TRX250R.ORG

Workshop => The Mad Scientist => Topic started by: PNWrider on March 01, 2014, 09:04:53 PM

Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: PNWrider on March 01, 2014, 09:04:53 PM
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
(http://forums.trx250r.org/vbulletin_imports/71_953_2017-04-18_6114.jpg)

TRX250r
(http://forums.trx250r.org/vbulletin_imports/71_954_2017-04-18_3415.jpg)

400EX Steel plate
(http://forums.trx250r.org/vbulletin_imports/71_957_2017-04-18_2680.jpg)

TRX250R Steel
(http://forums.trx250r.org/vbulletin_imports/71_958_2017-04-18_9579.jpg)

400EX steel in the middle of the fibers
(http://forums.trx250r.org/vbulletin_imports/71_963_2017-04-18_8493.jpg)


'89 lifter rod and needle bearing update with the thrust washer in place
(http://forums.trx250r.org/vbulletin_imports/71_964_2017-04-18_2567.jpg)

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

(http://forums.trx250r.org/vbulletin_imports/71_965_2017-04-18_9123.jpg)

(http://forums.trx250r.org/vbulletin_imports/71_966_2017-04-18_7770.jpg)

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

(http://forums.trx250r.org/vbulletin_imports/71_967_2017-04-18_7053.jpg)
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: kb250r on March 01, 2014, 09:11:46 PM
That's a nice detailed write up..awsome...looks like a good sticky to me...
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: Hawaiiysr on March 01, 2014, 10:14:24 PM
:encouragement: Good job
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: havinnoj 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.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: PNWrider 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.
Title: CLutch mod with pics (Neil aka C-Leigh Racing mod) Pic Heavy
Post by: hickwheeler on March 02, 2014, 02:36:04 AM
since I'm New to the r what does this accomplish
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: 250Racer on March 02, 2014, 07:19:20 AM
You are forgot to add about scuffing up the steel plates .
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rsss396 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
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: Allison#51 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?
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: Grande huevos 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
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: zcarlson12 on March 02, 2014, 10:58:04 AM
Nice write up. Pics of the R? I really like that frame color.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: Pumashine 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.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rsss396 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!
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: mx250r91 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.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rsss396 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
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: PNWrider on March 02, 2014, 12:47:26 PM
Quote from: Allison#51;27376
Why can't I find that thrust washer on the schematic? Is it included with the lifter rod needle bearing?

I've never noticed that before...good question though. I think My extra thrust washer came on the inside of my pressure plates. But sounds like Pumashine will be solving our problems again!
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: PNWrider on March 02, 2014, 12:56:27 PM
Here is a before and after measurement of adjusting the clutch arm using the clutch cable adjustments on the left side of the cylinder.

First one is with what my previous clutch arm adjustment was set at for the stock clutch plate and spring setup

(http://forums.trx250r.org/vbulletin_imports/71_968_2017-04-18_7452.jpg)

This is after adjusting the clutch arm, unfortunately the adjuster is on its last thread so I will be using either a thicker washer or two washers so I dont have to use the last threads of my clutch cable adjustments

(http://forums.trx250r.org/vbulletin_imports/71_970_2017-04-18_7335.jpg)

And again here is what my clutch cable adjuster looks like

(http://forums.trx250r.org/vbulletin_imports/71_971_2017-04-18_6036.jpg)
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: PNWrider on March 02, 2014, 01:00:27 PM
Here is a before and after measurement of adjusting the clutch arm using the clutch cable adjustments on the left side of the cylinder.

First one is with what my previous clutch arm adjustment was set at for the stock clutch plate and spring setup

(http://forums.trx250r.org/vbulletin_imports/71_968_2017-04-18_203.jpg)

This is after adjusting the clutch arm, unfortunately the adjuster is on its last thread so I will be using either a thicker washer or two washers so I dont have to use the last threads of my clutch cable adjustments

(http://forums.trx250r.org/vbulletin_imports/71_970_2017-04-18_4303.jpg)

And again here is what my clutch cable adjuster looks like

(http://forums.trx250r.org/vbulletin_imports/71_971_2017-04-18_9203.jpg)



Here are some measurements of the washers I used

The first is the '89 washer that came with my Hinson pressure plate

(http://forums.trx250r.org/vbulletin_imports/71_959_2017-04-18_4428.jpg)

The second is one that came off one of the older year pressure plates...not sure which, It is a little bit bigger
(http://forums.trx250r.org/vbulletin_imports/71_960_2017-04-18_5640.jpg)

I'm going to find a washer the same size as the '89 so it doesn't sit off-center of the clutch lifter because its so much bigger.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: KASEY on March 02, 2014, 01:11:26 PM
one thing I see not addressed .. spring wire size,, since these springs are not progressive the spring rate does not increase as they get compressed more,  the thicker the wire size on the spring the higher the spring rate , since a cr500 uses 6 springs and a 250r has 5 there isn't much difference in a single spring as far as spring rate goes ,
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: mx250r91 on March 02, 2014, 01:25:37 PM
Quote from: Allison#51;27376
Why can't I find that thrust washer on the schematic? Is it included with the lifter rod needle bearing?

http://trx250r.org/showthread.php?2489-89-clutch-upgrade

PN. 90608-072-000
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rsss396 on March 02, 2014, 01:48:59 PM
Quote from: kasey;27398
one thing I see not addressed .. spring wire size,, since these springs are not progressive the spring rate does not increase as they get compressed more,  the thicker the wire size on the spring the higher the spring rate , since a cr500 uses 6 springs and a 250r has 5 there isn't much difference in a single spring as far as spring rate goes ,

the more you compress them the more lbs you will see on a scale ( I have tested this ) and this is with no coil bind so if you shim them they will produce more clamping pressure.
now the the untested thing here is a 250r spring compressed to the installed height and a cr500 that is shimmed the thickness of a oil drain washer and another .025" for the extra thickness of the 400EX plate since the cr500 is 2mm shorter you probably need to shim it just to equal or increase the clamping pressure
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: 4WHLr on March 02, 2014, 02:43:14 PM
That second washer pictured looks like the one that goes behind the locking/tab washer that holds the inner hub on. Its way to wide to go in the pressure plate for the lifter bearing.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: mx250r91 on March 02, 2014, 02:47:29 PM
Applied spring force can be calculated pretty easily. Measure the wire diameter, spring OD, and count the number of coils and enter into here:
 http://www.maultechatv.com/techguides/spring%20rate%20calculator/index.php

This gives the rate in lb/in then multiply this by the distance the spring is compressed by the bolt (preloaded) and you get the force in lbs.

I remember Jason (ALL250R) tested a whole bunch of clutch springs a while ago on his site and the results were from weakest to strongest CR500<86-87<88-89
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: Allison#51 on March 02, 2014, 03:47:21 PM
Quote from: mx250r91;27399
http://trx250r.org/showthread.php?2489-89-clutch-upgrade

PN. 90608-072-000


Cool thanks!
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: Fire1 on March 02, 2014, 04:33:18 PM
Quote from: rsss396;27402
the more you compress them the more lbs you will see on a scale ( I have tested this ) and this is with no coil bind so if you shim them they will produce more clamping pressure.
now the the untested thing here is a 250r spring compressed to the installed height and a cr500 that is shimmed the thickness of a oil drain washer and another .025" for the extra thickness of the 400EX plate since the cr500 is 2mm shorter you probably need to shim it just to equal or increase the clamping pressure

So are you saying run stock 250R clutch with CR 500 springs and .025 aluminum washers.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rsss396 on March 02, 2014, 06:07:02 PM
No what I am saying is, it should be no different of a clutch mod if you ran a .025 thicker drain plug washer than what Neil's mod calls for.
the 400ex plate is .025" thicker than a 250r so instead of running out and buying a different plate why not just run thicker washers, obviously this is easier said then done but
if tony can find a sheet of aluminum that gives us that number then it would be much cheaper.

i do not know the thickness of the oil drain plug washer but just as a example if it we're say .080 thick then we want a .105" thick washer to run with the cr500 springs.
or maybe the stock 250r should just be shimmed to make the mod even cheaper, but I will say there is a big difference spring tensions out there so it needs a little experimenting with different springs to find which ones will give the holding power you are looking for.

Barnett springs are normally much stiffer than stock, so taking a stock spring and installing it with washers may just give you exactly what Barnett is already giving you. Without actual testing of the installed heights of the springs you are really just guessing.
My suggestions were based on Neil's example that has worked well for him, I cannot say it's any better than just a good set of stiff springs for a 250r.
I am only pointing out if want to run Neil's mod then it maybe cheaper to just run these extra thick washers
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rablack21 on March 03, 2014, 08:03:58 AM
Quote from: rsss396;27426
No what I am saying is, it should be no different of a clutch mod if you ran a .025 thicker drain plug washer than what Neil's mod calls for.
the 400ex plate is .025" thicker than a 250r so instead of running out and buying a different plate why not just run thicker washers, obviously this is easier said then done but
if tony can find a sheet of aluminum that gives us that number then it would be much cheaper.

i do not know the thickness of the oil drain plug washer but just as a example if it we're say .080 thick then we want a .105" thick washer to run with the cr500 springs.
or maybe the stock 250r should just be shimmed to make the mod even cheaper, but I will say there is a big difference spring tensions out there so it needs a little experimenting with different springs to find which ones will give the holding power you are looking for.

Barnett springs are normally much stiffer than stock, so taking a stock spring and installing it with washers may just give you exactly what Barnett is already giving you. Without actual testing of the installed heights of the springs you are really just guessing.
My suggestions were based on Neil's example that has worked well for him, I cannot say it's any better than just a good set of stiff springs for a 250r.
I am only pointing out if want to run Neil's mod then it maybe cheaper to just run these extra thick washers

I like this approach ^^^. And I agree, this seems like this will be cheaper and easier to do this mod and still get the same great performance. I am eagerly awaiting Tony's response for these requests.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: 250Racer on March 03, 2014, 08:22:04 AM
It worked for me last year when I was in a pinch. My clutch started slipping when heated up and I didnt have the time to get a new one before my next race. Springs and fibers were at their limit. I replaced one 250r plate with a 400ex plate, scuffed up the plates and put the washers on springs and no slipage.
Title: Clutch Mod with Pics (Neil aka C-Leigh Racing Mod) - Pic Heavy
Post by: rsss396 on March 03, 2014, 09:09:34 AM
that proves how just a small amount of shim can make a big differance since there is only about .025 differance between the 2 plates so maybe Tony could make up a tuning kit with .025, .050, .075 and .100 kits to try tuning the clamping power and/or adjust for wear in the clutch assembley