I have been trying to find a solution to a clutch that drags when my bike warms up. The scooter in question is a '99 Ultra Classic (FLHTCUI) with a little over 67k on it.

The clutch appears to be properly adjusted and has the proper free-play in the cable, and shifts smooth as silk until it has been run 10 or 15 miles...after that it is pretty near impossible to get it into neutral at stoplights, and if I don't shift all the way to 1st before I stop...well, I either have to kill the engine and bump it to neutral then restart, or lug a little to get it moving, then shift down. Shifting up as I accelerate is no problem at all.

I am currently running Harley Syn3 in the primary chaincase, and have very carefully measured it in to make sure that the level is right (just barely touching the bottom of the clutch spring when bike is level on a jack). I am comming to the conclusion that the Syn3 is just thinning too much as it gets hot to provide the proper separation/lubrication between the plates in the clutch pack, and have pretty much decided to try Redline V-Twin Primary oil. The tech bulletins and other information I have found make me feel comfortable that it might be the best solution to the issue I'm experiencing.

I went looking for the Redline, but have found none of the local auto or bike shops I have visited have it, but one local HD dealer suggested using Lucas 75w-90 synthetic gear oil. He said a number of his customers swear by it, and it is the same weight range as the Redline product, but I had not seen it mentioned in any threads I have read so far.

I bought a quart... Worst case, I figure I can use it in the transmission of my Ultra or the final drive of my Goldwing (yeah...I know that's a bad word around here....LOL) so it isn't going to go to waste, but when I got home I decided to order a quart each of the Redline primary and shockproof tranny oils from an online warehouse. I figure I might as well kill 2 birds with one stone and change out both fluids when I get it on the jack (I just changed the engine oil this past weekend, so that is no longer an issue for a while).

I guess the big question for the forum is "Has anyone here tried Lucas Oil 75w-90 Synthetic gear lube in their primary chaincase, and if so, how did it perform for you?"

 

I have been using Mobil 1 75-90 weight in my '07 Dyna since I started to change my own oil. I use that weight gear oil in the trans and primary and Mobil 1 20-50 synthetic in the crankcase.
No problems so far.

 

I haven't tried the lucas in the primary. That's gear oil and would best be used in the Tranny. I would recommend that you use the correct amount (1 qt for me) of Type "F" Automatic Transmission Fluid (any brand). I've used it in my Road King's primary for about 15k miles and the clutch engagement is much better than it ever was with Bel Ray Primary or HD Primary Fluid. Lots of others on here use it too. That's how I found out about it.

 

75-90 gear oil is thinner than 20-50 motor oil.

 

Redline MTL ( Primary oil) is a 70w80 manual tranmission lubricant that contains no moly. It has a pour point of about a 5w30 motor oil. I use it. The thicker you go the more drag you will get until the oil gets really hot. So the recommendation for the type F ATF might be a good idea. I would not use a gear oil on a clutch.

BTW, you can get the redline products at Summit Racing, Redline website or www.myoilshop.com

 

Thanks, all, for the feedback!
I'm gonna try the Redline stuff for a while and see if it really lives up to the claims, but I will take all of the suggestions to heart! If it doesn't work for me, ya know it's gonna get drained and "try sumthin' else"!
Y'all ride safe! I'll let ya know how it goes!

 

It you read up on the primary oils from Spectro, Belray,Torco,Drag and so on, you will see that they all are speced a GL5 gear lube. Says it right on the bottle.

 

From your described symptoms, I would say you need a new clutch.

 

I really hope not! It engages without any notable over-slippage regardless of the engine temperature, and stays solidly engaged when I accelerate, but starts to drag only when it's hot (using Syn3 from Harley).

I changed the drive oils tonight and refilled using the Redline products in the transmission and the chaincase (V-Twin Primary lube and Transmission lube with shockproof). I may not be able to test ride it for a couple of days because rain is moving in and the forecast has it raining through tomorrow too. I'll post an update about whether it makes a difference once I get a few miles on it.

I was surprised at the difference in two products that have the same basic weight rating, though....the chaincase lube looks like automotive transmission fluid and the transmission oil reminds me of an oily version of Pepto Bismol! Maybe good for heart-burn too? LOL

On a side note, I love the service I got from the online place I ordered it from: JEGS. I ordered late Wednesday and it was on my porch Thursday afternoon...with nothing extra paid for shipping. Guessing they must have a warehouse very close to me. The even included a cool cap and some nice decals in the box (along with a catalog of course)!

 

I'm inclined to agree that it is not the oil lubrication issue that is causing your problem. You mentioned your clutch appears to be adjusted correctly: How did you verify this? Because it occurs only when the engine is warm is indicative of expansion due to heat. If you have too much play you will not get full disengagement when the engine is warm. I'd verify my clutch engagement at the clutch hub. If it is correct then you have clutches or plates worn.