The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: snowman910 on October 03, 2015, 07:15:04 PM
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Hello,
I'm ready for reassembly after helicoiling a stripped (not by me) head and cylinder stud, and fiche and manual say no cylinder base gasket, just an O-ring, yet I've read that for other airhead models without cylinder base gaskets that some sealant should be used. What is the consensus, and if the consensus is sealant, which sealant to use? Also have read that if there is any ding from the connecting rod dropping to the flange (also not by me) that it should be "dressed out" or oil will weep. Any tips on the procedure to dress it out without making it worse, or anything else relevant to re-assembly? I've got the silicon grease for the pushrod tube grommets. Please also see my other new thread regarding question about the push rods.
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No base gasket on the R65.
When my 1981 R65 got new rings, I used just the lightest smear, and I mean light enough to kinda see through it, on the crankcase surface. My choice, and that of other Airhead fixers, is a tube of Suzuki #1207B gasket sealer.
A fine mill file dresses and any raised nick caused by careless POs. Really no concern if a bit of alloy rises up within the interior as the connecting rod will never be near it. Obviously, the idea is to get a good mate with the cylinder's base and the crankcase surface. Just the lightest touch to dress a nick.
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Many thanks, Montmil!
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Well, it is too soon to declare success, but the top end is reassembled, everything else too, and she started right up, and I haven't seen oil pouring out of anywhere, so here's hoping. I was seeing a lot more oil flow on one rocker assembly than any of the other three.
Too bad I'm in SE NC and it is pouring down rain and catastrophic flooding is predicted. Serious flooding is occurring.
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The rocker arm shaft has a passage way drilled in it, the shaft has to be positioned so the hole in the shaft is right up against the bushing in the head .
Otherwise the oil just flows out of the area and the rocker arms don't get enough oil .
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The rocker arm shaft has a passage way drilled in it, the shaft has to be positioned so the hole in the shaft is right up against the bushing in the head .
Otherwise the oil just flows out of the area and the rocker arms don't get enough oil .
Pull the valve cover and inspect the rocker shaft. You should see a small dimple at the top of the rocker shaft. The dimple reference mark should be towards the valve cover. if it it any other way 'round, you may starve the rocker and oil starvation damage could result.
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Thanks montmil and Rob_Roller. The dimple is correctly oriented, I was aware of that, but have double-checked just to be sure I didn't space out on it, and it was correct. My observation of one of the four getting a lot more oil was based on manual turning of the rear wheel to reach TDC (OT) to set the valve clearances, which I checked enough times to move some oil. I've now run it briefly with the valve covers off and it is pouring oil from all four, with much heavier flow than I would have imagined, and while it is not uniform, it is heavier than I would have expected on all four rocker assemblies. I wonder if it could be non-uniform and heavy flow because of end float variations from one assembly to the next are giving too easy and too early an exit from the assembly? Should I be clamping the rocker blocks or pinching them together as I am tightening the stud nuts to minimize clearance, and if one does that is it possible to get the clearance too tight? I've read of a C-Clamp method at low torque, but nothing of at what torque to apply light clamp pressure.
This is a 1982 R65, and does NOT have the upgrade to 1985 and up rocker assembly with shims. I did loosely squeeze the rocker blocks while torquing them down, but did both sides at the same TDC - I did not rotate to the next TDC for torquing the second cylinder and head stud nuts (and the valves were not affected by the pushrods because the adjusters were backed all the way to maximum looseness when I torqued the head nuts, but of course I did rotate to the next TDC for setting valve clearance so each side's valve clearances were set at next appearance of TDC (OT) after the intake valve for that side had closed.
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I would not sweat the oil quantity one bit.
Any noticeable oil flow will be more than enough for the rockers, the Airhead is, if anything, over oiled with the sole exception of the timing chain and tensioner which merely gets "enough" oil.
If you ever want a very sobering experience, hook a direct reading oil pressure gauge up in place of the oil pressure sender. I have seen pressures in excess of 150psi on cold start-up, which I can assure you is more than sufficient to blow a K-Mart direct reading gauge of indifferent quality. The abundance of oil and the high pressure with which it is delivered is the fundamental reason behind the long life of our little Bavarian babies.
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Thanks, Tony Smith.
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The abundance of oil and the high pressure with which it is delivered is the fundamental reason behind the long life of our little Bavarian babies.
Abundance of oil there certainly is. BMW's write up on the lube system reckons that at 60mph the entire oil capacity in the sump is recirculated every 10 secs. To use their own words "thats a lot of lubrication"