Leaky rear drive

[montmil]

The following tech tip is courtesy of SueCanada with assists from New Hampshire Mike and Eric:

So I learned something big at the MOA Rally... The dome on the 17mm rear drive filler cap is supposed to be raised up around about 3/16 inch over the nut. By walking over to New Hampshire Mike's R65LS "Tillie", I immediately saw that my LRB was not the same and needed work.

Eric cleaned the holes and separated the nut and the cap and cleaned it all up. Voila, no more oil spewing out and the only dirt is brake dust! I had always blamed the O-rings on the brake actuating arm for this problem or worse suspected the gaskets in the rear drive.

So if your rear drive appears leakey when going long and hard, make sure the rear final drive domed filler oil cap is raised up from its 17mm nut by about 3/16 inch. Keep the inner holes and under the dome clean.

If you don't have another R65 or R bike to look at, how would one ever know that the breather holes are hidden under that dome? Which on my bike is now, over the years, pushed down on the nut so flush it looks welded there and quite normal! Not in our manuals!

SueCanada

Thanks, Sue.  I went out to the shop and confirmed that the filler/vent bolts on both my R65s are squished down tight against the hex head of the drain bolt. Here's the 1981 with some oil mist possibly visible on the rear housing.



And this is the revised dome covering the vent holes. I'll wait until tomorrow morning when it's cooler and do a road test. Hope this works [smiley=thumbsup.gif]     Monte

[nhmaf]

Fingers crossed for ya - you can try the "press it to your lips and blow" test, or I usually just squirt some WD-40 or other cleaner into the inside (cap held upside down, and look for it to come out/up the sides.  God to wear eye protection during that step..
 

[montmil]

Fingers crossed for ya - you can try the "press it to your lips and blow" test, or I usually just squirt some WD-40 or other cleaner into the inside (cap held upside down, and look for it to come out/up the sides.  God to wear eye protection during that step..
 

I really don't have a high probability of success but it's worth a shot. It was so darned hot yesterday that I just stayed in the coolest place -with motorcycles- that I could find.

Previously tried the Press to your lips and Blow routine while searching for an exhaust system leak. Really should have first let that muffler cool down. [smiley=3stooges.gif]

Monte

[Yikes]

Just checked mine - zero clearance.  A quick fix when I get home.

Thank you Sue, Mike, Eric & Monte!   Who knew?

John M

[Bob_Roller]

That's one of those items, that I never even thought about checking for obstructions .

Add it to the yearly maintenance check when the weather finally cools down (November !!!) .

[suecanada]

All the credit for properly diagnosing the problem with my oily rear wheel drive and its need to breath goes to Eric (Eckhart Bromse) . My riding buddy long into BMW's. He will be 75 this October!! Doesn't look it does he Mike? Over the years when I/we use a socket to tightened down that filler 17mm nut, it will gradually push the dome top down. Maybe a deep socket would not push it down? Anyway, if ya don't know it's suppose to be raised there will be trouble in river city!!!!

Thank you Monte!! I think we may find that it was a smart thing to mention all this.

There is something is my mind that tells me I read something over at Boxerworks or Airheads...somewhere....about a breather hole our newer R65s didn't have or at the least not in the same place as the older bikes...anyone have any idea what I could be trying to recall??

[nhmaf]

Let's see.... Vent holes in gas cap, in speedometer/negative battery cable bolt on transmission case, and in breather cap on final drive..
There is a crankcase breather valve that was originall a spring with plunger disc valve thing which was changed to a reed type valve, possible with the R65 bikes but then also on all airheads by 1981, I think.
There are drains holes in the starter "housing", or the depression in which the starter sits, so that water that may get into the area from the slots in the starter cover may drain out to either side of the engine, I think.   I am not coming up with any other breathing orifii, though...
But, my memory is certainly not perfect..

[montmil]

A quick note on the "disassembly" of the rear drive fill/vent bolt...

Be advised, to remove the domed cap on my '81 R65 required breaking the spot weld at the very top of the domed cover. If you remove the assembly from the drive housing, you'll likely see a small area that indicates the weld. I noticed this after working the domed cover off the bolt extension. You may also spot it after cleaning the interior of the upper extension of the bolt.

I went on to trim some length off the dome cover than had to jig everything in place so I could silver solder the little dome back home. I really love my little BernZomatic butane torch.

If I elect to mod the '83s fill/vent bolt I believe I will try my Dremel mounted with a small cutoff wheel. Note to self: Use caution not to cut thru the interior vent pipe.

Monte

[Justin B.]

Somebody do this thing up in the Wiki...

[montmil]

WiKi dunt likey me 'n me Mac [smiley=mad.gif]  M

[Yikes]

A note of caution here, the clearance should be more like 2-3mm, definitely not 3/16.  Or best to just pry it up until the vent holes can be blown clear.  Moving it 3/16 will most likely cause it to separate into two pieces (like mine did  ) which you really don't want.  Nothing a little well placed spot of epoxy won't fix until the next parts order.

The good thing is you can really get it clean when it's in pulled apart.  But it's sure breating easier now!

Keep it between the ditches,

John M

[montmil]

So I took the bike out this morning after the recent "fix" on the rear drive fill 'n vent bolt. Beat on the scooter pretty good and gave it a hearty run. Two possibilities now exist: 1)I'm either out of gear lube or, 2) The better breathing bolt idea is working. I saw no oil drip hanging on the rear drive case.

Not yet ready to say that the stuffed venting was the total drippy oil issue, but so far...

Monte

[nhmaf]

IT is definitely easier on the hardware to put the nut in a vise and use a screwdriver or something similar to just tap-tap-tap the dome and its circular sleeve outward by tapping down toward the floot (dome end is lower, and vise jaws on the sides of the nut). It is just a friction fit down inside the nut/bolt and this avoids breaking welds  from prying on the edges of the dome.

[montmil]

IT is definitely easier on the hardware to put the nut in a vise and use a screwdriver or something similar to just tap-tap-tap the dome and its circular sleeve outward by tapping down toward the floot (dome end is lower, and vise jaws on the sides of the nut). It is just a friction fit down inside the nut/bolt and this avoids breaking welds from prying on the edges of the dome.

Ah ha! Thanks, Mike. Now I'm better motivated to tweak the 83's bolt.

[suecanada]

Yikes has it right for the measurement I guess....I guesses 1.7 mm too much maybe but the impt. thing is to raise it up. I can't properly remember if Eric had mine totally apart in two pieces or not. We sure tried to clean it up though. I had some Simple Green and others had WD40.

I just took another good look at my bike and I gotta say there is no new oil or drips and it is dry and clean even around that brake actuating arm pivot and there usually was a very small drip at the bottom of the drive...no more. And that is after say 1200 miles from TN to W.Va to Eastern ON and then the 6 hours back home again! Yah!