Honda TRX 450R banner

1 - 20 of 37 Posts

·
Lord of Combustion
Joined
·
14,065 Posts
Discussion Starter #1
Clutches..... wet multi-plate clutces..... they are wondeful pieces of equipment....

over the years there was an escallation of the number of plates used in the multi plate arrangement....and this was done to increase the surface area of the clutch plates to increase clutch holding power...instead of merely jacking up the spring pressure...and thus lever effort needed to work the clutch....

more & more plates is why motocross bikes have better clutch hookup combined with super easy lever pressures.... in the past here used to be springs so heavy that you would get arm pump from clutch use in a lap or 2...not so now.....

but that's the MX Bikes....not the Quads....

the bike clutches rarely need anything beyond the OEM setup for anything off-road.... the rear tire will typically break traction long before the engine would overpower the friction grip of the clutch pack....

not so on quads...think about how much more the quads have going on behind the engine than the dirt bike versions do:

1) double row axle carriers (yes, more bearings does = more firction)....

2) a comapratively HUGE axle to turn..... and you know you're just going to buy a wider\heavier one as soon as you can afford it... 2+2"

3) not one, but 2: BIG \ FAT \ MEATY\ HEAVY\ EARTH GRABBING tires....not to mention the 2 wheels they are mounted on


so...an azzload more weight to accelerate in the assembly... PLUS an azzload more tire connection to the terra firma we ride on


now... the ATV world is also way more engine building\ power obsessed than out dirt biking brethren...so we build big\ powerful engines to power all of that extra driveline stuff mentioned above.....

and what's still in the middle between of all that power, and all of thet driveline weight and traction??

your poor oem clutch...that was originally designed to handle the needs of the dirt bike....

and still, the oem clutches do an amazing job.....

In My Experience (not IMO)... the oem clutches are typically he best quality...none of the oem's want the warranty hassle, or bad reputaion...that would come from inferior clutch components....

and my own favorite clutch setup is the OEM clutch pack...with the steel plates sandblasted for extra grip.... without adding springs that would ruin the nice\easy clutch pull...and if i still need more spring pressure, i will try adding only half of the springs as extra pressure untis first...no sense going stiffer than necessary....

and seriously... the oem clutches with bead blasted steels will really hold tight with a lot of abuse....

i can usually see clutch slip during my frequent dyno sessions...long before it becomes a real world problem....

on a dyno graph... a slipping clutch will give a distinct, characteristic torque curve....the clutch will have a certain amount of torque it will transfer during the rise in rpms...of course the rest will be lost in slip\friction.... then once the torque increase per rpm is going to plateau, the clutch pack will finally "re-hook"..and what you will see is a funny, "hang-nail" like spike as the clutch stops slipping and snaps some interia momentarily into the reading....those graphs read less than actual torque up to that point...and a falsely high torque peak at that point... easy to spot a slipping clutch on a dyno graph...

anywhoo.....

on to this year in the michigan dunes (Silver Lake).... this season has seen more rains than any i can remember...the dunes have constantly had wet sand... that is, that parts that haven't been completely under water..LOL...for real...

so... this year is the year that clutches are taking an exceptional beating.... between a well built engine and good paddle tires in heavy wet sand...somethings gotta give....and it will be the clutch pack....

evidence of a slipping clutch is when you have increasing clutch lever free play.... slip = heat...and heat expands the plates thickness...and that shows up as increased free play.... which comes back into correct adjustment when the assembly cools down....

this year, just a couple passes has added enough slip and heat to my clutch packs (TRX and YFZ)...that the lever free play goes up by about an inch..... not good... and that is with bead blasted steels...plus 3 out of 6 springs with heavy pressure......

Sooooooooooooooo...... what's next?

centrifically assisted clutch pack pressure.... a centrifically weighted assy that put pressure over and above the spring pressure.....

such as the Direct Drive company's Lockout pressure plate assembly ...sold & used by site sponsor KBR...

there have been many centrifically assisted clutches ,for many years in the automotive industry.... the idea works well....

in all cases there will be some sort of weighted assembly that puts more clamping force on the clutch pack as RPMs\centrifical force increases.....AND it also means that there will be more lever effort needed to operate the clutch as rpm increases .... you can't magically add clamping pressure to the pack and not feel it when pressing against it to unclamp the pack....

lower rpm will not feel much added lever effort at all....high rpm will see the most

now... while it WILL work....KBR and many, many others have solved all sorts of clutch issues from clamping to reliability to longevity with the Direct Drive units.....clamping force increases with rpm...but clutches really slip worst during the steep part of the rise in the torque curve... so, in a magic world...it would be nice to have added clamping (and thus lever effort) only during steep torque rise through the midrange (which would also necessitate that your clutch be throttle position sensitive)....that aint happening.....

and..they do add flywheel weight to your rotating engine assy...which could be either good or bad depending on particulars.... just mentioning that it does....

so... i put direct drive clutches on both my trx and yfz..... incredibly detailed units, with CRAZY good tricked out eye appeal via the clear covers..... and quite a bargain price in out world too....

the yfz unit fits great all the way around..... no problems or special stuff needed...

the trx unit would require a special kickstarter offset for kick start models....and it requires quite a bit of brake lever cutting to get the brake lever even CLOSE to to original pedal height...not thrilled about that, but what are you going to do?

i'll see how they work next week when we have the Venom Test & Tune day at Bob's Raceway....and i'll put some pics up of the units fairly soon... hard to imagine more eye appeal on an engine part....
 

·
Registered
Joined
·
10,711 Posts
Good thread....nice write up...

I would only add/change one aspect....and that is this.... my clutch lever 'free play' gets LESS.....when my clutch heats up....

and yes...your clutch WILL heat up even when a lockout if your drag race.....

and an ASV 'quick adjust' and/or 'pro-perch' as they like to call it...is worth its weight in GOLD during these heat runs....




John...I agree about the brake lever thing......it was a PITA to get her ground down so she fit where I wanted it...and still worked properly......and...... be sure to remove your Lexan cover SS screws... clean them up....and use Loctite on them..... cuzz they do work themselves free quite a bit..... I actually purchased a complete set of these screws from DD about (2) years ago..... and I only have one spare screw left...... and this AFTER adding Loctite and a regular check of these screws.....

just some info so you dont lose your screws....lol






the lockout.....I run CR500 springs all the way around, HP tranny fluid, and Tusk fibers and dimpled plates..... been working good ever since.....




Here is a pic with the older style (6-bolt) lexan cover......you can see where the brake lever needed to be modified to fit underneath....

[attachment=31286:MVC_027S.JPG]



the newer 12-bolt version... sorry, couldnt find any close-ups....

[attachment=31287:MVC_024S.JPG]
 

Attachments

·
Registered
Joined
·
4,127 Posts
Thanks for the info,


this is one of my concerns here in the near future with my added torque/power id love to just keep the oem springs with the Dark synergy sprigs that i got, but if i wear thru them alot or get slippage im gunna have to find a different idea like the lockout
 

·
Lord of Combustion
Joined
·
14,065 Posts
Discussion Starter #4
hey Greg... your brake lever "spine" looks just like mine!...lol...

that's wierd about your clutch lever free play deal.... as metals do, the pack "grows" with heat....and since these clutches have a push rod that goes through the engine to "push" against the spring loaded pressure plate... the friction>heat>growth thing makes for a longer reach for the push rod...and that makes for more play needing to be taken up....

if it gets REALLY hot...your steel plates willwarp from friction induced heating...and then it's perma screwed...

if it didn't get REALLY ho though, when things cool down, if you adjusted your clutch while it was hot, you are now way too tight on play...and you are actually unloading some spring clamping pressure because of it... i like to have just a bit of free play at all times....


gotcha on the quick adjust clutch perches!
i love 'em.....
 

·
Lord of Combustion
Joined
·
14,065 Posts
Discussion Starter #5
Thanks for the info,


this is one of my concerns here in the near future with my added torque/power id love to just keep the oem springs with the Dark synergy sprigs that i got, but if i wear thru them alot or get slippage im gunna have to find a different idea like the lockout[/b]

i got by just fine with a good \ standard clutch setup for.... well, forever actually..... BUT...the wet sand really changed what was slipping...from tires to clutch!
 

·
Registered
Joined
·
10,711 Posts
High HP + Sand drags w/paddles.... = Lockout


John...yeah, I dont know why or have actually never taken the time to think about the equation.... but I know after several passes....I usually hafta turn the knob on my ASV lever to loosen her up........ but heck...it might just be that I am adjusting it when hot... and then it cools down sitting by on the side lines.....then I hafta adjust it again.....go figure.....I really thought mine tightened up after a few heats.....but as usual... im probably Bass Ackwards...... thats it... no more PRE-noon alcoholic beverages for me......



well....maybe no more..... lol
 

·
Registered
Joined
·
3,557 Posts
Kinda funny this came up now since I was going to ask a clutch question anyways. With my new build getting dyno tuned tomorrow, I didn't want to have any clutch slip like I did with my first dyno experience. So, I got a great deal on some HD250R springs and thought I'd give them a shot. I decided to put in three of the HD250R springs and three tusk springs. I've been told this is a strong combo being the HD250R springs are actually a stiffer spring than the CR500 springs. It did add a lot of clutch pull but the problem is, the clutch won't work with those springs. Anyone ever had this problem. They go right on with no issues but the clutch won't disengage. It's like they're binding up but I can see how. Anyone else ever try these springs?
 

·
Registered
Joined
·
11,022 Posts
and since where on the topic of clutches i also have a question

as for clutch fibers which are better kevlar, fiber, or cork? im going to buy a new clutch pack and wondered if there was big differences in the materials used

and how much faster will bead blasted steels wear out a the fibers? and how much does the bead blasted steels help? thanks
 

·
Registered
Joined
·
566 Posts
I used DD lockup clutch + OEM clutch on my KBR/Venom 501 bike which is on Extreme 22x11x8 12 paddles and IT PULLS HARD!!!

Here we go

http://www.youtube.com/watch?v=Losn6RUyJWw

Thanks for KBR and Venom :)[/b]
do you have an extended swing arm?


I realllyyy want a 501....hmmm and i have the cash now :whistle:
 

·
Registered
Joined
·
10,711 Posts
Kinda funny this came up now since I was going to ask a clutch question anyways. With my new build getting dyno tuned tomorrow, I didn't want to have any clutch slip like I did with my first dyno experience. So, I got a great deal on some HD250R springs and thought I'd give them a shot. I decided to put in three of the HD250R springs and three tusk springs. I've been told this is a strong combo being the HD250R springs are actually a stiffer spring than the CR500 springs. It did add a lot of clutch pull but the problem is, the clutch won't work with those springs. Anyone ever had this problem. They go right on with no issues but the clutch won't disengage. It's like they're binding up but I can see how. Anyone else ever try these springs?[/b]

Yeah....ive tried to tell people that those 250R springs dont really work..... they tend to rub on the stock OEM basket.... the std 250R springs....(aka 86/87 yr springs) will work.... but the HD (aka 88/89 yr springs) are just a tad too wide/thick...and tend to get hung up.... and they will not work at all in the DD lockout..... I never tried them in the stock basket...cuzz I already had a lockout when purchasing them...but several of my friends have said they rub and get hung up....so I believe em....

and...the HD250R springs arent actually stiffer.....they are just taller.... so if you compress them quite a bit... they can become quite stiff... but I have found the CR500 springs to work quite a bit better.......

I dont know about the different materials used in the clutch packs...... I know EBC offers some different types.... etc.... I got stuck on Tusk by accident.... and am very glad I did..... at first, I heard only the stock Honda clutch packs would hold up.... but after burning thru 3/4 $150 clutch packs I decided to stop buying those and go for cheaper.... since they were burning up anyways...I figured I might as well burn up cheap ones....plus keep a spare around... so I did.....Tusk... $40 or so back then.... and they come with stiffer springs and pre-dimpled plates.....so I didnt hafta sand blast all my honda plates anymore..... at any rate....I burnt up at least (2) Honda sets AFTER installing the DD lockout.......hence my reluctance to continue to purchase these expensive clutch packs..... finally.....with the DD lockout, tusk clutch pack, HP tranny fluid..and the addition of CR500 springs... I no longer have any clutch issues....(I apparently traded them for tranny issues....lol).... at least I found out that the Tusk clutch kits work quite well....and I have no problem recommending them to anyone.....

jmho....
 

·
Premium Member
Joined
·
1,294 Posts
I run 3 heavy duty Barnett or EBC springs and 3 YZ450F dirt bike springs (stiffer then yfz quad springs) with my DD lock Out and this works good. Seems to lock up enough off the line when I dump the clutch but not to hard of a lock up (allows some slip) to create a bog or just to keep the rpms up, and not let them fall down and the motor out of peak hp/tq rpm range. I also might add small washers to the arms for more clamping force while spinning too. I also like the clear cover because I can actually look down and see if I have enough free play in the able adjustment by how much the clutch pack disengages. I also would like to add that I don't ever have a problem with shifting and the clutch pull in a drag run because I left off the throttle a hair when pulling in the clutch. This relieves the clamping force and also (in my mind) saves the shift forks in the tranny.
 

·
Registered
Joined
·
286 Posts

·
Admin
Joined
·
2,546 Posts
CR500 springs are money, I have been using them + Sand blasted clucth plates for about 3 years now.
 

·
Registered
Joined
·
2,211 Posts
CR500 springs are money, I have been using them + Sand blasted clucth plates for about 3 years now.[/b]
Thats what I run...works like a champ.
I also added a 1/8 thick bronze bushing with the spring........just abit of extra insurance.
 

·
Registered
Joined
·
2,211 Posts
I have even more stress on my clutch........big power+great traction+fat azz!..........LOL.

I surprised how long mine has held up........once it starts to slip it goes all most instantly.
 

·
Lord of Combustion
Joined
·
14,065 Posts
Discussion Starter #18
some pics of the trick looking Direct Drive clutch setups (from site sponsor KBR).....

the YFZ...with a smoke colored lexan cover....great fit....nothing needs modding....

[attachment=31312:2008_072...rive0011.JPG]


and the TRX....with a clear lexan cover.... 04-05's will need DD's special billet kickstarter to clear it... and all of the TRX's will need some brake lever trimming to get decent pedal height

[attachment=31313:2008_072...rive0013.JPG]
 

Attachments

·
Lord of Combustion
Joined
·
14,065 Posts
Discussion Starter #19
I have even more stress on my clutch........big power+great traction+fat azz!..........LOL.

I surprised how long mine has held up........once it starts to slip it goes all most instantly.[/b]

lol... i forgot to add fat azz on my deal too.... plus quads already weigh as much as a dirt bike WITH a rider....before any rider even gets on them.....kind of like riding a dirt bike 2 up...

agreed on the slipping deal.... once they start to go.... they go down the tubes quickly...
 

·
Lord of Combustion
Joined
·
14,065 Posts
Discussion Starter #20
straight on shot of the TRX's DD....

you can see the weight arms on the pressure plate....the have the allen bolt and locknut on them as "weights".....the ones on top are just hanging down until the engine spins and puts some centrifical action in the mix....

and you could add or subtract weight from each arm with washers like terse mentioned.....


i even wonder if the arms themselves...with no added bolt assy...would add enough pressure to be worthwhile....if that were enough, then you'd have less flywheel weight, and less lever actuation pressure needed at high rpms.....


[attachment=31314:2008_072...rive0014.JPG]
 

Attachments

1 - 20 of 37 Posts
Top