Fork oil changing

Rear springs[ External] donot rub them selves against anything, Internal springs on full compression press against the inner stanchion wall, Some cheapo stanchions have a fairly course internal finnish, i would think the spring would soon rub of the finnish with powder coat. Stock spring steel gets easyly worn away :!:
Split the spring into 50mm lengths with plastic connectors, Vince will report soon?

kommando said:

Wonder if powdercoating the springs would reduce the rattling/noises, rear springs are powder coated.

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Cut springs/shortened springs increase their spring rate, so a stack of sections of stock spring will be stiffer. Cut springs leave a sharp prong end at an angle and would soon work its way through composite washers unless heated and flattened/ground off out as seen on the ends of factory springs. You may find you like a softer section stuck in the stack. This is how I got 4+ rate progressive spring action with 6" strokes and allowed sag set above or below factory level.

I filled oil 2 ways, the Rip Van Winkle way spilling almost as much a filling with a syringe, so final amount a dozen ml off guessing and by slow feed funnel though top nut/caps, one hole to fill one hole to vent. Just draining via the drain plug leaves about dozen ml inside. Peel's kit and use found ATF too thin so tried power steering fluid just right but PSF or brake fluid does not have rust inhibitor effect like other lubes/oils and absorbs moisture so i found if forks sit up a season they can rust inside to binding lock up, ugh. Its possible to over fill to hydrolock but you will not discover this until fork pumps out the remaining air a ways away - depending on how fast and bumpy you go after filling and pumping up dn ok at shop. This does provide another way to learn about the funny dynamics of forks with isolastic suspension.

I finally got to the forks on the 71 Fastback,had purchased a new set of Andover Norton stanchions and a rebuild kit also from them.
The kit comes with a new top bushing and lower sleeve but wonder why my forks have a bronze (?) sleeve also that seems to be able to float on the old stanchion,basically three stanchion supports within the fork lower.
There is not a replacement in the kit and can not see it on the AN website or in my manual ?
Also is there a recommended replacement fork spring,I measured the ones in the bike at 474 and 476 mm (18.66" - 18.74") which are most likely the originals given the red paint on the top coil,is there a service limit length perhaps.

I have seen this bush/spacer before,
i guess it is designed to blank off the holes with a view to improve the damping, But it will not.
Or to restrict the final extendsion travel?

Time Warp said:

I finally got to the forks on the 71 Fastback,had purchased a new set of Andover Norton stanchions and a rebuild kit also from them.
The kit comes with a new top bushing and lower sleeve but wonder why my forks have a bronze (?) sleeve also that seems to be able to float on the old stanchion,basically three stanchion supports within the fork lower.
There is not a replacement in the kit and can not see it on the AN website or in my manual ?
Also is there a recommended replacement fork spring,I measured the ones in the bike at 474 and 476 mm (18.66" - 18.74") which are most likely the originals given the red paint on the top coil,is there a service limit length perhaps.

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Thanks John.

I will leave them out then since I am fitting your cartridges.
That leading OD edge has been relieved by hand otherwise look like a oem part.
A nice sliding fit on the stanchion but a push fit to the lowers bore.

john robert bould said:

I have seen this bush/spacer before,
i guess it is designed to blank off the holes with a view to improve the damping, But it will not.
Or to restrict the final extendsion travel?

Time Warp said:

I finally got to the forks on the 71 Fastback,had purchased a new set of Andover Norton stanchions and a rebuild kit also from them.
The kit comes with a new top bushing and lower sleeve but wonder why my forks have a bronze (?) sleeve also that seems to be able to float on the old stanchion,basically three stanchion supports within the fork lower.
There is not a replacement in the kit and can not see it on the AN website or in my manual ?
Also is there a recommended replacement fork spring,I measured the ones in the bike at 474 and 476 mm (18.66" - 18.74") which are most likely the originals given the red paint on the top coil,is there a service limit length perhaps.

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They're there to limit extension travel, since the original design has the cartridge running out of travel before the bleed hole in the upper leg meets the top bronze bushing. That's why they bang when being lifted onto the center stand. They should be inserted into the lower leg in such a manner as to be snug against the top hat-shaped bronze bushing, and should possibly have a swipe of a low-energy-release locking agent added so as to keep them at the top.

Thanks for that.
I had only cleaned the lowers up ready for reassembly and not really taken much notice of the internal proceedings at this stage.
It seems odd that Andover Norton do not include this factory bodge sleeve stop in the rebuild kit as any pollutants embedded in the bore of it could be harmful to those nice new AN stanchions as they pass though it.
I was somewhat doubtful so went out and put a leg back together with the old parts and indeed instead of a top out spring like near every other fork it does use a mechanical stop as a top out so no wonder there is a clunk. :lol:
The cartridge does have more travel but why does it not have a internal top out spring as the soft stop extension limit like modern cartridges ? and dare I say as Triumph damper rods have of the same vintage.
The overlap of the stanchion and lower was some 95 mm (3.74") at full clunk.
I will double check the interference of the sleeve in the lower tomorrow,you are right it needs to stay up against the top hat bushing to avoid it possibly wearing the bore of the lower.
Perhaps that is why they have known to wear,that sleeve sliding down then getting knocked back to the top bushing and so on until the stanchion lower sleeve gets excess running clearance due to wear in the lower.

appears to me and my helpful mentors focusing on the whole range of Roadholder variations, Norton used too short of a spring in Commandos so to keep the spring from bouncing with slack on top outs they shortened the damper rod to stop against the damper cap on the fork extension beyond the spring length so clunks in fork just to lift them to move Cdo at home or on speed bumps and wheelies. All the Convent type extra bushes fall down to the bottom to cover holes whether desired or not. Extra long top bushes made up will give the hydro stop as designed it but still limit the fork travel to 4". When the damper rod is long enough the forks will not clunk at top but give an indefinite silent soft stop/reversal sense of never topping out to notice by sound or feel. Factory spring and common progressive springs are also too weak to prevent bottoming on much of a speed bump or even hard braking. If sticking with Roadholder internals might try long damper rod and slicing spring up to put in a 2" strong section and 2" rather weak spring on stanchion or a weak spring and rubber bumper under damper cap. Not a bad thing on moving the bottom out damper tube holes up where they function and make two smaller holes staggered above bottom stop for progressive sense of approach to silent indefinite short stop-reversal sense that never feels like it bottomed out completely.

The original design speak's of the holes in the lower stanchion closeing off the produce a hydraulic cushin, this was never the case..the larger hole..is, well to large!.
plus the two holes never gets covered by the top bush anyway!
Study the manual and see fore yourself,
the extra bush act's like a sliding valve, the oil trapped between the lower-upper bush's is prevented from exiting through the holes, anyway i built this into the Lansdowne damper, the last 15mm is a positive cushin as the escaping oil is closed off before full travel.

"Do me a favor. when you have the oil from your forks ,hang a magnet into the jar, swill it about and hang it up tp drip dry, then wipe the magnet with a clean white paper towel ...report if anything is found please.It should be a faint gray colour? hopefully Not!!"

Today I changed the fork oil...ATF, actually. Lots of Aluminum dust in the mixture but no ferrous material - magnet came out of the oil clean. The left fork had a lot more AL dust the oil than the right. In fact, the right fork's drained oil still looked reasonably clean. The fork's action seems to be a little better with fresh ATF but I admit I may be feeling what I'm hoping to feel!

But I have to admit that based on the way the fluid looked, I'd definitely agree that it should be changed annually. Maybe I'll even do that from now on!

guys, have we a consensus opinion as to what weight oil for stock forks?

I read various recommendations from ATF to 7.5, 10, 15 and even 20 weight

a pretty much standard weight rider, along, of say 175 pounds who mostly putts around?

and is the 150cc amount still the way to go

I've always used 20W fork oil which is not always easy to find, but I did and with my original setup, it seems fine. I just putt around too and nothing bottoms or tops out.

I'm down to 175 from 195 now too. I never thought I'd see the 170's again, but more calories from fruits and vegs instead of carbs and protein did the trick. Only took 2 months too. I couldn't believe it, but it's a lifestyle change, just get away from the junk and processed foods (and booze too)

Dave

For factory Roaholder no kits involved stick with 20 wt and above. I run same oil as engine 15/40 or 20/50 in my stock forks after finding ATF and power steering fluid too thin and gear lube too thick. You can not go very much by the grade listed on fork fiulds as each company has its own way to measure then its own way to report. Its nicer to run more volume but 175 ml is getting close as I ever will again to full up.

If you look at the owners manual (at least for my '73) , Norton basically said anything from ATF to 20W50 (incl everything in between) was OK. That leads me to believe that it all depends on your weight and how you want the forks to feel. I use ATF because I have the Fauth fork mod and that's what the instructions recommend.

Greg Fault's kit used ATF because that's what seemed to work best for me at the time but now like power steering fluid a bit better but that risks lack of rust protection as its brake fluid like hydrophilic. No reason not to mix and match ATF with some 50 wt. Its worth creeping up on maxium fluid fill but its very upsetting when hyrdroloc hits 1/4 mile after thinking all was well. My Trixie is still factory forks and heavy engine oil needed.

Depends upon where you live, ambiant temp as a huge effect, 15-20 c 10 grade....get to 30c plus ,you may well require 20 grade or higher. the original manuals recommend thicker engine oil in summer,and lighter in winter...so why are forks excempt?

1up3down said:

guys, have we a consensus opinion as to what weight oil for stock forks?

I read various recommendations from ATF to 7.5, 10, 15 and even 20 weight

a pretty much standard weight rider, along, of say 175 pounds who mostly putts around?

and is the 150cc amount still the way to go

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