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Valve Adjustment bolt out of travel

Werner1111
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Re: Valve Adjustment bolt out of travel

Post by Werner1111 »

Perhaps someone installed the only valves they had sitting around, just to get it on the road, and they were the wrong length (too short).
R69 R90/6 R100/7 R100S R1150GSA S2R1000

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srankin
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Re: Valve Adjustment bolt out of travel

Post by srankin »

Perhaps someone installed the only valves they had sitting around, just to get it on the road, and they were the wrong length (too short).

This is a debility that is part of Previous Owners Disease, WHAT is the history of the bike? It IS very possible if the bike is second hand to you, the previous owner should never been allowed to touch a wrench. I hate to say it but it is a common malady in airhead BMW bikes.

Unfortunately even the heads themselves could be wrong, LOL, it is surprising how much mismatched and screwed up parts an airhead can have bolted on to them and still run fairly good. Same goes for wear and tear. Perhaps the 22K is NOT the original mileage, maybe more like 220K?

I really wish I could be more positive and give you a quick straight answer but I can't. At this point, I myself would pull the head and jug off, inspect the lifters and cam. I don't know if Snowbum's website has a list of dimensions for lifters, and valves for each year and model bike. But after disassembly as much of a comparison to specs would be advised.

Perhaps, contacting Matt Pakerhouse, Brook Reams, Anton Largidare, Tom Cutter. or Ted Porter would help? I won't promise they will help but it can't hurt to ask. St
Owner of a 84, R80RT and 78, R100RS

gregflyn
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Re: Valve Adjustment bolt out of travel

Post by gregflyn »

Thank you again for all the great responses.

Previous owner told me he barely touched the bike. He had a collection and this one was bought for the Wife and not ridden. It obviously gets murkier further back in the history. Previous owner was a Doctor or son of one. And also barely rode it.

This is my first BMW but I’ve had a few other bikes. I’m also a Marine Engineer. Without being too modest, I really think I could tell if this was a Partscaster. The whole bike looks original, and stock original.

The worst thing I found in the 6-7 years of owning the bike is that some idiot Shaker-Can sprayed the engine silver 🤪. I spent hours getting what I could off.

I certainly hope that someone who does that wouldn’t trust themselves with a wrench. But who knows.

From here, my most important questions.

Did thickening the head gasket help with Pinging? Did it hurt the bike to ride around with so much less compression? Am I going to hurt anything if I just flip the lock nuts on the valve adjuster bolts and head on down the road?

Thank you all again for the responses.

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schrader7032
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Re: Valve Adjustment bolt out of travel

Post by schrader7032 »

I don't recall if you had discovered that there were base gaskets. Certainly the R60/5 and R60/6 were prone to pinging due to the cam profile. So, a thicker base gasket would lower the compression ratio. The gasket is shown in the parts listings and I think is 0.67 mm thick.

If you think there might be a valve wear issue, I would be watching the valve clearances over time. If the gap begins to close up after shorter and shorter intervals, then you would need to address that issue more quickly before it drops a valve.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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srankin
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Re: Valve Adjustment bolt out of travel

Post by srankin »

Hello Greg,

Sorry I winged on about the previous owner and POD. Hanging around an airhead shop a couple of days a week, I see all kinds of bikes come in for service and repair. It is really sad how some people care for their bikes.

Anyway, good news the bike is NOT a Frankenstein's monster.

So to answer your last questions, lowering the compression by adding a base gasket reduces the possibility of pinging. And if the proper thickness gasket was used it would not affect ride ability unless you are on a race track. I don't know the particular specifications for you bike but I would guess it would have a compression ratio of 9.5 to 1. As Kurt mentions perhaps with that model's cam timing, pinging may have been a problem. By adding the base gasket, more or less the compression ratio would be lowered to 8.5 to 1, which is what BMW did overall for the US market bikes in the early 80's.

As for putting on the lock nuts and riding Kurt's picture shows the proper set up and length that should be showing on the lock nuts as I am used to seeing on my two bikes and my previous third.
It would be a really good idea for you to continue to solve the issue rather than to continue with what you had.
At this time, unless someone else has an idea other than what has been discussed, I would suggest Writing one of the known repair shops and asking them for help. I believe Snowbum will respond, Tom Cutter at Rubber Chicken Racing will answer email questions if given a small donation. Ted Porter used to do head repairs, has now stopped that to concentrate on suspension work. I have written to him in the past and he has been very gracious to answer questions then. I have also written to Anton Largidare, he is a good source of information. Brook Reams, who is a frequent contributor to this post is also gracious with replies. I don't know if there is anyone at Max BMW who could help.

Sorry, I can't be more help. If you were close by, I am willing to help in person, such as it is or, I know a dedicated shop. I don't mention the name as the owner is running it as a retirement thing, and is content to remain low key. Good luck, St.
Owner of a 84, R80RT and 78, R100RS

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srankin
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Re: Valve Adjustment bolt out of travel

Post by srankin »

LOL okay after a long book, a short answer. Put the lock nuts on, snap a picture and let us see what you have, then at that point I'll say ride or keep looking.

Forgive me, I am just the kind of person who is in favor of keeping two high mileage bikes in "proper trim". So, I tend to be anal about important things being 100% right.

Your situation if it were on my bike, would be driving me crazy to figure out the why and how to correct. I guess my persona is carried at times into the forum. St.
Owner of a 84, R80RT and 78, R100RS

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cbclemmens
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Re: Valve Adjustment bolt out of travel

Post by cbclemmens »

ST;
My R75/5 has 160 lbs of compression. 160/14.7 = 10.9. The compression ratio (cylinder volume at BDC divided by cylinder volume at TDC) can be estimated as follows: Engine compression divided by atmospheric pressure = compression ratio. Meaning the bike has a 10.9:1 compression ratio. I would think a R60/5 would have a similar compression ratio since the stroke is the same.

Greg:
Did you check the compression with a gauge? If it is the same on both sides, then the gasket configuration would be the same. Therefore the difference has to be in the valve train.

Craig

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srankin
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Re: Valve Adjustment bolt out of travel

Post by srankin »

Craig, thanks for the information, I was more trying to make a point about adding the base gaskets to reduce compression to prevent pinging. LOL I was too lazy to look up the actual specifications for that year bike.

Good question, is this problem only on one side or both sides of the bike?

Also, still no answer to if adding a base gasket would cause this problem? I know base gasket installation was common back in a lot of cases. As I never had the need to do it myself, I never encountered any problems related to it. None of my local riders to my knowledge ever installed base gaskets either so I can't question them regarding the possible problems they had if any.

Certainly if there is no added gasket or gaskets, the assumption has to be the problem lies in the valve train.

It will be interesting to see pictures of the new valve adjuster screws in place and the amount of thread visible after the valves have been adjusted and tightened.

Who knows, this could either be a case of a previous owner doing something that has held up until now or even rarer yet a BMW factory mistake that has gone trouble free until now. It is amazing how much abuse these engines will take and still run fairly well. St.
Owner of a 84, R80RT and 78, R100RS

gregflyn
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Re: Valve Adjustment bolt out of travel

Post by gregflyn »

I haven’t checked compression. I don’t have a compression gauge and no other issues with compression. Both sides are the same as far as the adjustment goes. Both have the same stretched threads on the adjustment bolts. I haven’t had issues with the right side at all. I only checked the valve clearance because of the left side pinging at high acceleration. And it was well over time to do it.

How would I check if there is a base gasket? Just look? 😎. I would rather not pull the heads and cylinders. At least till I had a couple ideas on the issue and possible remedies with parts in hand. One thing if the bike was not running but it runs great.

I’ve returned the 2 pushrods I bought to compare to my originals and should get the new valve adjustment bolts this coming week. At that point I’ll open the right side and take a couple photos of the adjustment as it is now and then I’ll flip the lock nuts and install the new adjustment bolts.

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schrader7032
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Re: Valve Adjustment bolt out of travel

Post by schrader7032 »

In looking at the images of your valves and mine, there seems to be a difference in the adjuster. Also, you have some kind of conical shaped item that I'm assuming has the cup that captures the outward end of the pushrod. Your set up looks quite different than mine. I checked and that screw for the adjustment is part 11331744328. The grip length, the part with the threads on my /7 are longer than yours. That part number of for /5, /6, and /7 bikes as well as others...it seems it's the same for all Airheads. I don't understand why yours looks so different.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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