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How Many $2000 O Rings?

So how many miles are we talking to lack of lube damage to the camshafts and rod ends if the o-ring isnt skavished enough. I just finished an oil change. It has the smoothened canister edge on it. I put 2 shims on it this time, usually use only one. it measured 3.25mm or so without shims. Have put 10k on it in 2 years , only used 1 shim. at one time i used a gasket also, but no more. still tickin. i looked at the gap between the canister and engine and it was minute if at all. i didnt try to fit a feeler guage in there, shoulda. So, shoulda the engine have ground to a halt in the last 5k or 10k if things werent tight? It has 46k on it and i know the last owner only used 1 shim.
 
Todd -

According to the methods proposed by Oak, you're getting about 33% compression on the o-ring. His recommendation was more like 10-25%. If you dropped one of the shims, the compression would be about 26%...a little better. I'd be afraid that too much compression will deform the o-ring too much, thereby opening a gap and allowing some oil to bypass the filter. You squeeze on the o-ring, it's got to go somewhere...

Kurt in S.A.
 
PeoriaMac said:
But....don't you have a couple of them???
Yes Mac,.....I am ruined.
Todd, If you had a motor lubrication problem, you would surely know about it at 46K.
 
Jim, first of all , you Are a winner in my book.
Secondly, well I took apart the goods again tonight and found out that the canister was about 4mm away. .151" and the oring is .1575 thick. Thats not much compression even with one spacer. So I kept the two spacers in. They were .012" thick each. with the spacers and o-ring seated in, the oring came out about .52mm from the outer surface. The cover went on good, not hard at all. At one point in time I had on one shim, oring and gasket. The oil has been overchanged also with filters. Last filter element was clean.
I measured the gap between the canister and the engine and the crack is .008"

With so little room for error and high probability for mass destruction im suprised there isnt(was) an epidemic of blown engines. How many people have actually destroyed their engines due to this one senario. Makes me go crazy!
 
With the cannister depth of 4mm (as opposed to the 3.25mm value before), and using 2 shims, your oring compression is about 15%...that's a reasonable number. 1 shim only gets you about 8% compression...probably not good. Two is the way to go...

Kurt in S.A.
 
20774 said:
With the cannister depth of 4mm (as opposed to the 3.25mm value before), and using 2 shims, your oring compression is about 15%...that's a reasonable number. 1 shim only gets you about 8% compression...probably not good. Two is the way to go...

Kurt in S.A.


Cool, my first measurements were way off. I think my past gasket useage also would have resulted in bad things but so far so good. Havent torn it apart to measure the con rod big ends or anything else but it does run good. I cant believe the can is set so far back. Is this adjustable? I cant believe BMW would have made a mistake like that.
Do you guys know anyone who has suffered as a result of this?
 
woodnsteel said:
DO NOT, under any circumstances, buy an R75/5. The crazy-stupid simplicity will ruin you.
About everything I've read indicates it's the best of the airheads. Considering I'm about as simple as a sledgehammer, this may be the bike for me. Opinons? On the bike, not my simpleness.... :brow
 
The only shortcoming of the /5 is the absense of a kill switch on the handlebar. The /6 is a great bike also, but I like the combination instrument set in the headlight and the 4 speed transmission of the /5's better than the /6 set-up.
 
O-ring-I did it wrong...here's what happened

I got the order of the O-ring and shim mixed up during an oil change. With my wife on the back we got on the freeway and were going about 70 for a mile or two when the bike started to lose power. I pulled off the road and the motor died. When I pulled out the dipstick I got smoke coming out of the fill hole. I trailered the bike to a small independent mechanic in Ceres and he tore it down. The only damage was to the rod bearings. He replaced the bearings and put it back together. Almost 10,000 miles later It's still running fine with good oil pressure and no funny noises. I pulled the pan 6 months after repairs and found no debris. I attribute my good fortune to Syntec synthetic oil. I had no damage to the bores, the rings or the main bearings. I'm lucky I guess, but now I always have the service manual out when I change the oil and filter.
 
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