Final Drive Heat buildup

[Guest]

Out of curiosity, anyone ever check the temperature of the final drive after a ride?

My back wheel doesn't spin freely and I was thought I might use heat buildup to try to determine where the friction is coming from. After about 5 minutes at 70mph I checked the final drive assembly with an infrared thermometer. It was about 150 degrees F. Warm to touch...wouldn't want to leave your hand on it for long, but not too hot to touch.

I also checked the brake disc. I didn't use the rear brake on that ride and it was about 85 deg.

So if any of you shafties out there want to take a short ride and then lay a hand on the final drive, I'd be interested in the results.

This ride was on an '82 GS1100G. She's coming along nicely and turning out to be a very cool bike. This one's a keeper.

[Agemax]

if you didnt use the rear brake and it measured 85 degrees then it sounds like the pads are binding. remove the caliper and see if the wheel spins any better. if it doesn't then at least you have ruled the caliper out. then its time to look deeper

[katman]

if you didnt use the rear brake and it measured 85 degrees then it sounds like the pads are binding. remove the caliper and see if the wheel spins any better. if it doesn't then at least you have ruled the caliper out. then its time to look deeper

Well put, common to have a sticky cal piston on these old beasts

[tkent02]

What was the ambient temp when you did this test?
85f isn't much if it was 80 degrees out that day.
How hot does the 850 get in the same conditions?

[TheCafeKid]

Not uncommon for the final drive to be rather warm to the touch. Not retardedly hot, but warmer than one might expect it to be. Lot of friction and gear spinning going on back there...

[Dogma]

Some wild guessing here... Let's assume you use 30 HP to cruise at 70 mph, and the final drive is 95% efficient. That's 1.5 hp lost as heat. I could see that getting a bit warm. Imagine what an 1100 W (=1.5 HP) soldering iron could do to that gearbox after 5 minutes. (40 W for electrical soldering, 400 W is almost hot enough for plumbing.)

I think I'm guessing high, but there should be some heat generated, as TCK notes.

Pop the fill plug out and check the oil level in the final drive. How many miles since you changed it (and the secondary drive)? They're due every 4000 miles.

[Redman]

LarryA,

Two comments:

- Like asked above: What can you state about the gear lube oil? Level Okay? Changed in last year or two? or several thousand miles.

- Rear wheel doesnt turn easy. Put on center stand when its not turning easy, pry the pads apart and try to turn then. If lots easier, well then there is your problem. And will need to rebuild the caliper, or at least exerecize the piston by prying the pads apart and then pump lever and then pry apart again. (watch that resivour doeant overflow while prying the pads back) do that a few times. Then you will want to change out the brake fluid.

.

[Steve]

I don't think that prying the caliper apart is going to help his rear-end temps.
If the caliper were sticking at all, the disk would be reading considerably over 85 degrees.

Haven't had the GS out for a while , but I just got back from a ride on the Wing.
Was going to check the final drive temp for you, but can't find my meter.

.

[bwringer]

if you didnt use the rear brake and it measured 85 degrees then it sounds like the pads are binding. remove the caliper and see if the wheel spins any better. if it doesn't then at least you have ruled the caliper out. then its time to look deeper

85 degrees Fahrenheit is about 29.4 degrees in Celsius...

In other words, only slightly above ambient, so the caliper is fine.

[LarryA_Texas]

I did forget to mention that the air temp at the time was about 75deg...this is texas. So the brake was slightly warmer than ambient. I would think that would happen with just some contact friction with the pads, but that's why I asked the question. I will change the oil and check for caliper drag by removing the brake assembly.

What about grease between the final drive and the wheel? Any recommendations? Reading the final drive breakdown and re-assembly instructions in the shop manual looks like something I would like to avoid. I notice in several places a special tool is involved...followed by a picture of a hammer.

Just want to know if others have ever noticed the heat buildup on the final drive after a ride.

[Steve]

OK, finally able to get back with some numbers.

We were out for a short ride today. Went up to CafeKid's place to meet with Griffin and LarryD. The way back to my house includes a couple miles of city streets, six miles of freeway, then another couple miles to my house. Takes about 20 minutes. Temperature today was about 90. As soon as we got home, I held my infrared thermometer right up to the 850's final drive and got a reading of about 125F. Just for comparison, the final drive on my Wing showed 130F. Neither of these is blistering hot, but probably warmer than I would want to hold my hand on for very long.

.

[SqDancerLynn1]

WHat you are reading is perfectly normal

[Steve]

Yeah, I thought it was, I was just answering the original question posed by LarryA_Texas.

.

[lurch12_2000]

....What about grease between the final drive and the wheel? Any recommendations? Reading the final drive breakdown and re-assembly instructions in the shop manual looks like something I would like to avoid. I notice in several places a special tool is involved...followed by a picture of a hammer.

....

If you're talking about what grease to use on the mating splines, then use Moly60 applied with an old toothbrush to cover all surfaces. I would remove the wheel spline anyway to soak in 1" of kerosene to get all the old junk/dirt off and check for wear. If it's gold colored, then you might want to replace that soft metal spline now before facing roadside repairs. It is real easy to remove the spline....tap and straighten the locking ears with a good wide screwdriver, remove the 6 bolts and spacers, then use 2 flat head screwdrivers to evenly pry out the spline for cleaning and checking. I would not try to remove the pumpkin side's spline unless you suspect something wrong. It can be cleaned with the old toothbrush dipped in kerosene, wiped clean with a rag, and then apply a light coat of Moly60 grease to it also.

EDIT: I noticed you have the '82 1100G which will have the poor quality spline unless a PO already did the change!

[lucabond]

Just got from a ride and measured 117 deg at the pumkin. I had wondered about this myself.