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Old 06-26-2013, 07:00 PM   #46
disston
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I never heard of turning by the bob weights but have no reason to not believe it if Plaka said so. He has one of the World's most esoteric Airhead information collections around.

I don't think it would be so hard to put the clutch back together.

You can't rotate the engine if the trans is in gear and the wheel is on the ground. Maybe even if the wheel is off the ground. If you can get it in 5th gear rotate the wheel.

Figure this thing out will you. Or do you think Plaka will do all the thinking for you?

It sounds like you may be painting yourself into a corner. Be careful you don't pay attention to what is happening. It is possible to wedge the internals of the engine so you'll never get it apart if you're too hap hazard about it.

I suggest you put the rod bolts back in until you get the crank turned. And I also hope you are being careful to not bang up or ding the block around where the cylinders are bolted.
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Old 06-27-2013, 12:26 PM   #47
tbg OP
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Success!

Plaka was right, I just pushed on the weights on either side of the knob to which the piston attaches, and my engine spun neatly into position! Looks like the knob (crank journal?) has some light scratching but is otherwise intact. The main bearing insert has taken some serious damage, and looks to be almost completely shredded around the protruding lip. Other than a rather large scratch on the top of the crankcase, and what looks like a chipped tooth on the camshaft, most everything looks intact. Dirty, but intact.

I'll transfer the files to make a big post with helpful arrows and descriptions some time tonight or tomorrow.
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Old 06-27-2013, 11:01 PM   #48
Plaka
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Originally Posted by tbg View Post
Success!

Plaka was right, I just pushed on the weights on either side of the knob to which the piston attaches, and my engine spun neatly into position! Looks like the knob (crank journal?) has some light scratching but is otherwise intact. The main bearing insert has taken some serious damage, and looks to be almost completely shredded around the protruding lip. Other than a rather large scratch on the top of the crankcase, and what looks like a chipped tooth on the camshaft, most everything looks intact. Dirty, but intact.

I'll transfer the files to make a big post with helpful arrows and descriptions some time tonight or tomorrow.
In the immortal words of The Captain:

"What we've got here is failure to communicate"

We seriously need to work on some vocabulary.

The crank doesn't have "knobs". it has connecting rod journals and main bearing journals. You have been looking at the connecting rod journals. To see the ones for the main bearings you have to take the crank out. The only knob I can think of is on the steering dampener.

The camshaft doesn't have "teeth". It has some lobes. The chain sprocket on the front of it has teeth.\

You don't have a clutch pedal. Those are for cars. You have a brake lever/pedal on the right and a gearshift lever/pedal on the left. A brake lever is up on the bars, on the right. A clutch lever is on the bars on the left. When you speak of a brake lever, you always specify front or rear, thus hand or foot.

The main bearings run on the main cranhshaft journals. See above.

The connecting rods connect the piston to the crank. The 'big end' is split into the connecting rod proper and the rod cap, which bolts on. The bearing shells simply sit in the rod and cap. They are the same. The connecting rod bolts hold the cap onto the rod. Thay can only be used once, but you do use old ones for certain measuring operations. The piston end of the connecting rod is called the 'little end'. It has a pressed in bushing for the piston pin. A bushing and a plain bearing are essentially the same thing.

There are no "bob weights" (I misused the term myself). They are counterweights. Bob weights or fly weights go on governors. Different beast.

The piston is not connected to the crankshaft any more, or less, than your hand is connected to your foot. All a matter of where you draw the lines. Your brake light is connected to Disstons left thumb. It's worth drawing the lines in useful, and customary places.

Pictures will help vastly. Good pictures. Make sure the important thing is well lighted and in focus. I use a flashlight sometime and just cross hold it with the camera (as in night shooting with a pistol).

To communicate well you really need the vocabulary. Until you come up to speed on that (and you will pretty quickly) use a lot of pics,in every post...and crop out the unimportant stuff to keep them small.

If the connecting rod journal on the crank isn't too badly scored it can be polished out by hand with crocus cloth. However you need to figure out what happened. The pictures of the damaged bearing shell may be revealing. You marked which one came from the rod and which from the cap, right?

Does the dowel pin in the connecting rod face the front or the rear?
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Old 06-28-2013, 01:58 PM   #49
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Thanks for the vocab primer. Without you guys, I'd be like a toddler trying to describe... well, engine mechanics. To answer your questions: Yes, the main bearing inserts match with their rod/cap; the dowel pin that slips between the rod and piston seems to be identical on both sides, with matching circlips for both ends.

First up, the rod assembly. You can see the jagged edges on the main bearing insert that I spoke about. Interestingly, there seem to be two little machined divots on the inside of each bearing which I assumed are assisting orientation:


There are some hefty, uniform wear on the outer-lip of the piston rods:


Next, the connecting rod journal. I took the photo with a flashlight pointed and flash turned on, but the picture still only came out so-so. You can see the scratches on the journal itself:


Here is a picture of the scratch on the top of the crankcase. I've highlighted the two scratches on the inside of the cylinder to indicate how perfectly they all line up. My piston must have been going hog-wild in the crankcase:


Next, the lobe on the camshaft that I think may have a jagged edge. The photo is unhelpful, but frankly, I couldn't get a much better look at it than the camera could. I think I'll need to pull the pan and rotate the camshaft for a good look:


Finally, a few bonus photos.
Some orange goop on the right cylinder head that wasn't present on the left. I assume the goop is sealant?

And a picture of the alternator assembly, because I think it looks cool:


So I guess my working hypothesis is the main bearing insert went, freeing the rod to coast around the cylinder? Hopefully this weekend I'll get a chance to pull the oil pan, look at the camshaft more closely, and start getting the swing-arm off to look at the transmission.
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Old 06-28-2013, 02:37 PM   #50
Plaka
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Originally Posted by tbg View Post
Thanks for the vocab primer. Without you guys, I'd be like a toddler trying to describe... well, engine mechanics. To answer your questions: Yes, the main bearing inserts match with their rod/cap; the dowel pin that slips between the rod and piston seems to be identical on both sides, with matching circlips for both ends.

First up, the rod assembly. You can see the jagged edges on the main bearing insert that I spoke about. Interestingly, there seem to be two little machined divots on the inside of each bearing which I assumed are assisting orientation:


There are some hefty, uniform wear on the outer-lip of the piston rods:


Next, the connecting rod journal. I took the photo with a flashlight pointed and flash turned on, but the picture still only came out so-so. You can see the scratches on the journal itself:


Here is a picture of the scratch on the top of the crankcase. I've highlighted the two scratches on the inside of the cylinder to indicate how perfectly they all line up. My piston must have been going hog-wild in the crankcase:


Next, the lobe on the camshaft that I think may have a jagged edge. The photo is unhelpful, but frankly, I couldn't get a much better look at it than the camera could. I think I'll need to pull the pan and rotate the camshaft for a good look:


Finally, a few bonus photos.
Some orange goop on the right cylinder head that wasn't present on the left. I assume the goop is sealant?

And a picture of the alternator assembly, because I think it looks cool:


So I guess my working hypothesis is the main bearing insert went, freeing the rod to coast around the cylinder? Hopefully this weekend I'll get a chance to pull the oil pan, look at the camshaft more closely, and start getting the swing-arm off to look at the transmission.
You still don't get it about the main bearing___or the piston pins.

Remove the engine from the frame. Remove the crank, it's badly burned. My guess is that it cannot be salvaged. The rod is also badly burned, chewed up and looks badly distorted (camera??). it's junk too. Worth looking at the other one.
This damage looks like profound lubrication failure. That thing wasn't getting oiled. You want to find out why.

I would price out another engine. This one is about to get costly. it may be best to get another bike in better condition and part this one out. Make some money and save some nice spares for yourself.
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Old 06-28-2013, 03:59 PM   #51
disston
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+1 what Plaka says. You can play with taking it apart some more but it's not worth trying to fix I think. The crankshaft can be used as a door stop, the block might actually be usable but there are better looking blocks around. Use the block as a planter. Don't throw any of it in the trash. There's a lot of Aluminum there and people make some serious change recycling it.

You are in the market for a complete engine. The alternator and diode board and the covers and valve covers can all be saved in case new engine comes partially striped. Try the regular wreckers first, like Beemer Bone Yard. Better than dealing with an unknown on Ebay, maybe.

And yes, please learn the name of stuff. That is a rod bearing and sometimes called the big end rod bearing. When you take the crank out you are going to learn what a main bearing is.
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Old 07-02-2013, 04:36 PM   #52
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Thanks for the help guys. I'm not exactly rolling in the dough myself, so I think I'll probably try to part it out and get a smaller bike to learn on. Probably what I should have done in the first place.

I understand parting out a bike is a pretty involved process, any guides or primers ya'll could point me toward for a start?
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Old 07-02-2013, 06:16 PM   #53
Plaka
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Thanks for the help guys. I'm not exactly rolling in the dough myself, so I think I'll probably try to part it out and get a smaller bike to learn on. Probably what I should have done in the first place.

I understand parting out a bike is a pretty involved process, any guides or primers ya'll could point me toward for a start?
1) how much do you have in it?

2) how many miles on it?

3) are you ever going to get another airhead? (consider the dues you've paid so far vs starting from scratch on something else)
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Old 07-02-2013, 06:31 PM   #54
N-m
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Get the VW book. Read it cover to cover.

http://www.walmart.com/ip/1199599?wm...l5=pla&veh=sem

Or amazon, etc. No collectors editions.

Get another bike to develop riding skills on. A small one with decent resale value.
Can you elaborate on why this book would help an Airhead fan? I hope to be one some day.
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Old 07-02-2013, 06:34 PM   #55
N-m
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Lotta crossover with old air cooled VW. Both horozontal air cooled motors, the BMW a twin, the VW a four. Pushrod operated valve train. But the mechanical knowledge is the most important part. How to evaluate and tune things, exactly how it all works. Using different sorts of tools, making measurements, setting valves, etc. Different carbs and transmissions/drive lines. You'll see what doesn't apply, but as a basic course in working on these things that assumes you know nothing, priceless. Doesn't talk down to you, just doesn't miss anything.
Thanks for the description on the book. It sounds like I need to add this one to my collection.
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Old 07-02-2013, 07:33 PM   #56
Plaka
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Can you elaborate on why this book would help an Airhead fan? I hope to be one some day.
Depends on how much you already know about engines and mechanics in general. The book assumes you know nothing and so it covers everything. From how an engine works and how to buy and use tools on up. Well written, well illustrated and very readable. The airhead is half of an aircooled VW engine, minus the fan and distributor. Different carbs. etc. So you can bootstrap from this piece of very good documentation to working on the airhead. Top and bottom end work, clutch, valve setting and tuning, coils, points and ignitions, etc. All the same.

My first car was a VW precisely because of that book. I knew of it and figured with that kind of documentation I could keep the thing going even though I knew nothing about engines, cars in general or even much about how to drive. Many VWs later I got into airheads partially because so much of my VW knowledge (and tools) crossed over and partially because a pal of mine was a BMW mechanic (and wouldn't let me park my Suzuki in the yard if I was visiting. BMWs only)


If you already have a pretty good base, probably skip it---or find a library copy (good luck!) and look it over.
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Old 07-02-2013, 07:58 PM   #57
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I understand parting out a bike is a pretty involved process, any guides or primers ya'll could point me toward for a start?
IBMWR is your friend. Just post it all up ASAP while the weather is nice and people are eager to keep their bikes on the road. Price it fair and it'll move fast.

Can't judge the specific condition of your bike, but ballpark prices for the major components assuming goodish condition:

Heads 150-200
cylinders and pistons 150-200
final drive 150-200
transmission 300-400
frame $200 if titled
tank $300-400
charging system $100
points can $100
wheels 150 each
carbs 150-200
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Old 07-02-2013, 08:15 PM   #58
tbg OP
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Originally Posted by Plaka View Post
1) how much do you have in it?

2) how many miles on it?

3) are you ever going to get another airhead? (consider the dues you've paid so far vs starting from scratch on something else)
1. $1800 + $100 in tools
2. 110k
3. I'd love to own another airhead, especially considering the dues. Unfortunately, I can say with some certainty that I won't have cash to buy another one outright for years. It isn't essential that I move the entire bike though, I can garage some stuff for a while.

@Airhead Wrangler - Thanks a bunch for pricing list! Are the fairings worth anything off the bike?
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Old 07-02-2013, 08:24 PM   #59
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Are the fairings worth anything off the bike?
To the right person, yes, but relatively few people want them. You might hang onto that for a while.
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Old 07-02-2013, 09:03 PM   #60
Plaka
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1. $1800 + $100 in tools
2. 110k
3. I'd love to own another airhead, especially considering the dues. Unfortunately, I can say with some certainty that I won't have cash to buy another one outright for years. It isn't essential that I move the entire bike though, I can garage some stuff for a while.

@Airhead Wrangler - Thanks a bunch for pricing list! Are the fairings worth anything off the bike?
The lower 3 panels and the sidecovers are the same for the RS and RT. The RS crowd is your market and they are valuable.

You can get into another airhead, and for cheap too, if you play it right. You want to keep as much of what you have as you can afford to and especially the parts required to repair a bike that has been wrecked by running directly into something. Also keep the parts that are usable but worth little on the market. So:

Keep the entire front end, front wheel, fender and hydraulics. Keep the frame for the time being and just leave the front end on it.

Sell the fairings, sidecover, seat, tank (at the very last), rear fender and tool tray. Sell the rear lights except the red rear lens (it's NA). Sell the subframe. Keep the rear drive, swing arm and rear wheel. At 110K there is enough spline wear that they just aren't worth much. May as well use them up yourself. Keep the instruments and cables, diode board, alternator, beancan. Keep the starter. Very costly to replace and you'll have to eventually. So part these to yourself first. Sell the block, and whatever is left of the jugs, heads pistons, etc. Not worth much given the condition. maybe $200? But keep the clutch if the disk is meaty. Sell all the rear brake parts you can, footpegs, carbs and plumbing, airbox, engine covers, racks and bags. Keep the controls and may as well leave them on the bars. Leave the harness on the frame. Sell the battery box, shocks. Keep the tranny, you will need it and they are costly. Keep the rocker covers if they are pretty nice. Sell the battery, and quickly. keep it charged.

You should be left with a rolling chassis and a bushel box of bits.

never sell tools. Ever.

Keep the hydraulic fluids (including fork oil) changed on schedule.




The start looking for your new bike. You are competing with all the breakers and flippers for that perfect wreck. You want an r80 or R100, crunched front end and frame. Something that T-boned an oncoming left turning Buick would be ideal. >75,000 miles. >$500 if you can do it. I'm not sure where to look. Ask your insurance agent where such bikes are to be found. Keep an eye on accident reports in the papers, post a Wanted on CL, Post a Wanted on IBMWR (But that place can be pretty thick with competitors, most of them pro's). Think about that bike you want every day. And I do mean every day. Be utterly relentless. Talk to accident lawyers. Talk to cops. Talk to the impound yard. Post signs on local campuses.


If you think the right thoughts, and stay at it, then it will come to you.

That wreck, if fairly recent, will have an engine that was running at least decently right up to the accident. As long as a jug didn't get slammed (you'll see bent and broken fins) it's still good. With the wreck in hand you'll know what you have, what you need and what's left over to sell off between the two. Dropping the engine into your frame is a quickie. The rear subframe from the donor should be good along with many of the other parts you sold off to keep up cash flow.

One frankenbeemer coming up!



But you have to think the right thoughts. It's worked for me, and for others, and it can be pretty spooky sometimes. Things just happen, very unlikely things, and here you've been thinking these thoughts...
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