Skip to content

Ask an Expert CB750FB Air assist forks Suspension

You are in... Forums > Ask an Expert > Suspension > CB750FB Air assist forks

Got something to say?

Got something to say?

Go to most recent reply



Nov 12

Posts: 2

Treforissa says:

CB750FB Air assist forks

Help! Can someone help me with a bit of advice. I have acquired a 1981 Honda CB750 which has had CB900 Air forks fitted. I need to know the best air pressure to use.

Reply to this Topic  
  • Posted 2 years ago (06 November 2012 16:16)

Post a message in Suspension

Fields marked with an asterisk * are required


Please note. You cannot submit more than 4000 characters as a message.

Upload image(s) from your computer (up to 3 images)


Terms of use

Use of our community areas and forums is subject to important terms of use. By joining our community and using the features you agree to be bound by these terms. See terms of use below. 



Aug 02

Posts: 500

Dabbsy says:

air pressure

I'd be tempted to leave them at zero and get the sag set up with a preload spacer and fork oil level instead. Reason is Boyles Law which states that for a fixed amount of a gas kept at a fixed temperature, P [pressure] and V [volume] are inversely proportional (while one doubles, the other halves). That means the air-spring rate gets very stiff very quickly, plus the volume is so small that it is very hard to set accurately.

[This Reply has been modified by the Author]

Reply to this Topic


Nov 07

Posts: 2432

smidget says:


'Hagon' and see if they supply a set of progressive fork springs for your model of forks it will solve loads of problems with setting the air assisted forks.

They changed the feed back of the front of my V Max which also has air assisted forks as standard, keeping the air pressures correct was a real bind.

Reply to this Topic


Mar 09

Posts: 4548

smoto5 says:

As the above two posts say,

long term solution is probably best to stiffen up the forks by mechanical means, if they aren't actually leaking air and oil at present, then the kind of small volume hand air pump used to set mountain bike suspension (schrader type valve fitting) or available from some of the better bike accessories suppliers (possibly MnP, Busters, Demon Tweeks, or suspension specialists like MH, KAIS, Pro Action) is the most effective way to accurately set the pressure, ordinary footpumps, compressors, bicycle pumps will tend to release air on disconnection, making accuracy difficult.

Air assisted or fully air only suspension can work, but needs a fair bit of maintenance and upkeep, once bushes and seals start to wear much, pressure will revert to atmospheric quite quickly and damping oil may also leak out, whereas mechanical sprung will still hold ride height even if oil is leaking out.

Oh, and pressures, which is what you asked :laugh:, should be online somewhere or in a Haynes, Clymer or Honda manual, don't think it'll be high though, maybe 10-20 psi, perhaps a google search is in order:smile

And you should set pressures with weight off the front wheel, forks extended for accuracy.

[This Reply has been modified by the Author]

Reply to this Topic


Compare Insurance

Save money by comparing quotes. It's quick and easy

Motorcycles for sale


It's only £13.99 to advertise your motorcycle on MCN

Sell your Motorcycle

Motorcycle pricing tool

New! Find used bike prices