50 wt. syn. in primary

[butch62236]

how about some opinions on running 50 wt. synthetic motor oil in my primary....it's good quality but dont know if its ok for clutch??? i'm planning on using 75-90 synthetic in my transmission......we use 50 syn in truck transmission and 75-90 in diffs.....great stuff....any thoughts? harley changes oils so often dont know what to think....

[DblackmanC]

50 wt. anything sounds too heavy for me! I use ATF type F with good success. You will get many different suggestions.
Dan

[madjack]

  Butch, My first thuoght is, probly be to heavy a vescosity, causing some drag in the plates. While alot of  guys are putting trans fluids in, with good results, I've been the gauntlit of products( tried them all). In the end I have settled on the H-D primary fluid. Only because it "seems" to work the best in my application. Gene

[pddredduece]

Your primary is like a clutch pack in a auto trans. 50 wt is to heavy. I use redline MTL,a lot are using Trick shift auto trans. fluid with good results, the plus to the trans. fluid is if you have a leak you will know it's the primary because the fluid will be red! I hope this helps!

[dakota224]

put the 50wt in the motor 

[Dennis The Menace]

Hurst Hot Shift fluid here...works great with my SE clutch pack...07 RG

menace

[05FLHTC]

Hurst Hot Shift fluid here...works great with my SE clutch pack...07 RG

menace

I ran out of the Redline MTL & went with the Hurst trick shift in mine a couple of weeks ago, seems the same and Trick shift can be had alot easier then the redline...cost is not an issue, it's only 1 quart twice or maybe 3 times a year.

[machinist]

Rotella 30w works great, Allison truck auto trans aproved, too.

[Horizonmech]

 50wt will work if you are stuck somewhere, but not out of choice.....30wt is OK but reg ATF in the primary is also good......oil in the primary is basically only for chain lubrication.....the HD clutch can and will work fine in a dry environment.......(ref 81-82 sturgis models)

[JC 92FXRS]

I've been running 20-50 syn in my primary (91 FXRS, stock setup) for years never a problem...just make sure it's "motorcycle" oil, i.e. NO friction modifiers. It will state this on the container. As far as gearboxes go...90W gear oil only for me.
The ATF guys are really common too, so I'm sure it works too.
These discussions commonly border on religion
Cheers, Jeff

[boooby1744]

dexron type,synthetic............cheap insurance............ the lighter weight will stand up to higher heat and will dissipate heat faster....imho.

[ridemyEVO]

If your a moderate rider on the clutch 50 would be ok but its a bit gummy for hard riding IMO.

[surf]

This a copy and past straight from Redlines website:

"MTL is a low 70W at very low temperatures and a high 80W, nearly an 85W, at elevated temperatures, providing adequate viscosity to prevent wear and deaden gear noise".

Ive heard there's a difference in weight measurements between gear oil and motor oil, but that still makes MTL sound like some thick stuff.

Not that there's anything wrong with that and I'm not trying to be a smart ass, but why do people say "Do'nt put thick oil in your primary, but use MTL.

[surf]

I just read a little further down the page on Redlines website:

 
MTL
MT-90
75W90 NS
75W140 NS
MTL

This 70W80 GL-4 Gear Oil (SAE 5W30/10W30 engine oil viscosity) is designed for use in manual transmissions and transaxles.

Did'nt realize the weight difference was that big between gear lube and engine oil. May have answered my own question.

   

[fxrp]

how about some opinions on running 50 wt. synthetic motor oil in my primary....it's good quality but dont know if its ok for clutch??? i'm planning on using 75-90 synthetic in my transmission......we use 50 syn in truck transmission and 75-90 in diffs.....great stuff....any thoughts? harley changes oils so often dont know what to think....

Butch,

Back when the synthetics started marketing to cycles they had to test the Harley lubes because HD didn't label them. Hell HD still doesn't label the primary and transmission fluids, the govt. made them label the motor oil.

At any rate the HD primary fluid tested to be no more than a 10w-40 motor oil and the transmission lube was a 75w-90 gear lube. With the wet clutch the lube you use can't have any friction modifiers. The Mobil 1 20w-50 has friction modifiers so those that use Mobil 1 often use the Mobil 1 10w-40 in the primary. Amsoil and Red Line for example don't use any friction modifiers so you can use their 20w-50 in the primary.

You'll get a lot of good suggestions here about products that work in the real world. Based on the replies do a little research and choose the lube you like.

Paul

[Don D]

I use ATF, simple to find and not expensive. Chain case resembles an automatic transmission, or tractor with steering clutches as related to oil needs.
BTW be careful comparing EP fluid advertised weights with motor oils. You will find when looking at the product data sheets that EP Gear oil in the range of 70W is closer to 30W motor oil 
All motor oils use detergants and anti-wear additives such as Zn and P. All EP oils have an EP additive package. Neither is needed in the gearcase.