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Old 06-18-2013, 04:32 AM   #31
disston
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Yes to what Plaka says. So far everything may be reusable. The parts will need more careful examination before being used.
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Old 06-23-2013, 11:23 PM   #32
tbg OP
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Got the piston head out. Unfortunately, with the rod in the way, no useful pictures could be taken of the crankshaft. I did get a better look at the chunk I pointed out in my previous posts:


That's a picture of the top-inner lip of the cylinder, taken from directly below. My apologies for the bad focus.

Additionally, I think a little chunk may have been torn from one of the camshaft's teeth. Perhaps that is what derailed the piston?
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Old 06-24-2013, 08:51 AM   #33
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Replacing a cam shaft is not as much trouble as a crankshaft. A cam pretty much just plugs in. A crankshaft has to have the free play adjusted by different size thrust bearings. On many engines if a journal is damaged they can be machined but on our Airhead engines if the rod journal or main bearing journal is damaged it is better to find another crank instead of machining the damaged shaft.

So the big question is still the condition of the rod bearing journal on the crankshaft.

You now have the cylinder and the piston off? And are waiting for the tool to remove the connecting rod?
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Old 06-24-2013, 09:23 AM   #34
Plaka
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Quote:
Originally Posted by disston View Post
/snip On many engines if a journal is damaged they can be machined but on our Airhead engines if the rod journal or main bearing journal is damaged it is better to find another crank instead of machining the damaged shaft.

/snip
Really? What makes uour airhead cranks so very special? It's half a VW crank. No magic metallurgy, no exotic plating, nothing. it's a Plain Jane crank like a hundred million others.They make oversize bearings for a reason...
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Old 06-24-2013, 10:56 AM   #35
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There are three problems with grinding an Airhead crankshaft. One...the radius in the corners of the rod journal are not always properly done. I don't know why this happens but it has and apparently continues to be a problem. Two...the crankshaft is hardened with a Nitride process. This needs to be duplicated. Is not always done. Three...the bob weights on the crank need to be removed for grinding. They often will fly off later because they weren't properly reattached.

All of these issues have plagued Airhead crankshaft grinding. Maybe the proper shop doing the job with proper techniques could avoid these issues. It's been tried. I think a few have succeeded but it looks like there are more failures than successes.

Maybe not impossible I agree but there are plenty of Airhead crankshafts available in the used market so this is the advised course. Get a used crankshaft in good condition. There is the hassle of having to now reshim for the different crank and this is above shade tree mechanics abilities usually but it can be handled by the proper mechanic.

Here is another discussion of the issue(s);

http://www.advrider.com/forums/showthread.php?t=644361

This has come up before. If you want to grind your crank then please do. But I'd like to know so I'm not riding next to you when one of the bob weights flies through the engine block.
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Old 06-24-2013, 11:06 AM   #36
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Quote:
Originally Posted by disston View Post
There are three problems with grinding an Airhead crankshaft. One...the radius in the corners of the rod journal are not always properly done. I don't know why this happens but it has and apparently continues to be a problem. Two...the crankshaft is hardened with a Nitride process. This needs to be duplicated. Is not always done. Three...the bob weights on the crank need to be removed for grinding. They often will fly off later because they weren't properly reattached.

All of these issues have plagued Airhead crankshaft grinding. Maybe the proper shop doing the job with proper techniques could avoid these issues. It's been tried. I think a few have succeeded but it looks like there are more failures than successes.

Maybe not impossible I agree but there are plenty of Airhead crankshafts available in the used market so this is the advised course. Get a used crankshaft in good condition. There is the hassle of having to now reshim for the different crank and this is above shade tree mechanics abilities usually but it can be handled by the proper mechanic.

Here is another discussion of the issue(s);

http://www.advrider.com/forums/showthread.php?t=644361

This has come up before. If you want to grind your crank then please do. But I'd like to know so I'm not riding next to you when one of the bob weights flies through the engine block.
So take it to a shop that knows WTF they're doing? All sorts of people can screw up anything. You hear the horror stories and they make great and entertaining news. Everybody wants to hear about how something is or got screwed up. But the jobs that come out fine, no issues, etc.---that isn't news. No Oh-My-Gawd!!! factor. You don't hear about it.

However I don't know the cost difference.
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Old 06-24-2013, 11:16 AM   #37
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Well I think it is a cost vs. reliability issue. You are right Plaka, that people seldom report what the fix is. They are too busy riding. That might be why there seem to be more failures than successful grindings. But the used market today has plenty of crankshafts. I have noticed an increase in prices but that like most used parts issues is a matter of how much in a hurry you are.

If you have the proper tools the novice even may reshim the crank but it's not for everybody. And the dial indicator and a few other things are not really cheap.

This whole thing is putting the buggy before the horse. Let's wait to see how the crank journal looks. They are not always bad after one of these.
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Old 06-24-2013, 12:47 PM   #38
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Well I think it is a cost vs. reliability issue. You are right Plaka, that people seldom report what the fix is. They are too busy riding. That might be why there seem to be more failures than successful grindings. But the used market today has plenty of crankshafts. I have noticed an increase in prices but that like most used parts issues is a matter of how much in a hurry you are.

If you have the proper tools the novice even may reshim the crank but it's not for everybody. And the dial indicator and a few other things are not really cheap.

This whole thing is putting the buggy before the horse. Let's wait to see how the crank journal looks. They are not always bad after one of these.
You can actually use feeler gauges in place of a dial indicator. But you do need a bit of skill with them, and a piece of ground bar stock to work from. But you can get around even that with a piece of angle and a carriage bolt. A cheapo dial indicator will also work, and rig a stand. It will be accurate, it just won't hold up. For occasional use it's fine. We get spoiled here in the first world methinks.
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Old 06-24-2013, 02:07 PM   #39
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Hopefully the crank journal is still intact!

I believe the socket will have arrived at my workshop tomorrow, so I'm heading down to pull the rod and the oil pan.
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Old 06-25-2013, 03:52 PM   #40
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Hit a bit of a hangup, ran out of time before I could find a solution:

I've unbolted the rod, but it is wedged high in the cylinder, so I can't seem to get it out. I attempted to rotate the engine with an allen wrench, but the largest wrench I can fit only strips away the socket.

Hopefully I'll have a chance to work on it some more tomorrow. Damn life getting in the way of my bike!
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Old 06-25-2013, 04:29 PM   #41
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I don't have a good picture in my mind of what the problem is. Both header pipes, cylinder heads, cylinders and pistons are now off the bike?

Both rods are sticking out the sides of the block? But they are not positioned nearer to the opening. Rod bolts have been removed on one side? And you can't turn the engine with the alternator bolt? And the rod is stuck to the crankshaft even tho the bolts are off?

The bike should be on the center stand. The trans in neutral to turn the crank by the alternator bolt. But try now to turn the engine with the rear wheel. Put the trans in 5th gear and with the rear wheel off the ground turn the wheel to rotate the engine.

You may have to bang on the rods somehow with a big screwdriver to get it free. Try not to cause more damage with the screwdriver and hammer.
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Old 06-26-2013, 12:09 PM   #42
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Hit a bit of a hangup, ran out of time before I could find a solution:

I've unbolted the rod, but it is wedged high in the cylinder, so I can't seem to get it out. I attempted to rotate the engine with an allen wrench, but the largest wrench I can fit only strips away the socket.

Hopefully I'll have a chance to work on it some more tomorrow. Damn life getting in the way of my bike!
If you got the rod caps off you can tap on the rod from the opposite side with a chunk of broomstick and a hammer, just.

You can also turn the crank directly by hand at the bob weights.

You want to work with the rods maximally extended from the block.
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Old 06-26-2013, 02:32 PM   #43
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Oh, I was under the assumption I could get all the bits off the left cylinder without having to go into the right. I only have the left head off.

The rod is free from the cylinder, but the base of the rod itself is too large to squeeze between one of the pieces of the crankshaft and the block itself.

Guess I'll pull the other cylinder.
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Old 06-26-2013, 04:23 PM   #44
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Yes you can get into one side or the other with out taking both apart. I only take both apart though because I only repair stuff in pairs. You do not have to do it this way if you don't want. many people would fix only the bad side. But I couldn't sleep at night if I did it that way.

Once you have both connecting rod bolts off the rod can be removed. You may use something to bang on it. Don't hurt it.
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Old 06-26-2013, 07:30 PM   #45
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The left rod is free-floating in the block, but there's not enough of a gap between the cylinder and the top of the block to squeeze out the rod itself.

Just finished getting the right side off. Was a much easier the second time around, although I had to whip out a hairdryer for the rod pin. Unfortunately, the right side seems to have the same issue as the left; the piston rods are in the wrong positions for easy removal. I'll have to rotate the engine, but there's... a hangup for that. Firstly my clutch pedal is disconnected, but I when I initially began taking apart the bike, I couldn't get the shifter into 4th or 5th, so I'll have to go after the bob weights that Plaka mentioned.

Hopefully tomorrow.
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