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 12-02-2013, 09:32 AM   #1
boyblu OP
Adventurer
 
Joined: Nov 2013
Oddometer: 22
R80/7 breakdown

A 1978 R80/7 Ride to inspection (with new turn-signal relay). At four miles, the red wire dropped away from the starter-relay plug (soaked in brake fluid from a leaking master cylinder). The engine cut out, cut in again for a hundred yards and died. Other wiring apparently tried to take over (right-hand cut off switch especially), melting insulation. The fact I didn't turn the ignition off immediately didn't help. Much smoke from the headlight and handlebar switch. Eventually we got it all replaced, but it was some mystery until we found the fallen-out red wire (as you know, red wires in BMWs are always hot). Anyone else? PS: new turn-signal relay survived it ok. PPS: It was a long walk home.
boyblu is offline   Reply With Quote
Old 12-02-2013, 11:54 AM   #2
Brun
Gnarly Adventurer
 
Brun's Avatar
 
Joined: Jun 2012
Location: BorderBurg, South East Oz.
Oddometer: 163
Quote:
Originally Posted by boyblu View Post
A 1978 R80/7 Ride to inspection (with new turn-signal relay). At four miles, the red wire dropped away from the starter-relay plug (soaked in brake fluid from a leaking master cylinder). The engine cut out, cut in again for a hundred yards and died. Other wiring apparently tried to take over (right-hand cut off switch especially), melting insulation. The fact I didn't turn the ignition off immediately didn't help. Much smoke from the headlight and handlebar switch. Eventually we got it all replaced, but it was some mystery until we found the fallen-out red wire (as you know, red wires in BMWs are always hot). Anyone else? PS: new turn-signal relay survived it ok. PPS: It was a long walk home.
Sympathy attached.
It's awful when you see that expensive OEM smoke escaping.
That red wire should have a fuse - a pretty simple addition.
And do check out the addition of a handlebar mounted master cylinder. The under-tank MC is a monstrosity. It doesn't work, it is costly to refurbish, and will plague you forever.

Please accept more sympathy for the long walk home.
__________________
Cheers
Charlie, and the lovely Brunhilde (74 R90/6)
Graduate, Wallace and Gromit School of Engineering and Design (pending)
Brun is offline   Reply With Quote
Old 12-02-2013, 12:33 PM   #3
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,955
The under tank master cylinders get a lot of disrespect. They can be made to work or at least not leak. If the bore for the piston is not corroded then just a seal kit and a new piston will suffice. If the bore is too badly pitted another MC may be found on Ebay. The problem with that is actually getting something better than the one you have. But they are common items and usually sell pretty cheap.

The mechanical linkage from the lever to the MC seems to be the problem. A new cable will improve that but it's not a great system. Converting to a handle bar MC is the best fix.

Try to have everything in order the next time out, OK? Do your own inspection before you go to inspection. I always repair the stuff I want to repair before inspection and then the stuff the inspectors want repaired after. I almost always leave some small item for them to find. Something that won't prevent safe riding.
__________________
.
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 12-02-2013, 03:19 PM   #4
Warin
Retired
 
Joined: Aug 2012
Oddometer: 1,939
Quote:
Originally Posted by disston View Post
I almost always leave some small item for them to find. Something that won't prevent safe riding.
I know someone who puts in a blown globe.

Personally I try for fault free.

boyblu;

You have had a hard lesson. Learn from it to maximize your benefit, by posting it hear some of us may also have learnt. Kudos.

How were the riding boots for walking? That is probably the worst bit
Warin 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 01:48 PM.


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