[DMC]

We have found for stock bikes any oil in the primary will work some better than others, but if you are a big bore boy or a stroker nut ;that the synthetic gear oils,,,,,75/90 really make the clutch hook up. I have built 110hsp motors and used the stock clutch spring as long as you use the 75/90 in the primary,,,,,,if you use 10/40 or 20/50 in the primary on these style of motors you will need to upgrade the clutch spring,,,,,,its the way it works around here for us anyways.

That's quite interesting, I have deducted from reading these boards, that some guys are using Mobil1 75W/90W in their trannies, but this is the first time I've heard of it being used in the chain case/primary. Looks to me like the heavier gear oil will add life to a clutch period. What do you like in your tranny and crank case?

It would just be to damn easy for me to use Mobil1 15W/50W in the crankcase and Mobil1 75W/90W in both the primary and tranny.

I have been reading up on this quite a bit today, and being somewhat possessed by the need to understand oil, I study it quite a bit.

You being a engine builder/motor head, I'm sure you have read up a bit on this subject as well. I don't buy into HD's Recomendation of 20W/50W Syn for all three holes, Not in the best lubricant available for each application.

Thanks for sharing

Don

 

[DMC]

Thanks for sharing the info on the Mobile1 15/50 red cap. The jury is in and I'm going to use that in the crankcase and primary, and Mobile1 75/90 in the tranny. I guess the M1 15/50 won't cause clutch slip. I'll be sending the lubes off for analysis, on the next service. If anybody wants to get a good analysis, I get very good ones from Shell. They list like 30 or more properties including TBN, fuel dilution, and viscosity.

Thanks Again

Don

 

[DMC]

As far as the primary goes no wet clutch manufacture will ever recommend a gear lube coming into contact with their clutches and has additives that could harm the clutch plates of time. That fluid was never designed for clutches. Also the clutch could care less if it is a 40 or 50 weight oil. The oil is only being used to cool the plate material during engagement and disengagement. Now with this said there could be some radical situations where a person might find something that works better, but it isn't meant for continuous street use and certainly not for long service life.[/QUOTE]


George:
I have read many of your posts on this board in a short period of time, and I respect that you have done your homework on this subject.

To say that no clutch manufacturer will ever recomend gear lube coming into contact with their clutches. Is just plain wrong. How many limited slip applications are there on the road? I work on Tug Boats and we have Rolls Royce thrusters on a Z Drive Tug that has Mobil Gear 629, in the box in a wet clutch application. Several of the other boats that we have use gear oil in conventional clutch/gearbox applications as well. And Some of the older boats use Mobile gear 630. The 630 is as 220wt oil, and the 629 is 150wt industrial gear oil. I don't think it has the hypoid rating however.

So I wouldn't say that no one is reccomending gear oil in a wet clutch application. Now in all fairness yes there are many manufacturers, that recomend hydraulic oil in wet clutch applications. I think this is the same scenario we run into with auto transmission lubes. It all depends on the clutch material. I have another interesting tidbit of info, DTT Transmission Builders up in the NW, are doing a test on a 47RE Dodge Truck transmission running Mobile1 10/30.

Yes there are just about as many oil opinons as there are a$$holes. Some are worth reading, some not. Go to any forum that has a discussion on oil, and you will see a lot of different opinions.
I can say that you are one of the more knowlegable Amsoil guys that I have run accross.

Thanks

Don

 

[DMC]

I am somewhat keptical about the Gear Oil in the primary, as I think it may make the engagement quite grabby. I would imagine that would cause difficulty when driving in traffic, and may increase wear.

I think I'm going with the M1 15/50 in the primary, put the 15/50 in the crankcase today and it was running about 195* in stop and go traffic. I think that is pretty decent.

Going to put the M1 75/90 in the gear box in the next few days as well.

I'm not knocking Amsoil by any means I just like Mobil, and Chevron.


I'll post back on this thread how it goes.

Thanks for all the good info guys.

Don