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Gas charged forks - vintage

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mitchntx

mitchntx

Follower of Rev. Doug
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First Name
Mitch
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Warren
I need to replace the fork seals on an 82 CB750F SS.

It has a Schrader valve and cross-over, equalizing tube and according to the book, I must relieve that pressure prior to removing the drain plug or fork caps. It is currently hold pressure.

My question is ... can I use shop air or should I use nitrogen?

I have a separator and drier used for painting on a leg of my shop air. Would that be sufficient? I doubt nitrogen fills were abundant in the early 80s so my guess is yes.

I do have a regulator and rigging to hook up to a nitrogen bottle ... just no bottle.
 
'86 Wing has air forks and uses a built in compressor with a drier. Manual warns on the models without built in air to use a hand pump to avoid over pressure conditions. Air range is 0 to 12 psi. Not sure if yours would have the same range or not? Hope this is useful.
 
mitchntx said:
I need to replace the fork seals on an 82 CB750F SS.

It has a Schrader valve and cross-over, equalizing tube and according to the book, I must relieve that pressure prior to removing the drain plug or fork caps. It is currently hold pressure.

My question is ... can I use shop air or should I use nitrogen?

I have a separator and drier used for painting on a leg of my shop air. Would that be sufficient? I doubt nitrogen fills were abundant in the early 80s so my guess is yes.

I do have a regulator and rigging to hook up to a nitrogen bottle ... just no bottle.
Click to expand...

Dry oil free shop air is fine

I use nitrogen for this kind of thing simply because I have it and I know it’s dry and oil free
 
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I would go through a bottle about once every 6 months while racing.
Ran air guns, purged air in tires after seating, set pressures ...

A single bottle would probably last years, now.


Thanks for the head's up, Mike.
I need to double check my regulator rig and see how low it will go.
 
As I recall, when I owned my CB750, the forks only run a max of 10psi (it is just trying to create a slightly stiffer fork spring by giving a bit of extra compression), we used to use a small bicycle hand pump to pressurize them. There is very little pressure in there, strongly recommend using a hand pump not a compressor its a small volume of gas..

Gary
 
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Good point, Gary.

Small volume and tiny pressure.

I think I still have one of those 15psi gauges that came with a Zuke GS I once owned.
 
I got some CO2 and some 78% nitrogen. That is pretty close. Plus do you really think the handling will significantly change? Hee Hee.
 
No. But moisture in a bike that mostly sits can make a difference
 
mitchntx said:
No. But moisture in a bike that mostly sits can make a difference
Click to expand...
And thats why I would use pressure regulated dry shop air or nitrogen over a hand pump. moisture

PLUS, a shock charging dry nitrogen set up is made to charge low volume chambers and has a zero loss pin valve.. Using a regular air chuck.... what you see on the gauge is not what is inside the fork after you remove the chuck.
 
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