Clutches slippng in higher gears

Hey! guy's well the 120"Ultima might be proving to much for the clutch set up. hotroadking, I believe you mentioned I might not have enough clutch set for it.Well the break in is done and of course when I tried to turn all those ponies loose thats when I find, maybe not enough clutch? Last year when I put the Ultima 6 speed in it also did the whole primary. cogs ,chain,hydrolic tensioner.kevlar clutch kit with the extra plates to do away with that stock double friction plate crap! 30 percent heavier spring also new pressure plate. I'm running 20/50 Amsoil in the primary. 1st 2nd 3rd 4th are good. I've felt it slip in 5th and 6th. Other then that, it's all good. The clutch is in proper adjustment. Reading thru some threads I see some about using ATF.What do you think?

I thuoght it was clutch adjustment at first. So I double checked and the adjustment was fine. I have a set new tires to put on it yet. So I did a burnout just to check to see if I could get to slip and it didn't. 1st and 2nd gear burnout holding the front breake. I was on a long straight of way and in 5th 2500 rpm and twisted it when the power started to come on 3200 ..3500 started slipping shift same in 6th. asoon as it starts in to the power band it lets loose? what do you think about the ATF. I was thinking of pulling the clutch pack and inspect and clean maybe scuff the friction plates up and then dump the ATF in it?

Most of the clutch makers recommend ATF in the primary(Except HD of course) Barnett and BDL say type F, Primo, Dextron III. I read in another forum a guy ran Amsoil 20-50 in primary and his clutch slipped and Amsoil rep said to run their Super shift ATF. I would think no harm in trying a jug of ATF and if its solves the problem ,great. How do you like the 120"?thinking about one in my heritage too.

Cool! I think I'll try it. The 120" is real nice, I'm lovin the power. I'd like to have it at the back wheel ,instead of spinning in the case, lol. I think you like it also if decide to go with it. The 120" went in like it belonged there. No real issues. Go for it ...........

they will always slip in the higher gears not the lower gears, the output is closer to 1 to 1 in the higher gears . Todd

strick9Rob,

i am with hotroadking. my 107 was slipping the clutch on my dresser. bought a heavier spring readjusted and tried again. but you could do like i do and exhaust all options and spend as much as you can on different sh*t that don't work and then go buy a rivera pro clutch. i finally bought the pro clutch and never looked back. just my .02

later...............................

With the ponies and torque yer puttin out with the 120" it would be a good idea to put in a clutch that can handle the output. I'm using a Scorpion and the other guys seem to like Primo, I don't know if one is better than the other,I'd say they're comparable but both are made for hi output applications. No sense havin all that power and unable to get it to the ground.
Try the ATF and if its still slippin,you know what to do next.

Hey ! hrk, paco, everybody, I just picked up some B&M trick shift synthetic I'm going to pull the clutch pack inspect & clean ruff up the friction plates. and give a try. If not, it'll be a while before I can put the money out for real clutch, I blew my wad, on the motor. I'll let you guy's know how I make out...
...........................Thanks,,,,,,,,,,,,later.

If the clutch is going to slip, it'll do it in higher gears long before it will in lower. In the lower gears there's a "torque multiplication" factor & the engine delivers more power to the rear tire than the engine is actually making. But not for long 'cause you have to shift & the stress on the clutch increases exponentially as you get to high gear, typically a 1:1 ratio. Overdrive trannys are even harder on the clutch in top gear 'cause while the engine is putting what it can to the clutch, the amount actually going to the rear tire is reduced.

With respect to oil, I wouldn't even consider using motor oil in the primary or the transmission because it doesn't have the "additive package" for the application. Neither does automatic transmission fluid. Special additives are needed to make a "wet clutch" work right & 75W90 gear lube with those additives is what the primary calls for. I personally use Red Line synthetic, but there are other good products - but all the same weight & with a similar "additive package". The ratings are different between gear lube & motor oil, but although 75W90 gear lube is about the same viscocity as 20W50 motor oil, they most assuredly are not the same thing.

In the tranny on the Land-Speed-Record setup I've always used Red Line "Shockproof" fluid which is quite different but made for an application like that. In that application the light version, but the heavier would be better for street use. My street Sportsters share the primary fluid with the trans, but in the LSR application they are separate & BT trannys are separate too.

You can throw the "one size fits all" sales pitches out the window - use the proper fluid for the application - or you'll wish you had. I hate to harp on this, but if you've seen as many engines, transmissions, clutches, etc. scattered in pieces as I have because the wrong fluid was used, you'd know why I do harp on it. Why blow up a perfectly good engine, tranny, etc. simply because the wrong oil was used for that application?

And here's another thing about clutches - setup is HUGE. Back over 6 years ago I needed a clutch for the Land-Speed-Record setup that hit a tick over 180 mph & was geared so tall it'd pull 77 mph in 1st gear. Spent all my "mad money" on the engine & while I looked @ the "Bandit" & "Rivera Pro Clutch" (both of which are very, very good & the drag-racers prefer the Bandit), the guy I was working with (& still do) who runs a Pro Nitro Harley drag bike & makes parts for them (got 2 U.S. Patents) said just go get a stock Sportster clutch.

Setup is everything, but a stock clutch will handle what you're doing. He's been working on such setups for over 40 years & I haven't, so I got the clutch & had him set it up. Now if 167 HP to a sticky radial tire & gearing that tall won't kill a stock clutch on a concrete racetrack, running 1 mile from a dead stop to 180 mph, I don't know what will. 2 years we ran that setup in LSR events (numerous records & a Championship) until we ran out of $$$ but trying to get back to the track again that clutch is still there & there's not a thing wrong with it.

And I don't like to speak badly about aftermarket companies who make parts for us, but I do have to mention what that engineer / H-D indy shop guy & another indy shop guy who deals mostly with Japanese "crotch rockets" have said - neither will sell or service Barnett clutch products because there are too many problems with them.

- Art

another option on a slipping clutch is a lockup pressure plate. some use flywieghts, some use ballbearings. with either you can use lighter springs, lighter lever . when engine gets over 1500 rpms the locker locks the clutch tight no slip. amsoil reccomends using there 10-40 oil in the primary now, and 75-90 gear oil for trans.

Hey Art, Can I ask a couple of questions? I'm using a scorpion clutch. Did the guys tell you what the problems are they have with them, and is there a way to cure it?(other than getting a Bandit or Primo)Why would the tech guys at these clutch manufacturers tell me to use ATF type F "it has the best friction modifiers for friction plates" is what the tech from Barnett told me,the instructions for the BDL clutch pack said to soak them in Type F ATF.Iv'e read on forums that Primo tells them to use Dextron III and Energy One's site says;
What should you presoak them in?

ATF Type F. (No Dextron. Has slipping adjacencies.)
20/50 motor oil - no synthetics.
B&M trick shift works very well. Just stick plates in a zip lock bag with oil for 10 - 15 minutes. Wipe off excess and install.
I can understand why not to use Syn oil in there because its grip not slip you want. I looked up Type F ATF on the net and it is used for pre '77 trannys not in the newer ones.
Would there be a difference in what you presoak them in and run in the primary? I guess thats a few questions not a couple eh.
I'm not trying to argue with you but would like to tap into your knowledge. I can see from your other posts you have a wealth of knowledge and are willing to share it,and the more I can learn from guys like you ,the better off I'll be.
Just checked out Bandit website.. They add a little more info,

NOTE: We recommend the use of ONLY automatic transmission fluid or Golden Spectro Gear SAE 80 Primary Chaincase Lubricant in our clutches. DO NOT use the HD oil or similar oils in the primary, especially with Kevlar plates. Using the HD oil will make the clutch drag and slip. ATF is inexpensive and works great, but can be difficult to prevent leakage in some bikes where the engine to primary case seal is not perfect. Golden Spectro 80 contains friction modifiers which actually increase the friction between the plates and allows the clutch to carry more power with the same spring pressure but is slightly higher viscosity than the ATF and can aggravate clutch drag in a bike with limited release travel. DO NOT use a full synthetic oil, these are often too “slippery” and will make the clutch slip.

Sure, anytime - might not know the answer though. If I do I'll tell ya - except for certain racing "secrets" ;-)}

From what the fellas told me, the Barnett clutches are prone to slippage & the whole clutch-pack can come apart. The fella @ ECS Engineering says he won't use 'em period & Lee's Performance says he got 6 setups to try when his "crotch rocket" customers started complaining - all 6 wore out in no time & that was that - no more Barnett products in this shop.

Both guys I know personally & have so much experience I don't doubt what they say. And both deal with engines that make HUGE power - LSR bikes we work on @ ECS & the "High Noon Racing" Harley drag bike there has run 6.98 seconds @ 208 mph in the 1/4 mile. I've used the dyno @ Lee's & he has several LSR records too - including riding the Suzuki Hyabusa that holds the track record over @ Maxton, NC @ a tick over 250 mph. I'm an engineer too, but when they speak, I listen.

You have a lot of variables, including what materials are used to make the clutch plates & what fluid @ what viscosity with which additives is needed - there is no "One size fits all" primary/clutch/trans oil. I'm not a chemical engineer (worked for one though) so I can't tell you what works best with what, I just go with what I know works.

When someone can prove to me there's something better I'll try it - but not until I see the results 1st. For example, I was a real "hard sell" on synthetic, but I liked what I saw with Red Line & even had a long conversation with a chemical engineer there. And another one @ Mobil about their synthetics.

I'm sold on Red Line now - numerous Land-Speed-Records with 4 Sportsters in different classes & my old '95 Sportster street bike likes it too. Used to use H-D "SportTrans" in it & switched to 75W90 Red Line - the gears click rather than clunk & the clutch is smoother too. And that fluid has the right additives for that application.

The "additive package" is what is crucial for the application. Oil doesn't "wear out" but the additives sure do & many which apply to this application do not apply to that. And for example, if you're old enough, you'll remember having to pour in a little bottle of additive when you changed the fluid on a vehicle with a "limited-slip" differential that has "wet" clutches in it. Don't put the additive in & the differential won't work right.

Those additives are in several fluids now & you don't have to buy that little bottle anymore (still got one for a GM "Posi" rear end), but you have to read the label of the product to see if it's formulated for your setup.

But a stock clutch setup properly with the proper oil will handle upwards of 200 HP & there's no need for an aftermarket clutch, unless you're a drag-racer making more power than that. As mentioned, a 1650cc Sportster making 167 HP has run 180.025 mph with a stock clutch.

- Art

Thanks Art, complete and thorough answer as usual. I had a feeling you were gonna say they are prone to slipping,got that goin on now. I thought it was the HD primary fluid I put in, because it was a lot thicker than the BelRay gear oil I put in first.But thats a a whole different story.(Road trip breakdown)So to fix the POS clutch I got ,I should be able to just change the clutch pack??(frictions and steels) and still use their hub,pressure plate,and springs I hope,be a lot easier than poppin out and pressin in another unit. I never believed in that 1 oil in 3 holes either, of course you all remember HD sayin Syn oil was a no no, until they came out with there own, then Holy Crap!! its good enuf to use everywhere.uke: B.S.
I do remember the lil bottle to add to the dif for the posi, but I was way too young to drive. So the ATF type F would be OK to use but 75-90 gear oil or the Spectro 80 would be better. And Red Line you feel works best.
When you go fast guys talk, I'm definately listening,you never stop learning.(Only a fool thinks he knows everything) I would never try to get the carefully guarded winning secrets from you. They're what give you the edge over the next guy. Can I guess that the guy that set up your stock clutch to put all that power to the salt ,doesn't use the stock diaphram type spring? Thats as far as I'll pry on that, I promise .

Being's that you've had problems with that unit & a lot of other people have too, it just makes sense to me to "bite the bullet" & get new stock one.

Yeah, a lot of folks forget that the same H-D dealers that are pushing the "one size fits all" synthetic were saying just a few years ago that they've void your warranty if you used synthetic @ all.

Of course under the Magnuson-Moss Warranty Act Congress passed in 1975 they couldn't actually do that, but people believed 'em anyway. Only way the warranty can be voided for not using a specific lubricant is if the dealer provides it for free or you use one not made for that application.

I would not use ATF in a Harley primary unless the clutch manufacturer specifically stated to & why. And many years ago we used ATF & specifically B&M Trick Shift in some manual transmissions for drag racing & while the shifts were quicker, you had to rebuild the tranny all the time too.

There's a "shear factor" with chains & gears that tends to wipe oil right off & that's a reason for 75W90 gear oil being recommended for a H-D primary - it's thick enough to resist that - ATF isn't. And again, it's the "additive package" that's crucial for the clutch working right - slipping when you want it to & not when you don't. Some fluids have it, others do not, but the label will tell you if that fluid is formulated for a "wet clutch" & the Red Line I get is.

Only thing I saw when changing from SportTrans (which was also gear lube with the right additives) was a little leak that didn't show up before. Some say synthetic causes leaks but that's not true - it just finds tiny cracks, crevices & imperfections better & the primary gasket on my '95 Sportster needed to be replaced anyway.

That clutchpack is bone stock. From where ECS Engineering is, Carolina H-D is the closest & while we talked about the Bandit & Rivera clutches, Earl said just go get a stock one. Setup is the key & since he's been doing it for 40 years & the dealership had the whole unit in stock, I just went & got it & let him put it in. I'd been running all over chasing parts anyway, so that was just another stop on the list.

Also, on the salt the tire spins all the way down the track so the clutch doesn't take a beating there - but it can @ Maxton, NC, where you're on concrete. But if the rider knows how to leave the line well, it's not a problem. The 3 years we ran there it never was & if we can get back this year, the same clutch will be run again.

Bone Stock clutch!!WOW, Well I guess there isn't a street bike around that would need anything but a Stock clutch.
Sorry to hijack your thread Strickt9Rob, but at least now there should be no doubt as to what clutch to run and what oil to run in it. Getting it set up right is the key.

Thanks again Art, you're making this the best site on the web.

Hey Art...just curious, who is it that recommends 75/90 wgt in the primary? Is this for stock bikes? I use it in my tranny, but have always used straight 40wgt in the primary without ever having a problem.