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Old 03-11-2013, 05:54 PM   #1
band-aid OP
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R60/6 Top end rebuild

Hi all,

I'm looking into some advice on a top end rebuild for my 1974 R60/6 with about 80k miles.

Currently the bike is running, and by my estimation, pretty well BUT I do have a lot of oil consumption issues. I am aware of several leaks but they are very slow and I do believe that it burns more than it drips. If I leave it sitting for several weeks (as i just have over the winter) I see less than a teaspoon of oil underneath it. However when I ride it, or get to ride behind it while a friend drives I observe smoke out of both pipes most of the time- it seems to fluctuate- burning more at shifts (both up and down) as far as I can tell.

This summer I took a 1500 mile trip on it and I found that it used about a quart of oil every 700 miles which seemed like a hell of a lot to me. I am running Rotella T by the way though I have tried other oils with the same result. I chose Rotella T because of its low cost and universal availability at auto parts stores and truck stops while traveling. I'm hoping not to open a new oil discussion thread but that information may still be pertinent.

The plugs don't look fouled to me (or my mechanic who I used for a tranny rebuild) They tend to be a tannish color- MAYBE erring to the slightly carbonized side- but not wet and definitely not black. I will pull them and post a photo when I'm in front of the bike.

I have also just noticed an oil leak at the front of the engine behind the alternator which I guess I will address in conjunction with a timing chain job in the very near future- as well as leaking pushrod seals. I replaced the clutch 300 miles ago and didn't notice a leaking rear main seal but I'm afraid to be honest that I was so focused on the clutch that between my tunnel vision on that job (and not pulling the flywheel) I may have overlooked the obvious.

So, my questions are several fold- What do you think is the major oil burning culprit? Rings or valves? Other? Compression is about 170 in each head (even a little on the high side?) Have not done a leak down test as I don't have the tester.

Here's the big question- I'm into doing the work myself but without a sophisticated shop, how much of a head/valve/ring job can I expect to do myself? Obviously any machining would be done by an outside shop (recommendations near NYC are helpful) but what can I do? Can I just send the heads away complete with pistons and expect to have them ready to assemble and bolt right back on?

I'm not a complete novice- I've replaced the clutch, throwout bearing, a timing chain and complete electrical system on another airhead, and do all my own routine maintenance but I've never taken apart the top end and I'm unsure of what's really a DIY job. I would appreciate any thoughts on how much of this work to do myself and how much to outsource and then bolt back on.

Thanks as always, guys.
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Old 03-11-2013, 06:53 PM   #2
photorider
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There are many here much wiser and more experienced than I but, I got the same bike, with about the same amount of miles and it was in overall similar condition when I got it a few years ago so maybe you can benefit from my experience. Disclaimer: I'm no mechanic. I'm just a guy that lives in an apt. that loves to tinker with things.

You can save a lot of money if you're willing to get a little dirty and take the different parts off the bike.

The timing chain (as you already know) is a DIY job. Can be a little tedious but that will take care of the oil leak behind the alternator cover.

If it hasn't been done, you may be due for a full valve job at 80K. I was. This is not a DIY job but there are several places where you can send the heads out to to get valves and guides replaced and you'll get them back looking new and ready to bolt on. It's not cheap, though. It can also take several weeks. I had Ted Porter do them and was very pleased with everything but the wait time. However, for me sending them out was the only option and in the end I'm glad I did it.

While you're in there I would consider new rings (which you can do yourself) and possibly a cylinder hone. When you're done with all that you will have taken care of the pushrod seal leak and any possible cylinder base leaks.

You've already done the clutch and transmission, after this you should have nice smooth running airhead for many years to come! (BTW if you didn't notice a leak when you removed the transmission and clutch I would just leave it alone).

It's been a very rewarding experience getting mine running just right and I hope you have a similar one.

Good luck with it!
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Old 03-11-2013, 07:24 PM   #3
disston
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I also don't like the arguing about oil. So I will not comment on which brand of oil you use. But you do not mention which weight oil this is and the weight is possibly related to the smoke. You should be using 20w-50 oil. You are allowed to use 10w-40 in the Winter but I would recommend the heavier oil since you do seem to have some oil burning.

With 170 pounds compression on both sides I don't think you need any serious engine work. There is a lot of talk about doing the exhaust seats but it is mostly the larger bikes that have problems with this. But an engine with that much compression shouldn't be burning oil.

It is possible you have breather problems and could convert to the modern reed valve breather to fix that. There are seals to do and and the push rod seals. All of this is DIY.

If you think you need more work than just replacing a few seals the heads usually get sent out and the owner will do the rings. If it needs pistons you get boring. For new rings it only gets honed.
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Old 03-12-2013, 03:12 AM   #4
Bill Harris
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Ditto on the 20W-50 weight oil.

Typically, pull the heads and jugs/pistons, send them to an experienced shop for cleaning, inspection and machine work, then reinstall. That is what the novice or the pro would do. I don't know who to recommend in the NYC area, but many "local" BMW shops use Randy Long:

Randy Long
Long's Mechanical Services
R.D. 1, Box 685-K
74 Risbon Road
Honey Brook PA 19344

610-286-5870

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Old 03-12-2013, 07:27 AM   #5
band-aid OP
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Thanks for the input thus far. I've called Randy Long and left a message. I think between my bike and two other friends we may be sending him three sets of heads so maybe we'll get a volume discount!

With regards to the oil- I'm running Rotella T 15w40, at Snobum's recommendation but perhaps I'll try 20w50 again. I think I've had the same oil consumption with both weights but it's an easy thing to test so next change I'll switch it up.

Disston, thanks for the advice on the oil breather valve. I'm going to look into that as well. If I understand correctly, a good indicator may be a wet air filter and or a slightly more fouled right plug vs left if the breather is faulty and leaking excessive oil into the right carb?

Anyone know what I should expect to pay for a valve job and cylinder hone?
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Old 03-12-2013, 07:46 AM   #6
disston
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Randy Long has got to be the busiest Airhead Machine Shop on the East Coast. Everybody, other shops, send their stuff to him. Right now is a busy time, I think almost anytime is a busy time. Don't expect any quantity discount. I don't think he is hurting for business. I actually wonder if the guy ever gets any time off.

He can probably give you an estimate of time for turn around but take this with a grain of salt. If he says 1 month or less maybe it'll be 5 weeks. I don't think he's slow at all but I do think he is really busy.

And of course this also implies a heart felt endorsement for Randy Long.
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Old 03-12-2013, 07:52 AM   #7
Biebs
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Wink Valve job cost

You will be in the $700 to $800 dollar range with all new valves.

Valves are expensive!!


Also your compression is high - you may just have carboned up oil rings and combustion chamber.

you can steam clean combustion chamber with watet spray into carbs

also run some mavel mystery oil in the crankcase and gas may cleanup oil rings.

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Old 03-12-2013, 01:02 PM   #8
Renner
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At 80k miles my first guess is the valve job will require new guides.
Maybe you're anticipating this. I would go with new valves too as their failure can be expensive.

My 75/5 was a subtle smoker which ran great.
One day a friend was riding it while I followed on his bike. I was convinced it was time to address the issue.

Short story: the cylinders were tapered far enough to require boring to second-over.
That was cheap but the pistons were a bit pricey.

Maybe your R60 won't be worn that much.

These engines can be worn way out of spec and still run very well; a top-end is often the tip of an iceberg.
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Old 03-13-2013, 12:57 AM   #9
Plaka
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Quote:
Originally Posted by band-aid View Post
Hi all,

I'm looking into some advice on a top end rebuild for my 1974 R60/6 with about 80k miles.

Currently the bike is running, and by my estimation, pretty well BUT I do have a lot of oil consumption issues. I am aware of several leaks but they are very slow and I do believe that it burns more than it drips. If I leave it sitting for several weeks (as i just have over the winter) I see less than a teaspoon of oil underneath it. However when I ride it, or get to ride behind it while a friend drives I observe smoke out of both pipes most of the time- it seems to fluctuate- burning more at shifts (both up and down) as far as I can tell.

This summer I took a 1500 mile trip on it and I found that it used about a quart of oil every 700 miles which seemed like a hell of a lot to me. I am running Rotella T by the way though I have tried other oils with the same result. I chose Rotella T because of its low cost and universal availability at auto parts stores and truck stops while traveling. I'm hoping not to open a new oil discussion thread but that information may still be pertinent.

The plugs don't look fouled to me (or my mechanic who I used for a tranny rebuild) They tend to be a tannish color- MAYBE erring to the slightly carbonized side- but not wet and definitely not black. I will pull them and post a photo when I'm in front of the bike.

I have also just noticed an oil leak at the front of the engine behind the alternator which I guess I will address in conjunction with a timing chain job in the very near future- as well as leaking pushrod seals. I replaced the clutch 300 miles ago and didn't notice a leaking rear main seal but I'm afraid to be honest that I was so focused on the clutch that between my tunnel vision on that job (and not pulling the flywheel) I may have overlooked the obvious.

So, my questions are several fold- What do you think is the major oil burning culprit? Rings or valves? Other? Compression is about 170 in each head (even a little on the high side?) Have not done a leak down test as I don't have the tester.

Here's the big question- I'm into doing the work myself but without a sophisticated shop, how much of a head/valve/ring job can I expect to do myself? Obviously any machining would be done by an outside shop (recommendations near NYC are helpful) but what can I do? Can I just send the heads away complete with pistons and expect to have them ready to assemble and bolt right back on?

I'm not a complete novice- I've replaced the clutch, throwout bearing, a timing chain and complete electrical system on another airhead, and do all my own routine maintenance but I've never taken apart the top end and I'm unsure of what's really a DIY job. I would appreciate any thoughts on how much of this work to do myself and how much to outsource and then bolt back on.

Thanks as always, guys.
Do a wet compression test. What do you get?

While you have a plug out shine a penlight in the spark plug hole with the piston at TDC on the exhaust stroke. Look at the piston crown for serious carbon build up. You can also see the seating surface of the exhaust valve (may have to check a bit before TDC) and see if it is badly worn (thin sharp edge=bad).

You can check the intake valve too but the exhaust will go first.

How does the power feel? How long have you owned the bike (in miles)?


I use a Streamligh Reach for lighting up the combustion chamber. it's an LED on a stalk business. You can make one with an LED, a resistor and a battery.

What grade of gasoline are you using? Whose?

With the rocker cover off an the right side, look at the area around the exhaust valve rocker (on the head). Lotta brown deposit? The intake valve side should be nice and clean.

Count the question marks, they all matter.

Plaka screwed with this post 03-13-2013 at 01:04 AM
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Old 03-14-2013, 03:03 PM   #10
chollo9
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bmwrench (ADV handle) in the Northeast just did my heads. Beautiful work, reasonable, fast turnaround for this time of year. His website is: http://thenickwackettgarage.com/bmw/

Impossible to know, but if compression is good, and the problem IS in the top end, I would lean toward it being the valve guides. Teardown is the only way to find out.
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Old 03-14-2013, 03:14 PM   #11
bpeckm
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Leakdown tests, etc are all good... but have you looked at the gobbler/pcv/crank vent system? They can throw a lot of oil into the carbs. Iirc the vent goes into one side only on the /6... take a look at that system before you get into the big-bucks stuff.....
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