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1973 R75/5 Back-to-road Project

BIG PROBLEM! Would appreciate your input....

I started going through things and did the following:

--Checked compression, both cylinders at 130, from what I read that seems to be good
--Started on the left side, checked rocker end play, set valve clearances and re-torqued the heads, valve clearances were slightly large but all fine now.

Now comes the fun part. The rocker arm clearance on the right exhaust valve was too large and I realized that the head bolt from the upper exhaust rocker block was loose (maybe 10 lbs or something like that). I adjusted the clearance, made sure the rocker arm still moved freely over the entire arc and when I tried to re torque the bolt, the stud was pulled out of the engine. I applied not even 15 lbs of torque and as you can see in the pic, the bolt sticks out further than the others.

Now what to do? I think what I can try is to take the rocker blocks off, tighten two nuts agains each other on the stud and ttry to turn the stud back into the engine case, hoping to catch a thread down there. Now if that doesn't work, what are my options?

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Probably will have to install helicoils or timeserts where the head bolts go into the engine case. Critical step to ensure that the oil feed holes on the upper studs are not occluded to prevent oil flow out to the valve area. Here's a website with some idea of what's involved:

http://www.gunsmoke.com/motorcycling/r80gs/cylinder_stud_repair/index.html

The critical thing is getting the insert exactly parallel with the original line of the head bolt. If not, even a small amount off at the engine case will result in a big difference at the rocker blocks. The drill guide is available out there...possibly Cycleworks sells one. In a pinch an old cylinder can be used to keep things aligned.
 
Drill and tap guide

There is a tool shown on page 20 of the September 2017 Airmail. hpd_online.com/stud_tool.asp High Precision Devices Inc,Boulder Colorado USA

I have a drill/tap guide that a very good friend made for me. It weighs as much as a bowling ball. Your /5 has 97mm openings for the cylinders where as my guide has a 99mm shank for later motors. Kurt is right about avoiding a blockage of oil flow on the 2 top cylinder studs. I used my guide on a 1988 R100RS that I owned at the time. It had 2 studs pulled loose.

I think a person could use an old cylinder to make a guide. Maybe you could knock off the bottom part of the cylinder below the fins and modify that.
 
Thanks, I had read through snowbum's page, seems like something I may not want to do myself. I still have high hopes that I can turn the stud back in and maybe find a thread or two that grab....
 
Dang, those tools are expensive! Probably makes more sense to find someone who has the tools, assuming I only have to do this once (knock on wood!).
 
What oils are you using?

While I am still pondering what to do with my head bolt I want to tackle some easy stuff and change my oils.

What engine oil are you using? My riding in CenTx can be in temperatures from the upper 50s to the lower 90s. I never really had any overheating problems with my R1200R, which amazed me, so hopefully it will be fairly similar with the airhead. Any brands of oil you prefer?

As for the transmission, drive shaft and final drive, the PO gave me 3 bottles of Castrol Hypoy C SAE-80-W-90 that have been sitting on his shelf for 10 years. Two of the bottles are still sealed, would you use them or does oil "expire"?
 
Olaf -

The March 2013 Owners News has an article I did on engine oils. You should use an oil specified by the users manual with is an SG/SH rated oil in the 20w50 grade. The article will show you ratings of oils and their chemical makeup.

As for gear oils, there will be opinions on whether to use unsealed oil or not. IMO, I would recycle those oils and just buy new GL5 80w90 gear oil. Just not worth any possible risk.
 
Thanks, I had read through snowbum's page, seems like something I may not want to do myself. I still have high hopes that I can turn the stud back in and maybe find a thread or two that grab....

I recommend Time-serts over Helicoils.

And Kurt is right about getting it perfectly square during installation. I just put two in the final drive of my R90/6, it's not something I would suggest you do yourself unless you have a machining background and have the proper equipment available to use.

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I recommend Time-serts over Helicoils.

And Kurt is right about getting it perfectly square during installation. I just put two in the final drive of my R90/6, it's not something I would suggest you do yourself unless you have a machining background and have the proper equipment available to use.

View attachment 64588

Yes I agree. It seems that I can get it done locally from a BMW specialist for a couple hundred bucks. Considering that I would have to buy/rent the guide and the fact that I have to get the oil channel in there, it's a bit too much for me....I want to do as much myself as I can but it stops here for me.
 
Yes I agree. It seems that I can get it done locally from a BMW specialist for a couple hundred bucks. Considering that I would have to buy/rent the guide and the fact that I have to get the oil channel in there, it's a bit too much for me....I want to do as much myself as I can but it stops here for me.
Excellent idea, being rational about your abilities will save you money in the long run. Btw, the guide they sell isn't really accurate enough for this particular job.

There is also nothing wrong with picking and choosing what jobs you don't want to do and leaving the things that you enjoy for yourself. I'm pretty sure I could learn to lace a rim, but I'm also pretty sure I'd be happier writing a check for that....
 
Excellent idea, being rational about your abilities will save you money in the long run. Btw, the guide they sell isn't really accurate enough for this particular job.

There is also nothing wrong with picking and choosing what jobs you don't want to do and leaving the things that you enjoy for yourself. I'm pretty sure I could learn to lace a rim, but I'm also pretty sure I'd be happier writing a check for that....

Spot on! Took me 3 hours to change the tire on my front wheel, I just wanted to do it, seems so easy when you watch YouTube videos.... I then happily paid 30 bucks to a dealer (and will do for the rest of my life) for installation of the rear tire. Never again!


Sent from my iPhone using Tapatalk Pro
 
Wow, that's a beauty!

I try to keep mine as original as possible, we shall see....I might take the bike to Harvest Classic in Luckembach on the weekend of 10/20. Only 200 mls round trip, I am hopeful I can make it. Now back to work, check points, airfilter, change fluids....
 
Confused.....

Did all my oil changes today. The Clymer says to fill up the final drive with 250cc, however it was flowing over at about 200cc. Can anyone confirm the correct amount that goes in there? Thanks!
 
Aftermarket manuals

Did all my oil changes today. The Clymer says to fill up the final drive with 250cc, however it was flowing over at about 200cc. Can anyone confirm the correct amount that goes in there? Thanks!

Just one of the inaccuracies you'll find in aftermarket manuals. The correct measurement is 100cc for the short wheelbase models and 150cc for the long. You can skimp a bit on these measurements because the oil gets thrashed around while you're riding. In all cases replace the crush washers whenever you change oils.
Also, you may hear about measuring the quantity of oil in the drive shaft housing using any which manner from a paperclip to the tip of a screwdriver. I've never seen any of these or other methods work with any accuracy at all! You might as well just drain the oil into a measuring cup/container.
There is the possibility of having the drive shaft oil migrate into the rear drive. There has been a lot written about this event. If you are going to change all the oils then it makes sense to remove the rear drive fill plug to check on the oil level before doing any draining. The level should be even with the bottom threads of the plug hole. If oil flows out when the plug is removed then it is obvious that you have said migration.
 
Whoa! Final drive or driveshaft housing?

I always filled the final drive to the bottom thread on the filler plug - and 150cc in the shaft housing.
Clarify? Please?
 
Just to clarify, I was talking about final drive, not drive shaft. When I add 200cc into the final drive, I am at the bottom thread of the filler plug, however the manual calls for 250cc.

I agree with thye quantities for the drive shaft, I read 100cc for SWB and 150cc for LWB.

Unfortunately I didn't measure the oil when I drained it, but there was "a lot" in the final drive and "very little" in the drive shaft so that sounds like migration to me.

But back to my original question, I only get 200cc into the final drive, by then it starts flowing over, can that be correct?
 
Just to clarify, I was talking about final drive, not drive shaft. When I add 200cc into the final drive, I am at the bottom thread of the filler plug, however the manual calls for 250cc.

I agree with thye quantities for the drive shaft, I read 100cc for SWB and 150cc for LWB.

Unfortunately I didn't measure the oil when I drained it, but there was "a lot" in the final drive and "very little" in the drive shaft so that sounds like migration to me.

But back to my original question, I only get 200cc into the final drive, by then it starts flowing over, can that be correct?

Fill to the lowest thread on the fill plug. That is full.
 
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