Driveline noise, need advice

[rev79xs11]

My 79sf has developed a whirring noise somewhere in the driveline. It is hard to tell where it is coming from, sounds like it may be a bearing. I ran it on the centerstand and listened to the final and middle drives and tried to listen to the trans but it is hard to make out anything there. I also drained the middle and final drives and looked at the fluid. Both had a bit of sludge on the magnet, seemed usual for 25k miles. Are there any common failures that I shouls check first?
I was thinking of pulling the side cover from the middle drive to look inside as this seems to be the noisiest when listening with a stethescope and turning the back wheel by hand.

any advice is greatly appreciated
Thanx in advance
Rev79xs11

[TopCatGr58]

Hey Ron,

Some sludge, especially after 25K is Xpected, but as long as there aren't any metal shavings, then I wouldn't be too worried about the middle drive. As long as you put in some good quality Gear/Hypoid 80/90 wt oil in it, then it should be good to go. They do make a whining noise as part of their normal operation.

Have you done the cam chain tension adjustment lately? The chain could be rubbing against the head.

Aside from the final drive oil, have you taken the drive off of the swingarm and checked the driveshaft splines, and regreased? The zerk fitting won't put the grease in the proper location, so you have to take it apart to properly grease the splines.
T.C.

[skids]

I have a 78E model that makes that noise. When I picked her up about 7(?) years ago, I changed the fluids and noticed a bunch of gunk around the drain plug and hole of the middle drive. It looked like a thick, milky substance, like ground-up chalk. I worried about that because the bike's middle drive (or tranny?) makes a noise like the granny gear of a pick-up truck. It isn't quite that noticable, but as time goes on, I think that noise is diminishing, or I am just getting tone-deaf. I have put many miles (35K) on that bike with no drive problems what-so-ever! (YMMV)

[rev79xs11]

Thanx TC, I plan to pull the swingarm tonight or tomorrow just because of the grease fitting problem. Have adjusted the cam chain recently too. The thing that bothers me is that this is a recent development. I saw something in the tech section about the rear bearing in the middle drives being dry, I may pull it and look inside just for giggles. Are most gaskets still available? Also wondering about trans gears, I may pull the secondary shaft out of the bottom too, maybe fix my 2nd and 4th gear shifting problems

[TopCatGr58]

The gaskets are available in KITS, but that's Xpensive if you're not doing that much work. Get some gasket material from local auto store and make your own!

The counter shaft gears are still available, but also expensive, hence the Dremmel fix idea. There is a synchronization process for the shift pawl. But could also have bent shift fork, or worn shift drum grooves, etc.! I don't recall what trouble you're having with the shifting? Have you looked at the Dremmel Fix tech tips? You may want to look closely at your 1st and 4th gear dogs as well as your 2nd/5th ones!
T.C.

[rev79xs11]

My shift problem is more noticeable on 4th than second. If I do the pre-lift on the shifter before I actually shift it helps but if I just shift it usually zipps into gear. Never jumped out of gear, once it's in it's ok. Shifting fast is almost impossible, at least a clean click. I'm almost afraid of what it looks like in there. Never found any signs of debris in the oil or filter. I have seen the dremel fix stuff and if I get lucky and don't have any bent forks or wrecked gears it would be great.