OEM FJ spring = $60 or something silly
FJR spring = $30
EBC Clutch Spring (http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=383786&store=Main&catId=&productId=p383787&leafCatId=&mmyId=2359)
Dennis Kirk Part #: 383786
Manufacturer Part #: CSK903
= $21
Who's gonna be the test dummy and see if it's any good? Probably available other places, but this is where I saw it (totally by accident no less).
(http://www.denniskirk.com/denniskirk/b2c/product_images/d/k/3/600pix/dk383786.jpg)
Might be good as a second spring for slipping clutches......
If it's stiffer than stock (which wasn't mentioned in the description that I could see) it could be an alternative to running dual springs entirely. Otherwise it could be used to back up a stocker, or for $40 you could buy two of them and run them that way. Just don't know.
Is the double spring set really cheaper than a $140 coil spring conversion?
By the time you factor in the added cost of the 14mm clutch m/c needed with the double spring set up, I bet it's closer than we think.
Quote from: andyb on April 12, 2010, 09:47:31 PM
Who's gonna be the test dummy and see if it's any good?
I am on it...I have a source for EBC as well. I will get one in hand and check it out. I think I can also check the tension compared to the new O.E. ones I have in stock.
Randy - RPM
Quote from: Pat Conlon on April 12, 2010, 11:27:23 PM
Is the double spring set really cheaper than a $140 coil spring conversion?
By the time you factor in the added cost of the 14mm clutch m/c needed with the double spring set up, I bet it's closer than we think.
Wussy! Be a man and stick with the 5/8 master.
DavidR.
Quote from: Pat Conlon on April 12, 2010, 11:27:23 PM
Is the double spring set really cheaper than a $140 coil spring conversion?
By the time you factor in the added cost of the 14mm clutch m/c needed with the double spring set up, I bet it's closer than we think.
I did the double spring set-up about 8 years ago, still have the original FJ master...... no problems. Why do we "need" a 14mm clutch master?
Quote from: RichBaker on April 13, 2010, 06:12:25 PM
Quote from: Pat Conlon on April 12, 2010, 11:27:23 PM
Is the double spring set really cheaper than a $140 coil spring conversion?
By the time you factor in the added cost of the 14mm clutch m/c needed with the double spring set up, I bet it's closer than we think.
I did the double spring set-up about 8 years ago, still have the original FJ master...... no problems. Why do we "need" a 14mm clutch master?
While video games, texting, and remote controls have done wonders for virtual hand eye coordination, hand strength is quickly fading from the gene pool.
Because while it's manly, the 5/8 master with double springs is difficult to modulate as well. My 60' times noticably dropped when I went to coil springs...
The 14mm master simply makes the friction point that much longer, spreading the work over more distance. Should make it easier yet to dial in the amount of slip you want.
Well,
I got the aforementioned EBC spring tonight when I got home. I have yet to give a full comparison to the O.E. unit, but by first impressions I probably won't be buying another one. I am not sure if they are distorting the spring to give it the advertised 15% better clamping force, but this thing is bent...
I will do some measuring tomorrow when I get to the shop and include some pictures of the obvious things I see by holding it in my hand.
I am not impressed and it doesn't look to good up to this point; more to follow.
Randy - RPM
Testing is complete and I can say that the one EBC I received does not match the performance of a new diaphragm spring, and out performed three used springs by just 1.03%. Each spring was cycled two times prior to taking a reading. Each spring/combination was rated three times and each rating was consistant. I checked each spring and combination from zero to over-center for maximum clamping force.
I tested three new Yamaha springs and the tested; 289, 291, 288 lbs.
I tested three used Yamaha springs and the rated; 250, 251, 250 lbs.
The EBC spring rated; 259 lbs.
Two new Yamaha springs doubled up rated; 581lbs.
New Yamaha and used Yamaha spring; 556lbs
New Yamaha & EBC spring; 553lbs.
Used Yamaha & EBC spring; 513lbs.
See pictures and captions;
(http://fjowners.com/gallery/80_21_04_10_8_31_22.jpeg)
Yamaha spring on the left, EBC on the right
(http://fjowners.com/gallery/80_21_04_10_8_34_17.jpeg)
Stock Yamaha spring, with center fingers machine ground flat to match spring retainer plate angle.
(http://fjowners.com/gallery/80_21_04_10_8_35_13.jpeg)
EBC Spring. Outer red "T" markings on outer edge of spring are the two contact points against that flat glass plate. The two red fingers on either side 90* to the "T" marks are the high point with the center of the kink between the center of the two fingers. The distance of the warpage of the spring is an equal .030 on each as show by the two feeler gauges.
(http://fjowners.com/gallery/80_21_04_10_8_35_32.jpeg)
Close up of .030 feeler gauge placed into kink of EBC Spring.
The quality difference of the two springs are as listed;
Yamaha:
Stamped manufacturing process.
Shot peened and heat treated finish.
Angle ground fingers to match angle of retaining plate.
Consistant measurements within factory specification.
EBC:
Plasma cutting manufacturing process (rough edges).
No shot peening of the spring before or after heat treating.
Spring has "kink" which allows a .030 feeler gauge to fit under each side of the spring.
Same .030 difference on the finger side of the spring.
Yamaha maximum spec for spring warpage at the base is .004.The EBC measures .030 on each side.
The minimum finger height spec is .240. The EBC spring measures .280 on the low side and .310 on the high side. The Yamaha spring measure .270 equally on all fingers.
Like someone said in an earlier post it might make a sufficient additional double spring. It might even be easier to compress due the reduced clamping pressure. If someone wants to try it as the secondary spring let me know. If after that it is determined to be an adequate spring for the double application I will consider adding them to my inventory.
If you decide to buy one to try it, make sure you install it under the factory spring so the retaining ring does not wear through from the unfinished & pointed edges of the fingers on the EBC spring.
Ultimately after getting the spring shipped here it comes to an $8.00 difference in the cost of the Yamaha and EBC springs. I cannot do the volume a Dennis Kirk can and get the EBC pricing as well as they are. I sell the Yamaha spring for $36.95 and the EBC would be listed at $28.95
Hope this helps with the decision making process.
Randy - RPM
FANTASTIC testing and writeup Randy!!! :good2: THANK YOU for taking the time and effort to do this for ALL of us!
Data = good! I know I will now NEVER buy an EBC clutch spring. It is also very interesting that it is only 40lbs or so that separates a new yamaha clutch spring from a worn one.
My clutch has been slipping lately and I will be ordering new discs and a new yamaha spring from you shortly.
Quote from: Marsh White on April 21, 2010, 11:10:43 PM
Data = good! I know I will now NEVER buy an EBC clutch spring. It is also very interesting that it is only 40lbs or so that separates a new yamaha clutch spring from a worn one.
That was my thought as well and I have been looking at the complete clutch system since I completed my findings. I think the spring looses some tension, the discs wear and the total thickness of the clutch pack diminishes, thus exaggerating the spring weakness. The more the clutch fibers wear, the more the spring slippage becomes apparent. By doubling up the spring, you have just increased the clamping force and the clutch fiber thickness is removed from the equation until the pressure plate bottoms out against the center hub, and it starts slipping again.
That's my theory anyway...
Thanks, Randy - RPM
Good info, shame it's a crappy item! I was so excited to see another option out there, too!
As far as your idea of having the stack height getting smaller and that making things seem weak, you're likely spot on. The spring only has a very short working distance, too much pressure and it's just flat (near infinite rate), too little pressure and it doesn't contact (zero rate). Compared to a coil spring, which uses a smaller % of total travel through each actuation as well as through the lifespan of the clutch pack, it's going to feel weak much sooner.
The easy way to tell would be to get a fairly worn, slipping clutch, and just jam another fiber or steel in it to bring the total stack height back up to preload the spring again. Hrm...
Quote from: andyb on April 21, 2010, 11:51:16 PM
The easy way to tell would be to get a fairly worn, slipping clutch, and just jam another fiber or steel in it to bring the total stack height back up to preload the spring again. Hrm...
It won't work...The additional thickness makes the slave cylinder stroke too short and won't allow the clutch to disengage. There have been several people try that with the racecar and next thing they know they can't get it in gear at all...
Randy
Then swap plates until you get the thickness required. Dunno if yamaha ever made spec thickness steels, I know kawasaki did for their early 90's superbike kit clutches.
Of course, simply swapping to new friction plates would be the right answer, and modding accordingly after if it still slips....
Thanks Randy thats great info and explains alot why they slip now and then.
Do you like the double spring or the after market presure plate? (bike or car)
Bob
I choose the double spring which is what I have in both the cars and bike right now.
Randy
I also use the double spring in the cars not as herky jerky on take off, as the aftermarket is. Do you use the stock master cylinder on the bike, Mine is also a 86 (best looking year) is it harder to pull.
Thank you for your imput.
Bob
Thanks Andy and Randy for the info. I have added this discussion to the Clutch Files.
Randy sent me his EBC clutch spring to test out on my slipping clutch for the purpose of determining whether or not it would be a good alternative as a 2nd clutch spring. The thinking behind this is that because it has less force than a Yamaha clutch spring that it would have an easier clutch lever pull than doubling up two Yamaha springs and still fix a slipping clutch.
Well I can say that it works great for this purpose! I just took a spirited ride where I was keeping my tach in the 7K to 9K range (which makes you go triple digit speeds - I didn't get a ticket - but it was close!). Anyway - it worked flawlessly! No slipping clutch no matter how hard I tried to get it to do so. The clutch lever pull is a little bit firmer than stock - but not by much. So, by virtue of it's flawed spring force for use as a single spring to replace the OEM - that flaw makes it a great 2nd clutch spring!
As Randy pointed out - just make sure you put it behind the OEM Yamaha clutch spring. Took all of 10 minutes to do. No oil draining required - just put your FJ on the side stand. Easy. Oh - you might need a new clutch cover gasket depending on how old your current one is - actually - the odds are pretty good that you WILL need a new one. Randy sells those for cheap too.
Thats a great test report, Thanks to both Marsh & Randy for doing this. It will be a good (cheap) easy upgrade for most members to take on.
Bob
Quote from: Marsh White on May 12, 2010, 05:19:57 PM
Randy sent me his EBC clutch spring to test out on my slipping clutch for the purpose of determining whether or not it would be a good alternative as a 2nd clutch spring. The thinking behind this is that because it has less force than a Yamaha clutch spring that it would have an easier clutch lever pull than doubling up two Yamaha springs and still fix a slipping clutch.
Well I can say that it works great for this purpose! I just took a spirited ride where I was keeping my tach in the 7K to 9K range (which makes you go triple digit speeds - I didn't get a ticket - but it was close!). Anyway - it worked flawlessly! No slipping clutch no matter how hard I tried to get it to do so. The clutch lever pull is a little bit firmer than stock - but not by much. So, by virtue of it's flawed spring force for use as a single spring to replace the OEM - that flaw makes it a great 2nd clutch spring!
As Randy pointed out - just make sure you put it behind the OEM Yamaha clutch spring. Took all of 10 minutes to do. No oil draining required - just put your FJ on the side stand. Easy. Oh - you might need a new clutch cover gasket depending on how old your current one is - actually - the odds are pretty good that you WILL need a new one. Randy sells those for cheap too.
Marsh,
And everyone else, I am going to hold off until after the WC rally to allow Marsh to get some more miles on the spring before I add them to my inventory. I know he will get plenty of good riding time between now and the end of the rally to see if the spring will have a problems due to heat and usage.
Marsh, thanks for trying it and we will chat again for a final evaluation.
Randy - RPM
Sounds good Randy! Yes, I only have 60 miles on the spring so far - after the West Coast Rally rally I should have around 2,500 miles or so on it. I'll post an update after I return.
Well,
I understand Marsh has put over 2500 miles on the EBC clutch spring that he installed on his bike prior to the WCR. As he had attested to the initial installation back in May it seems to be a good addition to the stock spring since it does have the clamping force of a new Yamaha spring. This means the clutch lever pull is still acceptable.
The followup from Marsh;
"Randy,
It works great as previously mentioned! I put over 2500 more miles on it and I rode hard and fast and rode the shit out of it...no sign of slipping what-so-ever! Highly recommended! Only a slight increase in lever pull.
Sincerely, Marsh"
I have not added them to my inventory at this time, but can get them and sell them to you for $28.95.
Let me know if I can be of assistance to anyone.
Thanks, Randy - RPM
Hi everyone... I've been lurking for a while, and hopefully someone can help me...
My FJ: I have a 1989 FJ1200. It has a 1398 Ross piston kit, Falicon crank, Falicon rods, Lazer Stage 6 head, .395/.395 WebCams with the Hayabusa bucket conversion, APE cam chain tensioner, 40mm flatslide Mikunis, Orient Express transmission, Pingel air shifter, Dyna 2000 with a Dyna 2-stage stutter box and shift minder, lowered 4" and stretched 4" , FZR wheels front and rear, (sticky) Mickey Thompson rear drag/street tire, 200 hp Nitrous Big Shot with a NOS progressive controller and a big Earls oil cooler (The nitrous system is currently on the bench until the rest of the bike gets sorted out with the fresh motor) The V&H sidewinder has been taken off and a V&H Super Sport pipe installed to tempt ZX-14s and 'Busa's to part with their cash when they underestimate the old-school air-cooled 'dinosaur' - as they like to call it.
Problem: Yeah, even with the 6 spring conversion, my clutch is slipping... It's an old Barnett kit that has 3 heavy red springs, and 3 lighter black springs. Does anyone know where I can get my hands on another 3 'red' clutch springs before I go back to Joe Hahn at Orient Express and ask (beg?) him to dig some up? The red ones feel about doubly as strong as the regular black ones.
Thanks in advance!
Scott
Go to, www.rpmracingca.com (http://www.rpmracingca.com)
Search clutch spring and you will find Barnett severe duty springs.
Randy - RPM
What an Intro? Luv to see some pics. There`s a growing number of guys here with heaps of red Paint but I`m sure the more intelligent black, blue & pink members will chime in on this one. ..........whooops there`s one now, just as I was typing. (Yep RPM`s ya answer)