Honda RVF400 NC35 Horipro

Honda RVF400 NC35 Horipro, Suzuka 8 hours

June 2019

Text and photos by Paul Pearmain and Matt Patterson, © TYGA-Performance

The inspiration for this build came from a visit to Motegi in Japan a couple of years back while I was attending and sponsoring Team SAG at the 2017 Moto GP. Working at TYGA has its perks! Actually, as it happened, it was a bit miserable during the main race because the heavens opened and you are not allowed to use umbrellas in the open grand stands. I had elected to view the race from one of these open stands and stupidly had no waterproofs. Once my nether regions got soaked through, I decided enough was enough and retreated to the Honda Collection Hall museum which was closer than scurrying back to our pit box. Honestly though, I was just looking for an excuse if truth be known. You see I have an admission to make, I’m addicted to HRC and I am sure many readers can relate to this affliction. While it is not dangerous, HRC addiction does tend to make people do irrational things like visit the Collection Hall in the middle of a MotoGP race. The museum is open all weekend after all and I’d already had one fix of the place on Saturday. But I had to go back and see some more HRC, and yes, as a consequence I missed Dovi and MM fight it out on the last lap in the rain. By then, I was all starry eyed and discussing RVFs with the museum’s assistant manager Tetsuya Iida san. Well, I say discussing, a bit of guesswork as he didn’t speak much English and I don’t speak any Japanese but we did share a moment with an example of the most successful, actually, probably the most successful four stroke racer in the modern period. The bike in front of us was the winning RVF750 from 1997 ridden by Ukawa and Ito. That’s the one painted in the very striking Horipro colours and that was what started it all…

Now it would have been ideal to use an RC45 to make a tribute of the winning bike of the 1997 Suzuka 8 hour. For one reason, it would be the correct model and cc and therefore somewhat a more accurate tribute. It would also make our job somewhat easier installing the special parts we had earmarked for the build. However, in life you have to take what you are given and make the best of it as they say. Instead of an RC45, we had a nice registered NC35, lots of suitable TYGA parts, and luckily for us, we also had a bunch of HRC goodies, some of which had been salvaged from a very written off RC45 endurance racer which we had squirreled away for a suitable and worthy cause. The NC35 we chose was already more than halfway decent having been restored in a previous project build.

Previous to that, it was in what I can only describe as a scandalous deteriorated state.

You can read about that part of the restoration HERE. Already 10 years have elapsed since when we had to unjam the rear hub and pull out the mouse nest from the swing arm. Doesn’t time fly when you are having fun? So here we were again, but this time with a nice and clean RVF400 with lots of components already installed. Many of these parts, such as the bodywork and front end was no longer required and we had no trouble selling these on to help recoup some of the funds required for the new build. So for a change, we were starting with a clean, well maintained machine, stripped back and no nasty shocks to be found. Off to a good start then!

We brainstormed a list of components that makes a Suzuka bike stand out from a stock RVF and tried to incorporate as many as possible, while obviously at the same time showcasing as many of our suitable TYGA products to help people with their shopping lists when they want to build something similar. First and foremost is the bodywork, when you think of endurance racers, teams always seem to go to a lot of trouble to remove a perfectly good headlight from the bike and put on a race fairing and then scratch their head and make a special headlight for the race fairing. I have never really understood that, maybe to save weight or safety but for whatever reason, no self-respecting endurance race bike has the original headlight set up so ours is no different but with a twist.

So our TYGA endurance upper fairing incorporates a stock headlight but cleverly covers most of it up so there is just one round hole. This has a Perspex cover over it and we chose the period correct yellow version so now when you look at the fairing, it looks like a yellow tinted spot light. Now, if the beam is not enough and you wanted, you can remove the cover on the right side and run it with two bulbs connected but I doubt we will ever do that. For the taillight, we stuck with the stock one and yes, again normally Suzuka racers use some small special lights but in this case, we stuck with what works and looks good. We thought about indicators but in the end elected to omit them in the interests of the racer theme. We can always add some later if we feel the need. (note you can spot the flasher relay and indicator switch in some pictures). Mirrors were retained in the interests of safety and legality (this is a road registered bike after all).

Because we can and because it looks cool, we elected to make a set of bodywork in carbon with Kevlar backing. This makes it incredibly light while strong at the same time. It also allowed us to have all the black parts kept in carbon look and leave the radiator surround in carbon. Even the lettering in the under cowling is actually stenciled carbon. Subtle but effective. While on the subject of the bodywork, we had to have one of those front fenders with the front part cut off for easy wheel removal. Yes, it is just for show but why not? Frankly rain protection is not top of our concerns.

Paintwork is maybe the most obvious thing you are going to notice when comparing this machine with most of the street RVFs out there. It was a difficult choice to be honest. The stock colours do look fantastic and were used at the 8 hour in 1994 and 1995 but looking at it from a commercial point of view, we needed something  that would stand out from the other bikes on google when you do a search. Yes, Horipro has been done before but maybe not as well as Pong managed to do it. As mentioned above, he was able to highlight the carbon panels by keeping them showing on the black parts. The decals are quite intricate and took several attempts. The lines on the tank still don’t line up perfectly and I would have asked him to change them but when we viewed the actual bike they lined up a lot worse than ours so it seemed in keeping to leave it that way. Same with some very minor chips along the edges of the panel where the carbon is showing through against the white. I kind of like this affect. Similar to but not so cheesy as the fake rust they put on vintage pickup trucks. Anyway, back to the paintwork, the colours are mostly neons and the thing really pops especially at dusk. I can see why it was chosen for a race that would take place at such a time of the day. Definitely a head turner and definitely worth the wait. Didn’t I mention it took nine months! Something to do with customer bikes jumping in front of the queue and trying to get the correct colours etc. Luckily, this was no problem as we had a lot more to do on the bike and this would take even longer.

By now, you’ve probably noticed in the photos some other special components, so let’s start with the most expensive one, the front end! These forks came from a Suzuka 8 Hr bike that had been totaled. We have a lot of the rest of the bike and it is not a pretty sight. Luckily the forks were spared and only suffered some minor scratches and the top of one was heavily damaged from contact with the asphalt. Matt was already in the process of making some fork tops for the NX5 racers and luckily, these Showas were similar so Matt was able to tweak the program and machine some to fit so they have gone from looking very beaten up to practically brand new when viewed from the cockpit.

The quick release bottoms are only slightly scratched so we left them alone. However, the pinch bolts were in a bad state, so Matt whipped out the vernier, took some measurements and knocked up a new pair. Matt’s next job was to make a custom wheel shaft and spacers to fit the forks and our modified TYGA triple clamps. Once this was done, we sourced from Gecko Motorcycles in UK a pair of period Brembo racing discs to match our period top of the range Brembo calipers. These were connected to  brand new Brembo period radial master cylinder via HEL brake lines.

The rear was also given the Brembo treatment, held in place by our TYGA bracket and again HEL brake line.

Wheels are PVM as commissioned by and exclusive to TYGA Performance with a 5.00 rear and a 3.50 front. These are forged aluminium and way lighter than stock and stronger than 20 year old Magnesium Magtek race rims. They were shod with 160 section Dunlop rubber on the rear and stock 120/60 section on the front. Not easy to find the front120/60 these days in Thailand and to be honest, we would have preferred something with a bit more grip given the choice, but like I said earlier, you make the most of what you have available.

The wheels are straight swap with the stock ones so they were an easy installation. While we were playing around with the rear wheel we swapped out the hub for a GT Performance HRC style one which holds the wheel in place by a big reverse threaded nut and a big chunky R-clip.

Rear suspension is still the one Matt built all those years ago which he made from parts of a stock NC35 unit along with NSR250 F3 shock to result in the one you see installed here. So it is both HRC and designed to fit and work on the NC35 which is exactly what is needed for this project. The remote reservoir is held in place by a TYGA carbon NC30 shock reservoir stay.

One thing that held up the reveal for a while was that we couldn’t bring ourselves to show the bike with that horrible 3.4 kg anchor of a subframe, and we needed to make a nice lightweight one to replace it so we decided to make one for production so this obviously took some time what with the need for Matt to make new bending tools etc. So we waited until we had this new TYGA product available before finishing the bike off. The subframe is a straight swap for the stock one but because we wanted to go for the racer look, we removed the rear fender too and installed the replacement spigot stay to hold the seat cowling in place.

This removal of the fender necessitated a new battery box, and we used the TYGA GP-T version which just required a couple of rivet inserts for the rear mounting points and it was ready to take the stock battery. If we were going to use this bike every day, then I think a lithium Ion battery would be the way to go but seeing as the bike will be parked and the lithium batteries need constantly to be charged or they go bad, we just left the stock battery on it for now. Apart from the parts mentioned above, the other chassis parts consisted of TYGA handlebars and of course a TYGA step kit which has a brake light kit installed.

Mechanically, the bike was not really changed from its previous incarnation.  With its TYGA race exhaust and airbox, it goes very well for a 400 sportsbike and if we do anything, I think it will be pretty substantial and involve Mike Norman and his magic and possibly ram air through a custom tank so watch this space but that won’t be for a while yet! As it is the bike puts out a health 62 horsepower at the rear wheel and being quite a bit lighter than stock, is not going to embarrass itself in similar company. We installed a TYGA twin stack system to keep it in keeping with the theme but other than that it goes just as well as it always did and we concentrated on other areas to make some subtle changes.

The next thing to mention is the bespoke dash. This was heavily influenced by the HRC ones on the factory racers. Matt, having joined me for the 2018 Motegi trip, and seeing the bikes first hand and up close again for himself, had the idea to make a dash using his 3D printer (TPU filament, for those interested - Matt) and installing an HRC rev counter and a digital temperature gauge. To finish it off, he made 3 warning lights, complete with special 3D  ‘hoods’ to be used for high beam, neutral and sidestand/or turn signal indicator depending on if indicators are fitted. The factory racers have these lights too but we suspect they serve a different purpose!  Anyway, all good except Matt decided he wanted to install an Ignitech ignition unit. This took some figuring out to get the rev counter to work properly but Matt is persistent and was able to get everything to work perfectly after a few hours with the multimeter. We even get the sweep of the rev counter dial when you turn on the ignition and it is back lit so that was a pleasant surprise.

The cockpit is finished off with a mini brake reservoir, a radiator overflow bottle and TYGA carbon air ducts. We obviously kept the switch gear which needed a bit of modifying to get the Brembo master to fit next to the kill switch. On the left side we opted for Domino clutch lever and perch to enhance the bikes racing looks and reduce a tiny bit more weight. That’s about all on this area of the bike.

Other touches we added to the bike include a TYGA carbon rear hugger/chainguard to keep road dirt off the rear suspension, TYGA carbon frame infills, and a TYGA keyless filler cap.

The engine is fitted with the TYGA carbon side covers and the air box lid is carbon as already mentioned. We should also mention the TYGA lightweight rear sprocket. Gearing was kept stock for street use. We probably should have changed that ten year old chain but hey, it hasn’t really had much more than a few 100 kms use so we saved money where we could!

You might notice the rear paddock stand guide on the left side of the hub which is a 3D printed prototype and something that we might put into production if there is interest.

 

For its shakedown, Matt took it for a few laps at Bira Circuit and this is what he had to say.

It always worries me a little when it's time for a track shake down on a project bike. No, there's no mechanical worry as such, it's more that I may get a little too enthusiastic and ruin all out hard work by parking it in the bushes......

A brief stab of the starter, and the trusty V4 burbles into life. A couple of brief blips to warm things up, clunk it into gear and trundle off down the pit lane.

They tyres fitted certainly aren't the best for track riding, but they actually weren't too bad, warmed up very quickly and allowed for some reasonably aggressive throttle antics. This was of course aided by the very high quality (for it's time) suspension that had been grafted on fore and aft. The rear hybrid shock is firm and well damped, so none of the usual, standard shock "squirreling" was encountered, and the front end, albeit intended for a full on Suzuka 8hr racer was compliant and absolutely rock solid on the brakes. And while we're on the subject of the brakes, WOW!! Considering that the RVF400 isn't exactly flabby, it's not exactly a featherweight either, but the factory spec front end and brakes were just brilliant. A couple of lazy fingers on the lever was all it took to haul the beast to a stop. The geometry is a tad on the conservative side and required a bit of muscle to get it through the chicanes, but the flipside of this is fantastic stability. So yeah, the handling is pretty much as hoped. No major moments, even with street spec tyres. If we wanted to sharpen things up then that's not a problem, as the hybrid shock is fully adjustable in all ways, including ride height.

The 400cc V4 engine really is a peach. They're deceptively rapid and have a distinctive howl when on the pipe. The NC is nothing like these little weed whacker strokers that I so adore. None of this frantic dancing on the gear lever to keep the motor on the pipe, just click a gear and let the torque do the work. In fact, having once been an instructor at a local race school that used NC30s, it became apparent quite quickly that screaming the knackers off these things isn't necessarily the fastest way round the track. Considering that apart from a pipe, an airbox lid and a bit of jetting, it's a stock engine. But it didn't disappoint.

The only problem I found was that there are no shop windows along the side of the track, so one can't cruise by and admires one's own reflection.

Eventually have to go back to the paddock as the fuel runs low, but then you can sit there and stare at the glowing bike as the sun goes down. Yep, this one was definitely worth the hard work. It looks stunning and is a joy to ride.

Matt

From a spectator’s point of view, the bike looked like the real thing with the yellow beam of light penetrating the dusk gloom and the vivid neon paint flashing by, not to mention the unmistakable sound of a Honda V4 racer. All in all, a very satisfying project and hopefully one that will inspire some similar builds by other owners. On a personal note, I’m looking forward to all the promotional photos and videos to be completed so I can take it for a ride up the twisties and park it in the house. I won’t need to fly to Japan anymore to get my next HRC fix!