My 1987 R80 has 66,000 miles on it and runs great except for an occasional high idle when hot. That's not much of a problem but I intend to rebuild the carbs and install an Alpha ignition anyway so that problem should go away. My concern right now is the cam chain. Looking back through the 28 years of maintenance records the PO gave me I see the chain has never been changed. And while I don't hear any kind of awful noise I do hear some at idle. I'm thinking it would be wise to go ahead and change it prior to a general tuneup to include the carbs,ignition, valves and carb balance. Thoughts? With that said what all do I need and where's the best place to get it? Chain w master link Crank sprocket? Crank sprocket bearing? Guide Tensioner Am I missing anything ? Thanks
I do them at 50,000 miles but many people have gone longer without incident. You can use noise and scatter on a timing light as clues, but who can tell the point in time where a tensioner pad will wear through? Not me.
If go ahead with it... http://bmwmotorcycletech.info/timingchain.htm Text heavy, but it has pretty much all the info you'll need for the job. Probably order a new tensioner spring as well as timing chain cover gaskets (the big one and the small round ones). I usually advocate replacing the woodruff key for either sprocket for peace of mind, because I had an issue with one once, but I'm not sure how common that is. I order from Bob's BMW in Maryland, but there are quite a few other sources if you are in the states.
Thanks for the replys! I'm thinking now I'm just going to ride this summer and worry about the chain next winter. Thanks Robert
That will almost surely work. I think there are at least four schools of thought regarding timing of maintenance. People can even be in different schools of thought for different repair items: 1) Do it early and keep everything at mid-life or better. I call this "helicopter maintenance". It has the advantages of best reliability and performance but costs more in terms of maintenance time and cost. This is the school I belong to. I have multiple bikes, can afford the time and parts, and consider wrenching to be an enjoyable part of the ownership experience. Call it "bonding" or something. 2) Do it at published or accepted intervals and let the "experts" figure out how long the parts can go. This is probably the most "sane" approach as a balance between excessive maintenance and excessive issues "on the road". 3) Try to fix it j-u-s-t before it is likely to fail. In other words, stretch the accepted interval as long as you think you can. This school is likely to look, listen, and measure for signs of a part nearing end-of-life. Some people are quite good at this either by experience or luck. I am not. It makes best sense to me for issues where the consequences of being wrong are not too large. 4) If it ain't broke, don't fix it. Frankly, I don't' care to ride with this school of owner or help him out of his self-induced jams. Because it WILL break and he will want me to fix it with my tools and spare parts (he carries neither). His bike is a pain to work on because everything has been run into the ground. Clearly, given the wide range of service life for parts because of individual part differences, particulars of installation, or conditions of use/abuse, members of all of these schools will suffer some failures. Just as clearly, the odds of failure go up as you go down the list. If I did not enjoy maintenance, I would probably move down to "school 2 or 3" depending on the severity of the failure consequences. The failure consequences include how much collateral damage occurs when it happens (think valve head popping off), and where I happen to be at the time (i.e.:Starbucks, or half-way to Inuvik).
Rob if you have no reason to think the timing chest needs attention then it probably does not. But if you do have a reason to look then it's best to look. Symptoms as I know them. Funny noises New noises Noises that other bikes dont have double/blurry image when strobe timing bean can (if equipped) turned all the way to one side of adjustment(arguable) I would bet, that if the tensioner and follower have not been changed, they should be. I wouldnt bet a lot..but I would bet. Mine were toast at your mileage. I dont know what happens if you go beyond "toast". In fact I have never seen mention of it.
Good post, 'Phile. Cases(s) in point, current maintenance points on my bike. Timing chain was replaced about 50-60K ago but this was the second (or third? I disremember) timing chain replacement and the crank- and cam-sprockets are the original 1973 items. It was originally slated for replacement per your Item #2. I've had ALL the parts for a timing chain job on hand for a couple of years now, but since it's not been rattling, or has had a jumpy "Z" mark or the ignition timing is not rotated to the far end on the adjustment range I've put it off on the basis of your Item #3. And possibly I'm headed for Item #4 on this. Added impetus: I've got a seepy crank oil seal that looks sloppy, I'm due for an oil change and major 3K Service and I've got traveling I want to do this Summer. Second item: clutch. This is running on the third clutch disc and the original pressure plate and pressure ring. Last clutch disc was done "on the cheap" since I didn't have time/money for a complete job. The pressure rings were deeply grooved and I knew that the life of that last clutch disc was going to be much reduced. So I bought complete clutch parts (incl the rear main seal) a couple of years back, figuring that I'd get the clutch when it started slipping (Item #3, maybe verging on #4). I've been running around with aweepy/seepy RMS for a year, figuring I'd replace it once I got to the clutch. And it only started slipping a couple of times when cold just a week or two ago, so it's time. And so on and so forth... And also on a "new to you bike" you'll want to pull maintenance on some items just to "zero out" the maintenance history of the bike. --Bill
I replaced the chain on my 1978 with the odometer (which I expect is not 100% accurate) showing 48k. Replacement wasn't really needed, but I decided to replace it when Motobins had a sale on their timing chain kits. That's part of "Saving money by spending money" economics - it involves higher level math and is very difficult to grasp conceptually. But, in my case, I like working on the bike so there is no anxiety or dread in such a task. I used a HF bolt cutter to cut the chain - and then returned the tool. I thought about keeping it, but since that was the first time I've needed one so far the risk seemed appropriate. It was a nice bolt cutter and fairly inexpensive, IMO. Otherwise, the only issue I had was remembering to put some grease on the master link clips so they stayed in place during assembly. Also, my year is somewhat unique having the cam gear timing slightly advanced compared to earlier years (this was the start of emission controls). So, I wanted to look at the gear and take some photos anyway. Replacing the timing chain at the same time wasn't much more work. But, the chain and gears were not noticeably worn.
I do enjoy working on bikes and I'll spend whatever is necessary to keep them running right. So based on the last few posts I've decided on a new course of action: I will get all the parts on hand but wait until the first totally rained out weekend to do the work. If it don't rain till August I'll still be waiting. Another factor is that I really don't want to chance a failure that would damage the top end. I realize that is a remote chance but this bike has 150/150 compression cold and I'm betting the top end has a long, long way to go. I know from the maintenance records the PO took exceptional care of those valves. I think I'll go ahead and get the crank sprocket too while I'm in there. Thanks Robert
I was thinking along the lines of a valve train crash due to broken cam chain, and I know that's a very remote possibility. And yes I do like to get my hands in the motor, mostly old Hondas until now. It's a kind of therapy for me. Robert
A rattle gun and three legged puller makes changing the crank sprocket very easy. The pulses from the rattle gun get the sprocket moving and keep it moving freely. If you warm the new sprocket up in hot engine oil before fitting it you can just about fit it by hand with a good tap with a soft faced mallet to seat it. Some folks don't change the sprocket but I've found the chain doesn't last anywhere as long if you don't.
