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 12-07-2013, 03:54 PM   #46
Rob Farmer
Beastly Adventurer
 
Rob Farmer's Avatar
 
Joined: Aug 2002
Location: Loughborough, Leicestershire. England
Oddometer: 5,415
I was lucky enough to have a talented engineer make me a shimming plate before he retired. It's a lovely thing, surface grind to give a perfect flat finish.

I'm not a pro. Bob (voyager) and myself rebuilt a considerable amount if gearboxes for the uk guys. All unpaid work with just the cost of parts being paid for. I've done quite a few paid jobs as well but no longer have the time since setting a business up.

Rob Farmer is offline   Reply With Quote
Old 12-07-2013, 08:11 PM   #47
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,836
Quote:
Originally Posted by AntonLargiader View Post
Yes, but that' a pretty small issue. So you may have to buy the coupler that matches your new input gear, no big deal.

Is the smaller coupler really NLA? Never noticed. I think I still have one or two. The new one is kind of ridiculously big.
Small issue? If the smaller cush drive 17.5 PFA gear is NLA that would require buying a new input shaft and cush drive coupler. Besides the later gear, of course. I call that a big deal? I have at least one of them myself but . . . .

Ridiculously big? I have never seen one break. The smaller ones break on a semi-regular basis. I think it was a much needed mod.
supershaft is offline   Reply With Quote
Old 12-08-2013, 01:11 AM   #48
Rob Farmer
Beastly Adventurer
 
Rob Farmer's Avatar
 
Joined: Aug 2002
Location: Loughborough, Leicestershire. England
Oddometer: 5,415
It's wear on the gear teeth that usually forces the need to change to the later components. Cheap oil and owners neglecting oil changes. Airheads in the uk used to be ridiculously cheap and were used as winter hacks and run on a shoe string. There's a legacy of that abuse in the bikes that survived.

In material terms it isn't a big deal to replace the input shaft and all of its components or any of the other gearbox internal components. From a financial points of view it's difficult to justify the expense to the owner of a gearbox. In the uk an ex change gearbox is around 350 + 20% vat so this becomes the benchmark that people work to. If you tell them their gearbox needs 200 of bearings, seals and gasket and 180 for a new input shaft and that there's wear on other gear components they will generally opt for a re conditioned gearbox from somewhere else. The down side of this is that the guys turning round the ex change boxes aren't going to replace the worn internals. They generally just replace the bearings, not always the expensive input bearing, clean up the case and turn it round as cheaply as possible.

We are finding in the uk that used, late gearboxes are disappearing at an alarming rate as people snap them up as spares on the off chance that they may need one in the future. I bought a job lot of spares from somebody moving away from airheads and now have the ridiculous situation of having ten spare gearboxes. The plan is, when I have some spare time, is to rebuild them and sell them on.

Rob Farmer screwed with this post 12-08-2013 at 01:16 AM
Rob Farmer is offline   Reply With Quote
Old 12-08-2013, 01:34 AM   #49
DiabloADV
Semi-Occasional
 
Joined: Oct 2010
Location: Nor Cal, USA
Oddometer: 2,228
Quote:
Originally Posted by AntonLargiader View Post
Depends what you have, what you need and how much you want to spend to preserve its incompatibility with the future. ...
What's your situation?
I'd just like a bigger highway gear. I have a 74 box with all new bearings and the upgraded shift cassette. And a stripped kicker gear -- so I'll just leave out the kicker on reassembly and plug the hole. But all the other gears are pristine.
__________________
1974 R90/6 w/1050 kit. Motor only. Seeking a frame.
1970 R60/5

'91 Bill Holland Steel w/Dura Ace
'01 Z3 3.0 Coupe. The Clownshoe.
DiabloADV is offline   Reply With Quote
Old 12-08-2013, 04:56 AM   #50
AntonLargiader
Beastly Adventurer
 
AntonLargiader's Avatar
 
Joined: Aug 2003
Location: Charlottesville, VA
Oddometer: 4,203
Quote:
Originally Posted by DiabloADV View Post
I'd just like a bigger highway gear. I have a 74 box with all new bearings and the upgraded shift cassette. And a stripped kicker gear -- so I'll just leave out the kicker on reassembly and plug the hole. But all the other gears are pristine.
You could use the tall non-X 5th, a replacement 3rd, and a shift fork. That way you can keep using the breakage-prone intermediate shaft.
__________________
Anton Largiader largiader.com BMWRA.org
AntonLargiader is online now   Reply With Quote
Old 12-08-2013, 05:13 AM   #51
AntonLargiader
Beastly Adventurer
 
AntonLargiader's Avatar
 
Joined: Aug 2003
Location: Charlottesville, VA
Oddometer: 4,203
Quote:
Originally Posted by supershaft View Post
Small issue? If the smaller cush drive 17.5 PFA gear is NLA that would require buying a new input shaft and cush drive coupler. ...
Is the 991 gear really NLA? I'll check this coming week. If it is, then if you want to consider '86 another break point then go for it.

I was thinking about a different coupler change ('87-on) and forgetting about the shaft splines. The '87-on 39.5mm coupler is the fat one. Not sure if I have any of the '85-'86 37mm ones around but I think you are talking about the pre-'85 ones breaking.
__________________
Anton Largiader largiader.com BMWRA.org
AntonLargiader is online now   Reply With Quote
Old 12-08-2013, 09:15 AM   #52
DiabloADV
Semi-Occasional
 
Joined: Oct 2010
Location: Nor Cal, USA
Oddometer: 2,228
Quote:
Originally Posted by AntonLargiader View Post
You could use the tall non-X 5th, a replacement 3rd, and a shift fork. That way you can keep using the breakage-prone intermediate shaft.
So...what you're saying is...upgrade the whole shaft?
__________________
1974 R90/6 w/1050 kit. Motor only. Seeking a frame.
1970 R60/5

'91 Bill Holland Steel w/Dura Ace
'01 Z3 3.0 Coupe. The Clownshoe.
DiabloADV is offline   Reply With Quote
Old 12-08-2013, 10:24 AM   #53
AntonLargiader
Beastly Adventurer
 
AntonLargiader's Avatar
 
Joined: Aug 2003
Location: Charlottesville, VA
Oddometer: 4,203
Quote:
Originally Posted by DiabloADV View Post
So...what you're saying is...upgrade the whole shaft?
In addition to the 5th gear, 3rd gear and now two forks? See what I mean?
__________________
Anton Largiader largiader.com BMWRA.org
AntonLargiader is online now   Reply With Quote
Old 12-08-2013, 11:55 AM   #54
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,836
Quote:
Originally Posted by AntonLargiader View Post
Is the 991 gear really NLA? I'll check this coming week. If it is, then if you want to consider '86 another break point then go for it.

I was thinking about a different coupler change ('87-on) and forgetting about the shaft splines. The '87-on 39.5mm coupler is the fat one. Not sure if I have any of the '85-'86 37mm ones around but I think you are talking about the pre-'85 ones breaking.
I don't have the years memorized. Our boxes are so old it really doesn't matter anymore. I just tell by looking into them. Who knows what your going to find inside. Pre-'85? I mean the smaller cush drive. The ones that break on a semi-regular basis. The bigger modified ones won't fit on the earlier shaft for different splines however they did make a few later PFA gears for the earlier shaft. I think those are NLA.

At Rob: I think I have seen the earlier cush drive setup break more than I have seen them wear. I have also seen them wear and have nothing to do with cheap oil or infrequent oil changes. I think some of them tend to wear for their heat treatment being a bit off. IF anything.
supershaft 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 07:03 AM.


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