My first restoration (R90/6) where to start?

[khoury]

I wanted to post to seek some guidance on how to approach the "restoration" of my first BMW. I'm not seeking to do a complete tear down but rather to get the most bang for my limited time/dollar with the ultimate goal being reliability.

The bike is a 1975 R-90/6 w/63k miles and the information I received on upkeep etc was limited. It runs and sounds good, but the carbs are leaky monsters and I'd suspect there is a lot of routine maintenance that did not occur. What are the most vital tune-up/mechanical issues to address first, or put another way- what is a good sequence of improvements? Thanks for any advice.

 

[bikerfish1100]

first, buy a Clyner's manual so you know what you're doing. next; leaking carbs is bad, so fix them first. then go thru with a basic tune-up: adjust valves, change all fluids, set points/timing, etc. once it's running you can sort thru the other stuff -suspension, appearance, etc.

 

[brentde3]

I'm in the middle of my first rehabilitation as well (a 1976 R90/6). I agree with the notion that the carbs come first. They're great when they're not leaking on your foot

Next: All the consumables. Plugs, plug wires, air/oil filters, tranny and final drive oils, etc. Valve, timing, points after that.

Then ride it!

Picture please!

 

[26667]

in my experience, everything rubber must go. A '75 w only 63 k on the clock hasn't been ridden enough. that is to say, it hasn't been maintained enough.
If you open up any component, do whatever else you can reach; whatever's available having unscrewed, unbolted whatever you've got so far. Don't make yourself go back and re-open that system/area of access. You'll save yourself time, and time is money.
I know. I know, "time is money." write that one down.

Grease turns to glue eventually.

 

[Bill Burke]

Congratulations and welcome aboard. I would respectfully suggest that you join the Airheads Beemer Club and consult the member "dAIRectory" which contains lots of contacts in the Twin Cities. You can save a bundle with a little help from a fellow airhead. With some careful attention to detail and a thorough examination of the basics, you'll be on your way to your first (mostly) reliable riding season. Making your bike reliable for the long haul will depend upon its current condition. Find the local airhead "barley therapy" group and introduce yourself. Airheads are always happy to help each other out.

http://tinyurl.com/9jsffa

 

[gstom]

Rest assured that you will end up way deeper into this project than you originally intended. It is very hard to resist the urge to limit yourself to a minimalistic restoration, as you have everything apart and "Well... since I have gone this far ..I just as well do......." Enjoy the project, but don't be surprised if it becomes more involved than you initially thought.

Post some pictures if you can!

PS: Voice of experience speaking!

 

[2slowwheels]

Is this the one from Rochester with the Hannigan fairing?

 

[crazydrummerdude]

what is a good sequence of improvements?

1) Take a bunch of "before" pics.
2) Post them to the forum.
3) Rebuild and balance the carbs.
4) Take a bunch more pics.
5) Post them to the forum.
6) Investigate the integrity of the petcocks, then 4) and 5).
7) Investigate the integrity of the valves, then 4) and 5)
8) Investigate the integrity of plugs/wires, then 4) and 5).
9) Investigate the integrity of the brakes, then 4) and 5).
10) Investigate the integrity of the transmission and "drivetrain", then 4) and 5).
11) Investigate the integrity of the tires, then 4) and 5).

I say "investigate the integrity of ..." because I'm a cheap-ass, and replacing everything just because it's old is inefficient and definitely not thrifty.

 

[James.A]

Time is money only if you have to meet a deadline. Of this, there is no doubt.

What other bikes have you owned? If your prior experience is Brit bikes,or pre EVO Harleys, your'e gonna love your /6. If this is your first vintage bike, you are in for a rude awakening. If you are a "high dollar cat", breathe a sigh of relief.

If the bike runs and rides O.K., the first thing that I would do is to replace the clutch cable. Also, lube the barrel fitting where it connects to the handle. Similarly, inspect and lube the throttle assembly on the right side hand set.

Your leaky carbs are quite likely to be caused by the floats. There are fairly heavy bent wire bales that hold the float bowls to the bottom of the carbs. They can be pryed backwards fairly easily. This allows you to inspect the bottom side of the carb body. You may have to lightly tap on the bowls to dis-lodge them. A full carb gasket set is likely to be needed. I judge floats by color. I had a 750 that got to running bad and I found that one of the floats had turned BLACK. The less white they are, the more likely the need replaced.

At 63K and change, you have to look at the transmission input shaft. Your bike has a single plate, dry clutch. More specificly, you must inspect the spline where it interfaces with the clutch disc. Without a reliable assurance that this service has been done recently, you gotta get in there and make it right. If not by mileage, then by age.

If the bike runs O.K. now, it will not likely set you back much more than $1000 to make it right in the near term. Of course, this asumes that you do the work yourself. Wheel bearings, steering head bearings, fork seals, springs, etc., must all be inspected and put right.

Your front brake master cylinder, which is under the tank, must be inspected for leaks and bled out with fresh fluid at the very least. This is often neglected because it is UNDER THE TANK. You'll have to remove the tank. Go ahead and purchase 5 feet of new fuel hose.

Everything rubber is suspect.

If your'e not good with lawn mowers or old-timey farm tractors, your'e screwed. The early airheads were designed for farmers and proletarian workmen, y'know, simple folk.

Meeting up with local Airheads is the best thing you could do. With the right care, your bike could run FOREVER.

As crazydrummerdude and others might attest, I am available for consultation. Pre-1977 airheads is all I've ever, or would ever own.


You may send me a Private Message (PM) through this forum, and I will send you my phone number.

Simpla Fi.

All the best, James A...

 

[James.A]

Having spent a half- hour creating this post, feel free to send me $10. Nyuk,...Nyuk.

 

[manicmechanic]

Hey, Jim, sounds like a weekend roadtrip.

 

[sumran]

Welcome. You have aquired a fine machine and should enjoy it more as time goes on.

I would change all the fluids. Replace the brake fluid and clean the gas tank. Since you are in the frozen north and have some time, I would work through the electrical system and clean all of the terminals.

The first thing I would do is find the local airheads. Having an experienced airhead along will help make the job pleasant and educational. Here is a link http://www.airheads.org/component/option,com_contact/catid,80/Itemid,43/ for the airmarshals of the airheads club. You will see one on the list for your state. Give them a call. Before you know it, you will have two or three knowledgeable BMW owners available that will gladly help you with whatever you need. They will likely have whatever parts you need stashed in their garage and will be happy to share. That way, progress can continue while the replacements are being delivered.

Clean and adjust the points, adjust the valves. Rebuild and sync the carbs. Be sure the brakes and bearings are in order. Ride. Observe. Tweak. Repair as needed. After a little while it will be mostly riding.

Keep us posted.

 

[James.A]

Hey, Jim, sounds like a weekend roadtrip.

Yeah, we've done this before.

 

[dduelin]

One service item that needs to be done immediately will cost you only several hours time and a few dollars for the grease is an input spline lube. The clutch design requires the clutch disk to slide back and forth on the input shaft. If the splines are dry they wear and when they wear enough they strip and the shaft and disk are ruined. This is a $600-$1000 repair - not a bad trade off for a $9 tube of Honda Moly 60 paste.

I had this happen to me 3,000 miles after I bought my airhead and it was an expensive lesson to learn. Yes, fix the gas leaks from the carbs so the bike doesn't burn up but plan to do the spline lube soon.

THere are lots of on-line resources for this job and it isn't hard to do. We can help you.

 

[26667]

Having spent a half- hour creating this post, feel free to send me $10. Nyuk,...Nyuk.

Do we all have to send you the ten bucks, or just the origianl poster?

 

[robsryder]

You've gotten some good suggestions already. You may not be interested in a "restoration" as some would define it, but rather making certain that you have a comfortable and reliable bike.

The most important things are for the bike to go and stop when desired. So it will likely be necessary to address those areas as a priority. Gas has to be able to get to the carbs, then to the engine in the proper mixture (fuel tank, petcocks, carbs, airfilter). Shifting should be deliberate with the desired gear available, with no unusual noise (transmission, driveshaft, clutch).

The fuel must be ignited to push the pistons (ignition, timing, valves, head, piston, rings, valve guides, oil filter, oil pump). The exhaust should exit the engine in an orderly manner with a pleasing sound. (exhaust).

The bike should start easily and the lights should work (charging system, battery, lights, starter, switches).

The bike needs to stop (brakes) and handle reasonably well (suspension, steering, swingarm, and wheel bearings).

For the airheads that I've purchased I've gone through each of the aforementioned systems. I have taken as long as two years to do this. I have other bikes and am willing to take my time. I have good sources of parts (Re-Psycle BMW is nearby, and I've made numerous purchases from others: ebay, Airhead Cycle Salvage).

Some of the airhead gurus don't like the Haynes or Clymer's manuals as they have some procedural errors that can cause problems. I do have the Haynes, Clymer's, BMW factory manual, and much other stuff downloaded from the internet. I tend to check all available sources before attempting something for the first time.

Internet sources include IBMWR, Airheads, and Snowbum's websites.
http://www.ibmwr.org/r-tech/airheads/index.shtml
http://www.airheads.org/
http://bmwmotorcycletech.info/techindex.htm

 

[orbitangel]

To "Restore" or "Repair"

You've gotten some good suggestions already. You may not be interested in a "restoration" as some would define it, but rather making certain that you have a comfortable and reliable bike.

The most important things are for the bike to go and stop when desired. So it will likely be necessary to address those areas as a priority. Gas has to be able to get to the carbs, then to the engine in the proper mixture (fuel tank, petcocks, carbs, airfilter). Shifting should be deliberate with the desired gear available, with no unusual noise (transmission, driveshaft, clutch).

The fuel must be ignited to push the pistons (ignition, timing, valves, head, piston, rings, valve guides, oil filter, oil pump). The exhaust should exit the engine in an orderly manner with a pleasing sound. (exhaust).

The bike should start easily and the lights should work (charging system, battery, lights, starter, switches).

The bike needs to stop (brakes) and handle reasonably well (suspension, steering, swingarm, and wheel bearings).

For the airheads that I've purchased I've gone through each of the aforementioned systems. I have taken as long as two years to do this. I have other bikes and am willing to take my time. I have good sources of parts (Re-Psycle BMW is nearby, and I've made numerous purchases from others: ebay, Airhead Cycle Salvage).

Some of the airhead gurus don't like the Haynes or Clymer's manuals as they have some procedural errors that can cause problems. I do have the Haynes, Clymer's, BMW factory manual, and much other stuff downloaded from the internet. I tend to check all available sources before attempting something for the first time.

Internet sources include IBMWR, Airheads, and Snowbum's websites.
http://www.ibmwr.org/r-tech/airheads/index.shtml
http://www.airheads.org/
http://bmwmotorcycletech.info/techindex.htm

Khoury,

ALL the advice which has been given so far is GOOD advice.

I especially like the way robsmoto has summarized the priorities.

I have some further suggestions for your consideration:

1. Give yourself as "much time as it takes" to perform a detailed inspection/cleaning.

2. Begin this by "field stripping" the bike - this is VERY easy to do on an airhead!

Hinge the seat up and remove it. If the circlip still exists on the rear seat hinge pin (pretty unlikely) remove it and throw it away. Slide the seat off the hinge pins and remove it.

Turn off the petcocks and remove the fuel hoses. Remove the tank. You can ALREADY see a lot of the things you need to see.

Disconnect the battery grounding cable at the transmission.

Remove the 2 bolts holding the starter cover on and remove the cover.

Remove the intake pipes, the L/H air filter cover and the filter. Then remove the R/H filter cover. Next, remove the battery. You will likely see a lot of rust on the battery box and a number of defective rubber mounts. All this is easy to clean-up, paint, etc. You can also clean off the top of the transmission, beneath the airbox.

Remove the front engine cover. You will also want to remove the valve covers to inspect for proper clearances and possible valve recession.

Plan on changing the oil and filter, cutting the filter and spreading it open to inspect for metallic debris. DO observe correct filter assembly procedures. This is critical.

3. Now that you can see everything, perform a DETAILED, THOROUGH inspection of EVERYTHING, including all wiring (especially the stuff inside the engine cases.)

The diode board rubber mounts will probably be sagging or completely shot.
Replace those with solid mounts (several sources.) To properly inspect the wires in the engine you will need to remove the diode board and probably the starter.
The harness will need to be physically UNPLUGGED and wiring REMOVED to inspect the connectors and to ensure no bare/chafed/burned/deteriorated wires. This may seem like a lot of work but it really is not. It will pay big dividends later-on.

4. Keep a running LIST of things that need repair or replacement. Replace whatever you can, as you are able, critical things first.

5. Don't ignore the chassis. The engine mounting studs wall often be loose. If that engine isn't clamped in there nice and tight, handling will be squirrelly. The same goes if steering head bearings are loose or too tight/notchy.

Check axle bearings for play.

Just inspect EVERYTHING! Did I say make a LIST?

This can (and should) become a labor of love and the more attention you give that fine machine the happier the two of you will be together. Life will be GOOD!

Happy motoring!

 

[kstoo]

All of the above and take digital pictures of everything as you disassemble and inspect. There is no memory like digital memory and a picture tells ...
Learn how to take macro (extreme close-up) pictures.

$0.02

 

[amiles]

Lots of great advice listed above.

If you can find some way to swing it, buy a Harbor Freight bike lift (the kind that is like a hydraulic table) The price is reasonable, the quality good It's only weak point is the wheel vise.

Having one of these will make the work that you have ahead of you much easier and efficient, believe me.

The Airhead and Snowbum sites will become your bible.

 

[308NUT]

I wanted to post to seek some guidance on how to approach the "restoration" of my first BMW. I'm not seeking to do a complete tear down but rather to get the most bang for my limited time/dollar with the ultimate goal being reliability.

The bike is a 1975 R-90/6 w/63k miles and the information I received on upkeep etc was limited. It runs and sounds good, but the carbs are leaky monsters and I'd suspect there is a lot of routine maintenance that did not occur. What are the most vital tune-up/mechanical issues to address first, or put another way- what is a good sequence of improvements? Thanks for any advice.

Can you post a picture of your bike before you tear it apart. Would love to see it, also the serial #. I used to have a 75 R90/6 would be cool if it were my old bike.

Wade