Gear Lube

As part of refreshing and tuning my recently purchased 1980 XJ650 Maxim, I intend to replace the shaft drive differential fluid. I've been extensively searching through and reading numerous posts on the subject, but I'm still left with a couple questions on what should be a seemingly easy subject. First, I know an 80 weight oil is what is called for, but many on this site seem to be using a 70/90 with no issues. I purchased a quart of 75W-140 full synthetic however, and now I'm wondering if that will be too high a viscosity or not. Should I look for something else? Second, I read on a posting that you shouldn't use gear lube with a GL-5 rating, but instead, use GL-4 rated lube because it won't eat the bronze. The GL-5 rated full synthetic I'm looking at states on the bottle that it protects against the corrosion of bronze and copper bushings, so I'm wondering if this is still an issue. Thanks for the help once again!

 

We have been through this bronze issue before and afar as we know there are no bronze parts in the XJ final drive. So the GL-5 is ok. I also wouldn't worry about the 75-140w unless you are driving in Canada in the winter. For Nevada, Mo. it should be fine. We have also found out that the synthetics are better for the final drive since they keep the gears running cooler.

 

Use the Best stuff you can get.

You won't be doing it that often.

I do mine once a season. 85/140 Synth (Sunoco)

 

Rick is right, use the best you can get.
I put Lucas 75/140 Synthetic Gear Oil in mine.(because thats what we had in the shop at work). It's a really good grade of gear oil.

 

Thanks for the help guys! Most of these things seem like common sense to me, and I usually guess right, but I figure it's better to double check on some of these simple things when possible just to make sure I don't screw something up. So far this 1980 Yamaha has been a lot easier to work on than the 1981 Porsche 924 Turbo I bought a few years back...it still hasn't seen the road..

 

Similar issues come up with the crankcase oil too.

An 80 weight is an 80 weight.

A 75/90 has the viscosity of a straight 75 when cold, and the viscosity of a straight 90 when hot (whetever temps cold and hot are, the guys at the American Petroleum Institute set the test specs). Bottom line is the 75/90 will work better than a straight 80 at low temperatures and better than the 80 at high temps.

The petroleum engineers have been busy since the early 1980s, we have more multi-viscosity lubricants and broader ranges than were available when the bikes were made.

Same thing with the motor oil. I think (too lazy to open book) the manual calls for 10w30 for cooler temp riding and 20w40 for higher temp riding. No reason not to slap a 10w40 in to cover the whole range. Given the age of our machines and the likely larger than stock clearances in bearings 20w50 is probably a good choice unless you like to ride down into the 30s and below.

 

An important factor, age ... yes; but there are some guys who have LOW Miles on their bikes.

You have to go with circumstance and how you ride and how often.

Once it gets warm enough to ride; my car is parked and the bike is my main ride. I'd go to the Train Station to pick up my wife on the bike, if we didn't stop at Duncan Donuts on the way back.

Plus, since I'm one-up ... and pretend I'm running second to whoever is in front ... I need Oil in there that will let me play Gran Prix all the time.

I've been very satisfied with Castrol GTX 20/50. It's the Main ingrediant to all my wins on the Gran Prix Circuit.

I ride like there are no roads ... only Race Courses. And, I keep the Max Tacked-up and in the Power Band ... all the time.

 

Rick, it sounds like you ride your bike the way I drive my car. I'd probably ride my bike that way too, but that's probably not safe since I've only been riding for a few weeks now. I'm not real sure what is considered low mileage for a 1980 bike, but mine's just over 10,000. Seems low to me. Oh..and a quick question since I can't find the post I saw this on before, does anyone know what the starting VIN # was for the 1980 650 Maxims? 4H7-???

 

1980 XJ650G 4H7-000101 to 4H7-100000

1981 XJ650H 4H7-100101 to 4H7-300000