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 04-21-2014, 11:03 PM   #1
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
Bmw r90/6 top end, transmission rebuild

I'm overhauling my daily rider for a trip to Colorado in mid June. I've been working on it for a solid 10 hour day now an will add pictures tommorow this is a list of what I'm doing, top end rebuild, transmission rebuild, clutch, fork rebuild carb rebuilds, electrical system freshening up, front brake system overhaul, greasing bearings and general poking around of anything else. I am doing all the work myself and posting pics and updates here, should make for some entertaining photos. Cheers
Jwcasillas is offline   Reply With Quote
Old 04-21-2014, 11:18 PM   #2
DiabloADV
Semi-Occasional
 
Joined: Oct 2010
Location: Nor Cal, USA
Oddometer: 2,174
Doing head work too? How so...?


Sent from my iPhone using Tapatalk
__________________
1974 R90/6 w/1050 kit. Motor only. Seeking a frame.
1970 R60/5
1981 R80G/S Renovation under way. For sale Spring '14
'91 Bill Holland Steel w/Dura Ace

'01 Z3 3.0 Coupe. The Clownshoe.
DiabloADV is offline   Reply With Quote
Old 04-21-2014, 11:45 PM   #3
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
When I was 16 I worked at a cylinder head shop. All I am doing is replacing guides and lapping valves my seats are great. Might polish as well.
Jwcasillas is offline   Reply With Quote
Old 04-22-2014, 12:02 AM   #4
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,027
It may only need valve guides but you won't know till the heads are apart. If it has BMW parts now then BMW parts should be used. Cylinder head work is usually considered specialized these days and not done by most riders. Not many years ago the riders did do more of this work.

There are a couple of special tools needed to even get the transmission apart. You should have access to a large shop press. Standard 20 ton usually works.

This is a lot of work you list. I think I got the idea, a rebuilt bike is what you want, so you are doing a years worth of work in 1 month?

The problem with projects of such a large scope is that bugs aren't worked out of one system before the next system is taken apart. So when the inevitable problems pop up they become difficult to diagnose.


Good Luck. I hope you get to make this trip.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is offline   Reply With Quote
Old 04-22-2014, 01:41 PM   #5
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
I am supported by a group of old school mechanics, the transmission is already rebuilt, the heads are apart and cleaned, I mic'd the bores at 90.18 and they are almost completely round so I honed them and will install rings whenever SFO bmw sees fit to get them to me. I gathered my parts and got my ducks in a row before I started this. The seats look like somebody in the past replaced them with hardened ones as they are almost flawless. The guides however are original and leaking mildly. I will probably do a YouTube video of me doing the guides and lapping the valves. This is my 5th airhead I have done all these jobs before with the exception of the forks; just not on the same bike at the same time. This is an every day rider with 90,000 miles. It is my transportation so I won't have it out of commission long. This will not be a show bike and I will not be spending massive amounts of cash on it as I would be better served getting a new machine. In short I am very practical about what I'm in the middle of. Photographic evidence will be posted this evening
Jwcasillas is offline   Reply With Quote
Old 04-22-2014, 10:28 PM   #6
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
I'm not saying there isn't any voodoo magic required in mechanical work but what bugs are you referring to? In my limited experience mechanical things function or don't a 90 tooth gear will always make a 30 tooth gear spin three times faster. If it doesn't it needs replacing. I am following the shop manual, the advice of Dave Gardener, Ted Porter, Dick Sullivan, and Robert Fleischer. I know this is do able right.
Jwcasillas is offline   Reply With Quote
Old 04-22-2014, 11:29 PM   #7
chollo9
Screwed the Pooch
 
chollo9's Avatar
 
Joined: Jul 2003
Location: Silk Hope, NC
Oddometer: 1,010
Sounds like you're all over it and have about the best support one could ask for, keep us in the loop.
__________________
"It's not that I don't like people...I just find I am happier when they're not around"
chollo9 is offline   Reply With Quote
Old 04-23-2014, 09:29 AM   #8
SculptD
Smells like tech
 
Joined: Jun 2013
Location: SF, CA
Oddometer: 293
Quote:
Originally Posted by Bill Harris View Post
There is more to transmission repair than knocking it apart and replacing parts. There are things that need it be done that require the knowledge acquired through experience. Not enough gotten by following Internet advice, a Clymer's and having a knack.



--Bill
While I don't quibble with the gist of this as far as the specifics of airhead transmissions, I do quibble plenty with it as a general philosophy.

How is one to get experience? Whatever will we all do when the gurus are all dead, and only the completely inadequate remnants of their web musings remain?

I work with college students, and as the years go by I find them more and more paralyzed by the need to be told what to do by an expert before they will do anything. That's not how I got to know what I do, and I bet many an airhead guru learned the bulk of what they know by plowing right ahead on their own and making heaps of mistakes along the way. Anybody who tells me about the "right" or "best" way to do something gains my immediate suspicion. By the advice expressed above, my winter rebuild should have been mostly sent out to various shops. All I need do is sign the checks. What would I have then gained? An impoverished experience.

Anyway, I don't get it, as the OP seems to have a whole lot of experience.
__________________
R75/5 SWB, Aprilia Falco. Both compulsively modified. And an R100s is on the way.
SculptD is offline   Reply With Quote
Old 04-23-2014, 02:50 PM   #9
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
Here is my bike
Attached Images
 
Jwcasillas is offline   Reply With Quote
Old 04-23-2014, 02:51 PM   #10
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
clutch bolt destroyed by yours truly
Attached Images
 
Jwcasillas is offline   Reply With Quote
Old 04-23-2014, 02:54 PM   #11
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
honed the cylinders last night there are smooth spots where the rings are but i wouldnt hone ant more or risk giong out of round
Attached Images
 
Jwcasillas is offline   Reply With Quote
Old 04-23-2014, 02:57 PM   #12
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
bore is 90.18mm and not too out of round
Attached Images
 
Jwcasillas is offline   Reply With Quote
Old 04-23-2014, 03:00 PM   #13
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
I am not replacing these I will true them with a sharpening stone and tempered glass as a true reference. I have done this on cars quite a bit. after i do that i will use a rotary scoring brush to crosshatch for even wear characteristics. i am only changing the diaphram spring and the friction material.
Jwcasillas is offline   Reply With Quote
Old 04-23-2014, 03:01 PM   #14
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
1
Attached Images
 
Jwcasillas is offline   Reply With Quote
Old 04-23-2014, 03:02 PM   #15
Jwcasillas OP
Adventurer
 
Joined: Feb 2014
Location: S.F. Bay Area
Oddometer: 43
what your piston sees
Attached Images
 
Jwcasillas 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 07:33 AM.


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