Boxerworks.com

Hi All. I am the new owner of a 1977 R75. The bike has an unknown past. The odometer reads ~24K kilometers (~15K miles?); not sure if that's 24K, 124K, 234K... I do know that the bike has been sitting around for a long time (although I'm not sure how long). Anyway, my first of what will surely be many cries for help is this:

The bike has a loud ticking noise coming from the right head. I have performed the following (not necessarily in this order):
1) adjusted valve clearances to .004 intake and .008 exhaust
2) inspected all valve train components (needle bearings good, pushrods straight, no unusual wear marks, etc.)
3) set rocker arm end play to "tighter than a butterfly wing but not as tight as a mosquito wing"
4) retorqued head nuts to 26ftlbs

No joy; still ticking. Upon closer inspection, I have noticed that the right side exhaust pushrod does not seat in the same way as the other three pushrods. When I pull out the other pushrods, they come out about 3/4 of an inch and seem to catch on something (rubber seal?, guide?) before coming all the way out. The right side exhaust pushrod does not do this. Also, the noise seems to come more from the area of lifter than the valve train. Before I start tearing the head off the bike, I thought it would be a good idea to seek some advice. Thanks in advance for your help (and for reading this looong post).

Welcome, Beemerick.
Check out #10 and 11 here....
http://w6rec.com/duane/bmw/valve/index.htm
I bet this is your problem. I never knew about the very simple adjustment of the pillow blocks when torquing the heads until I found this forum. Click to enlarge the photo, the one with the giant channel locks.
Yes, when you are torquing your heads, follow the procedure on the link above. I bet that will quieten the noise. It did for me. If you don't have a set of huge channel locks, you can use a big C clamp. I've even used my hands/fingers to pinch the pillow blocks as required during the torquing, and it worked.

The first question, as always, is did you set the valve clearance on the compression stroke?
Second question...Did you align your pushrods so they don't rub on the sides of the tubes?
Sounds like you probably have an understanding of this, but I need to ask.
Someone may have put the head gasket on upside down if the rods are catching on something.

Have you taken the pushrods completely out and inspected the lifter-side of the rod? I believe these should have a ball on the other end which then fits into a concave indention in the top of the lifter. I wonder if something has happened either to the ball on the rod or the top of the lifter. It could be that the other three resist pulling out because of oil film suction or a tight fit on the top of the lifter. The 4th rod doesn't because it's screwed up inside.

Kurt in S.A.

Thanks to all who responded.

Check out #10 and 11 here.... http://w6rec.com/duane/bmw/valve/index.htm I bet this is your problem. I never knew about the very simple adjustment of the pillow blocks when torquing the heads until I found this forum. Click to enlarge the photo, the one with the giant channel locks. Yes, when you are torquing your heads, follow the procedure on the link above. I bet that will quieten the noise. It did for me. If you don't have a set of huge channel locks, you can use a big C clamp. I've even used my hands/fingers to pinch the pillow blocks as required during the torquing, and it worked.

Randy, I did see this resource. I did not have the giant channel locks so I used a c-clamp the first time through. For the second round, I used my fingers which worked just as well (the bike has the split style "pillow blocks".

The first question, as always, is did you set the valve clearance on the compression stroke? Second question...Did you align your pushrods so they don't rub on the sides of the tubes? Someone may have put the head gasket on upside down if the rods are catching on something.

Matt, yes on the compression stroke (after the intake valve opens then closes?); aligning the pushrods, I did not, but they weren't rubbing anywhere (and no marks on the rod itself). What is the process for this alignment? As for the other rods catching on something, this more of a positive, repeatable feel from the other three (non-ticking) rods. Do the push rod seals help guide/dampen/contact, etc. the rods?

Have you taken the pushrods completely out and inspected the lifter-side of the rod? I believe these should have a ball on the other end which then fits into a concave indention in the top of the lifter. I wonder if something has happened either to the ball on the rod or the top of the lifter. It could be that the other three resist pulling out because of oil film suction or a tight fit on the top of the lifter. The 4th rod doesn't because it's screwed up inside.

Kurt, I did take all the rods out to check them; all were straight and all ends looked good. The offending rod does positively seat on the lifter...

Again thanks for your responses, I will continue to dig for information. Other than the LOUD tick, the bike start easy, idles well, great power, no smoke. I fear I may have to remove the head to get to the bottom of this... I would rather not.

You need to check if any of the pushrods are touching the inside of the pushrod tube at full extension, valve wide open. I made this mistake when I used a large C-clamp like you did. The weight of the clamp pulled the whole rocker assembly down, so that after I torqued, it was a hair too low. Not evident when the valves are closed, but the pushrod drops down in the tube when open. Look for the pushrod with the fresh shiny ring of wear around it where it enters the tube. Looking at your post again, I realize you should have the later rocker setup. so this may not apply.

Rick, if your bike has 1977 heads on it then the rocker arm blocks should center themselves on the heads close enough that the push rods should not hit the tubes. Read this: http://www.largiader.com/tech/rockers/ and you will see the difference.

Adjusting rocker end play is still needed on your heads and can make a lot of noise is too loose or one of the thrust washers is missing.

Welcome BTW.

Here is a trick that often, but not always, works. Remove the valve cover with the engine hot, or under whatever condition it makes the tick. You didn't say what rpm it ticks, but it is usually at idle. Sometimes one can use a rubber tube to try to hear the source of the tick, but that usually fails as the sound can be telegraphed to another place.

Instead, using your thumb, press on the rocker arm adjustment spot and the pressure may change the tick. You can try upward pressure and downward pressure. What you are looking for is to locate the exact valve causing the tick. I am sure that some are a bit shy of putting fingers in a running engine and I was too the first time, so I used the handle of a small hammer. Nothing happened, so I began using fingers and I still have all 10. Very little oil will spill at idle.

Also, with the piston on compression, the pushrod should ride just a bit above the center of the hole in the head. As it pushes the valve open, it goes lower in the hole. Visualize the center of the hole. The pushrod should start out high and end up low by the same amount.

It can hit and you may not see a mark on the pushrod. Of course the pushrod should be centered as far as right and left are concerned.

On high mileage slide type carbs I have seen them so worn out that they can make that tick. It may be possible for your carb to be the problem, but I have never seen it, nor heard of it.

Duane Ausherman wrote: On high mileage slide type carbs I have seen them so worn out that they can make that tick. It may be possible for your carb to be the problem, but I have never seen it, nor heard of it.

These two sentences confused me.

Major, yep, badly written. What I didnt' say is that I have never seen it on THAT type of carb, only the old fashioned slide type. Those have slides, but opperated by the vacuum. They too could wear out.