Author Topic: Clutch slipping from 3rd gear on. (Read 5785 times)

TRXforever · « **on:** June 02, 2014, 08:20:33 PM »

OK I just put a new top end on my R. It is a Paul Turner Hyperdyne with a power head. Also put boyesen rad valve with carbon fiber reeds, and a NEW 38 A/S carb. Clutch was fine before the install, but now the clutch slips from 3rd gear on up. Grabs GREAT in first gear, grabs decent in second gear, and just revs out from there. I do have a magura hydro clutch, but never any problems there. It even has a fresh bleed performed. I have a NEW cable and lever to put back on to eliminate the hydro just have not had time to put it on yet. I read up on the c-leigh clutch upgrade and am possibly going in that direction (CR500 springs with the drain washers and a single 400EX steel. I just want to make sure it is not something silly before I spend the $175 for the OEM disks and fibers. Has anyone ever ran into this before? Maybe the ton of extra mid range grunt is just so much more than the stock jug setup? Any feedback would be appreciated fellas.

kb250r · « **Reply #1 on:** June 02, 2014, 08:53:17 PM »

Have you pulled the clutch cover to see if the fibers are worn and need replaced,maybe you were on the edge of needing a clutch and that extra omp did it in...

Pumashine · « **Reply #2 on:** June 02, 2014, 08:54:20 PM »

Its not silly but it seems to be when it happens. Like you got so much power your bike can't hold up any more. I know friction disks are expensive but after spending $$$ on your bike the clutch should not be neglected. If you don't have a new basket your looking at spending around $400. You really don't need to replace the steel plates. Slight sanding will renew the surface.

I put all new friction disks on every time a new build happens. Just cheap insurance!

TRXforever · « **Reply #3 on:** June 02, 2014, 09:07:31 PM »

Thanks for chiming in PUMA! I have a newer hinson basket with maybe 4 hours on it, with stock inner hub and pressure plate. The fibers looked good when I had it apart three times to do the stinking waterpump, but I never mic'd them. What is your opinion on the 500 spring and washer set up with the single 400EX steel plate. Maybe the OEM 250 springs are a little tired? Do not know the age of the springs. I have heard the 500 springs are more for the huge HP motors. My jug does have ALOT more oomphm, but not THAT much more. It was built for Mark Ehrhardt by loren in 94 with marks own midrange port specs.

And the possibilities of the fibers being fried are pretty good right now kb250r!

kb250r · « **Reply #4 on:** June 02, 2014, 09:19:12 PM »

I would say it's defiantly not a power thing,something is a little out of spec or worn causing the slip..that hydro clutch is not adjusted to snug pulling on the actuator arm causing slip is it?don't even know if it's possible never used a hydro clutch before..

Pumashine · « **Reply #5 on:** June 02, 2014, 09:56:34 PM »

You really can't go by the looks of the friction plates. I have a stack of 100 here and they all look great to me. Even if you mike them you have to take the difference from the base thickness verses to overall thickness. The actual thickness of the friction pad is only .006" thick. I was reading a thread a couple months ago where Dave rsss396 was saying the stock springs with the added shim should work just as well. I am for making up a couple hundred of those drain plug washers in .080" and .100" if you guys want a cheap upgrade.

TRXforever · « **Reply #6 on:** June 02, 2014, 09:57:06 PM »

I have ran the hydro with the last three motor set ups I have had without any problems, but it is getting aged! I am going to go back to cable for this set up. There is no adjustability at the cable holder like a cable. There is only a ferrel to slip into the cable holder. I would agree that is not an overpower issue. I am going with all new fibers and springs. Just need to decide on the single 400EX steel plate with CR 500 springs and drain bolt washers under each spring, OR new OEM 250R springs. I shouldn't need the 500 set up from excessive power. I am leaning towards the OEM springs and fibers

kb250r · « **Reply #7 on:** June 02, 2014, 11:03:33 PM »

I think there are a few people that like running the ESR Springs, maybe check on them as well..hd springs and fibers $85.00 might be worth a shot for the price

C-Leigh Racing · « **Reply #8 on:** June 03, 2014, 11:35:29 AM »

Its all about how much pressure, that pressure plate can compact all those plates together so they cant slip.
Shucks, I've took an extra metal plate & put in a pack at a race, where the inside plate had all the fiber worn off & the clutch went back to working.
The 500 springs, are like a go between, difference between the stock 250R springs pressure, kinda like the same idea as moving the clip on the carb needle to fine tune the fuel.

Tony, you need to get those washers in stock, so folks that know can fine tune that pressure plate pressure.
Remember though, that pressure plate can only travel so far before it bottoms out on the inner clutch basket & you know the clutch will slip after that, right kb, lock up or not you need the clutch pack thick enough to keep the pressure plate from bottoming out.

I think a whole new set of fibers all together, will measure 0.860 or somewhere there abouts.

My daughters 350R, got the same ol plates in it from 2004 & the engine was freshed up one time since then. Pressure plate pressure boys.
Neil

Tbone07 · « **Reply #9 on:** June 03, 2014, 11:43:33 AM »

Put as much pressure on that pressure plate as possible, get some new fiber plates and get the 400EX plate too. I run that setup in my 350 with no problems

I don't understand the CR500 springs with washers. If the CR500 springs are softer and you try to make up the difference with washers, then what's the point?

If you're worried about stiff clutch pull...make sure the cable is lubed and fresh.....and try to find a lever with reduced pull like the ASV

C-Leigh Racing · « **Reply #10 on:** June 03, 2014, 11:58:58 AM »

Tbone, really, what part of fine tune didnt you see.

Like you dont have to do that or go through that process, just for those that want to do it & maybe custom their clutch pull to their liking.
Neil

Tbone07 · « **Reply #11 on:** June 03, 2014, 12:02:31 PM »

Quote from: C-Leigh Racing;35700

Tbone, really, what part of fine tune didnt you see.

Like you dont have to do that or go through that process, just for those that want to do it & maybe custom their clutch pull to their liking.
Neil

No I definitely understand what you're saying Neil.

But wouldn't it make more sense to put as much pressure on the plates as possible and adjust the "feel" of the clutch pull elsewhere? Like at the clutch lever?

TRXforever · « **Reply #12 on:** June 03, 2014, 02:22:06 PM »

I ordered new OEM frictions, and a single 400EX steely, with some new barnett springs. Also got an ASV lever with a NEW OEM cable. Gonna see if that works for me. I really like the hydro though, not totally ruling it out yet. I got to thinking about it and the clutch does not engage until the very end of the lever motion. That would indicate thinner frictions, meaning worn out?