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R69S restoration

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schrader7032
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R69S restoration

Post by schrader7032 »

Yup, just you and me in this lonely wilderness!! Not really, but the only ones up at this time...

According to BMW, my bike was built in Apr/May 1968 but was delivered to a German dealer in Dec 1968, so it is a 1969 model. Thus the date on the piston crown makes sense. Another thing that I've been meaning to check is the existence of a date on the back of the speedometer, another clue as to the manufacture date of the bike. I have a Wixom fairing and am not ready to get in behind that to look at the back of the speedo.

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

808Airhead
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R69S restoration

Post by 808Airhead »

OK,took off the right side head & barrell,and everything was going good and then I looked at the piston and you guessed it,a spun small end bushing!!! :( :? :( :? I mic'd the small end of the rod and it does not appear to be bellmouthed,so a new bushing should still press in.
The big ends appear to have no play,but only removaln of the crank and a dial gauge will tell the absolute truth.
So far I am into it for new pistons,rotating valves,re-bore,and possible crank re-build........ :roll:
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

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thaemlitz3321
Posts: 91
Joined: Fri Oct 27, 2006 3:00 am

R69S restoration

Post by thaemlitz3321 »

I tore my engine down and found the oil pump gear shattered. Engine was as bad or worse than yours. I tore my engine down to the timing gears and had the jugs/heads off. Dan at Cycle Works split the cases and really gave it a thorough go over. Pistons and rings were expensive, but he charged minimal prices for bearings, boring, resurfaced the valve tappets and checking all tolerances, refurbished crank arms, etc. Really nice guy, seems know his stuff, great communication by email and phone.

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schrader7032
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R69S restoration

Post by schrader7032 »

split the cases

I'm not familiar with that term for the R69S. Is this more of a general term, more suited to the older, pre /2 machines?

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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Bruce Frey
Posts: 536
Joined: Fri Oct 27, 2006 3:00 am

R69S restoration

Post by Bruce Frey »

The last of the twins to have a spit case was the R12/R17 (not sure about the WWII R75 however). The R5-R71 had 1 piece tunnel cases, which followed onto the postwar machines.

I assume that "splitting the cases" a generic term for engine disassembly, especially if you have experience with leaky British iron.

Bruce

808Airhead
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R69S restoration

Post by 808Airhead »

I agree,he more than likely was talking about having the crank removed and associated bottom end work.
Have ordered some stuff for this project from S.Meyer,small stuff like repro speedo,wiring harness,headlight rim,and some other small things.
Getting the parts stash started 8)
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

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R69S restoration

Post by 808Airhead »

So far my first rebuilding effort is focused on the final drive.The final drive was leaking which was apparent from the heavy staining,but luckily with 30K miles there was little/no wear on the ring & pinion.There was one unfortunate circumstance where the shock lower bolt was overtightened in the past and the thread lug which is a press fit in the final drive was "spinning"which made removal impossible.
I proceeded to cut the bolt head off and took it to a machinest that "knurled" with a chisel the lug outer diameter which,with the help of some loc-titemade it once again a press fit.He ensured me it was never going to rotate again and said it may be difficult to ever remove it in the future! :lol:
That was a relief since this is not something that ios common and there is no "oversize" lug available.
Work commenced and proceeded to remove the very hardened and leaking oil seals,as well as the large ring bearing.
The pinion bearings and ring needle bearing are still good,however the large bearing had a rumble in it so that,as well as all the seals/gasket are being changed.
The ring has PERFECT wear marks and was advised that it should be no problem to re-use the shims since I am still using the original r&p and housing.
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

808Airhead
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R69S restoration

Post by 808Airhead »

Ok,I have realised that even though the bike has relatively low mileage,a hack mechanic worked on it!
The pistons are,incredibley perfect with .003 skirt to wall clearance,so I can actually re-use these.The crank however has a little "work" done on the front generator taper,but this IMO is not a big issue,since the generator armature was still tightly on there.
The flywheel had .003 runout,which is good,and the taper was tight since it "popped" off of the crank,however it was NOT torqued properly,and I was able to loosen the bolt with a simple 1/2 inch ratchet instead of a breaker bar........then to my JOY :roll: ,I saw a sheared flywheel key,and slighty rough taper on the flywheel,only by the key.I will attempt to clean this up,replace the key,and hopefully be able to get the good runout measurement.
This crank is looking pretty messed up,so far I have 2 rough tapers,and a small end bushing that "fell out"......maybe a $2500.00 Mobile tradition new crank is in my future :?:
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

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VBMWMO
Posts: 1322
Joined: Sun Aug 23, 2009 7:49 pm

R69S restoration

Post by VBMWMO »

I have acquired a R69S and will be doing a complete restoration,and hope to photograph my progress as I go.Since I will not be making my own web page to document this,I will popst about it on this thread.The bike is complete,and has 33k on the clock.Has been re=painted once and tape-pin striped.The seller says the mileage is original.I will be splitting the motor,doing all new bearings/pistons/rings/slingers,etc.and doing all the work myself.
I will talk to Vech about the crankshaft,but does anyone here recommend a /2 crankshaft expert??Thanks,will post pictures soon. 8)
Dedicated to the Preservation of Classic and Antique BMW Motorcycles.

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Here are some progress shots

Post by 808Airhead »

Here are some progress shots of th eengine rebuild on my R69s restoration project,I have been working on it here & there and am really enjoying getting things done on this project.Currently,I am focusing on the mechanical aspects of the restoration and have so far finished rebuilding the final drive,and have now moved on to the engine.The engine has been stripped and clean,also have soda blasted the cases and evaluated what was good & what needed replacement.The crank that came with the engine had a spun small; end bushing,but otherwaise was true and the big rollers had .0002-.0003 play,so was good,however I scored a fully rebuiklt by cycleworks crank for only $500.00 and decided to use this instead.New front & rear main bearings were purchased,as well as slingers,and screws,seals,locking tabs for flywheel & oil pump gears,etc......
One part that was rather costly was the rear main bearing carrier,the original was damaged by a previous ham-fisted rebuilder & luckily they are reproducing this with a CNC version and it is beautiful,and costs $170.00!!That coupled with the $180.00 Mark-Swiss reproduced brass cage rear barrel bearing made for a expensive little motor!!
1.Engine in the oven,heated to 280 degrees & removed and placed on the bench.
Image
2.Once the heated case was on the bench,I pulled the crankshaft out of the freezer and it literally slipped right ion the rear holder and was very relieved there was no pounding/cursing/hammering involved!
You can see the new bearing carrier & barrel bearing.
Image
3.After installing the new front bearing in the bearing carrier,this was installed carefully by following the procedures in the factory manual.Basically pressing the bearing on until the carrier almost touches the case,and then drawing the carrier to the case with the nuts & bolkts that attach it,then drawing thje crank forward in the case.
It was very relieving when everything was going as planned and the crank rolled smoothly except in one small area of rotation.I saw the sling was lightly rubbing ion the fron carrier and instead of removeing the bearing carrier,I lightly tapped the edge of the slinger and this instantly gave enough clearance for a very smoothly turning crank.This was a minor issue,and it was due to the fact that the reproduction slingers are not exact and in factr have to be "worked" a little to fit in the big end pin and Vech has accounted for this by stating he has to "make them fit" as best you can.This seems to be the mantra for reproduction parts......
Image
4. A picture of the new Benchmarkwerks double lipped Viton seal,and for a 40 dollar seal,I hope it works as good as it looks/much as it costs.
Image
5.Here was a VERY time-consuming and nail biting procedure!Setting the runout on the flywheel.This took 4 different attempts and really learned a lot about this procedure.One of the best things was I had purchased the INVALUABLE Barrington manual and this gave wonderful insight into this procedure........it gave a technique of "pulling" one edge of the flywheel away from the block while tightening to help offset large runout values and even it up around the circumference.
I followed their tip of applying 25ft.lbs of tq. and measuring each time.......this was a wild rollercoaster ride of highs & lows....crank it down 25ft. lbs.....in spec,another 25 ft, lbs....up to .008 off! (spec is .004 or less)the another 25 ft. lbs,.006 off!.......loosen bolt,try again!I used a marker and made marks of the high & low spots spots and would keep trying with different combinations of tightening/pulling/measuring and 4th time was the charm......I got it to 176 ft.lb with a .............drum roll please............002" runout!!!! I was so stoked after being methodical,I felt it really paid off.This should make for a smooth motor & good clutch action.
Image
Look closely,you can see the .002"!!! Yay!
Image
6.Here is the flywheel installed.I thought it would be neat to right a little message in permanent marker and it reads my name,the date,and "it took 2 hours to get the .002" runout!"Maybe one day when I pass someone will see that little message and get a kick out of it!
Image
7.Just for kicks I decided to install the beautiful big sump and it is wonderfully mader,great fit & finish.
Image
I used the dark cork gasket and coated it with Permatex aviation sealer (brown tarry liquid)and looking forward to getting this engine finished and moving in to the body/chassis.........
Image
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

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