Most people would say that if no one has ever done a particular VFR mod, there's probably a reason. Oh. Yeah, that does make sense...
But another way of looking at this would be to say that most people obviously don't enjoy challenges!
There are a few reasons why the SC63 triple clamps are nevertheless a good candidate for a VFR fork swap, and a few reasons why they're not. The pros:
1. They've got a 35mm offset. Most other VFRs have a 40mm offset, but the "traditional" Frankenviffer fork swap uses triple clamps from the CBR900RR Fireblade series (929, 954) or VTR1000 SP1/SP2/RC51, all of which have a 30mm offset. A 10mm reduction in fork offset is substantial, so trail will be increased quite a bit unless other things are done to decrease it (such as raising the rear or lowering the front). The VFR1200 yokes' offset is closer to the RC36's yokes' offset, so fewer other changes to the suspension would be required compared with using 30mm offset triples.
2. They don't need completely new bump stops. The VFR1200's bump stops are too tall, but only by about 5mm, so they can be shaved down fairly easily (I used an end mill mounted on the chuck in my drill press). They're not in exactly the right place, but they can be drilled and threaded to use M6 bolts as adjustable bump stops.
3. The VFR1200 yokes appear to be very strong. Coming off a heavier bike, it's not surprising that they are very substantial.
4. There's no need to use a different lower bearing. They use the same upper and lower bearings as the RC36, so no need to use a 3mm spacer (which is required to fit the CBR/RC51 SP1 lower yoke into the RC36 headstock.
5. In theory, yokes with more offset should = more steering lock. We'll see if it makes any practical difference, but the traditional swap noticeably reduces steering lock, so more would be better.
The cons:
1. The RC36 fairing stay needs to be seriously modified. Yup, there's no way around that. By "seriously" I mean the main top fairing stay will have to be cut and welded in order to even clear the VFR1200's lower triple.
Facing forward and looking down through the LHS top yoke opening in this pic, you can see the lower yoke opening--that's as far as it goes before it hits the fairing stay! FIrst it hits the side of the fairing stay's horizontal tubing (both sides do this), but even if that tube were flattened it wouldn't get very far before hitting the mounting brackets (again, on both sides). I can see that the offending parts of the fairing stay can be cut away and new bits welded on, so that is what I plan to do. Unfortunately, I haven't welded anything in about 10 years--and I wasn't very good then!
2. The lower clamp has 55mm fork tube openings. (Most USD forks used on Frankenviffer swaps are 54mm in the bottom clamping area.) This is not really a huge issue. When I bought my lower triple clamp from the ever-helpful KenG he included some 0.5mm aluminum shim stock, which can be wrapped around the fork bottoms to effectively increase the fork diameter to 55mm, which should then clamp perfectly in the VFR1200 lower triple clamps. (The upper is the same size as the others.)
3. The VFR1200 upper triple clamp is not really a gull wing. It looks like the 929/954 top clamp from the top, but it is really just sloped on the top; the bottom surface is flat. Of course, you cannot use another top clamp because it would have a different offset, too. But the difference is not much (and it is sloped), so this shouldn't affect the clip-on location too much.
4. It's not very easy to find VFR1200F triple clamps. They're available from Honda, of course, but like all OEM parts, they're very expensive even from a good discount Honda parts place like Partzilla. I have been scouring eBay US and UK for VFR1200 front end parts for months, and have seen very few sets appear. Not enough crashing, guys--please see what you can do to increase the supply!
So, over the next few months/years/decades I intend to do this swap, using SP1/SP2 forks and front wheel, and will post my "progress" here. Obviously, the main problem is the fairing stay. I've got some ideas and I think I can modify the stay, but it could all go pear-shaped, too. I wonder if my welder still works?
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JZH
Most people would say that if no one has ever done a particular VFR mod, there's probably a reason. Oh. Yeah, that does make sense...
But another way of looking at this would be to say that most people obviously don't enjoy challenges!
There are a few reasons why the SC63 triple clamps are nevertheless a good candidate for a VFR fork swap, and a few reasons why they're not. The pros:
1. They've got a 35mm offset. Most other VFRs have a 40mm offset, but the "traditional" Frankenviffer fork swap uses triple clamps from the CBR900RR Fireblade series (929, 954) or VTR1000 SP1/SP2/RC51, all of which have a 30mm offset. A 10mm reduction in fork offset is substantial, so trail will be increased quite a bit unless other things are done to decrease it (such as raising the rear or lowering the front). The VFR1200 yokes' offset is closer to the RC36's yokes' offset, so fewer other changes to the suspension would be required compared with using 30mm offset triples.
2. They don't need completely new bump stops. The VFR1200's bump stops are too tall, but only by about 5mm, so they can be shaved down fairly easily (I used an end mill mounted on the chuck in my drill press). They're not in exactly the right place, but they can be drilled and threaded to use M6 bolts as adjustable bump stops.
3. The VFR1200 yokes appear to be very strong. Coming off a heavier bike, it's not surprising that they are very substantial.
4. There's no need to use a different lower bearing. They use the same upper and lower bearings as the RC36, so no need to use a 3mm spacer (which is required to fit the CBR/RC51 SP1 lower yoke into the RC36 headstock.
5. In theory, yokes with more offset should = more steering lock. We'll see if it makes any practical difference, but the traditional swap noticeably reduces steering lock, so more would be better.
The cons:
1. The RC36 fairing stay needs to be seriously modified. Yup, there's no way around that. By "seriously" I mean the main top fairing stay will have to be cut and welded in order to even clear the VFR1200's lower triple.
Facing forward and looking down through the LHS top yoke opening in this pic, you can see the lower yoke opening--that's as far as it goes before it hits the fairing stay! FIrst it hits the side of the fairing stay's horizontal tubing (both sides do this), but even if that tube were flattened it wouldn't get very far before hitting the mounting brackets (again, on both sides). I can see that the offending parts of the fairing stay can be cut away and new bits welded on, so that is what I plan to do. Unfortunately, I haven't welded anything in about 10 years--and I wasn't very good then!
2. The lower clamp has 55mm fork tube openings. (Most USD forks used on Frankenviffer swaps are 54mm in the bottom clamping area.) This is not really a huge issue. When I bought my lower triple clamp from the ever-helpful KenG he included some 0.5mm aluminum shim stock, which can be wrapped around the fork bottoms to effectively increase the fork diameter to 55mm, which should then clamp perfectly in the VFR1200 lower triple clamps. (The upper is the same size as the others.)
3. The VFR1200 upper triple clamp is not really a gull wing. It looks like the 929/954 top clamp from the top, but it is really just sloped on the top; the bottom surface is flat. Of course, you cannot use another top clamp because it would have a different offset, too. But the difference is not much (and it is sloped), so this shouldn't affect the clip-on location too much.
4. It's not very easy to find VFR1200F triple clamps. They're available from Honda, of course, but like all OEM parts, they're very expensive even from a good discount Honda parts place like Partzilla. I have been scouring eBay US and UK for VFR1200 front end parts for months, and have seen very few sets appear. Not enough crashing, guys--please see what you can do to increase the supply!
So, over the next few months/years/decades I intend to do this swap, using SP1/SP2 forks and front wheel, and will post my "progress" here. Obviously, the main problem is the fairing stay. I've got some ideas and I think I can modify the stay, but it could all go pear-shaped, too. I wonder if my welder still works?
Ciao,
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