Norton Roadholder modifications (2009)

The easy way to make old Roadholder forks work an awful lot better, while retaining original appearance is to fit internals from modern 35mm forks, which is something that is very common on "P65" trials bikes.

Here is an easy roadholder fix.....

Carbonfibre said:

The easy way to make old Roadholder forks work an awful lot better, while retaining original appearance is to fit internals from modern 35mm forks, which is something that is very common on "P65" trials bikes.

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I had considered that, but then the Lansdowne kit came along. Can you list some popular models with 35 mm forks? It could be handy for other projects. I reckon there would still be many hours of work to get them to fit the stock Norton forks, even if they were suitable.

Hello. Forum members, Having seen/read all the Mods going on here,up-side down forks ? Well is that going a little to far :?: why stop there. surly the whole idea of the Commando is to "Have a Commando" that looks like one? otherwise buy a modern bike, why stop at up-side down forks, stick a Honda CBR 1000 engine in.lots more power,super smooth etc....infact we could change all the parts...just leave the tank and side panels on , NORTON on the Tank ,,, sorted.
Hang about ! i think thats on the cards. it will not be long before New Nortons roll out from donnington with across the frame four cylinders.Took BMW a while ,but Sales Demanded it.

I think if the Original Road going Commando cannot be " Updated" meaning none appearance changing Mods. to a riders satisfaction .....then GET A NEW BIKE :!:

you're right there Mr. Bould. Appearance is very important to some and no big deal to others. It's an opinion thingy that's all.

One, well maybe two additional shortcomings I dreamt of last night is how the hydraulic bump stop is relieved at each end of the full stroke.
It seems to me that any period of engagement into the bump stops will suffer the same period of release, more or less depending on the load and reaction.
In my mind I have solved the compression end to have immediate release upon rebound. The extension end seems more complex. Has anyone devised an elegantly simple scheme without altering the main tubes that can be shared? Here is the situation as I see it: the tubes are reaching full extension the vent holes are restricted and the fluid is being squeezed through the clearances. When the action reverses then the tubes want to compress but the fluid now has to be sucked back into the damping area through the same small clearances until the vent holes are uncovered. This means slow fork compression for that same time period. Is there a simple solution to this without altering the main tubes?

Commando dampers have more travel than the spring compressive length=5 1/2 in ,when owner's say "Bottoming out" they are refering to the coil bound spring,
I have no doubt this is the case,
The taper on the damper base serves no purpose, in Commandos, the dampers i produce all have a taper... Manx.Dommie sets that need it,[short dampers] the alloy bases are produced on a CNC its cost effective and easy to make them all the same.
Norton made all damper base's with the same taper as a standard item....G15 and N15 use 25 inch stanchions and the same spring,When the spring is fully compressed the stanchion is 2 in from that taper :!: Plus the N15 was supposed to be a scrambler,No thought at all had been taken into Fork Damping .Same 50 year old primitive design...look at the Iso lastics,couple of big rubber washers, to stop your eye balls falling out? say no more :roll:

With longer damper rod the forks can extend so top bushes cover the stanchion holes as Norton designed and give perfect silent indefinite hydraulic stop. W/o the spring spacers or longer spring, Convenient loose bush extenders or longer top bushes also work but don't give more travel over factory coil bind spring length. Bottoming is solved by age old mod of moving damper holes up above the useless bottom tapper. Progressive bottoming is gain by size and hole staggering towards bottom on damper tube. I don't want a modern cycle I just want to out handle them and sure can with a Norton that is essentially still factory up front. I have tested modern dirt bike to elite sports bike forks and to me they are not up to how I ride at times, whether that is believable on not I ain't seeking any better. Do ya know what happens to fork length when starting to lean for a turn? I do and it ain't no down loading on them unless of course its a inferior handler that must brake while leaned. hehehe. Again I repeat you can not injure the forks by hitting stuff at speed on fully extended unsupported over lap, they just compress instantly to length that can take the impacts. At least the factory design Roadholders do.

john robert bould said:

Commando dampers have more travel than the spring compressive length=5 1/2 in ,when owner's say "Bottoming out" they are refering to the coil bound spring,
I have no doubt this is the case,
The taper on the damper base serves no purpose, in Commandos, the dampers i produce all have a taper... Manx.Dommie sets that need it,[short dampers] the alloy bases are produced on a CNC its cost effective and easy to make them all the same.
Norton made all damper base's with the same taper as a standard item....G15 and N15 use 25 inch stanchions and the same spring,When the spring is fully compressed the stanchion is 2 in from that taper :!: Plus the N15 was supposed to be a scrambler,No thought at all had been taken into Fork Damping .Same 50 year old primitive design...look at the Iso lastics,couple of big rubber washers, to stop your eye balls falling out? say no more :roll:

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John — I don't have a problem with people modifying their Commandos with upside down forks, monoshocks, etc — in fact I welcome it. I prefer to keep my Commando looking like more or less standard, but that's just me. The technical innovations and modifications that people share on this forum make it fascinating. I will always visit threads such as Jean's to see what he's up to!

Isn't that how Kenny Dreer got started? which begat the 880, which begat the new Norton 961?... that was the result of "Commando" development to the max...
I agree, if you want to take the Commando to the max, just forget about it.. save the original Commando and just buy the new 961. Too precious few original or close to original ones left.

JD

john robert bould said:

Hello. Forum members, Having seen/read all the Mods going on here,up-side down forks ? Well is that going a little to far :?: why stop there. surly the whole idea of the Commando is to "Have a Commando" that looks like one? otherwise buy a modern bike, why stop at up-side down forks, stick a Honda CBR 1000 engine in.lots more power,super smooth etc....infact we could change all the parts...just leave the tank and side panels on , NORTON on the Tank ,,, sorted.
Hang about ! i think thats on the cards. it will not be long before New Nortons roll out from donnington with across the frame four cylinders.Took BMW a while ,but Sales Demanded it.

I think if the Original Road going Commando cannot be " Updated" meaning none appearance changing Mods. to a riders satisfaction .....then GET A NEW BIKE :!:

Click to expand...

I've taken it to both extremes, modifying Ms Peel to beyond what any of you, racers included can conceive of handling wise, yet though Peels looks Norton not really a Norton and parts book has no relation to it. So I got Trixie to keep a toe hold to tradition and compare with what's possible yet quite happy with pure factory stuff as long as not trying to match elite sports bikes, which Peel can easy exceed up to her past power levels. That means leaving em in dust up to the ton then not loosing ground to over 130. When I hear how easy it is to over whelm sport bikers in serious play with other fork mods I'll sure be impressed and hoot and hallow with ya in delight, but so far ain't holding breath while rest of the world catches up to hobot mod's. BTW just fixing forks ain't enough to over come basic Cdo rubber buggy faults.

Here a deal for ya, I'll buy a Fuath kit to give to any one that has the other kits and knows enough to ride hard enough to detect the vital differences. I'd love it if my modest fork mods surpass the more expensive kits but I'll toss mine out to have the best there is - so lets get to the bottom of this fork business once and for all time. Will be another year before Peel has track times to compare
with hot shots on hot bikes at local tracks they know like the back of their hand.

Here's another kit I found today, don't know how good it is.

http://www.cosentinoengineering.com/ind ... age450.htm

bwolfie said:

Here's another kit I found today, don't know how good it is.

http://www.cosentinoengineering.com/ind ... age450.htm

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It is extremely good! Pricey, but worth it to racers. Just ask Kenny Cummings.

Ken

john robert bould said:

Hello. Forum members, Having seen/read all the Mods going on here,up-side down forks ? Well is that going a little to far :?: why stop there. surly the whole idea of the Commando is to "Have a Commando" that looks like one? otherwise buy a modern bike, why stop at up-side down forks, stick a Honda CBR 1000 engine in.lots more power,super smooth etc....infact we could change all the parts...just leave the tank and side panels on , NORTON on the Tank ,,, sorted.
Hang about ! i think thats on the cards. it will not be long before New Nortons roll out from donnington with across the frame four cylinders.Took BMW a while ,but Sales Demanded it.

I think if the Original Road going Commando cannot be " Updated" meaning none appearance changing Mods. to a riders satisfaction .....then GET A NEW BIKE :!:

Click to expand...

Its all relative, I ended up with USD forks purely based on cost, about half the price of a damper kit, then add bushes and seals and a disc brake slider etc. Ideally I would have liked conventional forks but they are harder to find good ones at reasonable prices now. I will keep the roadholders and drum brake wheel which are both in good condition so it can be swapped back pretty easily, the better forks and brakes will be for actually riding the thing.

Indecently the forks and clamps were almost as close as you could get to fitting straight in, the bearing OD (taper roller) is the same as the Commando one, the axle is the same size (although this wont matter), the only thing out was the stem being 10mm too long so I made a spacer between the bottom bearing and the frame so it was flush with the bottom of the tube and another one between the bottom bearing and the bottom clamp

I think there are two paths: keep it stock as you reasonably can so
as to sample what it was like for the average guy in 1970 or
whatever when he rode or to mod it out with anything you choose
to go faster, better whatever.
Some guys restore old stuff some guys build hot rods.
Both respect the others skills but neither is interested in
going down the others road.
...and then there are some who do both. Nobody is
right or wrong, it is a hobby, have fun!

Getting back to forks.

My current theory:
There's nothing wrong with the standard forks theoretical travel, it compares well with modern machinery, the problem is the springs are so stiff you never get anywhere near using it.
The stiff springs also creates the problem of excessive topping out, to ease the harsh topping out people then put extremely heavy oil in the forks which again stiffens things up in the normal range of movement and again reduces the travel you will actually see. Its something of a vicious circle.

As an experiment try measuring the static sag of Commando forks, if you see any you'll be lucky and if anyone ever bottoms standard Roadholders they are either massively overweight and should go on a diet or have just ridden off a cliff.

Unfortunately no-one seems to make a decent spring for Roadholders so I'm getting a low rate set made, I'll report back how they work.

hobot soloved the spring issue, which requires full 6" travel or springs must be too stiff to prevent bottoming just braking or riding lumpy places. You can do this two ways, retain factory spring and add more compliant spring spacer or put in progressive factory length spring and various rate spacer springs. Ms Peel has adjustable sag by preload on damper rod exteneded top threads. She don't sag at fork until I sit on it, and then only 1.5-2" for 4" compression ease and couple extra inches of rebound dampening grace. Can also just cut up various length and rate springs and stack as desired. Cutting a spring increases its compression rate though so fudge accordingly.

Rich_j said:

Getting back to forks.

My current theory:
There's nothing wrong with the standard forks theoretical travel, it compares well with modern machinery, the problem is the springs are so stiff you never get anywhere near using it.
The stiff springs also creates the problem of excessive topping out, to ease the harsh topping out people then put extremely heavy oil in the forks which again stiffens things up in the normal range of movement and again reduces the travel you will actually see. Its something of a vicious circle.

As an experiment try measuring the static sag of Commando forks, if you see any you'll be lucky and if anyone ever bottoms standard Roadholders they are either massively overweight and should go on a diet or have just ridden off a cliff.

Unfortunately no-one seems to make a decent spring for Roadholders so I'm getting a low rate set made, I'll report back how they work.

Click to expand...

Interesting observation. I played around with softer springs but then the problem of excessive dive with the standard dampers arose, I spaced out the springs to get the necessary static sag. I still had to use quite thick oil even with new standard damper tubes, pistons and top caps. I also tried the extensions to the top bushes as supplied by RGM (forget what the kit is called). That set-up was fine for just cruising around gently but if you started to push it a bit or brake hard, there was not enough control. I eventually gave up taking the forks apart and got sick of the mess it made and bought the Lansdowne dampers!

I'll be interested to hear how you get on with yours.

Dave

Do you always refer to yourself in the third person?

I've used Hagon progressives, they're too soft in the soft section and too stiff under full travel.
I don't want 6" of travel. I'm happy with the standard range of travel.
The only reason to extend the damper rod is to fit the extra spring to give a net lower rate.
I'd rather put in a spring of the right rate to use the standard travel and maintain the overlapp.

Dave outlines the decades long findings of all the experts and experimenters and useless vendor kits. Steve hobot Shiver solved it with essentially factory Roadholder, much to my own amazemtn better than anything modern I've tested. May be other better ways to skin Roadholder cat but mine works a treat for me and seek no further improvement but less wheel and unsprung mass and got that done now but not yet felt out.

Rich also self contradicts himself w/o knowing it. The purpose of longer damper rod is Only to prevent damper valve colliding with damper cap, nothing else unless other mods done. If solid spacers used to get top out stop then fork travel too short to get away with soft center range spring action so every little road nuance become an annoyance. If softer spring used then forks hit top or bottom range too easy for even more annoyance and also handling upsets.

You need the 6" range to have spring length and variable rates enough it hardly ever tops or bottoms out unless hitting stuff at hobot speeds and conditions.
I run into limits of road bikes limited travel and dirt bikes too soft over travel and one reason they have wimpy brakes on vital front.

If ya want everything I have but retain stock sag factor, then just put in longer damper rod and a very soft spring spacer that will collapse on factory spring but prevent coil bind on full compression for soft silent indefinite bottoming out sense you ain't ever sure they did except for your chin hitting bars so teeth clack.

i lucked out guessimating the damper tube staggered bleed holes and the waist depth and length I put in the almost interference tight fit of 10 mm Al damper rod in factory size beat a bit damper cap hole. Simple enough to diddle new cap with close fit hole if rod not already about filling it up. Basically I restored factory gap for ~2" of travel centered on loaded sag position then left it alone the other 2" above and below this. Peel forks don't really depend much on the damper valve flutter, just its ability to push-pull fluid through the varying restrictions. When Peel lands on her nose there are no valves that open up to "over" relieve the necessary spike in dampening pressures to contain. The tractor valve spring become very high rate near its coil bind so forks don't bounce back as much as push back on bottoming no hard jarring shock back up grips, just extends back a bit beyond upper sag level because it runs into built in hydraulic resistance again, both my tight fit and the factory top bush on stanchion hole blockage.

I may still play with the damper valve to learn its secrets but don't need a thing more to seek spanking race bikes on track days or out running MX bikes in serious rough stuff feeling about as comfy smooth settled as any Cdo does on nice hwys. Yesterday I came across a head turner sight, Mt side cut away for THE Gravel, with zig zags cut back and forth along its face the bulldozers use to get to top and push blade fulls over the side to bottom they then can load up.
If a bike falls over there it will end up on bottom after endoing a bunch. My groin tightened in joy to see something worthy of Peels traction pulse hook up and Roadholders capacity.

Rodded Peel will slide her front tire in counter steer or straight steer over wavy pavement when leaned to max and hi powered grip enough the front is lifting out of traction, but not a hint of worry of wash out or loss of accurate aim nor hardly any effort to pilot to hold forks where needed while sliding. Axle nuts disappear in a blur of for/aft vibration but I can only 'see' that happening not feeling it at all. Its made me insane to get it back in spades, so beware.

ABove mods only help the fork travel action not their twist up spring back delays between pilot input and tire patch response, so fork brace needed also.
If ya ain't experienced fork turning to rubber bands between hands and tire patch then ya don't know what you are missing out on isolastic Commandos and likely can't appreciate what maxium fork performance can do.

I am about to embark on a Front Fork Damper Modification. I have read diverse & varying options, all purporting to be an improvement. Most are variations on Peter Crespin or JS Motorsport designs. Both of which are significantly different in hydraulic action.
The Crespin design blocks the existing 2 x 1/4" (or 4 x 1/4") holes in the damper tube, & redrills 2 x 1/4" holes just above the taper.
The JS Motorsport design blocks the existing 2 x 1/4" (or 4 x 1/4") holes in the damper tube, & redrills 1 only 1/16" hole midway along the taper.

Has anybody tried both designs & is able to provide a technical critique of both?