Commando with air ride assist on front forks

My latest Norton find is a 1975 that has an air pressure assisted front shocks. It does seem to work but you have to pump it up before each ride. Anyone ever see anything like this? It has pressure fittings on the fork nuts.

No but did blow out the lines on a Toronado with level ride. Frank said "hang on !" and we jumped full speed over the railroad tracks. Blew out all 4 lines on landing. Looked the same. No jumps.

Seems like a bad idea. My '82 Honda GL 500 has air forks. They were always sticky until I changed to progressive springs and skipped the air pressure.

May be an idea whose time has passed. Do any new bikes have air forks ?


Greg

Some old Guzzi's have these, made by Paioli and Sebac, I think, part of the cartridge. Don't seem to be very effective, as far as I can tell.
Here are a couple of threads which discuss them:
http://wildguzzi.com/forum/index.php?topic=51235.0
http://wildguzzi.com/forum/index.php?topic=30549.0
In the latter post, Leroy in reply #6, and Pete Roper, the inestimable Guzzi guru in reply #13, give a pretty thorough and entertaining account of what's happening in there.

Aren't all forks potentially air forks? That is what the air gap does - providing an additional spring. I always thought the pipework joining them together was poop though. Just something else to give trouble.

From my very limited reading, it seems that "new" mx forks have little bleeders to prevent the air pressure build up.

I had air forks on a couple of Suzukis. It was a bit of a pain to set as it was only about 1.5 PSI off the ground. You pumped it up to 20 or so and bled it of until it was just right. Those forks also had adjustable preload and damping. There was no balance tube but the manual cautioned that both sides were to be the same pressure.

If they leak down between rides, aren't they leaking down WHILE you ride?

goldwings have run air suspension since the early 80s with onboard push button adjustability options that can include desiccant air dryer in full setups, prob most are that way since the 1500

rear aftermarket air shocks became available on the earliest wings, late 70s, front fork aftermarket air cap kits became available,

i had an 84 fxrt harley that came with stock front & rear air suspension along with a one year only enclosed chain drive,

best to have an interconnection that way both sides are always at equal pressures & can be adjusted via one fitting,

supposed to be some anti dive effects also,

amount of air can be touchy & doesn't take much to overfill then blow seals, good to have an onboard/built in/interconnected gauge,

very convenient with big load changes, say solo light commutes vs 2 up full gear distance rides, or even sporty high speed runs vs city crawls, front fairings etc

as far as air ride goes, tons of that in the trucking world nowadays also

leaking down way too fast, first quick cheap easy check is soapy spray bottle all the connections for air leaks

i'd get an air pressure gauge & hook it in via a t fitting,

careful with pumping, a manual hand pump is plenty

i'm not aware of any info on this, prob someone just decided to drill/tap the tops for air fittings & give it a go

if your front springs are weak or shot, you can substitute that with air & get an easy ~ 2" rise in the front end by adding air & then relying more on the air for suspension, rather than the springs, however, if you spring a leak then you are back to the springs as they
are, this deal is the one that would involve max pressure testing

ideally you are well sorted with the springs that u have first, for the riding u do, then the air assist becomes mostly a minor convenience or inconvenience if it breaks, also less working pressure to play with

unless the prior owner gave some info, you're gonna have to work out pressures to work with, go too far & you will blow seals

baldy said:

My latest Norton find is a 1975 that has an air pressure assisted front shocks. It does seem to work but you have to pump it up before each ride. Anyone ever see anything like this? It has pressure fittings on the fork nuts.

Click to expand...

Many motorcycles over the years have had "air assist" in the front and rear suspension.

For the most part air in the forks is crap on a street bike...but I'm sure someone will argue that statement. Generally it doesn't really work very well with the most common complaint that the feel is soft and spongy. Might be something people want on a Harley or a Gold Wing.

I have a number of sport bikes that came with air fittings on the front forks. The majority of people who own these bikes do not put air in the forks because it tends to put pressure on the seals, causing leaks and premature failure. Most opt for thicker fork oil, less air gap or progressive springs to get stiffer suspension.

I can't think of anything air will do to improve Norton forks...and it may actually be a bad thing. If it was/is done to stop the bottoming issue there are better ways to fix that IMO.

Fork seals on the Norton are single lipped not double lipped as most are so will leak more. The biggest leak area will be the fork top nut, even if an o ring is used the nut cannot bottom out in the thread as the stanchion never comes fully to the top of the taper. I have had a fork leg assembly made with no internal spring, air is trapped inside, if you move the stanchion up you can feel the resistance of the changes in air pressure, you can also hear the hissing sound of air leaking. Doubt if any pressure added would last more than a few minutes.

dennisgb said:

Many motorcycles over the years have had "air assist" in the front and rear suspension.

For the most part air in the forks is crap on a street bike...but I'm sure someone will argue that statement. Generally it doesn't really work very well with the most common complaint that the feel is soft and spongy. Might be something people want on a Harley or a Gold Wing. .

Click to expand...

i'm not familiar with the gw 1500 -1800 line but pretty sure they are all air assist, if the front springs mainly perform suspension duties, i don't see how adding air turns that into soft & spongy, or have i felt soft & spongy when adding air, the more the air, the more it firms up

as far as a blanket crap on the street goes, i'd say that depends mostly on the intended purpose of the bike, you don't necessarily have an adjustment range to run light or heavy comfortably, with a given spring

it could very well be the norton forks, never intended for air assist, will not seal properly simply by adding air fittings to the fork caps

I have a 1978 GL. Years ago I installed an air cap kit manufactured by SW. It consists of two air caps, a connecting hose and a gauge. I put them on to help compensate for a Vetter fairing. I run them at 5-7 pounds of pressure and they never leak air. I also installed a set of SW air shocks in the rear. I am happy with the results. I can adjust for different loads simply by changing the air pressure on either or both ends. I also gained some ride height as a result. I think Dennis might be right saying they work better on a GL or a Harley, but I never load up my Norton like I do w/ my Wing so it would be an unfair comparison. I am willing to bet that the air leak that baldy is having is coming from the fork cap nuts or fitting. If it was coming from the seals he would see fluid also. I had bad seals on my GL and they still held air pressure. I think they have a place but it might not be on a Norton.

84ok said:

dennisgb said:

Many motorcycles over the years have had "air assist" in the front and rear suspension.

For the most part air in the forks is crap on a street bike...but I'm sure someone will argue that statement. Generally it doesn't really work very well with the most common complaint that the feel is soft and spongy. Might be something people want on a Harley or a Gold Wing. .

Click to expand...

i'm not familiar with the gw 1500 -1800 line but pretty sure they are all air assist, if the front springs mainly perform suspension duties, i don't see how adding air turns that into soft & spongy, or have i felt soft & spongy when adding air, the more the air, the more it firms up

as far as a blanket crap on the street goes, i'd say that depends mostly on the intended purpose of the bike, you don't necessarily have an adjustment range to run light or heavy comfortably, with a given spring

it could very well be the norton forks, never intended for air assist, will not seal properly simply by adding air fittings to the fork caps

Click to expand...

Yes, I should have been clearer on that. I think it may make sense for cruisers and touring bikes. I've never been into those bikes because I like lighter more responsive bikes. On those type of bikes (sport) it doesn't seem to work very well. There are better options to improve suspension.

I do have air bags on my trike, and they are okay particularly when riding two up or with a load. Not a good comparison, but one application where it works. You have to remember to let the air out which I always forget. :shock:

Thanks for the great responses. I just want to add that I do use a small hand pump and there is still pressure the next day. It is holding pressure for a day of riding.

i'd do basic air leak checks & fix simple stuff (like o rings), if found, right away, an easy gauge fitting simplifies filling, adjusting & at a glance, always knowing what's what,

i'd also make sure the springs are in good shape/sorted

shoudn't be any reason for leaks in the bits added on including thread connections, where just going with thread tape alone, can make a

yuuge lol diff

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