Norton Fork Springs with Lansdowne Fork Kit

I have the Lansdowne Fork Damper Kit and was wondering what fork spring folks are using (progressive or stock), oil weight and oil volume. I rebuilt my forks with stock brass bushing, leak proof seals and progressive fork spring. The bike rides like its on rails in the corners, but I find the ride rough on sharp edge bumps. I've played with the oil weight and volume without much change in ride quality. I'm wondering if stock fork spring will give me a smother ride or is stiction and the fact I'm on an antique front end not going to change the ride.

I used progressive, and I think 15w oil as that's all I had. Standard oil volume. Can't help u anymore though as mine isn't finished yet.

LANSDOWNE DAMPER SETTING; 190Ml of S.A.E 10 fork fluid in each side. Starting with a quick health check on the bush's [Free sliding test]
1, Back off both rebound and compression three full turns out from full in. Your forks should now compress and rebound smoothly ,with no hydraulic resistance and with no stickyness...and no audable knock! Which in the early drum models can be the brake plate slot. Misalignment ,wear in the slider,tight oil seals ,bush's etc will need attending to.
2, It is important the forks move freely as this [chopyness] will be compounded by the hydraulic damping effect. Stock springs are well suited to the lansdowne Kit..Infact reports suggest Progressive springs are a bit "Floppy" mid position....The very nature of progressivly wound springs gives a softer "start" .
3. When all in the machanical department is correct, the dampers can be set, Start with the compression side. Adjust the needle until the forks compress smoothly, avoid over adjustment at this stage. Road feed back will be not the same as garage "pogo Testing" The speed a fork as to respond on the road is ten times faster ..over adjustment will produce a harsh feed back/and reduce weight transfer.
4 Rebound settings should feel progressive with the "Topping Out" just dialed out. The adjustments should be gradual. Start with approx 1-1/1 turns out, then 1/8 incruments..The Dampers very quickly react the small change's in adjustments...On the race bike 1/16 turns give differant feed back.

5, Mr John Dunn ,Tec Adviser Norton Commando Owners Club as just finnished testing a pair..His responce will be published in the Norton owners mag soon...If anyone may want to read is comments/settings please send your email address to me i will forward it on to you..you may find it interesting...So watch those settings..and dont over do them!! Email jrb19502005@yahoo.co.uk

bmwbob said:

I have the Lansdowne Fork Damper Kit and was wondering what fork spring folks are using (progressive or stock), oil weight and oil volume. I rebuilt my forks with stock brass bushing, leak proof seals and progressive fork spring. The bike rides like its on rails in the corners, but I find the ride rough on sharp edge bumps. I've played with the oil weight and volume without much change in ride quality. I'm wondering if stock fork spring will give me a smother ride or is stiction and the fact I'm on an antique front end not going to change the ride.

Click to expand...

Progressive are to hard after the "soft " close wound coils have been compressed,,,watch out for Andys report.

LEAK PROOF FORK SEALS ADD CONSIDERABLY TO FRICTION/FORK STICTION - RATHER USE STOCK SEALS AND GATERS.

bmwbob said:

I have the Lansdowne Fork Damper Kit and was wondering what fork spring folks are using (progressive or stock), oil weight and oil volume. I rebuilt my forks with stock brass bushing, leak proof seals and progressive fork spring. The bike rides like its on rails in the corners, but I find the ride rough on sharp edge bumps. I've played with the oil weight and volume without much change in ride quality. I'm wondering if stock fork spring will give me a smother ride or is stiction and the fact I'm on an antique front end not going to change the ride.

Click to expand...

Andy from Germany emailed me, He Had installed the Lansdowne kit. plus Progessive springs..He was not happy with the "Over Hard Ride" Changed the Oil...No differance.
Reverted back to the stock Norton springs..Is responce....Great!...Yet another adverse responce to Progressive Springs.
I think Pro" wound was designed to compensate for the original poor dampers....I had spent some time testing the original setup, But could not see how the stock set worked..The two uppermost holes supposed to get progressivly blanked off by the top bush...Dont get even near! The damper rod stops this from happening.
Stock Norton Rebound will work providing the clearance between the rod and piston balance's oil viscosity...But that could be a long winded process. So someone installed a progressive spring to produce an "effect " of compression damping...But once the close wound coils are used up, then its to firm!..[ 16 stone riders still have some usefull travel left] .Use the standard spring.and let the built in lansdowne compression damper do its job. Happy riding.

Hi Some heavy riders are happy , it appears 16 stone riders are pleased with progressive springs...what about forks with no springs? The lansdowne repulsion system, Stacked magnet's repelling each other...replace the springs Now thats what i call PROGRESSIVE!...Down side a bit heavy, plus side super smooth action with no rattle's or that nasty spring grating ...Yes is the LANSDOWNE "MAGNOTRON" SUPER FLOATER.....a vairable switch responds to the front brake pressure which in turn induce's a current to increase the electro magnetic force...anti dive! If any one is intrested you can contact me at my home address on Mars :lol: Other wise its the old Lansdowne Kit....... :wink:

That's right. After changing two things at once (progressive springs and new dampers), I had the problem of a very stiff fork.
I'm heavy as well (110kg including riding gear, don't know how many pounds or stones), and thought it would work for me.
I went back to original springs and left everything else as recommended: 190cc of 10 grade oil. That's it! Every ride, every day a grin on me face now!

Cheers, Andy

I was already using RGM's progressive springs before I fitted the Lansdowne dampers, and I can't say that I noticed any undue fork stiffness afterwards (I'm usually somewhere around 13.5-14 st./189-196 lbs./85.7-88.9 kg. (OK-well I've no bathroom scales, so I don't know exactly!) so I might try the standard springs to see if they feel any different.

Now I'm starting to get some miles on mine, I'm finding the forks work well when being pushed hard (easy on the local roads :roll: ), but are a little sticky when doing the static brake test.
They were like this before I put the (progressive) springs in, and I'm 99% sure this is due to new bottom bushes in old sliders, so I'm awaiting a bit more bed-in time before I start tweaking stuff.

If it was a race bike I'd be looking to do something about it; like sleeving the fork sliders for instance, but we're not in that territory here!

It's still early days, and I'm still shaking everything down, so no long rides just yet (although I'm gaining confidence by the day )

I don't know the source of RGMs progressive springs, but they're not Wirth - I have these in my Duke, and they're excellent, although the Duke did have serious spring issues.