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Discussion Starter #1
This isn't specifically about a V-Strom fork cap, though I'm sure the caps on a Strom can suffer from the same issue. I know a lot of guys on here have a lot of machining experience, so I'm seeking some advice.

Like a lot of ham fisted mechanics, I bunged up one of the sides on the fork cap nut when I was removing it from my Super Tenere while changing the fork oil. It's not bad, and I'm pretty sure I'll be able to remove it again, but it got me to thinking about a better way to get the cap off than using the soft aluminum nut.

I was considering two possibilities:

1) Drill two shallow holes in the fork cap on either side of the nut, and use a pin wrench to remove the fork cap in the future.

2) Machine an aluminum donut the same diameter as the existing for cap. Drill a series of holes around the circumference of this donut (I'm thinking maybe six holes, like a #6 size). Then tap corresponding flat bottom threaded holes into the top of the fork cap, and screwing this donut to the top of the cap. Since the threaded holes would have to be pretty shallow, I figured that six of them would provide a pretty secure attachment. Then, drill holes into the donut that would correspond to the pins on a pin wrench. The donut would be 3/16" thick, which should provide plenty of depth for the pins on the wrench.

The biggest downside I can see is that I don't know how deep I could safely drill holes in the fork cap.

For those of you who have machining experience with aluminum, would this work? I've attached a photo of a Super Tenere fork cap. These things are $300-400 new, so if there was a way to salvage the old one, it would be worth a shot.

 

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I don't know much about machining or fork caps, but I've got a sudden, inexplicable kraving for Krispy Kreme.
 

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Take it to a machinist to get a really good answer.
 

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Ive never had a problem or caused damage removing fork caps using a 6-point Snap-on deep well socket. These sockets are flank-drive, and apply force to the sides of a nut rather than to the corners. The key is to loosen the cap before you loosen the bike's lower triple clamp bolt. If off the bike, I I have someone hold the upper tube in their hands while I use a 3/8" impact wrench and repeatedly give the socket short bursts to loosen.
 

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Discussion Starter #5
Well, sadly, the damage is already done, so I'm looking for a solution that allows me to salvage the existing fork cap, if possible. I followed the proper sequence in loosening it but I let the socket slip off while I was loosening it.
 

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RC, I dont know the extent of the damage from the pic, but it's possible to carefully hand-file off the damage, straighten up the sides, and as I suggested use a Snap-on 6-point socket for removal/installation. Ive had to do this when presented with damaged caps by other riders.
When servicing forks, I use a 12" 1/2"drive extension and 3/8" adapter, and position the socket dead in-line with the fork before I apply any rotational force to the cap.
That cap must be made of Unobtanium, as it was shown for $267 on MR Cycle's website.
Just asking, but what is the wrench size of that cap nut?
 

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Discussion Starter #7
That actually isn't a photo of my particular fork cap, it's just a photo from online of a Super Tenere cap. I put it up there for reference. The damage on mine was minimal; one corner was slightly rounded off at the very top, where I allowed the socket to slip a little. I still have solid edges on the nut; however, as soft as that aluminum is, any slips in the future are just going to make it worse, so I was fishing about for a way to basically improve the way a wrench grips the fork cap.

The nut is 24mm. $267.00 is actually a good price; I've checked various websites and seen it all the way up to around $350. Dealership prices are around $425.00. Frankly, that's nuts, and this is the sort of thing that usually drives me to start thinking about another way to do it. Supposedly, a fork cap from an 05 Yamaha R6 will fit, and I did find some junked forks on eBay; only problem is that the fork caps on the R6 have two different part numbers, and only one matches the part number of the Super Ten. I'm not sure which part number goes on which fork, so I'm hesitant to buy a salvaged one from eBay.

Fortunately, this is an "I wonder if this is possible" type exercise at the moment, since I won't need to do fork maintenance for a couple years (unless I lose a seal, of course). I just think that a pin wrench that fits into holes that are near the outside edge of the fork cap would give more control and leverage that that soft aluminum nut.
 

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You might consider welding 6 slabs onto the facets of the nut / then machine them to accept a larger size socket.

Obviously, you would identify / buy the larger socket first.
 

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Discussion Starter #9
You might consider welding 6 slabs onto the facets of the nut / then machine them to accept a larger size socket.

Obviously, you would identify / buy the larger socket first.
I was thinking about that too; basically, machine a much meatier hex nut out of aluminum and weld it to the fork cap, with the new nut thick enough (like 1/4") that there's plenty of edge for a socket to grip. This would be more expensive, since it involves more precise machining and welding, but at the prices they want for a new one, it still might be feasible.
 

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I was thinking about that too; basically, machine a much meatier hex nut out of aluminum and weld it to the fork cap, with the new nut thick enough (like 1/4") that there's plenty of edge for a socket to grip. This would be more expensive, since it involves more precise machining and welding, but at the prices they want for a new one, it still might be feasible.
Having seen some of the other things you've accomplished ... I think you could streamline the fabrication of this repair by buying two new sockets. One of them can have the top sliced off so as to be used as a jig for the welding. With hand tools you can present it to the welder ready to zap.
 

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Rounded corner? If you get a socket that takes the bite along the flat wouldn't that be decent?
I'm worried every time I have to undo and replace the Strom caps. That fine thread and the spring load have me concerned.
 

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When doing fork caps, I use an axel nut spanner for the appropriate size and hold it down onto the cap with one hand and the top triple clamp loosened and give the spanner a little " Luv Tap" to remove it. After I change out my oil or do what ever needed to be done internally, I would use never seize on the threads to ensure they would not gall going back in...or out next time work needed to be done. Over the years I have accumulated a good assortment of sizes from bike salvage yards. If you still wanted to do the pin mod, you could drill two or three 1/8" or 3/16" holes in a spanner a just deep enough for a roll pin to help drive the hex on the cap.
 

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Discussion Starter #13
Notacop: Yeah, I think there's still plenty of flats on the nut that a socket will work, but there's so little metal there that, once there's a weak spot, I'm afraid that's it's potential for failing it a lot higher. I'd like to prepare for that rather than have it happen in the middle of a repair. As for spring pressure, there isn't any in a USD fork when you loosen the fork cap; the upper tube just unscrews and slides down, exposing the cap, spring, damper rod assembly, etc. You don't encounter any spring pressure until you take the fork cap off the damper rod assembly. I built a special tool for that out of a trigger clamp and an old woodworker's bar clamp.

NVDucati: That sounds like a good way to do it. I could give the socket section to the machinist, and tell him to machine a hex sided donut to fit in that socket. I would try to fabricate the nut myself, but I'm not precise enough with hand tools to rely on making something that has to fit that exact.
 

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Discussion Starter #14
When doing fork caps, I use an axel nut spanner for the appropriate size and hold it down onto the cap with one hand and the top triple clamp loosened and give the spanner a little " Luv Tap" to remove it. After I change out my oil or do what ever needed to be done internally, I would use never seize on the threads to ensure they would not gall going back in...or out next time work needed to be done. Over the years I have accumulated a good assortment of sizes from bike salvage yards. If you still wanted to do the pin mod, you could drill two or three 1/8" or 3/16" holes in a spanner a just deep enough for a roll pin to help drive the hex on the cap.
Believe me, I definitely used anti-seize when I reinstalled the fork caps after doing the maintenance, and I used a torque wrench to make sure it wasn't any tighter than it needed to be (torque settings don't change with the Permatex anti-seize I use, according to their data sheet).

I would prefer a pin wrench to using a roll pin as a driver; I'd rather exert equal gradual pressure on both sides of the cap at once rather than concentrating all the force on one side. A steel roll pin might end up elongating the hole in the softer aluminum as you hit it with a hammer. I'd use that method if I needed to get the cap off and wasn't worried about reusing it, since it works pretty well for loosening a frozen nut.
 

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RC, try THIS: Get a Snap-on 24mm 1/2" drive 6-point deep-well socket. Have the very bottom of the socket either ground or machined off flat. The bottom of the socket is slightly rounded, so a flat bottom is needed to gain full nut contact. Hand-work the nut to clean up the rounded nut corner. With a flank-drive squared-bottomed socket, there should be more than enough surface area to handle nut removal/installation torque. Ive been very successful with this procedure on various fork caps. You can get the socket and grind it flat and rework the nut yourself at minimum cost. Ive had to do this on Yamaha R1s, various GSXRs, CBRs, etc.
 

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Discussion Starter #16 (Edited)
RC, try THIS: Get a Snap-on 24mm 1/2" drive 6-point deep-well socket. Have the very bottom of the socket either ground or machined off flat. The bottom of the socket is slightly rounded, so a flat bottom is needed to gain full nut contact. Hand-work the nut to clean up the rounded nut corner. With a flank-drive squared-bottomed socket socket, there should be more than enough surface area to handle nut removal/installation torque. Ive been very successful with this procedure on various fork caps. You can get the socket and grind it flat and rework the nut yourself at minimum cost. Ive had to do this on Yamaha R1s, various GSXRs, CBRs, etc.
I'll definitely do that for the next time I take the forks apart. Basically, the rest of this is a mental exercise in finding a solution for a worst case scenario.

I'm looking at flank drive sockets as we speak LOL.

WOW! $46.50 for a socket!
 

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RC, look at Matco sockets also. Usually considerably less expensive than Snap-on, and they have their own version of flank drive.
 

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Discussion Starter #18
I'll give them a try too, MAZ4ME, and thanks for the heads up. When I saw the design of the flank socket, my first thought was , "well d'uh, that would have worked a lot better".

What does Matco call their flank sockets?
 

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CJ, Matco calls theirs "150-degree Chamfer" Cornwell calls theirs "Cold Broached"
Matco CD24M6A Chrome 24mm 1/2" drive 6 point
Here are some numbers: Matco CDP24M6V Black Oxide 24mm Deep 1/2" drive 6 point
Cornwell TM3224L Chrome 24mm Deep 1/2' drive 6 point

Hope this helps! Terry
 

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Well, having taken off probably thousands of fork caps, I've got three thoughts.

1) First and foremost, make sure the top triple pinch bolt is loosened.

2) If the cap feels like it's on really tight and the corners might round off, use a hand impact. NOT an electric or air impact. No matter what's driving the 6 point socket, be careful to keep it square on the cap. While I don't doubt that the flank drive sockets work well I've never used (or needed) anything other than the set of Craftsman deep impact sockets I've had for years.

3) LEAVE THE *$&@%&% TORQUE WENCH IN THE BOTTOM OF THE TOOL BOX!!!!!!!!!!! Fork caps need very little torque when being reinstalled, choke up on the ratchet handle and just snug them up.
 
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