TRX250r.org

Author Topic: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy  (Read 13564 times)

Offline PNWrider

Thought id do a write up on the Clutch mod that Neil has shared with us numerous times.

Start off with the parts

Quantity                          Part #

1 - 400ex clutch steel plate        22321-MV4-000
5 - Trx250r Oil drain washer        94109-12000
5 - cr500 clutch springs             22401-ML3-910
5 - trx250r Steels
7 - trx250r Fibers


Edit:
Also thank you 250Racer for reminding me about scuffing the steel plates. Just use a fine sand paper to scuff up the surface of your plates.
I've even heard of rubbing the plates on a concrete floor works too.

And here is some Pictures and measurement differences of the install


Here is the spring difference. Both Honda OEM
CR500


TRX250r


400EX Steel plate


TRX250R Steel


400EX steel in the middle of the fibers



'89 lifter rod and needle bearing update with the thrust washer in place


Got all the drain plug washers lined up with the pressure plate holes.
 Make sure while tightening down the bolts the washers dont get out of alignment, could see it snapping off the clutch basket threads





Because there was a gap with the lifter rod and the pressure plate I was able to adjust the clutch cable.
But if you're out of adjustment slack then you can just add another thrust washer in between the needle bearing and the pressure plate

« Last Edit: March 02, 2014, 01:04:02 PM by PNWrider »

Offline kb250r

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #1 on: March 01, 2014, 09:11:46 PM »
That's a nice detailed write up..awsome...looks like a good sticky to me...
Atc - 350 6mill
Atc - 350 4mill
Trx - 431 puma

Engineered by C-Leigh Racing

Online Hawaiiysr

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #2 on: March 01, 2014, 10:14:24 PM »
:encouragement: Good job

Offline havinnoj

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #3 on: March 01, 2014, 10:28:22 PM »
Thanks for posting.  We are working on a new FAQ & Tech Write Up section and this will fit in nicely.  I'll move it there when the section is ready.

Offline PNWrider

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #4 on: March 01, 2014, 10:35:29 PM »
Quote from: havinnoj;27343
Thanks for posting.  We are working on a new FAQ & Tech Write Up section and this will fit in nicely.  I'll move it there when the section is ready.

Thanks guys! Let me know if there is anything else I can add or missed.

Online hickwheeler

CLutch mod with pics (Neil aka C-Leigh Racing mod) Pic Heavy
« Reply #5 on: March 02, 2014, 02:36:04 AM »
since I'm New to the r what does this accomplish
88 ESR 330 5mil stroke
88 ct350pv (BOF Build)
Puma coming soon

Offline 250Racer

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #6 on: March 02, 2014, 07:19:20 AM »
You are forgot to add about scuffing up the steel plates .

Offline rsss396

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #7 on: March 02, 2014, 08:46:10 AM »
Quote from: hickwheeler;27359
since I'm New to the r what does this accomplish

By adding washers to the springs you are compressing them more and increasing the spring pressure therefore increasing the clamping power of the clutch.

By adding a thicker steel clutch plate from a 400ex you also compress the spring more and increasing the spring pressure. The reason the thicker plate compresses the springs more is the clutch plates and fibers assembly is now taller on the inner hub so the pressure plate is now pushed out farther but the springs are held in by the inner hub so with the pressure plate farther out the springs are compressed even more.

Now you may need to add a small washer like shim behind the pressure plate to get the clutch arm located correctly because of the extra thickness, in the case of PNWrider the clutch stack is .64mm or .025" taller, this may not seem like much but that is allot in clutch arm movement. IMO a .020-.025" thick washer should be added to the push rod bearing/pressure plate

Now IMO you can do a clutch mod a couple other ways also

1 - add another 250r steel disc and double it up with another steel disc in the clutch assembly, normally this is installed toward the center area of the clutch assembly this will add 1.30 mm to the clutch plate and fiber stack so you will want to add about .050" shim washer at push rod bearing/pressure plate, the 250r springs can be used with mod but they get very stiff and normally just drag guy will do this
The bad thing IMO about the extra plate is the extra rotational mass added which is normally not a good thing to add to the engine.

2 - instead of the thicker 400ex plate in Neil's mod try finding a washer that is .025 thicker than the oil drain washer being used in Neil's kit. this will accomplish the same thing as the thicker 400ex plate without the extra rotating mass.

Maybe Tony can cut us washers if that is possible to accomplish this
« Last Edit: March 02, 2014, 12:05:45 PM by rsss396 »
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline Allison#51

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #8 on: March 02, 2014, 10:42:56 AM »
Why can't I find that thrust washer on the schematic? Is it included with the lifter rod needle bearing?

Offline Grande huevos

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #9 on: March 02, 2014, 10:52:28 AM »
Quote from: PNWrider;27344
Thanks guys! Let me know if there is anything else I can add or missed.


Maybe be more specific on what the clutch arm arc means, and what it should be set at? How exactly to find/measure this?

This is a awesome write up and should most def be a sticky!! I can't tell you how many threads I've read over the years asking the same questions on this upgrade! I have had issues with getting everything adjusted properly on this setup but I can tell you it's well worth it especially when you get into the big bores

Offline zcarlson12

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #10 on: March 02, 2014, 10:58:04 AM »
Nice write up. Pics of the R? I really like that frame color.
Laeger 310R

Offline Pumashine

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #11 on: March 02, 2014, 11:21:19 AM »
Quote from: rsss396;27366
By adding washers to the springs you are compressing them more and increasing the spring pressure therefore increasing the clapping power of the clutch.
Maybe Tony can cut us washers if that is possible to accomplish this

Yes, I will make these washers up that go onto the push-rod bearing as a shim or replacement all together. I can throw in all the aluminum oil drain plug washers for free with the shim or replacement washer. The $.50 each is 10X what they cost to make.
Puma 408, Puma 431,  Pilot 412, Puma 431, Mini-tooth 486 Trx450r
89mm  Mini tooth Shearer in frame pipe chromed! Mounted with Cascade QUIET[/

Offline rsss396

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #12 on: March 02, 2014, 12:01:35 PM »
Tony I think we could forget the thicker 400EX plate and shim for the push-rod bearing if you could just make the .025 thicker aluminum drain plug washers to use with the cr500 springs. I dont see a differance in the setup this way because you are creating the same amount of extra compression of the spring and it will be allot cheaper. If so you could sell these as a nice quick up grade for guys and I dont think anyone would complain about paying you .050 a piece for these, if they do then they dont deserve the the upgrade!
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline mx250r91

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #13 on: March 02, 2014, 12:06:30 PM »
I never understood using weaker springs (CR500) and then using washers to increase their preload. Why not just use a stronger spring to begin with? If you want a strong clutch, the 88-89 springs are hard to beat. If the clutch pull is too hard, the 86-87 are a little lighter, but still stronger than the CR500 springs. I think the 400EX steel plate is a great way to get a little more life out of worn clutch discs as it makes up for the thickness lost to fiber wear.

Offline rsss396

Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
« Reply #14 on: March 02, 2014, 12:17:11 PM »
You would have to check the installed height of the 250R spring compared to a cr500 with shims to truly know and there are Barnett springs that are typically stiffer than stock.

I actually have done this on the cr500 springs for tuning a lockup clutch and marked each set of springs with the lb rating that I read on a scale.

I used a shipping scale and set up my milling machine travel to compress the spring at close to the installed height and noted the lbs on the scale.

I then used these numbers to adjust the amount of clamping pressure at takeoff before the lockup clutch started to add clamping force
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.