Clutches slippng in higher gears

Clutches Slipping

Art,Thanks for the info I think I'll try the redline in makes more sence I don't think that B&M trick shift is good for the primary. Like you mentioned about the shear factor even thuogh it's a sythetic ATF. there no viscosity I'm thinking chain and gear wear would be excellerated?? Any way I'm going to do what you suggested 75-90 RedLine .I'll lett you know How I make out.It seems like it only slips when you really excellerate hard in 5th and 6th if you roll up on it easy its holding. I dont ride that hard all the time, but it's just, that I wish it wasn't slipping. You know what I mean? ...Thanks....strickt9Rob.

Red Line specifically, but that's the right weight with any brand. One thing about H-D is they often don't put the weight of the product on the label - like the SportTrans fluid I used before (which was 75W90) & also front fork oil. Also, gear oil ratings are confusing in that they're not the same as engine oil - 75W90 gear oil is closer to 20W50 engine oil.

It's easy to assume that 75W90 is way too heavy since you wouldn't put 75W90 oil in your engine. But the API (American Petroleum Institute) classification method is different & gear oils are formulated quite differently too. And the "additive package" is quite different. While lots of folks get away using an engine oil in the primary/trans, it's far better to use the product formulated for the application & I alwys have.

- Art

Yeah, it'll get slung off the part of the chain that's not in oil & wiped off the gears a lot easier & faster than gear lube, which is formulated so it won't. And with repect to the clutch, if the right additives aren't in the fluid, a thin & real "slippery" oil like syn. ATF can certainly make the clutch slip.

I'm very pleased with it, both for street & racing use. Only downside is it's so darn expensive.

Hey strickt9Rob , For what it is worth i did a 883/1250 conversion had no clutch issues before but since the conversion top two gears on heavy roll-on also light up my clutch.Also checked adjustment per the HD manual it was right on.Was running Mobile1 V-Twin 20-50 , dumped and went back to the HD primary chain/gearcase fluid , with some improvement ,still slips though on heavy roll on.

Hey Art, This is what is on the back of the Castrol Hypoy C gear oil;
Hypoy C 75W-90: exceeds API Service GL-5 lubricant for extreme pressure conditions and provides superior low temperature performance for smoother gear shifting and differential operation in colder climates. Maintains a thick oil film even under higher temperatures and is recommended for service fill of limited slip differentials calling for an API Service GL-5, SAE 75W-90 gear oil.

I was a kid(12) when my dad had me working on his cars, and my poor memory thinks that the limited slip differential is "Posi" which is a clutch pack in the rear end. Is that right?

Sounds like that Castrol would work just fine for you. And to answer your question, yes. There are different type "Posi" differentials, but most have clutches which are designed to be "locked up" going straight, but allow slippage of up to 11% when turning, as the outside tire has to go farther & faster.

Clutches Slipping

Hey Guy's , Well here's where I'm at, after pulling the clutch pack cleaned and scuffed up the steels. replaced the fluid with Redline 75-90 .It seem's to be working. I took a ride down the NYS thruway to Newberg ,OCC had thier grand opening,Well any way it was a good test for the bike hammered down and back 160mis. round trip running average 85-90 mph couple times 110+ didn't feel any slipping. But I'm im still going to go with somthing different when I put some cash together. Maybe the Ultima open drag primary. Any way. Thanks for everyone's input Art, hrk, paco,everybody..... later

Glad to hear the bike is working right again, strickt9Rob !!

You may want to go with a different primary setup, like open with belt-drive, but you shouldn't need to do that. They are neat & if I was made of $$$, I wouldn't mind getting one myself. But since I know a stock clutch will handle 167 HP / 125 ft/lbs torque on concrete in a bike geared so tall it'll go 77 mph in 1st gear, I'll stick with stock. And I'll stick with the Red Line 75W90 too.

One other thing I'll mention is I've got a Zippers trap door which seals the Sportster trans off from the primary & you can run a different fluid in the tranny like a BT. In that setup I use Red Line "Shockproof" fluid in the trans. It's recommended for BT's too & I saw that another guy in this group uses it in his BT & is pleased with it. It's formulated specifically for trans applications.

It does not have the additives for a wet clutch though - the 75W90 does. So that's why I use the 75W90 in the primary & Shockproof in the trans. The 75W90 will work fine in the trans too, but the Shockproof will take more of a beating & at the track, the trans does get beat on - especially with an air-shifter.

Clutches Slipping

It seems to be hookin' up real good like you said, hrk I mght be revisiting the issue.but right now it's all good. I'm not out pounding it every time I ride it but when I do lite it up it seems to be holding.....So for now it's good.....Thanks Guy's.................later