Last night I did a 5K fluid change on my RK. At the 1K service ("free" at the dealer) I had them use Syn3 in all 3 holes. I really disliked how the bike's clutch behaved with Syn3 in the primary, so swapped that out with Redline Primary fluid after a couple hundred miles, and am very happy with that change (got rid of the minor clutch slippage at take-off).

I replaced the Syn3 in the crankcase with Mobil1, which I'd used exclusively in my previous H-Ds.

Now for the "cocktail". Was too impatient to order Redline tranny with shockproof - heard many good things about that - and instead bought a qt of Royal Purple 75-90 and a qt of Royal Purple 75-140 gear oil. I put a 50/50 mix of the two in the tranny, just to see how it dealt with the infamous H-D "clunk". Well, so far after riding it this morning, the clunk is still there to almost the same degree - some improvement, but not dramatic. Downshifts do seem to be quite a bit quieter, though. We'll see how it goes. Have no idea whether mixing the different weights will prove to be better/worse over the long haul, but thought it would be interesting to see. Colder weather commencing here, so didn't want to go full with the 75-140 this time.

 

Interesting you are experimenting on a brand new bike. Good luck with it.

 

So, what does that equate to, like a 75-115? I really don't believe you would have even noticed a difference in either one you used, not sure what the logic is behind mixing them, but hey, to each his own .......

 

Yeah, I guess my (il)logic was to try to approximate a 75-110 without searching all over to find a place that stocked a synth in that spec. I know Mobil1 makes that product, but not easy to find locally and figured why not just give it a go with both combined from a mfr (Royal Purple) that has a good rep, and see if any noticable difference. Yep, experimenting with a new bike, but figured the downside risk was not significant and might pay off with a positive result. Poor scientific approach to testing, but I plan to keep an eye on it and I replace fluids earlier than required anyway; it's easy to monitor/replace with a qt off the shelf - and working with the bike is good time spent.

 

i'm thinking that you're not gonna see any adverse effects from that. i'm running royal purple 75-90 in my tranny right now. as far as positive effects go, some people have unrealistic expectations (not saying you do, but....) of what their oil is gonna do in these old timey gear boxes. but if it makes you feel better, i'm sure it can't be any worse than the syn3 you had in there to start.

 

Bingo on the Syn3. No unrealistic expectations, just curious. I have such a small set of "data" that unless I saw a dramatic improvement/issue, I couldn't really offer yea or nay to the results being a direct result of what I tried. After riding last night, I did notice even smoother shifting, but honestly don't think the 50% 75-140 has done anything more than a full dose of new 75-90 would have accomplished. I'll take it as it goes, and see if down the line the shifting improvement stays. May also try the Redline gear oil next time, if I plan ahead a bit better. Cheers~

 

I knew a guy that tried that same mix, trans seized up, and caught fire, the bike burned down to the ground, within 100 miles!!!





not really!! let us know how it works

 

LOL! Fluids are such a touchy subject on here, so it's nice to see responses from the folks so far who 'get' that this isn't like me trying to split the atom in my kitchen.
Latest update (after a massive 75 miles) is that the 'clunk' into 1st is still only somewhat less clunky since the cocktail. However, finding neutral appears to be easier (both up or down, where with the Syn3 it was sometimes difficult coming up from 1st and was almost impossible coming down from 2nd), and gear changes at speed in all gears is a bit quieter. Given the minor differences I'm seeing, I think it likely it's just use of a better product vs. using a mix that results in a somewhat "higher" range. If I'd let the Syn3 go longer before changing I might say it was just due to new fluid, but the Syn3 looked very clean when I drained it. On the other hand, it could be that I replaced the H-D chrome oil filter with a black one.

 

22K bike.....don't skimp on fluids.

Buy the shock proof and do it right.

~Joe