Air question

Concerning a reply in another thread. CAN you do without the air function in your front forks? ('82 xj750) I'm sure in the last 30 years that a LOT of folks have just ignored that little air valve. Is it just a "supporting" feature to the springs and oil or an essential feature? Would your forks be softer or harder without it? Would you have to run more fork oil without it? BigFitz, O&B, Hogfiddles, Chacal, anyone? Y'all know these bikes better than I do. And I promise not to make a dramatic exit. Mojo

 

Just promise not to drill your crankshaft and you won't have to run away shamefaced from the forum anyway lol

I think you could run without air yes, as you said a lot of bikes probably have no air in anyway. You'd experience softer than normal forks (the air is effectively acting as preload).

You could I suppose fit spring spacers to adjust preload if your forks didn't hold air and you wanted more, but personally I'd say just make them hold air again like they were designed. you'd probably end up spending the same on different lengths of spacers/time and effort to try them out/fork oil etc as you would fixing an air leak (not to mention if they leak air they can leak oil too).

Not sure if the air has any other function than preload, have heard about it also helping the oil not to froth but not sure how valid that really is...

 

Thanks, I just wondered. I'm planning on building a new front end anyway, but when I get mine up and running I'll have to use the stock front end for a while. That was just something I hadn't considered.

 

750E-II_29Rbloke, This is just an observation, and meant in the nicest and most respectful way, but you just joined about 5-6 weeks ago and already over a thousand posts! Man you must've been vaccinated with a phonograph needle.

 

i was thinking the same thing. its kinda crazy

 

Rah rah rah *spits dummy & throws toys out* you disrespecting me motha$%&*er I gonna quit the forum! :lol: :lol: lol yeah I have a lot of time on my hands when I feel well enough so I spend a lot of it here... I don't get the phonograph needle thing though why's that? (never heard that before)

P.S. it's over 1400 now 8O

 

"Vaccinated with a phonograph needle" was said of people who blathers all day long. This is sort of an old expression, I haven't seen or heard it for 30 years I guess, and i've never thought it would apply to someone who types all day long...

 

Wow OK I'll quit blathering then

 

ever use one of those tire pumps, long tube with about a 18 inch stroke.
they get real hard to push at the bottom of the full stroke, but if you only lift it half way they go right down.
same with your forks, the air pressure builds real fast as the fork goes down but if you start with less air in them they go down much easier.
more oil is like less air so the pressure builds faster.
continued..........so i stay ahead of Rbloke

 

but after a point it gets hydraulic lock and stops like a brick.
spring pre load helps but springs kind of stay the same through the whole travel, air gets harder the more it's compressed

 

4300 ? i got jipped

 

never mind

 

Blatherer

 

I also have a 82 750 and i don't leak oil but I do need to need to add air from time to time. New shock absorbers come charged with nitrogen to keep the air that is entrained in the oil from coming out of solution under active loading. The internal pressure keeps it in solution. Over time while springs don't loose the load per inch they carry they do loose length or sag. So new springs would be better. Shims would help fixing the leaks if you can find them would also help. I don't know about you but I live on a short income due to my wife being unemployed and having a 4 year old son to raise. My bike is not on the priority list. It gets what it needs to keep it on the road and safe, not for sure running like it did in 1982.

 

Thanks guys, I think I've got a better idea of it now. Bloke, I guess we're even because I didn't get the "spits dummy" thing. But it's all good. I'm a dyed in wool hillbilly and if I typed like I talk most folks here would need a translator.

 

lol did you manage to look it up? It's kind of an expression of somebody throwing an unreasonable & immature temper tantrum over very little (kinda like a baby spitting it's dummy/pacifier out when it's upset and wants to have a scream about it)

 

OK, Gotcha. Thanks

 

Just wanted to blather about it to raise my post count hahaha I'll catch Polock yet! :lol:

 

Well getting back to subject here, I needed a fix for all the air that came shooting out of the little hole when the bits were removed, and i put pipe camps or straps or whatever they are called over the holes with sections of rubber vacuum belts underneath so as to make a complete seal and they held the air in very well. ugly but well.
Pretty sure the Polok knows something about plugging these holes and I kinda hope he'll interject here for a moment because I'm two steps away from drilling some cranks here, that crank drilling kid was funny for a minute there. Pretty sure he had the wrong forum, riceburnernitrous.com.customs.neonglowblingrocketchicksrule was server overloaded.

 

Well getting back to subject here, I needed a fix for all the air that came shooting out of the little hole when the bits were removed, and i put pipe camps or straps or whatever they are called over the holes with sections of rubber vacuum belts underneath so as to make a complete seal and they held the air in very well. ugly but well.
Pretty sure the Polok knows something about plugging these holes and I kinda hope he'll interject here for a moment because I'm two steps away from drilling some cranks here, that crank drilling kid was funny for a minute there. Pretty sure he had the wrong forum, riceburnernitrous.com.customs.neonglowblingrocketchicksrule was server overloaded.

 

You might be able to use an oil resistant epoxy to fill the holes. Be sure to prep the surface by thoroughly cleaning all them with a high-flashpoint degreaser. Personally I'd do this with the forks off of the bike and the springs out to be sure none of the epoxy drips into the fork legs.

Another option is to use an aluminum rod that is about .01" larger than the hole and press it into place (again that would need to be done off of the bike, but the forks wouldn't need to be torn apart.

 

Blather away nice having "regulars" you can count on to answer questions.


And you anf Polock in here made me laugh pretty hard.

 

What about the innards after the holes have been plugged?

 

As long as the plugs are flush with the inner and outer walls of the fork tube you won't have any issues. Press the plug until it's flush with the inner wall, then cut and dress the excess so it is flush with the outer wall. If you have any doubts about doing the work a machine shop should be able to get it done for very little money (bring doughnuts and talk nice).

The only change that you're making is to eliminate the ability to change fork pre-load by adjusting the pressure of the air spring (air is springy when compressed). With the air ports blocked off you have a fixed pre-load that can only be adjusted by adding, or removing, spacers for the fork springs.
Personally.... I think replacement o-rings are worth the cost. I like being able to adjust pre-load for different conditions (one up, two up, loaded with gear, etc.).

 

the thing about blocking them is if one leaks, then the forks are uneven. that cant be good.
the best way to make sure their sealed would be tap them and lock-tite a screw in them