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Sick R100, follow up

O

oldowan

Guest
You guys were dead on, it was the valve clearance (all four). I had never done that adjustment before as the bike is still new to me. I took out my manual and followed the procedure ( had to run out in the middle of it to buy a torque wrench). All the valves had 0 clearance. I thought I was doing something wrong, so I went through the whole thing again. Sure enough, 0 clearance on all four. I set them all to spec, put it all back together, started it up and it idled just fine, no coughs or hiccups.
I just wanted to thank all you guys for your help, it was invaluable.
If you're ever passing through Denver, give me a ring because I owe you a beer or two.
Thanks again,
Mark Reidy
Denver
720.256.7552
 
Great! Glad it worked out...now you can keep an eye on the clearances over time...it'll give you some insight on the health of the heads.
 
There is a reason why BMW sets the Maintenance Service Interval at 6,000 miles. In my experience, when the state of health of the valves was newer, they would be just starting to close up about this time, so when changing oils, etc., valve adjustment was just part of the ritual.

When the valves start seriously closing to near zero in a thousand miles or so, the end is near, and the sooner a valve job is done, the better.

Also, BMW changed the valve clearance specs more than once since your bike was made. I ended up using .006" Intake and .008" Exhaust. I remember reading numerous iterations of these values like .004 & .008, .006 & .010, etc. as kind of an ongoing discovery during those days as unleaded fuel became the norm and the EPA squeezed harder on emissions to the detriment of the older engines. The 6 & 8 seemed to work pretty good.

If your bike has not yet had a valve job, it likely does not have the hardened valve seats. If this is true, then the valve job will be more costly with the extra parts and machining required, but there is no alternative.

Ride Safely,
Brickrider
 
brickrider said:
If your bike has not yet had a valve job, it likely does not have the hardened valve seats.
Click to expand...

BR -

Are the seats really "hardened"? My understanding is the new seats conduct heat much better than the '81-84 seats they used. Heat was the killer... The new ones could be harder...I don't really know the specifics of the metallurgy. Certainly, they work in the hot environment better. Just my thoughts...
 
Hmm...Good Point.

I don't know the exact metallurgy for sure either. I remember that this was the terminology when the new part numbers for the changed valve seats first came out. They were called "hardened valve seats" by everyone talking about the problem in comparison to the original ones.

It does stand to reason that the material is "harder" in that it would take a much higher temperature to break it down, which in turn makes it more resistant to heat. So hardness in general nomenclature would mean, I suppose, relative resistance to heat, while hardness strictly in metallurgical terms may refer more to a material which is brittle.

I don't know that BMW ever released information on the exact composition, except to say, "Here are the new parts. Use these."

I also remember that for a short period of time, until BMW finished changing all these parts around, stainless steel replacement valves were all the rage. The hardness of SS was a claimed superiority over BMW OEM parts. I believe that fad quickly died because the valve seats were as much the cause as the valves. I believe they tried SS replacement valve seats, too. I wonder how many cracked under high heat and stress?!! There were many glorious predictions by aftermarket vendors as justification for the doggone stiff price they charged for those things, but somehow I don't recall any accolades regarding SS valve longevity by satisfied "real users".

In any event, the new parts are a band-aid. As I stated in the previous post, I could never get more than 40,000 miles on a valve job. Once they cranked the displacement up to 1000cc, the maximum capability for this engine was reached in the horsepower wars with the rice burners and the ever encroaching regulations of the EPA. The real solution is called an Oilhead. Take a look at where the cooling oil circulates.

Yes, I rode my Airhead hard and put it away wet more often than not. Paid the price, too.

Whatever the case, if the original valve seats are still in the 1983 engine, they need to be replaced. Mark, I suggest that you check the valve clearances after 1,000 miles. If they have begun closing, start checking with your dealer for service costs.

Ride Safely,
Brickrider
K1200LTC
 
Last edited:
Seat Material

The best place I could find information (other than in BMW archives!) on the materials in the '80s seats was from what Oak wrote in his March 2002 expose in the Airmail newsletter. Oak was a metallurgist IIRC and first reported on these problems back in the late '70s/early '80s in the MOA magazine. He's since resummarized them in this Airmail newsletter.

His information is that the '81-84 seats were made of stainless steel, high in a nickel/chrome-alloy. The '85-on seats were M-2 tool steel with high amounts of tungsten and vanadium. He mentions it was the same seat material used in the Harley heads of the time.

He doesn't mention anything about hardness, but does cover the issue with heat transfer, especially in the 1000cc motors and with the pulse-air system that was installed then.
 
Anybody tried using Valve-Tect or other "lead substitutes" to prevent the problem (or at least delay the inevitable)?

I invested in a couple bottles of Valve-Tect and have been using for a few hundred miles since first valve adjustment on buying the bike (with 22K and unknown history). Too soon to tell but I'll check again maybe 2-3K on.
 
Hi,
Leaded fuel, lead substitute, valve jobs, etc. only delay the inevitable for the '81-'84 boxers. The valve seats did not allow the valves to transfer sufficient heat and, therefore, the valves eventually deformed. New valves and guides cured the problem, for a while, until THEY also were affected. The only sure-fire cure is to replace the valve SEATS with the current ones offered by BMW. Depending on mileage and condition, probably valves, valve guides, valve springs, etc. should also be replaced. The problem is more pronounced on the 1000cc bikes, but it is there on 650, 800 and 1000cc motors.
 
keelerb said:
Anybody tried using Valve-Tect or other "lead substitutes" to prevent the problem (or at least delay the inevitable)?

I invested in a couple bottles of Valve-Tect and have been using for a few hundred miles since first valve adjustment on buying the bike (with 22K and unknown history). Too soon to tell but I'll check again maybe 2-3K on.
Click to expand...

I am currently using ValvTect...it was suggested by Oak based upon its use in old marine engines which still need leaded gas. I've been on some kind of lead additive for the past 20-30K miles...all seems fine. I misread the quantity instructions and was putting about 5-6 times too much per tankfull...I ended up fouling a spark plug after a while...doh! I just checked valves this weekend...90K on the original seats/valves. Everything was OK but one exhaust valve was a skosh tight...I could still get 0.008 in there, but it was more drag than I'm used to. I loosened it up to be consistent with the other valves.
 
:buds
oldowan said:
You guys were dead on, it was the valve clearance (all four). I had never done that adjustment before as the bike is still new to me. I took out my manual and followed the procedure ( had to run out in the middle of it to buy a torque wrench). All the valves had 0 clearance. I thought I was doing something wrong, so I went through the whole thing again. Sure enough, 0 clearance on all four. I set them all to spec, put it all back together, started it up and it idled just fine, no coughs or hiccups.
I just wanted to thank all you guys for your help, it was invaluable.
If you're ever passing through Denver, give me a ring because I owe you a beer or two.Thanks again,
Mark Reidy
Denver
720.256.7552
Click to expand...

:stick So when 9,000 plus BMW owners show up for the new Denver rally hope ya are warned:buds :buds :buds :buds :buds :eat :eat :bottle :bottle :D :D

Glad you fixed her.:heart
 
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