FF: Forks Brampton Steering Stops

ogrilp400

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G'day All,
What is it with Brampton Forks missing the steering stops on B head lugs and then the rear fork tubes banging into the tank? Am I missing some thing here? And no, there isn't a spacer under the bearings, its as far up as it can go.

Phelps.
 

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Cyborg

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On my B the FT124 steering stem sits up a little higher than yours and the rib (on the FT124) comes into contact with the steering stop. Although it does come in contact with the side of the rib, so would reduce travel more if the stem was slightly higher. Is the lower bearing outer race all the way home in the steering head? I assume the balls are the correct size. Has the lower outer race been recently replaced? If so, within reason you could tighten down the nut on the steering stem and see if the lower outer race moves up at all. It’s a normal procedure with taper rollers to torque things down to make sure everything is seated and then back off and re-torque to spec. That said, I’m a little nervous about putting too much torque on a loose ball setup. Best to make sure it has the correct “ring” to it when initially installed.
 

ogrilp400

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I have done four of these in recent years and they are all the same. I remember the first one I did and I thought something must be amiss, surely the rib should contact the stops on the head lug. Pulled it all apart but could not find anything out of place.
 

Cyborg

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Well that is weird. Although from looking at mine, it doesn’t seem very well thought out. Yes it would make a lot more sense if the rib contacted the stop directly. With mine, “it works” but wouldn’t take much wear to allow more travel.... given it contacts the side of the rib so hits the stop at an angle. I have another FT 124, so will have a look at it later today and see if there is anything noteworthy. I can’t really compare it to the one that “works” because it’s in the bike. Unfortunately I don’t have another B headstock to play with.
 

oexing

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Sorry, no, nothing wrong with bearings, just the stops on the head lug are plainly too short for a nice contact. I found this when designing a hydraulic steering damper for the Brampton and simulated the set with pastic bushes in head lug with same dimensions like the ball bearings. So I will extend the stops with weld by 1/4 " and do flats there for some rubber glued to them. A hard BAM!-stop would hurt my soul - unacceptable.

Vic
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Cyborg

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No need to apologize. You are correct. I had a look at my other FT124. Slid it into a C headstock which is different, but the location of the stops are possibly the same. No logical way to change bearing location or remove any metal, so only option is as you say to add metal.
This photo is without the inner race on the FT124 and obviously no bearings. In as far as it can go and still just catches the edge of the rib. The rib on the assembled B is farther down and contacts more on the side of the rib. Probably wouldn’t offer much protection for the tank if the front end was walloped.... or if you could induce a tank slapper.
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Cyborg

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Beats me... with mine... in order to get that rib to squarely contact the stops without adding some silicon (or aluminum bronze would be better) bronze to build up either the stops or the rib... one would have to machine the bottom bearing bore deeper and remove material from the bottom of the headstock so the FT 124 would clear. Doing that might necessitate some sort of modification at the top with the stem sitting higher. If you had 4 the same and mine is just “OK”, then I guess it’s the luck of the draw with whatever tolerances they built to. Did you search the forum to see if it’s come up before?
 
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vibrac

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When I raced with Brampton's I had a vee of alloy attached to the stop protrusion but then I was reducing the movement for racing I would look at my Comet but it's on the bench in a front wheel clamp at the moment
 

oexing

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Adding weld to the rib would produce a banana shaped Brampton part - not recommended. And setting the lower bearing seat higher is a very awkward operation, you have to keep alignment and parallel seats of upper and lower bearing absolutely spot-on - not easy to do.
So really you´d better add some weld to the stops on the head lug, no risk of deformation there, you can use simple arc welding with standard rods. The head lug is most likely low carbon steel casting so no problem with welding added to extend the stops. A few wet rags around and you could do it on the bike. The stops were effective on most Brampton bikes I guess, but just and no great contact face there so some mod is a good idea.

Vic
 
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