ADVrider

Go Back   ADVrider > Bikes > Old's Cool > Airheads
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-30-2011, 10:41 PM   #1
_cy_ OP
Beastly Adventurer
 
Joined: Sep 2011
Location: Tulsa, Oklahoma
Oddometer: 5,628
Bringing 74 R90S back to life after sitting 30 years

Bringing 74 R90S back to life after sitting since 1979 ... parked with only 7,300 miles on the clock.
purchased from the original owner's son. This bike was the 41st R90S made to USA spec's off the assembly line. one of the first R90S to hit American soil and quite possibly the lowest mileage un-molested R90S in USA.

Was torn between selling this bike, purchasing a modern bike with proceeds and keeping it.
At first I thought it would be a shame to put mega miles on this R90S. But came to conclusion, that's what it was made for.

After thinking about it for a day.... nah... more like an hour... keeping the R90S!
It's my goal to bring this bike back to 100% mechanical condition. reliable enough to tour.

This thread is to document the process, that is if anyone is interested...

30 years of dust






_cy_ is offline   Reply With Quote
Old 10-01-2011, 12:56 AM   #2
opposedcyljunkie
Heavyweight Boxer
 
opposedcyljunkie's Avatar
 
Joined: Feb 2007
Location: By the Lake
Oddometer: 4,779
Interested

Nice find and good decision to keep it!
__________________
OCJ
92 R100GS-PD Euro
01 Vespa PX150E - sold
05 Yamaha Fazer FZS-1000
07 R1200GS
opposedcyljunkie is offline   Reply With Quote
Old 10-01-2011, 04:42 AM   #3
_cy_ OP
Beastly Adventurer
 
Joined: Sep 2011
Location: Tulsa, Oklahoma
Oddometer: 5,628
tires were leaking so pulled down front tire, only to find natural rubber tubes inside are in perfect condition. valve stem was leaking.

need help in deciding which tire to put back. Bike came with a brand new Metzler 3.25 x 19 tire still wrapped. what shall I do? find a modern tire to install and put back the original Metzler or just install the new Metzler?

will need to fabricate a tire balancing tool with bearings. best tube I could find locally was a Japanese made IRC brand.

after replacing valve stem in rear tire, holding air fine.rear tire appears to be pliable, looks & feels like new. will leave it alone for now.


_cy_ screwed with this post 10-01-2011 at 04:47 AM
_cy_ is offline   Reply With Quote
Old 10-01-2011, 05:23 AM   #4
DoktorT
BigBrowedNeandereer
 
DoktorT's Avatar
 
Joined: Apr 2009
Location: Chewelah, WA
Oddometer: 1,144
What a great project. Getting to safe and reliable for use is a worthy goal. I see a two stage process. First stage is partial dissassebly for cleaning and inspection.

Safety means new tires and tubes.

A through cleaning of tank, petcocks and carbs is required for reliability. Do that once right and be done with that. Do pull the front cover. Go over all the wiring terminals under there as well as the headlight pod and under tank area. Clean and tight everywhere.

Just standard maintenance elsewhere. Valves, oil and filter, lube, splines, head bearing and swingarm tension, the basics. New battery then just test all lights and switches.

Flush and renew the brake fluid, then pull the handle as hard as you can and verify firm and no leaks. Rebuild master and calipers if required.

Then you can fire it up and test drive, tune the carbs.

Stage two is to put a few hundred miles on it and see if you got some leaking seals somewhere and monitoring for proper function of all systems.

Sure hope it wasn't stored with gas in the tank and carbs.
DoktorT is offline   Reply With Quote
Old 10-01-2011, 05:38 AM   #5
Detroit Steve
Homely Adventurer
 
Detroit Steve's Avatar
 
Joined: Feb 2008
Location: Further...
Oddometer: 491
DOKTOR T is right but left out one thing.


Clean and repack ALL bearings! the grease that was ok back in the day will be the consistency of candle wax today.


Enjoy that bike you lucky devil!!!!!
__________________
When you create with your brain, it is work
When you create with your heart, it is craft
When you create with your soul, it is art

Detroit Steve is offline   Reply With Quote
Old 10-01-2011, 07:37 AM   #6
DoktorT
BigBrowedNeandereer
 
DoktorT's Avatar
 
Joined: Apr 2009
Location: Chewelah, WA
Oddometer: 1,144
Quote:
Originally Posted by SlackerSteve View Post
DOKTOR T is right but left out one thing.


Clean and repack ALL bearings! the grease that was ok back in the day will be the consistency of candle wax today.


Enjoy that bike you lucky devil!!!!!
Covered under basic maintenance I did mention. That includes everything listed under maintenance in the factory manual, including the wheel bearings and LOTS of other things I. No need for me to be redundant to exhaustion on this.
DoktorT is offline   Reply With Quote
Old 10-01-2011, 08:28 AM   #7
elite-less
As above, so below
 
elite-less's Avatar
 
Joined: Dec 2009
Location: The Puget Sound Convergence Zone
Oddometer: 538
Great base for a project! I'll be checking on this.
__________________
Slash 5 Revive
elite-less is offline   Reply With Quote
Old 10-01-2011, 08:30 AM   #8
_cy_ OP
Beastly Adventurer
 
Joined: Sep 2011
Location: Tulsa, Oklahoma
Oddometer: 5,628
Quote:
Originally Posted by DoktorT View Post
What a great project. Getting to safe and reliable for use is a worthy goal. I see a two stage process. First stage is partial dissassebly for cleaning and inspection.

Safety means new tires and tubes.

A through cleaning of tank, petcocks and carbs is required for reliability. Do that once right and be done with that. Do pull the front cover. Go over all the wiring terminals under there as well as the headlight pod and under tank area. Clean and tight everywhere.

Just standard maintenance elsewhere. Valves, oil and filter, lube, splines, head bearing and swingarm tension, the basics. New battery then just test all lights and switches.

Flush and renew the brake fluid, then pull the handle as hard as you can and verify firm and no leaks. Rebuild master and calipers if required.

Then you can fire it up and test drive, tune the carbs.

Stage two is to put a few hundred miles on it and see if you got some leaking seals somewhere and monitoring for proper function of all systems.

Sure hope it wasn't stored with gas in the tank and carbs.
thank YOU!

this is exactly what I need. don't know if fuel was drained. after sitting that long, it's completely dry.
who knows, I could get lucky and find everything completely clean and ready for fuel. will know after tearing into carbs. if fuel bowl is full of gunk, then everything is getting flushed.

didn't catch the part about repacking bearings as this is my first BMW and are not familiar with scheduled maintenance yet.

brake master cylinder needs to be replaced or rebuilt. I'd do that even if was working perfect. calipers are not leaking, so leaving them alone.

notice the entire engine is painted black, not just cylinder base. this was pointed out to me by several Adv members already. No question this was done at the factory as engine has never been out. all the factory tie straps are still intact.

don't know but speculate that when BMW factory was setting up assembly line for USA spec bikes. first few R90S got a few things done to it that rest of this model run didn't get. Serial # 4950041 matches on engine, frame and ID plate.

_cy_ screwed with this post 10-01-2011 at 08:45 AM
_cy_ is offline   Reply With Quote
Old 10-01-2011, 08:39 AM   #9
kraut.burner
Smells güt!
 
kraut.burner's Avatar
 
Joined: Oct 2009
Location: Trenchtown
Oddometer: 460
subscribed
__________________
04' R1100S- Gone but not forgotten
74' R75/6 Café Classico
R75/6 Café project

kraut.burner is offline   Reply With Quote
Old 10-01-2011, 09:13 AM   #10
Renner
infamous wrench
 
Renner's Avatar
 
Joined: Jul 2007
Location: sunny SoCal
Oddometer: 2,041
I'm in

subscribed

Where-abouts are you located?

We're having a tech day here next week... though odds are pretty slim that you're close enough to drop by for a visit.

__________________
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
Renner is offline   Reply With Quote
Old 10-01-2011, 10:50 AM   #11
_cy_ OP
Beastly Adventurer
 
Joined: Sep 2011
Location: Tulsa, Oklahoma
Oddometer: 5,628
located in Tulsa, OK ... hope to visiting a few Adv riders around the country in the near future on R90S.

sure wish I was closer to attend... does anyone know if slightly higher compression engine 9.5 to 1 still will run on regular? no problems getting premium in US. but I suspect down south, one runs what's available.
_cy_ is offline   Reply With Quote
Old 10-01-2011, 11:22 AM   #12
Renner
infamous wrench
 
Renner's Avatar
 
Joined: Jul 2007
Location: sunny SoCal
Oddometer: 2,041
Quote:
Originally Posted by _cy_ View Post
... does anyone know if slightly higher compression engine 9.5 to 1 still will run on regular?
You'll likely get good responses on this.
My take is no, not very well... better if you retard the timing.
You might give it a try and see if it pings (which it probably will, especially under load/hill climbs), but much pinging would be quite detrimental so go easy.

Pretty sure our current premium is lower than the factory recommended octane for your R90S but I don't have the operators manual on hand.
in other words, best to run the highest octane available.
__________________
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
Renner is offline   Reply With Quote
Old 10-01-2011, 11:29 AM   #13
ooweel
Jobless, Its OK!
 
ooweel's Avatar
 
Joined: Jun 2004
Location: ShoeMashVille
Oddometer: 783
No Stalks?

You are not allowed to post 74 90s pics with out including pics of the mirror stalks.
ooweel is offline   Reply With Quote
Old 10-01-2011, 11:46 AM   #14
east high
Studly Adventurer
 
east high's Avatar
 
Joined: Oct 2009
Location: Portland, Oregon
Oddometer: 948
Quote:
Originally Posted by kraut.burner View Post
subscribed
Me too! BTW, Isn't this the second 'hey check out my original r90s' thread in as many weeks? Lucky sods
__________________
'71 r75/5
east high is offline   Reply With Quote
Old 10-01-2011, 12:16 PM   #15
jackd
Beastly Adventurer
 
Joined: Dec 2006
Location: North Cowichan
Oddometer: 2,984
Lucky you on finding this bike. As to your question on the need to use premium gas in your bike. A Triumph T100 that I restored had a compression ratio of 9:1 and I ran it on today's premium. If I really loaded it, it would still ping on occasion, so I made damned sure I never used regular gas. Seeing as your RS is 9.5:1, I would not even contemplate using regular gas. You have too nice of a bike to go for the less expensive grade of fuel. Put the additional cost of premium fuel as one of the expenses that come with owning a premium bike.
jackd is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 12:43 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014