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an unfortunate update to my long restoration process

B

brant914

New member
hi everyone,

I'm the guy with all of the odd questions
I've really appreciated all of the help and advice here.
I guess today ... is the day I need to start researching and learning about an airhead motor rebuild....

last friday a local airhead expert "Radar" came over and spent nearly 5 hours helping me get the bike to run for my first time.
I rode it carefully on friday and a bit more on saturday... 47 miles total. extremely fun!

drained all of the fluids and got myself ready for a break-in, service of valve adjust, head stud torque, etc...
well the bad news is that on monday I opened the oil filter and found it full of copper bearing material....

so the restoration project is now moving to the next level... I'm going to need a motor rebuild...
and need to find a good shop capable of doing this correctly... already intend to replace the camshaft due to the damage on the nose
and just hoping the crank isn't damaged yet...


anyone have any recommendations to rebuild a 1971 R75/5 engine?
really hoping to find someone in Colorado... but the proper experience and skill is more important than location
thanks everyone...


ugly oil filter picture below:

1.jpg6.jpg
 
I'm not sure if Matt Parkhouse is still working on bikes in the Col. Springs area. Do a search.
Good Luck!
 
Max BMW is an option, they recently obtained some sophisticated shop equipment for crank rebuilding.
 
How did the engine sound when you were riding? I know bad conrod bearings get very loud by the time they are shedding metal.
 
I would also suggest Mike Orloff who owns Martindale Motorcycle Works. He is the one who did the restoration of this year's BMW MOA Springfield Rally 1972 R75/5 prize bike.

Mikey Orloff
Martindale Motorcycle Works
4714 Redwood Rd
San Marcos, TX 78666

Tue-Fri 10-6, most sat 10-4 central time
(512) 357 2842
 
AntonLargiader said:
How did the engine sound when you were riding? I know bad conrod bearings get very loud by the time they are shedding metal.
Click to expand...

it actually did make a slight noise.
after 1 trip around the block, I told my friend that there was a very faint noise but only at 3000 rpm. above that and below that the noise vanished... I would have though rod knock, but at the time decided it could be a muffler vibration or something else as it was not through the entire rev range as I've experienced from other motors with rod problems. the next night when I pulled the filter, I realized fully what the noise was.
 
Is any of that stuff in your filter magnetic? You could rinse the element out in solvent and check with a magnet in a clear container.
 
brant914 said:
it actually did make a slight noise.
after 1 trip around the block, I told my friend that there was a very faint noise but only at 3000 rpm. above that and below that the noise vanished... I would have though rod knock, but at the time decided it could be a muffler vibration or something else as it was not through the entire rev range as I've experienced from other motors with rod problems. the next night when I pulled the filter, I realized fully what the noise was.
Click to expand...

Dumb question, but I'm assuming you installed a new filter prior to running the engine for the first time?
 
RPGR90s said:
Dumb question, but I'm assuming you installed a new filter prior to running the engine for the first time?
Click to expand...



not dumb....
and sometimes I do dumb things...

but in this case
new filter, new cam seal, new clutch, new rings, new head gaskets, rebuilt oil pump, new timing chain job, new pushrod seals, new rear main seal, and new everything except the bottom end prior to start up.
 
20774 said:
Did it sound anything like this guy's recent rebuild?

https://www.youtube.com/watch?v=pqMBzZAe8g0

He was going through a process of refurbing his lower end. He's pretty sure he has trashed his crank.
Click to expand...


no where near that much noise.
and had the local Guru (radar) adjust the carbs and tune it with me for 5 hours.
it was idling perfectly smooth... absolutely no noise at idle... and only a slight...weird... noise at 3000 rpm that went away above or below that rpm.

brant
 
ebeeby said:
Did you block the forend of the crank when you did the clutch?
Click to expand...

yeah seeing that material made me Fear This too. A rear thrust washer adrift.
Take the ft cover off , see if you can move the crank front /aft .
Take off the starter to see if you can move the crank fore/aft while levering on the flywheel

Hope not but hmm whats THIS I spy in my little shop???

bmw r100s crankshaft - 8.jpeg
 
sorry for my slow reply...
work got super busy for the last couple of weeks

I will pull the starter today and test for endplay
thanks for the advice everyone, I do appreciate it....

I used the cycleworks tool to hold the alternator during the flywheel job.
but will know for certain with this endplay check.. and at this point... I do want to learn and know so that It can be rebuilt.

a local guru (radar) also had the good idea of buying a used running motor
a really good idea... as I can take more time having the original motor rebuilt (numbers matching case) while still enjoying the actual bike in the mean time...
so if anyone had advice about where I should look for a running motor... I'm all ears.


brant
 
this the thrust washer that can slip off its pins if the crank moved forward.
One guess is the copper-color flakes in the filter originated from that forward / bearing face.
I presume the engine would "run" with it dislodged until something else failed from it

BMW R100S thrust washer - 1.jpeg
 
gtgt_bangbang said:
yeah seeing that material made me Fear This too. A rear thrust washer adrift.
Take the ft cover off , see if you can move the crank front /aft .
Take off the starter to see if you can move the crank fore/aft while levering on the flywheel
Click to expand...

finally had time to remove the starter last night.
(clutch is still installed if that matters... but I would think not)

no end play in the flywheel or alternator

the initial diagnosis over the phone (Matt Parkhouse) is con-rod bearings (which i'm told are copper with bearing babbit over them) may be correct.
brant
 
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