The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: quixotic on April 21, 2014, 09:08:58 PM
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Is it possible to easily pop one in? I just recall the smooth ride on my old slash 5, and I'm wondering what my options are.
I think my carbs are fairly balanced. When I have the manometer attached and I rev up to about 4,000 rpm, the tranny fluid is fairly level.
The only other thing that comes to mind is what a fellow in Calgary did. Using a triple beam balance and a dremel tool, he filed away a few grams on one of the pistons, until they weighed exactly the same. He also balanced the flywheel, but I forgot to ask how he accomplished that. Would the average machine shop be able to balance a flywheel? And what about the crank? And the connecting rods. What would give the best bang for the buck?
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The R65 is just gonna a bit buzzier than the bigger airheads.... but here are a few things you can try before you get into the serious engine work
-Make sure the valve lash is equal on both cylinders.
-Make sure your tires are balanced. My 65mph handlebar vibration was just notably improved by balancing the front wheel. I'm willing to bet when I get to the rear that the footpeg vibration will be reduced.
-Check and/or play with the motor mount torques. If you have the aftermarket rubber vibration dampers on your motor mounts, check to see if they are in good condition.
-Consider getting a set of rubber vibration dampers... but be warned that plenty of people have opinions on that subject.
-If the plugs and wires are old, consider replacing as a set.
-If the grips and footpeg covers are old and hard, new rubber might help mitigate some vibration.
-Wear wool socks :D
Your '79 already has the heavy flywheel! A shop that does flywheel resurfacing might be able to balance it for you. I'm not sure if flywheels are dynamically balanced as a matter of course, but a good dynamic balancing job would be the way to go if it's available. A local transmission shop could point you in the right direction.
Pistons could be balanced without getting too deep into the engine, but as you go further in you have to consider the total cost of the job. Little bits like the front crank roller bearing and other timing parts or head gaskets, pushrod seals, etc. all add up... and that's before you pay somebody to work on the stuff.
Could be a lot of work and money for not a whole lot of improvement. I'd at least consider doing all the tuneup sorta stuff now and deciding on the engine when the next winter rolls around.
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Is it possible to easily pop one in?
The only other thing that comes to mind is what a fellow in Calgary did. Using a triple beam balance and a dremel tool, he filed away a few grams on one of the pistons, until they weighed exactly the same. He also balanced the flywheel, but I forgot to ask how he accomplished that. Would the average machine shop be able to balance a flywheel? And what about the crank? And the connecting rods. What would give the best bang for the buck?
Balancing is a pretty easy process, you can even do most of it yourself. The pistons and rods (separately) need only a simple beam balance tool, a dremel and your time.
You can also do the crank and crankshaft yourself, but I suspect the expense of acquiring the tooling and learning how to set it up might make paying a commercial operator more attractive. If it were my money I would give them the crank and flywheel bolted together and ask them to dynamically balance them. Of course you can also have them done separately, but with rotating things the greater the mass, the quicker and better the results.
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As Luca said you already have the heavier of the two flywheels available to an R65. It's still not as heavy as a /5 flywheel though. Not sure by how much and it's also a little smaller in diameter. I've never heard of a type 247 flywheel being installed on a type 248. I doubt it's impossible if the appropriate clutch is also used.
Has anyone ridden both early and late model R65's and is able to compare vibration levels ? It might give a clue as to how much difference if any an even heavier flywheel would make.
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No, but I have ridden an R65 with a lightened heavy flywheel. Not too much weight taken off, I only had so much money - and it was balanced. The rest of the engine was not however.
I am surprised it vibes very much being a 79. But then my old bike (now Tony's) was pretty well run in a 79 which had been round the clock.
I do have to admit not having ridden an R65 which does exhibit the dreaded vibe.......just been lucky I guess.
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Has anyone ridden both early and late model R65's and is able to compare vibration levels ? It might give a clue as to how much difference if any an even heavier flywheel would make.
I have and my observation is that there was no noticeable difference in vibration level. Whereas, smoothness of gear changing, willingness to rev and general "keenness" of the engine were all heavily in favor of the later R65.
I have also ridden R50s and R60s. At the outset in terms of performance any R65 feels in a different league, but given the choice between an R50/60 and and R65 (assuming equal condition) I'd pick the R50/60 for the round the world trip as they have a degree of robustness over and above our beloved R65s. (And I will freely admit that most of that is parts left out - 4 gears not 5, drum brakes, simple forks, lower tune of engine, bigger clutch etc.)
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I have and my observation is that there was no noticeable difference in vibration level. Whereas, smoothness of gear changing, willingness to rev and general "keenness" of the engine were all heavily in favor of the later R65.
I thought that might be the case. You could expect a heavy flywheel to noticeably smooth an engine at idle but perhaps not so much at higher revs.
There is one benefit of a heaver flywheel that might be appreciated depending on circumstances and riding style. At low revs in particular, every revolution the crankshaft speeds up and slows down in between the power strokes. A heavier flywheel with more inertia reduces the cyclic speed variations of the crankshaft and therefore reduces the perception of lugging. Earlier bikes with heavier flywheels will be slightly happier at lower revs which may explain some differences in opinion about what revs constitute lugging.
When I read that revs must be kept above 4000 RPM to avoid lugging I smile and think they must be riding a very different bike to mine.
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Hum, Tony, the earlier bikes needed much more maintenance to clean the engine's internal often.
And this is a PITA.
Progress is evident on the BMW bikes as the general architecture had been kept the same.
I admit that riding on an old bike on bad roads will be better than on the newer bikes because they were designed for bad roads...
Recently I sorted out the sales slips for the BMW R65 I bought new in 1984 (bike produced in 82) and I was thinking some were missing. Checking the indicated mileage on the slips revealed that in fact none were missing. So IMHO she required very low maintenance during the 30 years of constant use I put on her... (it was my sole vehicle during about 20 years so was used to go to/from work) so if I had to tour the world I 'll do it on the trusty BMW R65 (after a very thorough review and tune up of course...)
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Hum, Tony, the earlier bikes needed much more maintenance to clean the engine's internal often.
And this is a PITA.
i am not sure I understand what general maintenance requirements you think applied to a /5 or a /6 that do not apply equally to a /7 or a R65. In any event, the oil technology changes over the period of time from a /5 to now would well and properly level that playing field.
To explain, my friend Bill bought a basket case Norton Atlas (750 precursor to the Commando in a Featherbed frame) in about 1985 and then over a period of several years restored it.
In 1989 Bill announced that he was going to ride the Norton to Phillip Is to watch the races. now Bill is a 1st class and very clever mechanic, but I'd watched him screw that Norton engine back together and I knew that nothing particularly special went into it. i also knew that back in the day (circa 1968), no Norton Atlas ever went much more than 3,000 miles without going "bang", there were simply fundamental design flaws in the oiling system for a start. i also knew that Bill's engine had not been apart in the previous years that he had been riding it post restoration so I very confidently bet him that he had no chance of getting to Phillip Is, much less getting there and back.
The parameters of the bet were that normal services work was OK, but anything deeper than that, meant he lost.
I rode with him to mid NSW, a distance of about 2500lm or thereabouts (and a little over half way to Phillip Is) but had to return for work purposes.
To my annoyance I kept getting phone calls from Bill telling me he was in Sydney, then further south and finally at PI. When the races finished he set sail back to Townsville arriving just on 4 days later, the Norton running like a Waterbury watch.
when it came time to settle up I begged him to tell me what magic he had performed that the Norton factory couldn't master 30 years previously. Bill asked me - "what is the single area of internal combustion technology that has had the greatest advance in the past 30 years?"
The penny dropped - OIL. That was why the Atlas engine could live in 1989 and could not in 1968, modern engine oil, detergent additives, chemical packs to allow the oil to absorb and carry chemical combustion by-products, friction modifiers and viscosity stability said it all.
For that reason alone I am confident that an R50 or an R60 in the here and now would prove a better long distance tourer than the R65 - now that is not a criticism of the R65 but the r50 and R60s were designed to comfortably cover long distances, heavily loaded over indifferent roads. With the greatest of respect to you, the r65 was not.
As a further comment - improved oil is the reason my R100RS has lived so long, i never got around to fitting it with an oil cooler, but I do have a oil thermometer dipstick. Traveling around the northern part of Australia i have frequently seen long term oil temps exceeding 130 degrees Celsius. I suggest to you that conventional 50/60/70s wisdom says that engine oil begins to break down and fail at sustained temperatures in excess of 120 degrees Celsius. Now I have always run good quality oil and changed the oil when due and run 20W60 in summer and 15W50 during what passes for our winter, but I do think that had the oil not been vastly superior to what was around when /5/6/7s were new it would not still be running almost 40 years after it was manufactured.
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I agree with your comments. I was talking about the /2 and their bearings on the crankcase.
Sturdy but more hours in the shop when maintenance is due.
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Going back to the question - I do not see why not- in theory. but am ready to be proved wrong.
Its the same transmission? Flywheel should fit the main shaft. A new clutch, etc, would be in order.
Let us know how you get on. Report in triplicate and all that.
Cheers
rev light
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(circa 1968), no Norton Atlas ever went much more than 3,000 miles without going "bang"
As the owner of a 1962 and a 1966 Norton back in the 60's I will attest to that big bang theory. Mine were well used and 300 miles seemed to be their limits. Shortly after that in the early 70's I had a 1964 R50(with funny forks) that was the most reliable bike I ever owned.
Aside from better metallurgy and machining equipment, oil is the big difference. I have a Ford Ranger truck that literally has never seen a wrench in 190,000 miles(other than brakes) absolutely unheard of in the 50's & 60's . Back then they were ready for the bone yard at 100,000, timing chains were a 75,000 mile item.
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Going back to the question - I do not see why not- in theory. but am ready to be proved wrong.
Its the same transmission? Flywheel should fit the main shaft. A new clutch, etc, would be in order.
Let us know how you get on. Report in triplicate and all that.
Cheers
rev light
Thanks. Will do. First on the agenda will be to recheck the valves, and the engine mount torques (have never done the latter), as per Luca's suggestions.
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Keep track of the motor mount torques and play with the values a bit, maybe between 55-45 ft lbs. It will move/change the high end vibration band. There was a thread way back and I think the OP had good results with 50 for the front and 45 for the rear.
The low end vibration around 3K under load is from lugging (at least as I notice it with the later clutch/flywheel). Best cure for that is to keep a little more wrist in it.
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borrow a bsa a65 for the day , your r65 will seem smooth as silk in comparison.
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Keep track of the motor mount torques and play with the values a bit, maybe between 55-45 ft lbs.It will move/change the high end vibration band
That worked for me moving the vibration up to revs I very rarely use.
Vibration is at a low enough level that I don't notice or think about it any more on a daily basis. Can't say that about any other bike I've had. Like the man said go ride an A65 or any other 60's/70's British twin except perhaps a Commando and that vibrated away as well, you just didn't feel it.
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don't get me wrong tho! i love grumbly old twins , i actually bought my r65 for its character and characteristics , but i wanted to be reasonably certain of getting where i was going !
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It's getting curiouser and curiouser. The typical high frequency buzz around 4 grand is still there, but it's minor and I can easily live with it. And at 5 grand, everything is as smooth as butter.
But this other vibration seems to be at a significantly lower frequency, so I'm guessing that it's somewhere in the drive train (either the shaft drive or the rear wheel). But the crazy thing is that it's intermittent. In a 20 minute drive, it'll surface for a couple of minutes and then disappear. But when it's there, it seems like something is in danger of tearing itself apart.
Any guesses? I think my next task will be to raise the rear end, spin the wheel by hand, and see if I can detect anything strange.
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I'm glad I had a look at the rear end. I had assumed that since the tranny and engine fluids were clear and at the precisely right levels (from the previous owner), the drive shaft and differential fluids would be also. Nope. They were dangerously low. Now that they're topped up, I'll do a fluid change soon and hope that I don't find any filings.
And even though I recently adjusted the tappets, I do detect a significant difference in sound from left to right. So that'll be on the imminent to-do list also. And I assume that any time the tappets are adjusted (when cold), the carbs should then be adjusted after (when hot).
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I had assumed that since the tranny and engine fluids were clear and at the precisely right levels (from the previous owner), the drive shaft and differential fluids would be also.Nope.They were dangerously low.Now that they're topped up, I'll do a fluid change soon and hope that I don't find any filings.
I wouldn't worry as levels for the drive shaft and final drive are not as critical as the gearbox and many run them deliberately low, particularly the drive shaft to prevent the oil migrating from one part of the transmission to another.