Fitting short stantions to Commando legs?

Hi,

I figured this should go in this section, as its technically a commando part

As some of you are aware, im building a Triton, now ive got some Commando fork legs (drum)
Ive been told that i can fit short roadholder stantions, and cut the damper rod down?
Im presuming that i have to cut the spring down also, im wanting external springs, so what are my options here?

Has anyone any knowledge of this, or done it before?
If so, any help or advice would be greatfull.

Steve.

steve828 said:

Ive been told that i can fit short roadholder stantions, and cut the damper rod down?
Im presuming that i have to cut the spring down also, im wanting external springs, so what are my options here?

Click to expand...

It's the length and rate of the springs that determines the "ride height". Fitting shorter stanchions won't "lower" the forks.
Shortening the damper tubes (or rods) will reduce the overall length of the forks at full extension, and shortening the damper tubes (preferable to shortening the springs) will the lower ride height if the same internal springs are used, but that will not alter ride height if you fit external springs.

I think you will find that there are two lengths of Norton Roadholder fork stanchion. The "long" one was fitted to things like the 19S (600cc OHV single), the "short" one was fitted to Dominators, Atlas, Commando. Apart from differences to accommodate drum brakes or disc brakes I don't think that there are any significant differences between, Domi, Atlas, Commando, except for the fork top nuts.

I think this is the case, but I'm happy to be corrected.

There is a reason why its not easy to fit external springs, I'm not sure what it is. Maybe something to do with beating several different colours of c##p out of the oil seals.

If you want to shorten the existing forks you are on your own.

cheers
wakeup

wakeup said:

I think you will find that there are two lengths of Norton Roadholder fork stanchion.

Click to expand...

I think there were (at least) five lengths.

Manx 20.375"
Short Roadholder 21.843"
Long Roadholder 23.312"
Commando 23.161"
Hybrid 23¼"
(Source NOC website)

wakeup said:

The "long" one was fitted to things like the 19S (600cc OHV single), the "short" one was fitted to Dominators, Atlas, Commando.

Click to expand...

Not quite. Long Roadholders were fitted to the pre-Featherbed models, and short Roadholders fitted to Featherbed models.

wakeup said:

Apart from differences to accommodate drum brakes or disc brakes I don't think that there are any significant differences between, Domi, Atlas, Commando, except for the fork top nuts.

Click to expand...

Long Roadholders had external springs and a different damping arrangement. Commando damper tubes are longer.

+ 1 on L.A.B's reply.
I lowered my ride height by shortening the damper tubes. I did this by removing the bottom (tapered) portion and fitting new ones which I made on the lathe. This lowers the height by about 1/2".
With the stanchion unchanged this gives 1/2" less travel to the bump stop.
I don't like the idea of cutting springs and that would necessitate shortening the damper rods too otherwise the spring could float at full extension.
While I was at it I fitted extra (nylon) bushes below the standard top bushes to create a genuine hydraulic stop at full extension; these had to be 1/2" longer than the regular covenant conversion bushes as the shortened damper tops out 1/2" sooner than normal.

Martin

You can lower the resting sag level by slicing off some factory internal spring and putting a weak spring spacer in place [instead of solid bushes as common in past] to keep the shortened spring from bouncing free on full fork extension and gain a bit more spring rate to avoid bottoming. Shortening a spring increases its spring rate, ie: stiffens it up some. Could source a shorter spring too, expesically if external.

I don't like the damper valve slamming under the damper cap to limit fork extension and that is not how Roadholders were designed originally - just a bodge I think with Norton using up only springs they had on hand from vendor that didn't stop in time w/o being paid by Norton.

I'd put a weak spring/rubber cushion above the damper valve for some soft top out restraint, instead of shortening damper rod for more damper cap thread beatings. IIRC there's at least 3" of clearance below factory damper rod, so at least that much lowering possible w/o fouling on damper rod length.