Well the story starts out with my motorcycle accident last August during Sportbike Northwest. I made the decision to rebuild the bike but wanted to upgrade the suspension by doing the RC51 fork conversion. After seeing how many issues that I was going to have to deal with (geometry issues, wanting superbike bars, etc.) I just decided to go ahead and design my own triples for the conversion.
Below are some pictures of what I have modelled so far. Any inputs are welcome.
Yeah, it looks kinda slim in there but I used the Vortex RC51 top triple to get a lot of the measurements from. There's actually about 15mm of bite on the short side there, which is 5mm more than the Vortex.
I'll email you some close-ups when I get time this week.
I'm almost done with the lower triple, then it's off to meet with my CNC guy on Tuesday.
I gotta get this thing done as it's totally holding everything else up. Should be kind of neat when I'm done. The thing that I think is coolest is the abilitiy to adjust the bar height by changing the size of spacer under the lower bar clamp block.
SEBSPEEDDon't you need a gullwing triple(like the 929/954) to keep the stock geometry?
Looks good otherwise!
The 6th gen doesn't have a gullwing top triple. A lot of guys use a gullwing top so they can mount clip-ons above the clamp with shorter-than-stock forks, but that's not an issue with bars and risers. If anyone doing an RC51 conversion wants a version of Tim's triple with gullwings and without holes for the handlebar risers, it's a reasonably easy change in CAD.
True. If you want enough fork to stick through the top triple that you can mount clip-ons above the triple, you need a gullwing. RC51 forks will mount without a gullwing; you just won't have much of anything to clamp to above the triple. In Tim's case, no problemo since he's using risers with a handlebar. :blink:
True. If you want enough fork to stick through the top triple that you can mount clip-ons above the triple, you need a gullwing. RC51 forks will mount without a gullwing; you just won't have much of anything to clamp to above the triple. In Tim's case, no problemo since he's using risers with a handlebar. :biggrin:
Makes you wonder why he didn't just use an RC51 top triple clamp and drill two holes in it to mount the bar risers. :huh:
Wonder no longer for I am here temporarily to explain all.
Well almost all :biggrin:
Please keep in mind that I work in the engineering (Civil) trades and suffer from a severe case of OCD. I realize that most of what led me to this is complete overkill for the average person that wants to do the conversion.
I had a visit last Thanksgiving at BLS's place and we had some fairly in-depth discussions concerning the fork offset of the VFR (40mm) vs the RC51 (30mm) and the effect the conversions have on the stock VFR geometry. I went home and began to do some research and analysis, mostly analyzing the geometry in AutoCAD and looking at the changes that occur when the offset difference is applied to the VFR.
At that point I had no intention of attempting to manufacture a set of triples as I felt that I could live with the geometry changes. I actually had a couple of RC51 triples (stock & Vortex brand) and my original intention was to use one of them with a set of MX bar clamps. I even looked at the LSL riser bar option for the RC51.
A fews things soon became apparent; the first being that the ignition switch will not bolt directly up to the stock RC51 triple top triple without modification (cutting or grinding). The second is that I run a RAM ball mount on the two bolts that mount the front of the fuel tank; with the RC51 LSL kit I would have to remove that as there would be interference there. Third, I wanted to use a set of preload adjuster knobs on the forks (yes, for the bling factor) and there was no way that they'd fit under the bars with the 30mm offset.
I came to the conclusion that, for me, it would be easier to try my hand at modelling what I want and having them CNC'd than to deal with modifying parts to fit my needs. After working with Darth Bling on the GSXR mirror mount models I knew that it couldn't be that tough to complete these and it's kind of fun too (in a sick OCD sorta way).
I'm trying to find a balance between form and function even though I might be leaning towards form a little more. Like I stated before: for most it will seem like a ridiculous exercise but, as most of my riding buddies here in the PNW can attest to, I'm a perfection freak smile.gif .
I should be wrapping up the lowers today and will meet with the machinist on Monday. If anyone has any questions (besides "why?" as I've tried to explain that here) feel free to post up or send me a pm.
I like your style. I made my own simply because I could & wanted to (no need because I had a gull wing in stock). If I had seen yours mine would have also had holes as that looks better to me than the one I made.
Ok, so I've got the lowers modelled (see below) and I'll meet with my CNC Machinist tonight or tomorrow to discuss the particulars. I'll probably redesign the steering stops and make them a bit more angular (easier to cut?). They still need to beefed up towards the bottom as the stock lower triple is flat and this one is gull-wing in shape based on the stock RC51 lower.
I'll post up when I get estimate on material cost, machine time, and machining costs later this week.
magellanCan't wait to see it all in 7075-T6. Now hurry up so I can finish assembly :pissed:
Just for fun - ok I'm a sick bastard.....
For the sake of engineering argument on materials, what about a 5000 or 2000 series aluminum such as 2024-T3? The 7075-T6 is strong as hell, but not so great in the fatique end of the stick. -It still maybe the best, just want to here other opinions.
mello dudeFor the sake of engineering argument on materials, what about a 5000 or 2000 series aluminum such as 2024-T3? The 7075-T6 is strong as hell, but not so great in the fatique end of the stick. -It still maybe the best, just want to here other opinions.
Tim really has his heart set on 7075. As far as fatigue, well, fatigue implies bending, and I don't see these things bending in the least except for on the rare occasions when the fork clamps are loosened. I guess I see it as a matter of choice rather than necessity either way. These things ain't gonna break... :pissed:
magellanCan't wait to see it all in 7075-T6. Now hurry up so I can finish assembly :blink:
Just for fun - ok I'm a sick bastard.....
For the sake of engineering argument on materials, what about a 5000 or 2000 series aluminum such as 2024-T3? The 7075-T6 is strong as hell, but not so great in the fatique end of the stick. -It still maybe the best, just want to here other opinions.
MD
How about Magnesium??? I machined Mr.RC45's triple clamps out of this least understood
metal of motion... I think it's by far the best and lightest material...
7075 T6 is one of the highest strength aluminum alloys available. Its strength-to weight ratio
is excellent and it is ideally used for highly stressed parts... consequently you may design the
triple clamps with a thinner wall thickness and still achieve the desired strength...
2024 is one of the best known of the high strength aluminum alloys. With its high strength
and excellent fatigue resistance, it is used to advantage on structures and parts where good
Ha ha ha. I was just over at Tim's place this evening visiting and I made some off hand comment that he should machine the clamps out of magnesium. tongue.gif
Ha ha ha. I was just over at Tim's place this evening visiting and I made some off hand comment that he should machine the clamps out of magnesium. tongue.gif
Admittedly in my engineering travels I have not had the opportunity to play with magnesium. But doesnt that material degrade over time? (years) Kinda why the major mfrs avoid it for structual parts?
Oh, and BTW, my 7075 material is in and my machinist says we're cued up to begin this weekend. If all goes well I will post up photos of the finished product early next week! Woot!
mello dudeAdmittedly in my engineering travels I have not had the opportunity to play with magnesium. But doesnt that material degrade over time? (years) Kinda why the major mfrs avoid it for structual parts?
I'm thinking 2024 is a strong candidate.....
MD
Magnesium resistance to weather exposure is good in rural or inland atmospheres... color will
change to dark gray if unprotected... parts may be treated in Dow 7 giving magnesium the
characteristic chocolate brown color so many motorcycle parts are painted to resemble... Dow
#7 is dichromate treatment...
My triple clamps were treated to MIL process which is a chrome pickle treatment for magnesium.
I forgot to mention that the machinist made one small mistake when tapping the holes in the top clamp for the bar clamp mounts. He tapped the hole with an M10x1.25 instead of the standard M10x1.5.
I panicked when I couldn't find any stainless socket head capped bolts in that thread at Mcmaster-Carr. When I googled the thread size the first place that came up was Yoyodyne and their vast supply of titanium bolts. Ugghh.
I then had the dilema of purchasing the two bolts that I depserately needed for the bar mounts and use stainless for the rest or go "whole hog". Well, $220 bucks later I'm in it for the win!
I sure hope to hell this whole thing turns out ok.
As for the bolts, could you have bought the stainless socket heads extra long and not fully threaded and then single point threaded them or used a die on a lathe? Basically cut off the non usable threads and cut new threads? Nice job on the clamps, now onto the 5th generation.
This kind of gave me the excuse to buy the titanium hardware. I had said to Magellan and Darth Bling earlier in this project that I would buy the exotic stuff if I didn't have to pay more than $100 for it so the necessity/opportunity more-or-less pushed me over the edge.
I am, however, concerned about potential galling between the 7075 and the titanium. I have some Vibratite thread patching compound that clearly states that it minimizes galling/stripping. I hope that I don't have too much to worry about.
I believe that these would work on 5th Gens. That is, if it works on my 6th Gen after bolt up.
cassandtimI am, however, concerned about potential galling between the 7075 and the titanium. I have some Vibratite thread patching compound that clearly states that it minimizes galling/stripping. I hope that I don't have too much to worry about.
I believe that these would work on 5th Gens. That is, if it works on my 6th Gen after bolt up.
Yes, these are direct bolt-ons for a 5th gen, as long as you're installing RC51 (or same diameter) forks.
As far as galling, it'll never happen as long as you use anti-seize or Vibratite. These parts will never experience widely ranging heating and cooling cycles which cause dissimilar alloys to gall when in contact with one another.
Beautiful parts, proud papa! :biggrin: Can't wait to see it all installed!
I love titanium, but would for my project have used steel in the clamping area, stainless or a chromed stee. That being that under failure the ti bolt would fracture, and the steel would stretch. I wouldn't worry about the galling, based on my experience that disimiliar metals are more unlikely to do so. If you are going to apply any material to the threading section, torquing the titanium bolts might not be accurate. Most torque standards that I know of are dry states. Are you going to clear anodize and if you are going to color it, are you going for a UV stabilized color?
I had to use a gull set up for my R to keep the stock stance and allow me to use RC51 bars above the triple. I love that lower! Could use it on my bike!
mello dudeStem questions - so did you make a stem from steel alloy or is it Honda part? What is the oven/freezer trick?
(I can make a guess, but it doesnt hurt to ask.)
I used the stock RC51 (SP1) steering stem. I do intend on modelling the stem as I would like to have one machined that uses the internal thread style top bolt similar to the Aprillia and Ducati stems.
Because the stem and lower clamp use a force fit (0.002") I put the clamp in the oven at 300º for 35 mins and the stem in the freezer overnight. I put a little marvels mystery oil on the stem as well per Larry's advice and they went together with a tap from a dead-blow hammer and hardwood dowel.
BusyLittleShopYou're welcome Tim... the clamps look the biz... 40mm offset is very important because it preserves the VFR
quick handling rate whereas the stock RC51 offset doesn't... the only the thought that comes to mind is to
gull the top clamp like the bottom in order preserver the VFR's front end height and in addition there might
be enough room to hang a clip on...
If you weight them post the number so I may advise prospective customers...
Because I'm going the "Superbike Bar" style setup there's no need for clip-ons. I did do the measurements on fork length differences and it came out (measured from center of axle to top of fork):
Stock = 772mm
RC51 (SP1) = 759mm
Stock fork is supposed to be set 41mm from top of top clamp to top of fork (per Honda service manual)
So I should have 28mm of fork tube above the top clamp when done.
I have pondered modelling a set of gullwings in case somebody would rather go with clip-ons. It's all about finding the time.
I will weigh these after I get them back from the anodizer but I suspect that with the bar clamps and associated hardware they will weigh a little more than the stock RC51 triples.
I am hoping that I might be able to offer up the .DXF files after I verify that everything works well on my bike so that others can do this same conversion. I have discovered through this whole process that "where there's a will, there's a way" and it's not as tough as initially thought.
End of thread · 50 posts recoveredWayback Machine snapshot 29 Jan 2020
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