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Another Inverted Fork Conversion (6th Gen)


VFR800R

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I'm glad this thread was re-bumped as I'm sure a good few of us are drooling at the prospect of future fork it swap. I didnt catch the excell spreadsheet last time I read the thread - well now I downloaded it and saved it in my bike tech folder. The sheet deserves a "Holy shit!". Very cool.

Hey VFR800R - How's things going for ya?

MD

Edited by mello dude
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Hello again folks!

The project has been in a holding pattern for the last 6 weeks or so. I am executing a move from San Diego to Newport, RI, so the bike has been packed up in a moving van since December 28. I got my house in Newport (with a garage!) today and should be taking delivery of the VFR (oh, and all my other household goods) on Friday. Then, we will see if I can shimmy the bike down into the basement to begin the tear-down process...

I found a machine shop here in Newport that should be able to build me my last required parts: axle spacers (titanium, I have a few chunks of 6Al-4V to sacrifice for the cause), front rotor spacers, and rearset mounting brackets. I still need to measure, solid model, and make drawings of said parts, but that will be pretty easy (not many dimensions on the spacers, a few for the rearset brackets).

While those parts are getting machined, I plan to tear down the bike, install the CBR954RR triple (with new All Balls bearings), and modify the steering stops as necessary to ensure they have the proper range of motion. I used to be of the opinion that those stops weren't particularly important until I low-sided on Palomar Mountain and squashed my left thumb between the handgrip and the tank. That was exacerbated because I had a tank bag mounted and the magnetic flap reduced the gap between grip and tank by just enough to screw up my opposable. Now I'm a firm believer in those lock stops.

I also have a few other random pieces to install: Motovation frame sliders bought here on VFRD and a carbon fiber hugger scored on eBay. I will also take a few other measurements with the intention of "fixing" one of the big design flaws (I feel) Honda committed on the VFR800s. I will explain further after I have done more research.

By the way, NYMBYSS those Ohlins forks look niiiice. I didn't know anyone had yet accomplished a 6th Gen Ohlins transplant.

Lacy

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One question I always ask myself when I see one of these threads is, are the VTEC forks really that bad? I find the swap to upside downs with full adjustments very intriguing.

Three words - BRAKES, BRAKES, BRAKES...

VFR brakes are fine, until you try serious brakes. All the other benefits of the USD fork swap (increased stiffness, lower unsprung weight, closer tolerances reducing play, more adjustability, better selection of aftermarket upgrades, good looks...) are just extra benefits :wheel:

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One question I always ask myself when I see one of these threads is, are the VTEC forks really that bad? I find the swap to upside downs with full adjustments very intriguing.

Three words - BRAKES, BRAKES, BRAKES...

VFR brakes are fine, until you try serious brakes. All the other benefits of the USD fork swap (increased stiffness, lower unsprung weight, closer tolerances reducing play, more adjustability, better selection of aftermarket upgrades, good looks...) are just extra benefits :wheel:

Sold!!!! I'm going to blame this all on you just so you know. wink.gif

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Hello again folks!

The project has been in a holding pattern for the last 6 weeks or so. I am executing a move from San Diego to Newport, RI, so the bike has been packed up in a moving van since December 28. I got my house in Newport (with a garage!) today and should be taking delivery of the VFR (oh, and all my other household goods) on Friday. Then, we will see if I can shimmy the bike down into the basement to begin the tear-down process...

Looking forward to future progress Lacy. It's a pain when life gets in the way of projects huh.

Jason - go to it. Collect a few parts and start a topic :cool:

Speaking of which, I haven't updated mine for a while... :wheel:

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  • 4 months later...
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Folks,

A little spy shot (or preview) of what is coming:

gallery_10025_5394_486498.jpg

If you look hard enough, there are a few interesting things in the photo. There's evidence of one massive failed project hidden in there, which I will post up after the bike is back together and I have exhaustively updated the actual front end conversion.

Until then...

Lacy

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Is that a front mount radiator I spy in the box back there?

Good eye, Toro. Good eye. There are actually a couple of them floating around the garage. I would bet that you looked at other radiator arrangements for the VTEC when planning the supercharger installation, and ran into similar roadblocks.

I hate the side-mounted radiators, so I planned to find a way to shift to a front mounted radiator (or radiators). I'll detail why it didn't work later, but I believe that Honda moved the engine forward in the chassis with the 1998 VFR800 (which begat my beloved VTEC), which leaves VERY little room to play with up there. Trust me, I tried.

gallery_10025_5394_454484.jpg

Perhaps later, I will give it another shot. At this point, I just need to button up the highest priority parts of the project and get it on the road.

Lacy

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Yep, I've been down that road as well. There is a reason why my kits do not run a front mount intercooler or standard style oil cooler. It would be possible with a multi-piece, custom radiator setup, but not at a realistic price.

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Guest Pete McCrary

Folks,

A little spy shot (or preview) of what is coming:

gallery_10025_5394_486498.jpg

If you look hard enough, there are a few interesting things in the photo. There's evidence of one massive failed project hidden in there, which I will post up after the bike is back together and I have exhaustively updated the actual front end conversion.

Until then...

Lacy

Lacy:

What's the exact color you used on your wheels? I had mine done in the Subaru WRX BBS gold. Guy that did them works in a body shop. He put about 5 clear coats over them. They look great.

Pete

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Folks,

A little spy shot (or preview) of what is coming:

gallery_10025_5394_486498.jpg

If you look hard enough, there are a few interesting things in the photo. There's evidence of one massive failed project hidden in there, which I will post up after the bike is back together and I have exhaustively updated the actual front end conversion.

Until then...

Lacy

Lacy:

What's the exact color you used on your wheels? I had mine done in the Subaru WRX BBS gold. Guy that did them works in a body shop. He put about 5 clear coats over them. They look great.

Pete

Looking nice..

Bin that hideous water cooler thingy.... You will save a good half Kg+ there! A small empty HRC bottle should do. Just top up yr rad. you dont need spare coolant water if you maintain it every trip out.

Will an RC45 hub fit right into that swing arm?? Instantly transforming the weight issue... coupled with a 520 chain conversion..

Edited by B4D80Y
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Folks,

A little spy shot (or preview) of what is coming:

If you look hard enough, there are a few interesting things in the photo. There's evidence of one massive failed project hidden in there, which I will post up after the bike is back together and I have exhaustively updated the actual front end conversion.

Until then...

Lacy

Lacy:

What's the exact color you used on your wheels? I had mine done in the Subaru WRX BBS gold. Guy that did them works in a body shop. He put about 5 clear coats over them. They look great.

Pete

Pete, I'm 99% sure the powdercoat is Tiger Drylac Sahara Gold 49/90137 (interior/exterior). The powdercoater tried to find a match for the Marvic magnesium front wheel I had, and Sahara Gold turned out to be close but not perfect. It will be good enough for my purposes.

@SEBSPEED: I'm pretty excited about the Asphalt black/gold wheel combination. I think it's going to look pretty awesome.

@B4D80Y: I agree on the HRC coolant overflow bottle idea. As for the RC45 wheel hub, I don't know. A rear wheel change is waaay down the road in my plans. However, the 520 chain conversion is closer....

Lacy

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Something looks wrong with that wheel, even with the angle I would expect to see a bit of the other lip.

Must have gotte nthe angle just right... but to be safe, here's one more of different wheels...

GOLDSUNWEB.JPG

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I'll start the update with the teardown. First, the fairings came off and were scattered around the garage. Then I put my motorcycle jack under the bike and slid a couple of 2x4 chunks under the oil pan to lift the bike from the engine instead of the headers. Then, off came the braking system, front wheel, clip ons, and forks. Before disassembly, I measured the original fork position (from the top triple clamp to the top of the forks) in case they ever go back in, and used the dowel method to measure the distance from the bottom of the steering head to the front axle so I could set up the new forks with the stock settings (actually, I will pull them up 5 mm to help account for the increased trail from the new triples, and also raise the rear end, both of which will steepen the rake and reduce trail). The VFR after disassembly:

gallery_10025_5394_4162.jpg

Next, I tackled the triples. I decided to use CBR929RR/CBR954RR triple clamps. The '06-'07 ZX-10R forks I will install have the lower machined surface positioned such that the CBR lower triple, with its flat profile, grabs in the right spot; RC51 SP1 triples grab too low due to their gullwing shape. I thought I could use the existing steering stops instead of just cutting them off and designing a new stop. So, I put the lower triple in and started shaving the stops with my Dremel (it turns out the stops are closer to the steering stem on the CBR triples than the VFR ones, so first I had to remove material from the stem side of the stops to get the triple up into position). My "machining station" is shown here; I don't recommend this, as I got aluminum filings EVERYWHERE and will be washing the bike naked before reinstalling the fairings to clean it up. But, it was much handier than pulling the triple, taking it to my basement, putting it in the vise, cutting 1mm off the stops, refitting the triple, and repeating about 50 times.

gallery_10025_5394_460888.jpg

You can see my initial cuts on the left-hand stop here (sorry for the out-of-focus shot):

gallery_10025_5394_395167.jpg

It turns out the CBR stops are much farther forward than the VFR ones, so the stops would never make contact with the original frame pads on the VFR. After mulling it over, I realized I could shape the stops to work against the bracket on the front of the steering head. That took a LOT of careful shaping of the stops; I removed a little material at a time, then would refit the triple to see if the stop allowed the steering lock to function. This took a while...

I also had to file away a little bit of material from the frame (eek!) to get the stops to contact the steering head well. It's hard to see, but I just flushed-up the part of the boss at the front of the steering head, just below the lower fairing stay bolt, where the stops will contact (there was left over casting flash from the factory):

gallery_10025_5394_331001.jpg

After gaining ground with the stops, the next hurdle was the oil cooler and its mounts. The outside edge of the triple contacted the cooler and mounts, as RustyA discovered with the RC51 SP1 triples on the VTEC, but in a different spot. I'm operating on the "first, do no harm" principle on this build, so I'm trying to do as little irreversible damage as possible, which prevented me from just lopping the oil cooler mounts off. Eventually, I decided to trim the mounts and cut a relief into the triple between the clamp bolts. First, the mount trim; you can see where I removed some material on the inside edge of the mount:

gallery_10025_5394_391300.jpg

Next, the triple reliefs:

gallery_10025_5394_222487.jpg

That got me sufficient clearance with the mounts, and eventually I trimmed my stops to get sufficient range of motion in both directions. The completed, sanded lower triple:

gallery_10025_5394_138353.jpg

In total, I took off over half of the original stops. I think the new stops and the "new" frame pad at the front of the steering head will be sufficient to limit bar movement in all but the worst crashes. I took RustyA's advice and used Duplicolor Self-etching primer and their silver wheel paint. After masking, installing the All Balls lower tapered roller bearing, and greasing, here is the finished product:

gallery_10025_5394_196824.jpg

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I installed the All Balls steering bearing set (thanks HS for your great maintenance guide!) and then moved on to the next stage. Here are a few shots of the triple after installation; you can see how the new stops contact the frame and how the outer edges of the triple clear the oil cooler mounts:

gallery_10025_5394_77647.jpg

gallery_10025_5394_470553.jpg

gallery_10025_5394_425163.jpg

gallery_10025_5394_366819.jpg

I then took a few minutes to install the forks, wheel, and brakes to make sure everything fit. It did! Simultaneously, I was having my rear wheel powdercoated at a machine shop that was also cutting me some new parts (spacers for the front axle and the rotors, and rearset brackets). While I was waiting on that, I took a detour into another project I have been daydreaming about: a front mounted radiator. I looked at a lot of options, and bought a 2004-2005 GSX-R600 radiator and fan for a test fit a while ago. It was narrow enough (surprisingly), but it was too tall to fit since the front cylinder head sticks out so far. I then thought about two radiators, but struck on the idea of cutting a chunk out of the middle of a literbike radiator. So, I bought a 2008 ZX-10R radiator on eBay and it looked like it might work (it was narrow enough, and fairly tall, which would allow me to cut out quite a few tube rows). Here is the radiator, and my cardboard prototype for fit testing:

gallery_10025_5394_443197.jpg

The replica is curved and everything, by the way. I removed the stock radiators and pushed them and the oil cooler lines aside, then set about fitting the cardboard rad. I started by cutting out a strip at the leading edge of the forward head, then opened up the hole to get clearance to push the radiator back.

gallery_10025_5394_723117.jpg

My concerns were the front wheel and fender contacting the radiator, the side fairings fully enclosing it, and the forks and lower triple hitting the top of the radiator. I figured I could remove about 30% of the tubes from the radiator (the ZX-10R puts around 165 hp down, while the VFR's max seems to be around 110 hp, or about 66% of 165, which I rounded up to 70% to add some fudge factor), so I cut a hole that corresponded to removing 15 of the 50 rows. Everything looked pretty good:

gallery_10025_5394_508152.jpg

I don't have a shot of it, but I pulled the forks waaaay up in the triples to simulate full wheel travel of 120mm, and it looked like the tire and fender would just barely contact the lower fins of the radiator. I optimistically figured the cardboard replica was thicker than the actual radiator, which may have bought me some room there. Things looked very tight, but probably workable.

gallery_10025_5394_414810.jpg

The real problem came when I fitted the side panels. You can't quite see it in the following picture, but if you look hard enough, behind the left fork is evidence of the deal-breaker:

gallery_10025_5394_529522.jpg

The radiator's lower corners would stick out from the sides of the fairing panels!

gallery_10025_5394_55415.jpg

Well, so much for that plan. While the ZX-10R radiator was narrow enough at the top, the VFR narrows at the bottom too much to enclose the ZX rad. Add in the close proximity to the headers and the curve of the radiator, and you end up with rad corners poking out of the fairing. I was fairly disappointed after spending the better part of a weekend mocking up the rad and jamming it into place, but it was a good try. And I have since come up with a new plan; I just need to score a 2008+ CBR1000RR radiator from eBay and find a really good aluminum welder...

After giving up on the radiator, I tackled the oil cooler again. With the ZX-10R radiator, I was going to relocate the oil cooler somewhere by having -AN fittings welded to the original line ends and using braided stainless lines to move the cooler. With the radiator plan dead, I decided to stick with the original lines and only move the cooler a little bit. I made brass spacers and used long bolts to space the oil cooler down enough to clear the lower triple clamp, which turned out pretty good. Some minor oil line bending was needed, but now the oil cooler bolts to the stock mounts and everything fits:

gallery_10025_5394_374362.jpg

The next installment will cover freshly machined parts, powdercoating, and maybe a weight-loss estimate. Stay tuned...

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Very cool. Can't wait for the finished product.

I wanted to convert my bike to radial brakes using adaptors for the RC51 forks and use 330mm CBR 929/854 rotors, but the extra expense was a deterrent.

So I just got new 320mm rotors and called it a day.

One of my rotors was badly bent in the crash, so I needed at least one new rotor anyhow........

gallery_554_5200_815276.jpg

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