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Discussion in 'Airheads' started by fxray, Feb 26, 2015.
FXRay, those aren't shims, per se, they are insulators. They weren't used on the later series bikes (/5 and later) but were used on the /2s and earlier. The idea behind them is to insulate the springs from the heat of the heads, causing them to weaken and have shorter life. The /2 heads ran hotter than the later heads with less oil flow and utilized double springs (an inner and an outer).
Thanks for the comments, folks. Pokie, that clears up a mystery -- insulators from /2 days, huh? Somebody in this bike's past must have thought if the insulators were a good idea in his /2 experience, they might be good for this /6 as well. Whether they were meant as shims or not, they would add some preload to the springs. I guess if it hasn't hurt the cams or lifters by this time, I may as well keep them? I still have to measure valve stems and their clearance in the guides, etc. I'll decide from that what to use or replace. Anyway, thanks for the insight.
Meanwhile, after all my whoop-dee-doo with prepping my hardware, I ran the batch up to the plater today. He was kind enough to turn them around quickly so that I could take the finished parts home with me, thus avoiding a second round trip of about 440 miles.
I gave him the parts, went and had a breakfast sandwich, and drove to the beach for a look at Lake Michigan since I was so close. After about 1 1/2 hours, I went back to the shop and my parts were ready. He works faster than I do!
Next step is to sort them all back into the appropriate plastic baggies. The picture makes it look like there isn't much in there at all. Looks are decieving -- it'll take a while to sort back out.
I haven't done much with the R90, but there is a little progress. All the hardware is sorted back into labelled baggies. Nary a piece went missing at the plating shop, and it all looks good.
I mentioned a while back that I had tried to seal up the cylinder, head, and valve cover from the left side and glass blast it in my cabinet. It didn't work as well as I had hoped. There was some media inside when I opened it up. The glass had leaked in where some bits of plywood around the spigot of the cylinder had let go. Before I blasted the second cylinder, I smeared putty around the outside of the plywood and then wrapped and stapled a piece of aluminum coil stock around the outside to shield the edge grain. That worked pretty well.
When I took off the "bandages" there was no glass inside.\
For my next trick, I butchered up another piece of scrap plywood to make this:
It's my redneck honing plate. I know you are supposed to torque your cylinders to a steel plate, similar to the way they will be on the engine. I think that's more critical if you are using a stone hone. I just wanted to break the glaze with a ball hone, and this was a way to hold the cylinder while I did that.
I used the same threaded rods that I used for the blasting process to hold the cylinder like this:
The all-thread was too long for this job, but I didn't bother to cut them off. If I ever work on another airhead, I can use them again for blasting.
Then I turned the whole shebang upside down and fitted it inside my city trash recycling bin with some bolts through the sides. I put a plastic tray in the bottom to catch the oil. Conveniently, I found that drip tray in the bin when I emptied it out to use it as a honing barrel:
I used a 3 1/2" diameter flex hone, 240 grit, made by BRM Brush Research Manufacturing, which I sourced from McMaster Carr.
While I was cleaning out the recycle bin, I fished out a 2 liter soda bottle and cut off the top. This was a good size to hold the hone to pre- soak it in oil. There is special honing oil, but I used some 10W-30 off the shelf.
Then I used my variable speed electric drill to drive the hone at a moderate speed as I worked the hone fairly rapidly up and down through the cylinder. It is important to have the hone spinning before it enters the bore and keep it spinning till it is all the way out. Here's one cylinder before honing to clean up and break the glaze:
And one that is done:
It looked O.K. to me, so I did the other one. There they both are;
Next step will be to scrub them out with a plastic brush in hot, soapy water. I have a toilet bowl brush that I bought just for this purpose and it has worked great on my Triumph and my Honda. When I think the bores are clean, I will wipe them with a white paper towel that has just a bit of detergent oil on it. If there is any gray on the towel, that will be honing residue, and they will need further scrubbing.
Once they are clean, I will rub in some oil and then do my best to wipe it back out with a clean paper towel. That is all the lube there will be for first startup.
While I'm at it with the hot soapy water, I'll use a different plastic brush to scrub the outside to remove any glass residue. I had to look quite a while to find a brush with bristles long and stiff enough to clean to the bottom of the fins, but I wound up getting a whisk broom with plastic bristles that should work fine.
I plan to paint the barrels and the heads. We'll see how that works out.
O.K. purists, avert your eyes. Today I shot some paint on my cylinders and plan to do the same on my heads. The valve covers are blasted and will simply get some Rub 'n Buff. I realize BMW chose to leave the engine in raw alloy, but I think they should have painted all of it. Remember, my jugs started out like this:
I didn't care for the look, hence the blasting described above. I could have left them raw, but I figure it would only be a matter of time before they started to oxidize again. If the fins were easier to clean, I would just deal with it, but I chose to paint.
After scrubbing the honed bores as I said earlier, I masked off the jugs and used the same bits of all-thread that I used for blasting and honing. This made it pretty easy to rotate the parts during painting. I put on two light coats of primer and one fuller coat, then did the same with the finish paint.
I used Duplicolor DE1612 Engine Primer:
On top of that, I used Duplicolor DE1615 Aluminum:
Duplicolor also makes a paint they call DE1650 Cast Coat Aluminum, and I strongly considered using that. Some people say it looks more like the original finish on a BMW engine. I got some and sprayed a couple pieces of aluminum coil stock for comparison. Here they are, with the DE1615 Aluminum on the left, and the DE1650 on the right. The DE1615 is a bit more silver colored, while the DE1650 is a bit more gray. They are actually pretty close.
The DE1615 is a closer match with the Silver Rub 'n Buff that I already used, so for no other reason, that's what I went with. If I had used the Pewter Rub 'n Buff, the DE1650 might be a little closer. Regardless, I'm happy with this.
Next task will be to inspect the heads a little more closely and see what work they might need.
Good to see your back on track with the project.
Your ramblings are rather addictive, mate. Loving your "work" - don't strain yourself.
You heard about Mr. Vetter's prang, yeah?
Thanks Jim. I'm trying to get back with it, at least to the point where I can hit it harder come wintertime. With the good riding weather, it's kind of hard to stay focussed.
Thanks, Dave. No, this is the first I heard of his accident. It sounds like he will recover, but it sounds like he was hurt badly for a low speed crash on a residential street. It's a good reminder that a deer crash can happen any time, any place. Like the rest of us, he's not getting any younger, and that makes it harder to heal. I've seen deer dash up alongside my house and then run across the street, sometimes in groups of four or five. Here's some that were grazing in my back yard a couple years ago.
Three months ago, I shut the door on my '74 R90/6 project and walked away from it. There was work to do on the other bikes, and riding to do as well. Now it is time to get started with it again.
One thing that was noteworthy since the last post (at least to me anyway) was that I went to my first ever Airhead Tech Day. If you have been following along with this thread, you know that I have no airhead to ride yet. You may wonder how or why I went to a Tech Day.
The answer is that since I have an old Triumph TR6, I met up with some guys from the BritBike.com forum. Like me, they are not snobs for one particular brand of motorcycle, so they have BMW Airheads in addition to their Triumphs, and there is an old Indian and even a Harley or two, along with some Japanese brands in their possession. With that in mind, one of the guys invited me to this Airhead Tech Day in Lexington, Illinois, and I went over there on my TR6. I guess it was about 50 miles from home.
This was in September. There was a weather front passing through, which made for a rather British looking sky -- how appropriate:
At the Tech Day, there were already a couple bikes up on lifts when I got there, and people were eating pulled pork sandwiches and other goodies, and having a cold beer or two. I parked the Triumph and took a few bike pictures:
By way of research for me, there were some R90/6 bikes there:
And even an R90S model as well:
I wouldn't mind having his front brakes:
A nice R60:
Even one of these:
And one of these, but I don't think those last two were German marques:
Then a guy came riding in on this:
We struck up a conversation and, though I didn't realize it till I got home later that day, I figured out that he was the dealer who had sold my bike to its original owner back in 1974. This would have been at the shop he once had in Colfax, Illinois, called Cycles Unlimited, which I think I mentioned way back at the start of this thread. How cool is that!?
Since that day, I have been back over to see him on the Harley and we have been e-mailing back and forth. I am very glad to have made his acquaintance. Funny how motorcycles put people in touch with one another. It's a small world after all.
I have actually done a little work on the bike, but I'll talk about that later. This is long enough already for tonight (some might say way toooo long).
First I've heard of it, too. Thanks, too,
Fxray, who did you use for your cad plating? Does he/ she do mail order? I'm neck deep into a project that will need a bunch of cad plating and don't know who to turn to. Thanks!
Since you live in Colorado, your best bet for cadmium plating work would be Colorado Plating Company. They were formerly called Aero Propeller & Accessories. Their website says that they are the only cadmium plating shop in Colorado. I have not personally done business with them, but I know of a number of satisfied customers in the British motorcycle world. They do receive and ship via US Mail, or Fedex or UPS, etc. I was going to send my stuff there, until I found a guy closer to home. He does great work and is very reasonably priced, but he will not package or ship anything. He operates strictly on pickup and delivery. Since he is a one man operation, he said shipping would take up too much of his time. You can well imagine that he is busy enough already and can turn the shipping business away.
For anyone near Waukegan, Illinois, the shop I went to is:
1424 12th St.
Waukegan, IL 60085
Howdy! Just went thru a lot of this thread, but I admit I didn't take time to read the whole thing! I did get thru the bits RE C Vetter and your fairing & fender- very cool, I guess it pays to be close to Mr V's "ground zero"!
I see now how you get your bikes to look so great. You have my admiration and respect fer sure, of your patience, thoroughness, and abilities. I personally don't possess very much of any of those particular qualities!
Or maybe it's just time I'm lacking. (see how I rationalize?)
Anyway, I'll tag this thread and check back in from time to time... As I heal up, dream (or fantasize) of what's next after crashing the R100RS.
I'm glad you found your way in here. I wouldn't even be on this site if you hadn't started the vintage-brit-superthread on here. I sorta followed you over here and then was blown away by the amount and variety of content on advrider.com. You have nothing to rationalize. I am a big fan of you, your bikes, the way you use them, and your photography skills. That R100RS crash was just plain tragic, but at least you are still around. I hope you are healing well, and I still hope there is something you can do with the bike.
When I left off working on the R90, I was cleaning engine parts, so that's what I took up again this week. I've gotten the pistons sorta kinda clean. I haven't pulled the rings off yet -- just cleaned in place. Doing some reading on here, I find that the Deves rings which seem to be on my pistons would work better on Nikasil jugs rather than the iron sleeves that I have. This thread looks interesting, wherein bmwrench makes a recommendation on rings. Also, the Deves page has some good reading.
The Clymer book tells all about how the pistons and cylinders are size graded, A, B, or C. They say the grade letter is stamped on top of the piston. I did not find that, but there are some stampings under all the crud:
I believe the R is for RH side of the bike, and vorn is German for front, so I should be able to get the piston back in there correctly. I'm a good one for marking stuff for location / orientation with a sharpie pen and then accidentally cleaning it back off before I reassemble. That can give some bad moments.
A closer look at the size stamp:
I guess that means I have C Grade, which Clymer lists as 89.980 mm. What's a few silly microns between friends when you're writing a service book?
I cleaned the cylinder heads as well as I could in my parts washer. I know that most people would have just bead blasted them, but I'm too paranoid to do that to gasket surfaces or internal engine parts. They came up pretty clean.
There's still some carbon staining in the ports, but I decided that life is too short to get all that out. I know the process starts all over once the engine runs again. With the heads cleaned up, I took a look at the valve guides. I have a set of small hole gauges, and the guides looked pretty good from using that. The trouble with the small hole gauge is that you don't get instant feedback about the whole inside length of the guide like you would with a dial bore gauge. My friend loaned me one, and I believe my guides are good to go:
The dial bore gauge is more sophisticated (expensive) than what I have, but they work pretty much the same way on their business ends:
My valve clearances are well within spec for Clymer and and the FSM.
The valves themselves cleaned up O.K. on a wire wheel. I was leery of doing that, but some people who should know said to just go ahead and do it. The valves are hard enough to take it. I was still as gentle as possible.
The margin still looks good. In the interest of "if it ain't broke, don't fix it" and general cheapness, I plan to put these back in the head and do the acetone test. I'll pour some acetone in the port and watch to see if it leaks through into the combustion chamber. If nothing comes through after about 10 minutes, I'll call it good. Otherwise, I know a couple of places to get the valves touched up.
I also need to check the valve springs for free length.
I mentioned earlier that I found what I thought were shims under the valve spring seats. Pokie set me straight on that:
Stacey, the dealer who sold this bike when it was new, confirmed this. He is a proponent of using these, and the fact that I found them in my engine is a good indicator that he may have done a top end job on here once. He had a box of those insulators on the shelf when we were talking. I haven't carried any of the parts over to show them to him, but probably should do that.
All of this begs the question: "How many miles are on this bike anyway?"
The original owner didn't remember the engine ever being apart, but that was long ago and far away. Owner #2 only rode it a short while before he parked it for its long sleep. I have never ridden it or even heard it run, so I can't really even say for sure if the odometer works. It shows 38,933 miles, so why would it have needed a top end job? Yet, it has these non-standard insulators, Deves rings, hex head bolts on the oil pump cover, and other signs of repair. Maybe 138,933? Who knows? The footpeg rubbers aren't worn much.
I've been on the fence about the timing chain. It must be original, because it is an endless chain -- no master link. It looks to be in good condition and could probably run on a lot longer. My problem is that I have the engine torn down to the point that it would almost be stupid not to change it. I already bought the tool kit from Cycle Works, just because. I probably ought to just go ahead and do it. I believe I will -- I ordered the parts from Moto-bins last night.
I just found this thread, and indeed it is timely, as I am dealing with my out-of-bike engine right now as well, a 1974 R90/6 engine that is mounted in a /2 frame, i.e. a conversion.
I read a lot about the timing chain, as I was hearing some chain slop before I tore down, and read that the chains actually stretch very little, that the primary wear-indicator is in how hooked the teeth are on the crank and camshaft. I did find an extremely-worn chain tensioner, so I will replace just that.
Learning a lot here, thank you!
The last time I saw a cam chain tensioner worn as badly as the one in your picture, and I really hate to say this, well, uh, it was in a twin-cam Harley that let me down about 300 miles from home. Seems I made the mistake of actually accumulating miles on that bike, which the factory evidently didn't expect anyone to do. But that is another story completely. I don't know any more about these airheads than what I have read, but the gist of that is:
The sprocket on the crankshaft wears faster than the one on the cam.
Some people replace the crank sprocket with every chain replacement, but replace the cam sprocket with only every second chain replacement.
Some believe that replacing only the chain and the crank sprocket while keeping the old cam sprocket will drastically shorten the life of the new chain.
Some believe that changing only the chain and tensioner, but keeping both the old sprockets is equivalent to pissing into the wind.
Some advocate changing the cam sprocket in situ, while others say that is impossible to do correctly without removing the cam shaft.
Me? I don't know. I just put a new primary chain and tensioner onto the 51 year old sprockets in my TR6. The sprockets looked O.K. to me.
Yet, on this airhead, for some reason I decided to try to replace them. I placed the order with Moto-bins on Monday, I think about midnight by my clock. This morning (Thursday) the FedEx man came to the door with a package from the U.K.! Almost unbelievable. These parts were about US $172 cheaper than if I had sourced them stateside. Not only that, but I had a couple of questions for the folks at Moto-bins, and they answered my e-mails immediately. I'm impressed.
I don't plan to remove the camshaft. I would, except that I sorta got the cart ahead of the horse. I already redid the back end of the engine and I'm too stubborn to remove those single-use stretch bolts on the clutch and flywheel just to remove the woodruff key in the oil pump. Pray for this naive rookie -- I'm going in there.
Terrific thread Ray! Much enjoying it.
A third of my parts came from England too - its the money I know but maybe also because like you I own a triumph (but much younger and less cool than yours.)
We'll pray for you and even jump in there though based on your writing and pictorial style I got a feeling it's gonna go smooth.
Wow! I truly admire your dedication, thoroughness and attention to detail! Your work is extremely thoughtful and exceptionally well done!
I appreciate all the background on how you acquired the R90 from your friend and the Vetter story is quite unique. I've learned many new things in your thread that will help me have a patient and thorough approach to my 1953 Indian Chief restoration. Sometimes I loose my motivation and waiver when I am tracking down rare parts for the bike (which can take years). Your helping me keep the eye on the prize, and stay the course on my Indian.
Cheers, and my condolences to you on the loss of your shop mate.
Thanks for the comments, kaput13. I got into the cam chain job a bit tonight and found a minor surprise -- pictures coming up.
Thanks for your comments, DualSport. Funny you should post here today, I just read your R100 thread last night and enjoyed it quite a bit. I see you have a lot more that I should (will) read. A 1953 Indian Chief is a prize to keep your eyes upon for sure! Thanks for the comment on my little pal. We still miss his antics around here.
I've been puzzled as to why this engine has gone enough miles to have had a top end job, yet the timing chain and sprockets still looked good to me. I assumed it was the original chain since there was no master link. I've read that the wear is sometimes hard to detect, since the sprocket pockets wear a little, and the chain stretches a little, and it all adds up to trouble. But here I was with my R90 engine bolted to a secure stand, stripped to where the timing chain and sprockets were so easily accessible that I decided to make it all new whether it needed to be replaced or not. I had originally only torn it down this far to replace seals and gaskets and to "just have a peek inside":
The tensioner looked O.K.
But what's this??
Somebody found it necessary to grind clearance on the tensioner's backside so it would clear the front bearing carrier. I'm pretty sure the Germans didn't do this at the factory. This made me stop in my tracks and re-inspect the chain, searching for a master link. I used a little dental mirror and peeked behind each link, rotating the engine as needed till I had seen them all -- no master link!
I may be wrong, but I now think a BMW shop tech has replaced this chain at some point, and used the method recommended by BMW, where they fit a new endless chain. If that tensioner ever really needed more clearance, I'm thinking it would only have been that way with a brand new, un-stretched chain.
Just for reference, once I had removed the tensioner, I took a picture of the slack in the chain:
Once I figured out that there was no master link, I proceeded to use the bolt cutters I had borrowed this afternoon. Soon it was too late to turn back :
I pulled the camshaft sprocket first, using my new puller from Cycleworks. It did a good job for me. The sprocket broke loose with a little "pop" with reasonable force, and then came off the rest of the way, again with reasonable, but not excessive force:
Note the quill protector, with a hardened steel socket head capscrew in the end:
The sprocket came off with no trauma, and it was time to remove the little capscrew and run it into the end of the crankshaft for protection there. Cleverly, Cycleworks made it the right size for both spots. Note the end of the cam-shaft shown here, and the undamaged quill, which is a press fit into the end of the cam:
You wouldn't want to forget this hard-bolt-in-the-end-of-the-crankshaft step, unless you happen to like crankshaft repair or replacement as a pastime!
Now for the crankshaft sprocket and nose bearing -- both come off together. The puller is friendly to the bearing, pressing only on the center race. I have a new bearing, but would not be worried over re-using the old one.
Just fit one of the clam-shell pieces of the crank sprocket / bearing puller:
Add the other half of the clam-shell:
Add the outer ring to keep it all engaged:
Then get out the wrenches. I could have gone upstairs and gotten some bigger wrenches that would look a little more professional, but that would have meant . . . going upstairs. I inherited these two Crescent Wrenches (capitalized because that is the actual brand name on the handle) from my wife's grandfather. Every time I use them, I feel like he is right there with me. One is a whopper -- 14". The other is only a 10 incher. They did the job just fine.
And here we have our little trophy in hand. It didn't take a lot of force, but the task would have been easier if I had remembered to lube the threads and the ball in the tip of the puller bolt. I thought of that when I was halfway done, so i just kept going (tool abuse, but not too bad):
So, there's the front end all naked and bare, and ready to start going back together. This was my first time doing this, so in no way is this an expert "how-to" thread. It's just that I had searched in vain for pictures of these tools in use. I thought I'd go ahead and add mine for what it's worth.
Putting it back together should be an adventure unto itself. If that goes well, I'll post some pictures.
The same friend who loaned me his dial bore gauges and the bolt cutters that I used today, has come through with some more good stuff. When he sent me away with the bolt cutters, he also loaned me his tooling for measuring installed valve height and the related spring force at that height. He says that's important, so we'll see how that goes.