solution. Can I add another friction disc and plate to the stack just to increase the overall stack thickness and allow the pressure plate to actually put pressure on the discs? Could that cause any problems?
Thanks for the help!
Some photos are attached which may help.
