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Old 02-25-2011, 10:41 PM   #16
fishkens
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Quote:
Originally Posted by bmweuro View Post
This is quite simple. The push rod tube is pressed into the cylinder on all 1970-1995 Airhead Boxers. Always give them a little tap after at the collar after you have rebuilt your top end. Push rod seals and the sealing area should never ever have any sealant or oil when the are being installed. As the rubber dries up and shrinks you will need to do this again. I have also had success when they weep cleaning the area with brake clean very well and tapping them in.
Interesting. I've heard repeatedly that post-some 70's date that tapping the collar was not a god idea.

No sealant is my understanding but tapping the collar varies based on age, or so I've heard.
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Old 02-26-2011, 02:33 AM   #17
Bill Harris
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Quote:
Originally Posted by Wirespokes
So I've used Silicon grease since it's most compatable with rubber and plastics
Used to be that I'd put a faint smear of silicone sealant ("Blue Goo") on the pushrod tube seals when installing-- the idea was that it served as an assembly lubricant and allowed the rubber to slide and seat in it's cavity and then served as a secondary sealant. But you don't need to "lock" the rubber seal to the block with sealant, it need to remain flexible for the heating-and-cooling cycles of the engine. So the past few years, I've used only Silicone grease on assembling the seals. Even after several years on the bike, the grease still feels greasy upon disassembly.

OTOH, my opinion is that whacking the tube collar with That Tool is not a good idea. Early Airheads have a movable collar, later ones brazed. You don't want to move a collar installed at a set distance to fix a leak/weep/seep caused by an old rubber seal. Repair the leak by renewing the worn seal. The quandry is when you put a new seal on a PRT with a moved collar, the moved collar can put too much pressure on the new seal, deforming it and causing premature failure. So is there a spec for moving the collar to the "new seal" distance? Nope.

You can do the job fast, you can do the job slow, or you can do it half-fast... your option. :)
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Old 02-26-2011, 08:26 AM   #18
Wirespokes
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Quote:
Originally Posted by Bill Harris View Post
But you don't need to "lock" the rubber seal to the block with sealant, it need to remain flexible for the heating-and-cooling cycles of the engine. So the past few years, I've used only Silicone grease on assembling the seals. Even after several years on the bike, the grease still feels greasy upon disassembly.
Exactly! The seals needs to stay in contact as everything expands and contracts with heating and cooling cycles.
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Old 02-26-2011, 10:28 AM   #19
rudolf35 OP
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Wow!

I was not ready for all these replies. I will just use silicone grease and wiggle them in there; if they are needed! There is a slight amount of oil mist around the right jug PRT seals. So, I degreased the area and will test ride the bike for a week.
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Old 02-26-2011, 11:54 AM   #20
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[QUOTE=mymindsok;15282181]How are you going to remove a push rod tube from the jug by resetting the seals? You're putting pressure on a non-fixed keeper that presses against the seal but holds it's position through friction. The tube doesn't move with the keeper because they're not firmly attached to one another and you're only moving the keeper 1/16" to 1/8" at most anyway.
The keepers which are NOT attached to the tubes are very difficult to move unless pressure is very evenly applied upon it...something that aint gonna happen with a hammer and a piece of pipe at a crazy angle. Once the keeper digs into the tube its not going anywhere without bending the tube or breaking its seal in the cylinder.

Still, Your statement got me to thinking, so I went out to the garage and looked some R90 and R100 jugs. My conclusion is that it's simply not possible to hammer or press a push a rod tube, out of a jug, while the jug is bolted to the engine. Even if the tube was loose you couldn't do it because the push rod tubes are too long and even if they weren't, the lifters and cam are directly in the path of extraction.

I'm not making this up and I'm not trying to make this an argument... Please go look at some Airhead Jugs and explain how your scenario could be possible.
It's true you can't REMOVE the pushrod with the cylinder in place but you can compromise the cylinder/tube seal or shove the tube against the lifter or bend the tube. It's difficult to really know whats going on while you're hammering away.

Hammer if you want....but please not on my bike.

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