81 R100RS into a 80/7 frame.

[SteveD]

That's my COVID 19 project.
edit: just checked the vin...it's actually an 11/81 RS. Sold to me as RT, not that it really matters as the bits are all the same and there's no correct frame to go with it.
It might become a nekkid bike or an RS, but I already have that.

This list is an exercise in knowing what I have and what I need to get.

Feb 2018 I bought a small station wagon full of 1981 R100RS parts.
Frame-proved bent, so gave it to someone that wanted it for something?
Engine. Bean can attached.
The rotor and stator look a bit dirty. No idea if they work.
Transmission, 1981 on, with the clutch actuation bits....

No starter, diode board, swingarm/shaft, no final drive.

I have since bought another frame from an 80/7 and also a subframe
A steering head with lower triple. Needs new bearings. The steering damper rod and knob have arrived. Still need the adjuster bits. and I have the upper adjustment bits in the mail.
I have a SJBMW top triple.

Accumulated over many years...
Wheels, forks, rear shocks, brakes
instruments
Front brake reservoir and master cylinder, hoses, splitter
Guards
Battery holder.
Starter.
Clutch.
Transmission
Indicators
Headlight/housing/lens/circuit board.
Coils, HT leads, caps.
Regulator, bean can.
Both stands
All cables.
Headers & mufflers
Tank & 40mm Bings
Side covers & seat.
A box of 2-3 looms in a state of disrepair...might get one out of that lot?
RS fairings and frames.
Under seat and rear tool holders.
I have a pre 81 final drive. It'll need a cleanup and new splines.
Steering head adjuster nut, bearings. Lower steering damper assembly.

I need
the swingarm with shaft.
diode board.(might have one somewhere?)
Handlebars, brake and clutch lever assemblies.
Switchgear, though I do have some stuff which I'll need to inspect very closely.
Some relays.
Ignition switch and key.
Rear brake master cylinder and reservoir.
Additions:
oil pump.
Clutch bolts/washers x 6
Conrod bolts x 4.
Gaskets: all of them.
Camchain. (prob ok, but I'm in there)

Can anyone see if I'm missing anything from the list?

[SteveD]

These last two weeks I've started fiddling with this stuff. The frame and subframe are 75% stripped.

It'll need some welding done.
1. The brackets at the rear that the footpegs and mufflers hang from both have cracks in the usual spot.
2. The cross member on the subframe will get strenghtened.
3. The spot where the centre stand meets the frame will get some tidy up.
4. The centre stand will also get some slight modification and strengthening.
5. Undercoat & paint.

I got a little bored with sanding so took to the engine.

1. The top end was removed months ago.
2. The bean can, rotor and stator are off. How do I clean them up? Isopropyl alc rinse?
3. I've removed the camchain cover. That all looks pretty good.
4. Sump is off. That was putrid in there. Old oil wasn't milky.
5. Conrods are off. One bolt gave me some grief but was ok in the end. I'll do some pix of the shells for your opinions. I'll need your opinion on the crank. Looks ok to me but I'm no crank expert. Conrods and shells weight 571 and 572 gms each.
6. Cam followers are clean and no corrosion or wear.
7. The cam looks ok too, no corrosion/metal fatigue..

Next, I'll wipe the crank surfaces dry and inspect closer, take pix etc.

Then I'll remove the clutch carrier and have a look in there.

[SteveD]

Shells need replacing.


Journals look good. Light polish only.

[Rob Frankham]

The journals look a bit scored but you really can't tell just by looking at them... you need to check them for size, ovality and barreling. You're going to have to do that anyway to get the size and grade of shells you need even if they're perfect.

I would suggest this is something you need to do before you go any further with the project... If the journals are out of spec, you have a major decision on your hands... do you have them ground... many people supposedly in the know say this isn't a good idea with an airhead crank, citing instances of crank failure and the destruction of the hardened journal surface... others say it's OK. Do you replace the crank or do you just look for another engine. I would also suggest, if you decide to go with this engine, you need to check at least the mains and the oil pump housing before making the decision. A bit of extra time spent now may prevent a teardown and an even more difficult decision in the future.

Rob

[SteveD]

Thanks Rob.
As of today the plan is to remove the clutch carrier, the rms, the oil pump, then the cam chain and the front bearings, crank and cam.
I have 8 more days of leave whilst in lockdown so hopefully can get that done amongst other designated chores around the house.

The local BMW privateer shop near me do get someone to grind and repair them. They swear by their work too. I think they send them to someone in Sth Australia? I don't know who though.

Anyhow, I'll get more done this week and give an ongoing report of findings.

[SteveD]

Todays effort:
1. removal of the clutch carrier, the rms & the oil pump. The rms was as hard as a rock.
Difficult to see but there's a small smattering of blue silicone chips. A quick clean up..

No idea why this scuffing is there, presumbaly something came loose. It's also on the other side of the case.

2. removal of the camchain, camchain upper sprocket, tensioner and slide rail.

[SteveD]

The leading 4 edges of the inner oil pump rotor aren't perfect. They have some score markings.



I think it's kaput? Waddya think?

[SteveD]

This is from Brooks garage, a screen shot from one of his excellent videos.


These were my measurements. It'd be a waste of time reusing this oil pump I expect.


Tomorrow, the main bearing carrier and the crank to come out. I just need to work out how to heat the case to 275F.

[Rob Frankham]

The leading 4 edges of the inner oil pump rotor aren't perfect. They have some score markings.



I think it's kaput? Waddya think?

Yup... I wouldn't use them...

Rob

[SteveD]

Yep, they'll need replacing. Anyone got a excellent condition oil pump assembly on their shelf just gathering dust?

Their condition made me worry about the crank more than I had been. I pulled it out today and it didn't look too bad. It's already gone for assessment.



I'll wait until I know the results before I commit to any more effort and money in this, except maybe working on cleaning the casing.