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jim in the north
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This is a bear of a job. Tips:
Remove 10 mm bolt from lower fairing next to exh pipe.
Get 5mm Allen socket combo with 9 inch long 1/4-inch wobble socket extension
Getting three bolts out is no problem. It's getting them back in.
Grease the gasket so it's not wandering on you.
Cut a 2 inch long piece of 3/16-inch brake line.
Insert the brake line into the forward hole of the oil cooler bypass valve. This will hold it in place so you can get the bolts into the other two locations. It's still a miserable job but this tip makes it less so.

khittner
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Joined: 02/15/2012
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It doesn't have to be that

It doesn't have to be that hard, but some will probably think that I've only done half of the job. I never bother messing around with draining the oil cooler or holding it open with whatever bolt is intended for the purpose, in order to refill it. I just drain the warm engine oil from the pan, remove the three filter cover bolts, extract the old hinged filter, the cover gaskets and shim, replace all of the same with new bits, bolt filter cover back on, and pour in two quarts of new oil into the crank case. I start the engine to circulate the new oil, shut it off after a minute or so, check the oil level (somewhere between the high and low marks on the stick is fine), and call it done. The only filter-changing trick I have is a 1/2" hole drilled semi-inconspicuously through the right lower that lets me get a long 5mm ball-end Allen T-handle wrench into the back oil filter cover bolt---this mod dramatically eases access to that fastener, which otherwise required removal of the whole right lower to get to. In seventeen years haven't yet seen any sign of damage to the engine by foregoing the cooler drain/refill drill.

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Konrad

jim in the north
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allowable ring end gap on '83 R100RT

I am replacing valve pushrod seals on the machine at 85,000 miles. Oily mess on lower part on the engine. Being in this far, wondering about the rings. Performance was good but compression was down some at about 100 psi.
Can someone tell me the specified ring end gap? Everything looks good in the cylinders and carbon buildup in heads and piston tops minimal.
One other thing. I notice some light oil staining on crankcase up around dipstick opening and timing sight hole. Any worries there?
Jim

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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Per Haynes, end gap is:- top

Per Haynes, end gap is:

- top ring: 0.40-0.65mm
- middle: 0.40-0.65mm
- scraper: 0.25-0.40mm

Given that you have Nikasil cylinders, you can't bore them. If they look OK with no blemishes in the lining, then you're probably OK. They do require a special hone if you go with new rings.

As far as the oil staining, you might have a slight leak in the oil mist recovery system...check to be sure that the tubing is securing.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

jim in the north
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ring end gap

Thanks Kurt.
Looks like I'll be replacing the rings. Broke the scraper ring pulling it out to clean the carbon off the top of the piston.
Should have left it alone. Still have the rings in the other piston to do the check to the numbers you provided. Do I definately have to hone the cylinders when replacing the rings? If so, is this a job for a machine shop given the fact that these are Nikasil lined or can I buy the special hone and do it myself?

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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Honing is required to cut the

Honing is required to cut the glaze and set up the surface for proper seating of the rings. I would never try it, but it's sort of simple. Hook up the hone to a drill, run the hone through the cylinder maybe for half a dozen passes...I've only seen it done once...maybe there are some videos out there and/or some other more experience people will chime in.

I saved this information from Ted Porter...I consider his knowledge among the best when it comes to Airheads and engines:

Quote:

The type of ball hone used is also important. Brush Research Manufacturing
www.brushresearch.com the makers of the flex-hone (street name is ball hone)
recommend Aluminum Oxide in a 240 grit for Nikasil which is a less commonly
available hone (I had to special order mine from BRM). The more common
silicon carbide (which is used for cast iron cylinders) can be used if you
use a finer grit such as 320. The concern with using the more aggressive
silicon carbide is that the Nikasil is thin and if you have a tiny pit or
some other microscopic surface imperfection, the silicon carbide can lift
the Nikasil in that area.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

jim in the north
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ring end gap

Thanks Schrader,
Good information to know. Do you think that I could get away with replacing just the oil scraper ring which I broke and not the compression rings which showed an end gap of 0.035 in and look good. The cylinder also looks good. Can I do that one ring without honing the cylinder? Bob's BMW micofiche shows the rings only available as a set but maybe I can source an oil scraper ring on its own?
Suggestions?

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6327
Sure, you can do anything you

Sure, you can do anything you want. If you're willing to potentially go back in at some point...maybe, maybe not. The idea of honing is to ensure a rough enough surface to allow some abrasion of the rings to get them to shape to match the cylinder walls. Some people can look inside the cylinder and see that the existing grooves are good enough...I'm certainly not.

But in the end, it'll either work or not. You have the skills to get back to this point, so maybe no real harm. I guess you'll know in 500 miles or so if the oil usage drops to a reasonable level.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

jim in the north
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allowable ring end gap on '83 R100RT

Thanks again for info.
I am now decided to do all rings. No point in halfway measures.
On another point, when removing cylinders from crankcase I found silicone like sealer in around the4-inch dia o-ring seal and around the small head stud o-rings right at the crankcase. I dont think that the engine has been apart before but maybe it was and maybe to try to do a cheap fix on valve pushrod seal leakage. Certainly somebody ruined the threads on the exhaust stub on one side.
Does anybody know if BMW used a sealant in addition to these O-rings at the factory? I would doubt it..

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6327
I looked at my BMW Repair

I looked at my BMW Repair Manual for the R60/7 thru R100RS...it contains specifications for the '77 thru '81 models. It says that when installing the cylinder, coat the base of the cylinder with Hylomar, Caril-T, or Dirko sealant. Is says for the 1981-on models, do not use the sealant. That would suggest that at the factory, they wouldn't have used any on your '83.

There are a variety of sealants not available. And if I had a large o-ring (my /7 didn't), I would still use a good sealant in a very thin application, keeping it away from the two smaller O-rings. I think that the o-ring and the sealant would do a better job of preventing seeping than if only one of them were used.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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