Fork rebuild for MkIII. Tell me about performance upgrades?

I noticed Commando74's thread about clicking forks but did not want to hijack his thread so I am strating a new one.

I am about to rebuild my front forks and am wondering about upgrades that can be done to the internals to get better performance out of them.

I have purchased new Progressive front springs but want to know if there is anything else that can be done, besides doing the standard rebuild consisting of new seals, oil and bushings.

I have looked at Clubman Racing's site and they sell all aluminum internals like damper rods ect. Would this be a good way to go?

I would like some suggestions and information for upgrades I can do to the forks on my MkIII. Thanks.

Fork Upgrades

There is a lengthy but well writtten article addressing the design problems with the Norton Commando fork st the INOA website. It specifically has to do with the design's lack of hydraulic bump stops at both max extension & compression. Check it out here.....

http://www.inoanorton.com/Articles/Roadholder.html


Hope this helps,

Joe in St Louis

Thanks jumpjg. I read some material here posted by norbsa about the mod, or similar mod. I have seen info here about the Covenant conversion as well, but I have no idea what that is or where to get it here in N. America.

Clubman sells all new aluminum internals and apparently Rocky Point Cycle makes a fork damper improvement kit.

I want to completely redo my forks and chrome plate the yokes as they look a tad ratty.

The Covenant conversion is a worthwhile modification for the price, and can be bought from RGM in the UK, along with progressive springs, and goes some way to correcting the lack of hydraulic stops at both ends of the travel by blocking off the lower damper rod hole with an alloy plug, the hole is then drilled higher up the damper rod, so gives more damping control at full fork compression.

There is also an alloy floating sleeve that fits on the fork tube that blocks off the tube damper drillings as the forks reach full extension.

It is always a good idea to fit new damper tube caps and rods if the forks are being rebuilt as wear (and corrosion) causes a loss of rebound damping which can result in a clonk as the forks top out under acceleration.

In the UK there is Maxton Engineering who will completely re-work the forks, but this costs considerably more than the Covenant kit: http://www.esling.btinternet.co.uk/maxton/

Apparently the parts sold by Rocky Point are the same as the Covenant kit, according to Stan at Rocky Point.

I contacted Frank at Clubman, who was very helpful and informative and their aluminum damper kits already include the "Covenant Kit" mod so I will probably go that route and just get everything from one source.

THERE WERE THREE GUYS WORKING ON THIS KIT. WE TALKED AND LOOKED,
AND LOOKED SOME MORE.
FIRST STAGE, STRIP DOWN FORKS TO ONE
FORK STANCHION, ONE SLIDER, ONE STEEL BUSHING WITH CLIP TO RETAIN,
ONE HIGH HAT BUSH, ONE SEAL AND ONE SEAL RETAINER ASSEMBLE DRY
AT THIS POINT. CHECK TRAVEL, GOT SIX INCHES PLUS WITH NO DAMPENER TUBE,
VALVE, ROD OR SPRINGS.
OK SECOND STAGE, ADD STOCK DAMPENER TUBE
WITH VALVE SUPPORTING ROD, TUBE CAP, SPRING, STOCK SPACER, JAM NUT.
NO FORK CAP NUTS OR FLUID SO WHEN YOU SLIDE THIS BACK AND
FORTH THE SPRING ASSEMBLIES ARE COMING IN AND OUT OF THE TOP OF
THE FORK STANCHIONS TOPS. THE TRAVEL WAS FOUR AND ONE HALF INCHES.

NOTE THAT IN THIS STATE THE SPRINGS ARE LOADED AGAINST THE TOP OF
THE DAMPENER TUBE CAP AND ARE TRAPPED BY THE JAM NUTS AND THE
SPACER ON THE OTHER END SO THE DAMPENER VALVE IS TIGHT UP TO THE CAP.
UNTIL THE BIKE IS FULL ASSEMBLED WITH THE DAMPENER ROD JAM NUT
TIGHT TO THE FORK CAPS AND THE WEIGHT OF THE RIDER IS FELT THE
VALVE IS ALWAYS GOING TO STAY THERE UP AGAINST THE CAP.

THE STOCK LENGTH OF THE ROD IS LIMITING THE DISTANCE THE
SLIDERS CAN MOVE. DO THE SAME TEST WITH TWO INCH LONGER RODS AND
AN EXTRA SET OF SPRINGS FOR PRELOAD AND YOU GET BACK THE
SIX INCHES OF MOVEMENT. THE TRUE LIMIT, THE MAX TO BE HAD,
IS WHEN THE TOP OF THE STEEL BUSHING HITS THE BOTTOM OF THE
HIGH HAT.
NOW YOU DON'T WANT TO RIDE THE BIKE IN THIS STATE WITH
THE TWO BUSHES TIGHT TO ONE ANOTHER THERE'S JUST NOT ENOUGH
SUPPORT AND THE FRONT TIRE WILL BOUNCE BACK AND FORTH AT
STOP LIGHTS. SO WE CAME UP WITH THE TWO INCH LONGER MODIFICATION
FOR THE ONE AND ONE HALF INCHES OF TRAVEL GAIN SO THAT UNDER
NO CIRCUMSTANCES COULD THE DAMPENER VALVE BE USED
TO LIMIT THE TRAVEL FOR THIS WE WANTED A FLUID STOP AND NOT A ONE AND
ONE HALF LONG LOOSE FITTING BUSHING BETWEEN THE TWO
BUSHINGS ALREADY IN THE FRONT END LIKE THE COVENANT KIT HAS.

THE SPRINGS THAT COME WITH THE KIT ARE FROM FORD TRACTORS AND ARE
THE SAME O.D. AND I.D. AS NORTON AND PROGRESSIVE SPRINGS.
THEY START WITH A TWO AND NINE SIXTEENTHS FREE LENGTH AND HAVE
HAVE A BOUND LENGTH OF ONE AND NINE SIXTEENTHS FOR ONE INCH OF TRAVEL
. FROM WHAT WE KNOW THE STOCKS SPRINGS HAVE ONE HALF OF AN INCH TO GO WITH
THE SLIDER BOTTOMED OUT, THAT IS THE BOTTOM OF THE STANCHION HITS
THE BOTTOM OF THE SLIDER. WE ADD ONE AND ONE HALF OF TRAVEL
WITH LONGER RODS AND THE EXTRA SPRING ADDS ONE INCH AND
THE OLD SPRINGS HAD ONE HALF INCH TO GO SO THE SPRINGS SHOULD
BOTTOM OUT JUST AS THE FORK STANCHIONS DO.
NOW FOR THE FLUID CONTROL
IF THINGS WERE IDEAL ONE WOULD HAVE FULL MOVEMENT WITH HYDRAULIC
STOPS AT EACH END THAT IS NICE AND SLOW ACTING RIGHT AT THE
ENDS OF TRAVEL. THE BEST WE HAVE COME UP WITH SO FAR
IS USING ATF FOR FLUID AND LEAK PROOF BRAND SEALS IT WORKS
ON FIFTY BIKES SO FAR WITH NO ADJUSTMENTS NEEDED NOT
THAT THERE ARE NO ADJUSTMENTS. I HAVE ONE BIKE WITH STOCK SPRINGS
AND ONE WITH PROGRESSIVE SPRINGS AND I HAVE TO SAY
THAT I FIND THE PROGRESSIVE BETTER BUT THE STOCK SPRINGS WORK
WELL TOO.
ON THE CENTER STANDS THESE MODIFIED BIKES DON'T
LIFT THE WHEELS OF THE GROUND ANY MORE BUT STILL WORK FOR ME.
THE IDEA IS TO GET THE BIKE TO GO DOWN FROM YOUR WEIGHT
AT LEAST ONE AND ONE HALF INCHES. THAN RIDE AROUND WITH FOUR
AND ONE HALF POTENTIAL INCHES FOR BUMPS AND THE
ONE AND ONE HALF FOR POT HOLES. NORBSA
_________________

BY POPULAR DEMAND
THE KIT CAN BE HAD IN A ONE INCH SHORTER
FORM THAT STILL HAS THE SIX INCHES OF TRAVEL.
ONE INCH SHORTER FORK LEGS ARE NEEDED.
MANY WAYS TO THIS END. THEY CAN BE MACHINED
OR ORDERED NEW. THE NEW KIT USES DIFFERENT
SPRINGS AND REQUIRES THE USE OF PROGRESSIVE
SPRINGS AS WELL. SO IF THE TALLER STANCE WAS
HOLDING YOU BACK YOUR OUT OF EXCUSES NOW.
OF COURSE IT'S MORE MONEY BECAUSE OF THE
CHANGES. EMAIL ME DIRECT IF YOU LIKE AT:
NORBSA@HOTMAIL.COM

norbsa48503 said:

BY POPULAR DEMAND
THE KIT CAN BE HAD IN A ONE INCH SHORTER
FORM THAT STILL HAS THE SIX INCHES OF TRAVEL.
ONE INCH SHORTER FORK LEGS ARE NEEDED.
MANY WAYS TO THIS END. THEY CAN BE MACHINED
OR ORDERED NEW. THE NEW KIT USES DIFFERENT
SPRINGS AND REQUIRES THE USE OF PROGRESSIVE
SPRINGS AS WELL. SO IF THE TALLER STANCE WAS
HOLDING YOU BACK YOUR OUT OF EXCUSES NOW.
OF COURSE IT'S MORE MONEY BECAUSE OF THE
CHANGES. EMAIL ME DIRECT IF YOU LIKE AT:
NORBSA@HOTMAIL.COM

Click to expand...

Does this infact mean that the fork is basically being lowered overall by 1" ?

Razed and lowered at the same time. Longer rods mean more travel witch lifts the bike cutting the one inch off gets it real close to stock again.