75/5 restoration evaluation

[Alfetta]

So I recently acquired a 70 beemer along with a 77 convert.  After several hours looking at both bikes I decided to start with the beemer.  There is a lot less going on with that bike.

The "mechanic" that I picked up these bikes from, seemed to like to remove heads and bits, then push them into a corner...   the BMW suffered busted fins in his attempt to pull the jugs.  Pistons were ceased hard, but using Ozark engineering I managed to extract them

Rods look good journal bearings feel good and I don't see any rust inside the engine.  I think it's a solid candidate for restoration....

[Canuck750]

Very clever puller you came up with, I love DIY tools that the average Joe can make themselves! 👍

[cliffrod]

It’s easy for me to spend your money, but I think it’s an excellent project to do.  We had a sorta one owner 1970 R75/5  that ping-ponged back and forth between that original owner and 1-2 others at the shop as personal wealth ebbed and flowed for 20+ yrs.  Then it was sold outside of the circle and is now forever gone from our grasp...  At least it’s still local, parked next to a very, very nice V7 Sport.

That was a really great bike.  Hopefully your project will turn out well.

[Alfetta]

The plan as of right now, is to keep my OCD in check. clean repair and replace the top end and see if i can get the old girl running. If so then on to the niddley bits to make it rideable.  This bike came without a title so this project may end quickly if i can't get past this hurdle.  any advice here would be a help (PM me please).

The bike is showing 60K miles on the clock, and i think that it is accurate (just doesn't look like its been to 160K) so if i get it running. with the jugs off I didn't see anything ugly in the bottom end. rods feel tight, wrist pins are in spec. therefore i am inclined Not to crack into the cases. Due to the age and time sitting, I am worried about all the rubber seals, and im wondering if I should replace them now, or wait for evidence on need ?? 

my overall plan for this bike is to get it operational, every thing working, sell it, and use that money to invest in the convert.
nothing against the BMW, but the convert is what i went for, and i suspect the cost to restore it will be a bigger number than the BMW.

[faffi]

I like your plan

If you need tips, this bloke offer lots https://www.youtube.com/@BrooksAirheadGarage

[Antietam Classic Cycle]

The plan as of right now, is to keep my OCD in check. clean repair and replace the top end and see if i can get the old girl running. If so then on to the niddley bits to make it rideable.  This bike came without a title so this project may end quickly if i can't get past this hurdle.  any advice here would be a help (PM me please).

The bike is showing 60K miles on the clock, and i think that it is accurate (just doesn't look like its been to 160K) so if i get it running. with the jugs off I didn't see anything ugly in the bottom end. rods feel tight, wrist pins are in spec. therefore i am inclined Not to crack into the cases. Due to the age and time sitting, I am worried about all the rubber seals, and im wondering if I should replace them now, or wait for evidence on need ?? 

my overall plan for this bike is to get it operational, every thing working, sell it, and use that money to invest in the convert.
nothing against the BMW, but the convert is what i went for, and i suspect the cost to restore it will be a bigger number than the BMW.

I'll PM with a title service.

The front crank seal is easy to replace once the alternator is removed, so I'd do that. Definitely new pushrod tube seals. Other than those, I'd wait to see what leaks.

[cliffrod]

Run the numbers.  This isn’t a simple or quick clean tank & carbs, add battery & gas, get it running project.

Buy for $100 (making the Convert free- Guzzi content..) and sell quick as is for $500-$750 to make at least $400.   That’s a min 400% profit, which is a great roi, and little to no time spent/wasted. Plus, you’ll probably make someone happy with a good deal on a project they want.

Time spent aside, buy for $100, spend $1k-$2k (thinking the drip-drip-drip of new & used parts prices plus the mentioned ocd) to try to make the same $500 can easily cut roi to 25%-50% if that.  Just like a similar condition Guzzi, an unpretty BMW doesn’t bring top dollar. 

Unless you know a specific market/model really, really well, it’s really easy to spend so much fix-up money on a bike that you end up lucky if you break even.  Btdt.   If it’s all about making money to spend on the Convert, I would sell it as it sits for the same amount of net income vs diminishing return by spending lots more to get the same amount.   Then use the same profit to start on the Convert this winter vs next year..

[Alfetta]

i smell what your stepping in Cliffrod...  and perhaps it is the best answer, however in this section of the country, it's a bit of a tough sell.  A non-runner that isn't a Harley, Mustang, of lifted truck ! (then throw in the lack of title.)

but if you offering 500 send me a PM and put my OCD mind at rest....  it's the least you can do.

[cliffrod]

You’re funny….   Nope, not asking or offering to buy.  Way too many projects here to add another one. 

This is generally a good time to sell “winter project” bikes and anything classic- like that first year /5- available in the $500 price range is usually a good item to sell.   Compared to years ago, there are so few good bikes out there now for a rational price.  Because of the limited supply/opportunities plus new ways to resolve it, lack of title now isn’t the detriment it used to be.   If you sell it as is, what you make is basically pure profit.  The more you spend to make it marketable imho diminishes your margin.   

I would put it up for sale as is for $600 or $750 obo and see what happens.  Someone will probably offer much less, then be agreeable to $400-$500.  If I had the chance to buy the same bike same condition for $100, that’s what I would do.

[Alfetta]

A little (very little) progress on the Boxer..  As i am putting in a pool, I can only get to the bikes when the pool project is not demanding attention.

The piston rings were imbedded and seized in the pistons, I tried every thing that i know to loosen them up. Multiple boils in Diezel, Marvel Mystery, even 80% Vinegar.  but after many days of soaking, poking and prodding I gave up and started using a punch to remove them, and it was still a tough job.

Otherwise the cylinders cleaned up well, and so far the heads are looking reasonable (perhaps one exhaust guide). I did notice that one of the push rod tubes that are pressed into the cylinder has a loose ring on it (the ring that holds the rubber boot into the block).

So a question to you Boxer peeps...  I have a spare cylinder with pushrod tubes that are good, is it easy to knock them out and replace the bad one in my good cylinder, or epoxy bond the loose ring (or tack weld) back to it tube...

Sorry if in using all the wrong nouns !

[Alfetta]

It's been a while but i managed to get the right cylinder back in place. I was short shipped two push rod tube seals, so the left side waits.
Next is to get the carbs sorted and back on. then get the ignition as see if i can make some noise.

[Alfetta]

Its been quite a while since i touched the boxer. but the weather is pushing me indoors and the pool project is over. so i though i would give a little update (very little).
Keep in mind that my intent is not a restoration as much as just get it running and safely operational.

After getting the cylinders and heads basically sorted, i began to look for spark... none.  the points and advance device has a lot of surface rust so this will also need to be sorted, however i do not like working on crap that close to the earth, so i decided the i would pull the engine out and get it on the bench. this should also make cleaning it and additional inspection easier for this old man..

during the removal of the rear wheel, swing arm, and transmission, i noticed that the rear wheel had a few bent spokes and gouging damage from poor tire changes in the past, beyond being massively caked with crap. so I dove into my first BMW wheel re-construction... (yes, i have a hard time staying on task)

First:
i found it odd that there are 4 grooves perpendicular to the rim that reside between some of the spoke nipples. These do not go all around the rim and I have no idea why these exist, i have not seen the like on any other rims i have worked with. can explain function / purpose of these to me ?  I would love to know... (red circle in photo)

Second:
I love the fact that BMW chose to use tapered roller bearings, and despite the age, these proved to be in very good condition. However the process of bearing insertion / extraction is ...  well  ... unfortunate. I dislike the requirement to "grind" a spaced to achieve proper preload, and the hub heating as well. But it is what it is...German.

[Antietam Classic Cycle]

Here's an explanation about the wheel divots. https://www.w6rec.com/duane/bmw/5dents/index.htm

Guzzi used tapered roller bearing on the Loopframe drum brakes (except the for 4 leading shoe drum) but the shimming of them is much easier. Guzzi used a commonly available flat shim, BMW uses that "wedding ring" shim which is a bit of a pain.

[Alfetta]

Thank you ACC for the explanatory link,  i have been riding dirt most of my life, so i find it odd the the author of that article doesn't like rim locks, personally i find them very easy as every dirt bike has at least one on the rear rim.  The five dimples is a cleaver solution, however it begs the question, is it necessary as I have only seen them on the /5

regardless, the rear rim is back together, laced up, so i started looking at the drive box. I think there is evidence the main shaft seal is leaking. and the drive spline is less that optimal.  Kinda odd as the wheel spline looks quite good ???  now i wonder if there has been a wheel swap in the past, or if the drive spline is "softer" than the wheel spline ?!

[Alfetta]

Wheel and gear box done.  Going to slip on tire I just pulled from my V7. Now motor goes on the bench...

[Alfetta]

Engine case mods near complete...

Planning on using two "u" bends to put the carbs over each cylinder, or possibly making a manifold to a single weber side draft ???
So many options...

I wish the starter would mount pointing aft, maybe a VW unit could be used, that would make the weber option very slick..

need to fabricate a can to cover the alt, and one more to cover the points... Im thinking stainless restaurant tins may be an option...

[Alfetta]

Carb placement for manifold fabrication...

[SIR REAL ED]

That picture is im-freaking-pressive!  I salute your ingenuity and Redneckness!

I'm even a bit envious!!

Someone raised you right my Brother!

Carry on with pride!!

[Huzo]

That picture is im-freaking-pressive!  I salute your ingenuity and Redneckness!

I'm even a bit envious!!

Someone raised you right my Brother!

Carry on with pride!!

I join the line of people who salute your tenacity. Did you make a conscious decision not to have a threaded puller adaptation to extract the piston ?

[Huzo]

Wheel and gear box done.  Going to slip on tire I just pulled from my V7. Now motor goes on the bench...

Jeez that looks nice. No one seems to bother casting nice shapes anymore…

[SIR REAL ED]

Jeez that looks nice. No one seems to bother casting nice shapes anymore…

Isn't that the truth?

My Dad's shop had a drill press from about the 1920's.  The frame was beautifully curved, sculptured, artistic casting, complete with raised images of roses that weighed over a ton.  Mechanical feed, electric motor that weighed about 300 pounds, spinning about 180 rpm......  You could put a pencil in the chuck and it would push that pencil thru a 1/2" thick steel plate.

A very different era in terms of pride and craftsmanship!!!

[Alfetta]

3D printed Alt / Point cover.
will decide if im going to used the 3D part to make a mold to cast aluminum or just a form for fiber glass...
but im basically happy with the fit.