Front Forks

[mack]

Did the other standards go to an air assist front fork or was that limited to the specials?

[bikerphil]

Did the other standards go to an air assist front fork or was that limited to the specials?

The 80 and 81 Standard have air assist.

[jetmechmarty]

They got the air caps, but are not the same forks. Standards got KYB, and Specials got Showa. I believed the Showa is double bushed and the KYB single.

[MaximPhil]

Hi Mack,
I assume you know the Standard forks are different from the Specials My Venturer has two different air valve set ups for the top of the forks so I assume one is original and the other is not??
I have never run with the air as you need a hand pump to pressurise the fork chamber.
Phil

[spectra]

What pump is needed for the forks?

[MaximPhil]

What pump is needed for the forks?

HiSpectra,
To pressurize the forks you need a hand pump as the shock of a compressor will blow the seals. The challenge, on the Venturer any way, is how to get it attached. I believe they are Shrader valves similar same? as bicycle tire valves. Recommended pressures are between 7 and 40 psi.
Phil

[skids]

They got the air caps, but are not the same forks. Standards got KYB, and Specials got Showa. I believed the Showa is double bushed and the KYB single.

The older forks will not accept the newer caps and visa versa. Different threads.

[motoman]

HiSpectra,
To pressurize the forks you need a hand pump as the shock of a compressor will blow the seals. The challenge, on the Venturer any way, is how to get it attached. I believe they are Shrader valves similar same? as bicycle tire valves. Recommended pressures are between 7 and 40 psi.
Phil

True Phil, Schrader valves same as car or bicycle. Mine on my Venturer are easy access having the fully adjustable Heli-Bars which are totally out of way. I've found with the Venturer having the progressive springs from factory and using 15w fork oil(Silcolene), no air in forks, has no front end dive and rides handles nicely on LD rides.

[mack]

Fork swap

Yes Phil I know the forks are different from the specials to the standards. I can feel the road surface through the bars on my E and it doesn't plane out till 75-80 mph. What I'd like to do is swap out my original forks for a pair of air assisted 80 or 81 standard forks. This should make it more comfortable at lower speeds. Thoughts?

[MaximPhil]

Yes Phil I know the forks are different from the specials to the standards. I can feel the road surface through the bars on my E and it doesn't plane out till 75-80 mph. What I'd like to do is swap out my original forks for a pair of air assisted 80 or 81 standard forks. This should make it more comfortable at lower speeds. Thoughts?

Hi Mack,
I do not know enough about suspensions to comment on such a change.
I have never managed to get air into mine so like Brant just 15W oil and I have progressive wound springs which were installed in the Venturer . Mine were measured to spec when we did the resurrection back in 2009.
With 50+K km since then the springs are probably well used now.
Have you tried a good cleaning and perhaps replace the springs.
Ask JeffH as he had his forks custom built.

Phil

[mack]

forks

The forks were completely redone inside and out during the restoration and I put new springs in at that time. Andreas is looking for as set of G or H forks for me. No rush at this point. Going to winterize all three next week. Do one final cut with the lawn tractor about 12 acres, then pull the deck then winterize that, then get the snow blower tuned up for winter. Brought in several bush chords of fire wood last week. Heard it was going to be a colder than usual winter with above average snow fall. I have no idea what "average" is anymore! But best to be prepared for the worst and hope for the best. I don't care how much it snows, it's the freezing rain that I hate.

[jetmechmarty]

Depending how much pressure you run, I would expect air forks to asist with dive upon braking. You can do the same thing by adjusting the oil level. 15W oil from 10W oil will slow high speed damping.

Good luck with the winter, Mack.

[Jerry]

Just a short note on air forks. My XJ came standard with air-adjustable front and rear suspension. Air in the forks only changes one thing, and that is the point at which the forks will start to compress, or preload. Air does not change damping, rebound or spring rates.

Idea was to have the option of setting up a 'softer' ride for around town or long distancwe rides or a 'stiffer' suspension for canyon carving. Most riders compromise between the two by adding or removing preload to the springs via PVC pipe.

Progressive-wound springs pretty do much the same thing as air forks; softer ride over smaller bumps but more force is needed to compress the springs further.

There is also an argument to go to straight-wound springs due to their very linear handling characteristics and air pre-load is more effective with these springs.

After I installed new progressive springs in the XJ along with some PVC spacers (3 or 3 1/2 inch, can't remember now) I never used air in the front forks again. (Have a Windjammer IV on it.)

Granted, not using the adjustable preload air function means I don't get the maximum performance under all conditions, but then I don't push my bikes to the limit where this would be a factor. YMMV.

[motoman]

Just a short note on air forks. My XJ came standard with air-adjustable front and rear suspension. Air in the forks only changes one thing, and that is the point at which the forks will start to compress, or preload. Air does not change damping, rebound or spring rates.

Idea was to have the option of setting up a 'softer' ride for around town or long distancwe rides or a 'stiffer' suspension for canyon carving. Most riders compromise between the two by adding or removing preload to the springs via PVC pipe.

Progressive-wound springs pretty do much the same thing as air forks; softer ride over smaller bumps but more force is needed to compress the springs further.

There is also an argument to go to straight-wound springs due to their very linear handling characteristics and air pre-load is more effective with these springs.

After I installed new progressive springs in the XJ along with some PVC spacers (3 or 3 1/2 inch, can't remember now) I never used air in the front forks again. (Have a Windjammer IV on it.)

Granted, not using the adjustable preload air function means I don't get the maximum performance under all conditions, but then I don't push my bikes to the limit where this would be a factor. YMMV.

Hi Jerry, with many decades of moto-x under my belt, would have to disagree with air forks not changing dampeneing rate. Early on, before longer travel forks were used, several of us moto-crossers would drill and tap front fork caps for Schrader valves so air could be added in the range of 7-10psi. Fist time I did this was on a 75 Honda Elsinore 250 in 1975. Doing this not only slowed compressin rate to keep from bottoming front forks, but also put added sealing pressure against inner sealing lip of seals. Worked like a charm landing off of high jumps. Also, just to add, a year later, manufacturers started locating upper rear shock mount more forward, which angled top of rear shocks more forward. This caused LESS travel of shock allowing more wheel travel DOWNWARD givng rear of bike more downward travel distance. When Yamaha, being first to invent rear mono-shock on the YZ250 in 1977, this made handling charectoristics way above those of Maico, Huskavarna and CZ bikes from across the pond. So, yes, from personnel experience, minimal internal air pressure of forks DOES increase dampening affect and speed rate that compressin happens with front forks. Does make for a bit stiffer ride, but in the moto-x world, that is whats needed. Then the introduction of Ohlin 'piggy back' style gas shock were introduced first on Maico moto-cross bikes prior to ALL manufacturers, Japenese and European went with mono-shock pivot points that GREATLY reduced rear shock actual travel and gave LARGE travel distances at rear wheel, along with some 14in. of front fork travel having both compression and rebound adjustable dampening rate with the 'clicker' screw settings. ALL JAT to consider.

[Jerry]

Motoman:

Damping works in both directions; compression and rebound. Anything that affects either motion can be considered "damping" but as you know in an XS fork the major damping is done by the motion of the fork forcing fluid though holes in a disk. Any mechanical change in the forks will affect damping; the question is how much.

Changing the air pressure will have minimal effect on damping. It may change other factors, such as minimizing the fork's oil temperature change due to decreased suspension travel, but the main purpose is to change preload, the point where the suspension begins to move.