Pulling an airhead transmission- an UN rant
 

Lots of ugly crap going on right now. My wife's truck is acting up, my 'backup' car was stolen, and last week my '88 RS suddenly decided 2nd gear was fine for everything. I emailed Anton, and he said it's probably 'just' the shift pawl spring.
I had loaned the RS to a friend (for the last six months or so) because he was having issues with his bike. The very day after his bike got back on the road, the RS transmission stuck in 2nd.
However.... after work today I popped over to Dan's house (the guy I loaned the scooter to) and we pulled the transmission to send off to Anton. It took less than an hour. You gotta' love that.:D

I love the fact that I could swap my pistons in the time it takes some folks to change their oil.

The swapability of parts on these bikes is great too. It's easy to find parts since they went on so many bikes. I'm going to pick up a good used gearbox and heads and stick them in drawer somewhere. If I ever have problems I won't get my parts fixed. I'll just swap them out. Takes less time and it's cheaper.

However what I dont love in my love-hate relationship with my Airhead is the fact that you have to send that gearbox off to some expert with the special tools and knowledge to repair what is really a simple mechanism.
Ditto the rear bevel drive.
Ditto the shaft that connects the two.

It's the most frustratingest bike I ever owned.:cry

I just fixed my gearbox, being able to say that gives me a warm fuzzy feeling.

When mine started acting up my line of thinking went like this: If I can pull the gearbox myself that will save me some money. Then I thought, if I pull it I may as well crack it open and save a little more money. So I built a flange puller and bought a hydraulic gear puller, lets pretend I needed one of those anyway. After I cracked it open I realized how simple it really was, it wasn't like a tightly wound clock at all. I replaced the worn parts slapped that baby together and I'm on the road.

What I mean to say here is that you probably could have fixed that ol' gearbox yourself. Heck if I can do it...

The above is not true for everyone, many here included. If you are inclined, have the skill set, and want to purchase the requisite tools then you can repair everything you noted above yourself.

Absolutely True!! The last time I had a gearbox problem (many years ago), I had more free time, and just did the work myself. I'm not rich now, but I am 'time poor', so off to Anton it will go.

Exactly. Like many things, it's a value-of-time juggle.

Anyone can do the job, and do it right, but... how much time do you want to spend learning versus riding.

I feel neutral on the fact that I took my R90 heads and transmission to a shop, because while I have the tools (and probably half the experience/knowledge) to do it myself in my shop; it was done right the first time, and fast. I can live with that.

that's the basis of an economy
 

I think you guys are talking about the basis of an economy. No one has time to learn to do everything themselves. Even subsistence farmers need plowing tools from a blacksmith.

Actually, I agree with Reryder on the trans. I don't understand why they have to be as complex as they are. I've worked on other trannys and these are about the most fiddly of them all. I've worked on trannys ever since my first Hondas back in the 60s and there wasn't anything special about them. I've worked on car and truck trannys, and even replaced some synchros on an old School bus I had - now that was a BIG trans! Intimidated me at first, but shouldn't have. Everything was bigger, but just the same stuff. I've worked on the older Volvo over-drive trannys I used to be into, and except for the Chinese puzzle aspect, they were pretty simple. None of this careful, ultra-precise shimming that's needed with these airheads.

Now, the final drives, well, that's par for the course. All gears like that need very careful positioning to ensure they mate properly. But the splines wearing out...yeah, that's funky. I hear Oak came up with some sort of solution for that some years back. Never heard exactly what it was though.

Yes there are some of the guys on this forum who have learned the tricks and my hats off to them, but i agree with wirespokes these airhead trannys are pretty darn fussy from all i can read up.
I think you made the right choice by letting Anton fix it.

My tranny gave up the ghost at 100,000 miles. Put about 250 miles on it after loosing 3rd and 5th gears, by the time I got home 2nd was making all kinds of unpleasant noises. Ended up spending about 1,100 in parts and about $420 in labor to fix. For $420 I'll let an expert fix it. Not worth it to me in time, research and fabricating tools to do myself and I lilke working on bikes, cars etc. I don't need excuses to buy tools.
Not to mention a guarantee on workmanship.

I have actually dug into both my gearbox and rear end, but both times had to run up to my BMW mechanic buddy's place with tail between my legs.

I just could not make the special tools required in my workshop with no lathe, drill press or welder. Plus I did not have a dial gauge to send end plays. I usually set end plays in Harley gearboxes by feel and it works fine, but BMWs are so finicky in that department I would not dare.
And Triumphs, well what end play?

I finally got a good heat gun and propane torch so I can at least dismantle my own rear end, but took it to the maestro who had the shims and dial gauge to set the plays.

And after watching how he does it - an aircraft engineer with 30 years of working on Airheads on the side - there are a lot of small but esentially important tricks you must know, and the manuals do not tell you.

He makes a good living on the side repairing gearboxes and rear ends that have been rebuilt by amateurs and some professionals who work on other bikes and think they can do the same with Airheads.

Despite that, here are some pics of my homemade tool to remove the input bearing collar on my airhead rear end.

I made it out of a threaded water pipe connector, 1.5inch nominal size, I think.
Put some bearing blue on the threaded input bearing collar so it made a mark on the pipe fitting. I then scribed those lines and cut away the metal between the four tags. Using more bearing blue for a final fit.

http://i249.photobucket.com/albums/g...eldrive058.jpg

http://i249.photobucket.com/albums/g...eldrive064.jpg

http://i249.photobucket.com/albums/g...eldrive061.jpg

http://i249.photobucket.com/albums/g...eldrive057.jpg

Then I cut two slots in the other end to fit my large square shank screwdriver, to turn the tool with.
http://i249.photobucket.com/albums/g...eldrive067.jpg

Bolted the rear end to the bench. Heated it spitt sizzlin hot with my heat gun and propane torch, and unscrewed that input bearing collar. Bit of pipe over the end of the screwdriver provided torque to overcome the Loctite. But it actually popped out reall easy. Two hours to make the tool. Two minutes to do the job.:clap
http://i249.photobucket.com/albums/g...eldrive069.jpg

Crude yes, but the working parts were a nice fit for a nice drive.
http://i249.photobucket.com/albums/g...eldrive073.jpg

And here is how I locked the rear end to get the input drive nut off before all this:
http://i249.photobucket.com/albums/g...eldrive011.jpg

Placed the bevel unit on the wheel, splines engaged, and used a ratchet tie down strap wrapped around the input boss and the tire and spokes to stop the bevel unit from turning as I torqed the input nut til it came loose. Applied torch also to overcome Loctite.

Nicely done dude, seriously, the tool may look crude but this a case were function is more important than form.

Getting tooled up is a lifetime process, I have a long way to go myself. I'm fortunate enough to have a good friend with a bad tool habit. He loaned me the caliper and time on the drill press.

I made my output flange puller out of stacked up washers welded together, now that baby is crude...but it worked.

I think the trick is also in knowing the tweaks.

Anton and others are kind enough to produce webpages full of this sort of information:
http://www.largiader.com/tech/airtrans/
http://jhau.maliwi.de/mot/gearbox.htm
http://bmwmotorcycletech.info/transmission.htm

And I suppose if you research enough you can do it, but I wonder if some of the airhead transmission guru's don't have a few tweaks up their sleeves to make these transmissions shift better, or last longer etc.

some tricks are so simple but you gotta know them, just like the guy in this link, i will bet he is faster at this than any one you know.

why didnt i know this when i owned one of these.

http://www.youtube.com/watch?v=BQhfcdQf1QA