Today I bought a pair of roadholder forks on an autojumble, including yokes. The yokes have a width of 7" and the fork measures (from top of nut, to bottom of the lower slider) 31,5". External springs are fitted and the left slider is still in one piece, no welding done, which I'm quite chuffed with. When opening the top nuts, there's no dampening rod attached.
The overall length seems exceptional and makes them even longer than long roadholders if I have got the facts right. The man seling it told me they came from a scrambler and he wasn't sure about the internals. Which could explain the extreme length.
My question is: to fit these forks in a featherbed frame for racing, which parts (if any) will be usable and which parts need to be replaced? My guess is I'll need shorter stantions (or shorten these ones) and go for the internals of the later short forks. But I've come across so much information on the internet (some contradicting, some just opinions that seem more like guesses), that I'm not sure what to believe anymore about interchangeable parts.
In short (no pun intended), can I shorten long roadholders or am I better off selling these and find a pair of short ones? I prefer the former, as I had a hard enough time finding these.
Thanks in advance for your insights,
Tim
Shortening....
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Thank you Alan, I'll have a…
Thank you Alan,
I'll have a go. It's reassuring to know the sliders can be re-used, as do the dampeners with some modifications. I might have to get new stanchions, as the old ones aren't far from smooth. The external springs have made them quite rough with a slight thread like pattern on them.
I'll go for internal springs to prevent that in the future. Then try how it rides (which might take a while) and see if all the different types of recommended modifications for dampening are needed and if so, which of them actually make sense.
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Long road holder sliders…
Long road holder sliders only differ from short ones by the way the shrouds fit and the oil seal is retained. But they do not have damper tubes, just a tapered rod at the bottom. It's not clear what you have from your description however short roadholder dampers will fit right in without any modification to the sliders. As you say you'll also need a new set of short roadholder stanchions and bushes/seals - I'd recommend Andover for them - I have found the quality from other suppliers isn't as good. You'll also need a set of dampers tubes, dampers, rods and springs, and fork screw caps - I think RGM sell improved dampers which moves the oil hole to avoid harsh bottoming out.
I've put short roadholder/commando internals into my long roadholder sliders (on 2 bikes) and am happy to talk you through it if you like but it is straightforward.
I'm not sure how serious your racing is but I'd guess that getting the best suspension at the front is important so even if you bought a set of used forks unless you were very lucky you'd prob want to change the stanchions springs and internals anyway!
Lastly and perhaps most importantly look closely at your yokes - long roadholder yokes are different to short roadholder yokes the stem is a different diameter and I'm not sure how easy it is to fit them to a featherbed frame.
I should add that I had an accident earlier this year going to the club meeting at Sammy Millers - the end result was a new set of stanchions and short RH sliders from Andover - they are noticeably smoother than their predecessors! However they are not cheap!
ps on my scrambles bike my long roadholders measure 31" from the axle to the top of the fork cap - and there is some sag.
Dan
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The long and short of it.
Hi Tim,
If you have long Roadholder yokes these will not fit the featherbed frame with-out a lot of conversion and then the steering angle will be completely wrong as the long type yokes have a raked angle between top and bottom yokes, whereas the short type are parallel to the steering head. If this is your first Norton build, you will need to get all the information sorted or you could end up with lots of unsuitable parts.
As Dan says, it depends how competitive you want to be. A standard Model 50 engine will need extensive tuning as the bikes in that class are capable of speeds of 110+ mph. Your budget of £4K will be a challenge to get all the good parts for a quick bike, but also racing in the U.K. is expensive these days with a week-end meeting costing around £400 altogether.
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Just to say scrambles racing…
Just to say scrambles racing is much cheaper - ~ £50 annual licence and £50 entry plus fuel. Engine build is equally expensive! My model 50 is now a 520.
dan
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Semi serious racing
The racing will be done in the Netherlands and it's semi serious. They're demo races, so you can win by being the most consistent rider. However, we all know the way to be most consistent. ;)
For me, it will just be the fun of being with like-minded people and enjoying the bikes. And I want to prove that classic racing can still be done on a budget. This means the engine stays original (ish), but of course I'll be trying to get the most out of it in that configuration. Luckily, I'm not a heavy guy, which adds at least 5 mph top speed for free. And I'll be relying heavily on the razorsharp steering of the featherbed frame and roadholder forks to keep momentum.
This means Dan is right and the forks would always have been subject to renewing of parts anyway. Unless you're very lucky, they're always worn out. The thing is, up to now, I didn't know which parts were interchangeable. I do now, so I'm glad this forum exists! If the stanchions would have been good, I would have shortened them. But after close inspection, they've definitely had it.
And Richard, you've got a good point there about the steering angle of the yokes. I only knew there was a difference in stem diameter (I've got the thin one), but never knew about the angle. Thanks for that! However, if I search for this, the only thing I can find is a post on this forum, mentioning SC (sidecar) yokes having an angle. Is there somewhere where I can find all this information? Mind you, I'm happy with the information given!
Back to Dan; scrambling would be great, but regretfully I'm rubbish at that. It's a shame the UK race meetings are that expensive. Yet, they might be a bit too competitive for what I'm building. Saying that now, let's see what happens when I'm finished and get a taste for it.
***edit***
I've checked the yokes and they're not at an angle. So that means at least the sliders and the yokes are re-usable. Regarding the RGM dampers: are they recommendable? I was told by a ManxGP rider to just build the forks to original spec and try them, before trying to alter the dampening characteristics. If it's just the bottoming out part that's altered, it seems like a sensible improvement.
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Shortening RH. I did this years ago and it ended up a moderately easy job. Do NOT think of shortening the stanchions from the top, getting a tap for the nut thread will be (nearly) impossible. But a good job on the bottom with a lathe was easy enough. Again shortening the internal damping rod was straight forward. BUT I would recommend that you sort out the internal damping rod (and spring) before you start work on the stanchions. So you know where you are going with the project.