Red Smoke Revival: Bringing an Airhead Heirloom Back to Life

[photomd]

Subscribed. Beautiful bike with a great story: can't wait to read more.

[Plaka]

Originally Posted by 100RT

I have the center stand down then I start with the right side, I tilt the bike then slide a 2x4 under that side then use the lift handle to lift and slide the left side under. To lower I start with the lift handle side. Been doing it for years.

Thanks!!

I shall try this, I think 1.5" lift will do me. I tried some games with rocking it and building up stacks of plywood but wasn't happy.

[Plaka]

Originally Posted by d mc gee

As Paul(R100RT) mentioned there was a change in the early 80's bikes to brazed push rod tubes. Using a drift can damage the tubes. Also when the time comes to replace the pushrod tube seals there is the issue of getting the tubes back into the head at the proper depth. The correct course of action would be to replace the seals, and at that time also address the exhaust nuts since their removal is part of the process. Needlessly obsessing about the nuts is unwarranted. There is plenty of info on Snowbums website about the very subject. http://bmwmotorcycletech.info/

You seem to be on the right track, get it running, figure out what the bugs are, get them sorted out, and then ride and enjoy your heirloom. Some folks here would have you tear the whole thing down to the smallest assembly and fix or address any issues that have ever went wrong with one of these bikes. Tinkering with things that need fixed as they come up should be an enjoyable and rewarding experience, and also keep you from becoming mechanically overwhelmed.

I don't have any problem with the pushrod tubes on my '83. Tapped them completely out of the jugs with the drift, switched them intake for exhaust and put them back with soft face hammer. The depth is totally noncritical, Set them too shallow initially and then set them correctly with the drift after torquing the heads. The tubes are a slide fit in the jugs, not the heads. Didn't notice if the rings on the tube were brazed or welded. Don't imagine it matters. It's not like you are putting big force on them. if you have to, the seals are too hardened and need replacing.

When I braze stuff the strongest rod I use is Harris 56% silver. The metal will fail before the joint ever does. I imagine BMW can do as well or stronger. Welding can actually make a weaker joint.

I agree with you (strongly) on the mechanical overload thing. I mention the matter because it doesn't appear on maintenance schedules but is pretty important given the age of the machine. Worth checking out at next opportunity, takes only a few moments. if one is frozen, no biggie, just walk away. Put a new nut on the shopping list and work it into a parts order somewhere. When an opportunity presents with someone experienced at cutting them off at hand, then deal with it. Nice off-season project. The important bit is getting it on the radar.

You can pull the heads without touching the exhaust nuts, if that needs to be done. So you can replace the push rod tube seals without touching the nuts. To be kosher, you do replace the 3 sealing o-rings at the base when doing the pushrod tube seals and of course the head gasket. You can do it without totally pulling the jugs but it isn't the best way to go unless you are very broke/pressed for time.

As has been mentioned, unless there is massive leakage at the seals, it is a trivial matter. You can leave it until the pushrod tubes are getting rusty and then deal with those at the same time. The exhaust nut threads in the head are very not trivial. If there is corrosion going on you really want to preserve those threads. A year or so won't matter much but it is a fix sooner than later kind of thing.

[100RT]

Originally Posted by Plaka

You can pull the heads without touching the exhaust nuts, if that needs to be done. .

I must be still asleep, please tell me how to pull the heads with out touching the exhaust nuts. headers, crossover, fairing lowers??

[Airhead Wrangler]

Originally Posted by 100RT

I must be still asleep, please tell me how to pull the heads with out touching the exhaust nuts. headers, crossover, fairing lowers??

I was wondering that myself.

[Plaka]

Originally Posted by 100RT

I must be still asleep, please tell me how to pull the heads with out touching the exhaust nuts. headers, crossover, fairing lowers??

You have to pull the crossover and the muffler on the side you are working on. ditto carbs. He has the split fairing lowers so he can pull the lowers over the pipes. Rocker covers next. Ever pull the header to adjust valves? Nope. Now you are looking at all the head bolts/nuts. Remove them and unbolt the header support strap at the front engine bolt/nut. The head with header intact lifts away.

If you have a frozen exhaust nut and you want to get really surgical with getting it off, putting the head on the bench is one way.

[mneblett]

Mike, in addition to the steering head bearing tools, I also have an exhaust nut wrench. I also *completely* agree about cutting the nuts off if they only slightly move before tightening up again. Now's the time to start a daily dose of penetrant (e.g., Kroil) to the nut/thread junctions to let the stuff work its way into the threads.

[Lornce]

Oh, yeah. The steering head bearings...

At 24k miles I bet you a donut all you need to do is clean out and replace the dried up original bearing grease then correctly adjust the existing steering head bearings.

imho, fwiw, ymmv,
Lornce

[jackd]

Originally Posted by Lornce

Oh, yeah. The steering head bearings...

At 24k miles I bet you a donut all you need to do is clean out and replace the dried up original bearing grease then correctly adjust the existing steering head bearings.

imho, fwiw, ymmv,
Lornce

That's all my GS needed.

[supershaft]

Originally Posted by Plaka

I don't have any problem with the pushrod tubes on my '83. Tapped them completely out of the jugs with the drift, switched them intake for exhaust and put them back with soft face hammer. The depth is totally noncritical, Set them too shallow initially and then set them correctly with the drift after torquing the heads. The tubes are a slide fit in the jugs, not the heads. Didn't notice if the rings on the tube were brazed or welded. Don't imagine it matters. It's not like you are putting big force on them. if you have to, the seals are too hardened and need replacing.

When I braze stuff the strongest rod I use is Harris 56% silver. The metal will fail before the joint ever does. I imagine BMW can do as well or stronger. Welding can actually make a weaker joint.

I agree with you (strongly) on the mechanical overload thing. I mention the matter because it doesn't appear on maintenance schedules but is pretty important given the age of the machine. Worth checking out at next opportunity, takes only a few moments. if one is frozen, no biggie, just walk away. Put a new nut on the shopping list and work it into a parts order somewhere. When an opportunity presents with someone experienced at cutting them off at hand, then deal with it. Nice off-season project. The important bit is getting it on the radar.

You can pull the heads without touching the exhaust nuts, if that needs to be done. So you can replace the push rod tube seals without touching the nuts. To be kosher, you do replace the 3 sealing o-rings at the base when doing the pushrod tube seals and of course the head gasket. You can do it without totally pulling the jugs but it isn't the best way to go unless you are very broke/pressed for time.

As has been mentioned, unless there is massive leakage at the seals, it is a trivial matter. You can leave it until the pushrod tubes are getting rusty and then deal with those at the same time. The exhaust nut threads in the head are very not trivial. If there is corrosion going on you really want to preserve those threads. A year or so won't matter much but it is a fix sooner than later kind of thing.

I could see maybe leaving the header on IF I didn't have a crossover. Other than that, it sounds like more trouble than it's worth.

I think installing pushrods like that is just asking them to leak at the cylinder. They are touchy enough there as they are. That is if you are not like Plaka. He doesn't consider an oil an oil leak until it is leaking enough to wash the parts involved clean. Personally, that's right when I stop calling it a leak and start calling it a gusher.

[Mikepotter86]

Originally Posted by mneblett

Mike, in addition to the steering head bearing tools, I also have an exhaust nut wrench. I also *completely* agree about cutting the nuts off if they only slightly move before tightening up again. Now's the time to start a daily dose of penetrant (e.g., Kroil) to the nut/thread junctions to let the stuff work its way into the threads.

Thanks or the advice and the generous offer of loaner tools, Mark. I'll start with a penetrant this weekend. As I may have mentioned I am without a garage so I keep the bike in a storage space a few miles away and hope for good weather or kind club members with garages when I need to work. I am hoping to knock out the brake work this weekend and then onto the steering.

[some_guy]

Mike I think we met at a BMWBWM tech day last summer. I've got a small garage, a Clymer manual, and some tools you can borrow if you ever need em.

[Mikepotter86]

Thanks, Some Guy! Did you ever get your hands on a Twin Max?

[Pezz_gs]

Great write up Mike, love the back groud story too!!

Look forward to reading your progress.

[some_guy]

Originally Posted by Mikepotter86

Thanks, Some Guy! Did you ever get your hands on a Twin Max?

Yep, bought one from a guy on BMWBMW's forum.