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I've also already picked up my next project. I befriended our local elderly Honda bike shop owner years ago - both being Moto GP fans with a penchant for race replicas.
He told me of a client who had an NS400R, which he'd owned for 3 decades, and not ridden at all in the last 10 years - who now wanted to sell it.

Initially, knowing they had crap brakes, suspension, wheel sizes (skinny 16 & 18 inch constar wheels) for which there aren’t sticky tires, stupid anti-dive forks and a compromised exhaust design that doesn’t let the engine Rev as freely as it would like - I thought I could just get it running well, then sell it on. My conscience told me “no”though, as the reason I’d been told of this bike was because my friend the bike shop owner knew I’d probably restore and make it better than it had ever been.

Tire Wheel Automotive parking light Plant Automotive tire


Some history: The NS400R had been offered to Japanese and EU markets to celebrate Eddy Lawson's championship victory in the GP500 championship; Honda's first GP500 title - where he beat King Kenny Roberts by a mere 2 points, at the end of the championship.
The capacity of the road bike was kept to 400, to make it available to mid-sized Japanese motorcycle licence holders. Although Suzuki offered the RG500 and Yamaha the RD500, Honda's 400 was said to be the best of the three competing manufacturer's 2-stroke big bikes, offering a better riding experience.

Unfortunately, these NS400's were so expensive they never really sold well, also being overshadowed by new sportsbikes such as the then new GPZ600R's, etc.
NS400R's were only available between 1985 and early 1988, before being discontinued. The market was by then being replaced by MC18 NSR’s (which were and remain revered and sought after, with newer models later improving and increasing NSR250 popularity & desirability.

Tire Wheel Fuel tank Vehicle Plant

Tire Wheel Fuel tank Automotive lighting Vehicle brake

Tire Wheel Fuel tank Vehicle Automotive lighting


Searching on yahoo.co.jp for modified NS400R’s, I soon came to the realisation that my donor NSR250 MC21’s original and now redundant wheels, a CBR600RR front end & shock combined with RVF750 discs & SP2 calipers would be simple but very effective bolt on improvements with little to no modification at all A 2004 CBR600RR weights near as dammit the same as the NS400R, and I’d get bump & preload adjustment in the deal!
Jim Lomas (JL) makes some beautiful expansion chambers & silencers too.
Combined, these and other known improvements would make it go, brake & handle much better….

Sadly, the reason for the bike sale, was because the owner suffered a stroke in 2021 (ominously, soon after being vaccinated with the Pfizer jab), and lost use of & strength of most of his right hand.
I struck a deal he was happy with, and once the paperwork was in order, collected it last week. It came with new piston rings, gaskets, Honda (Japanese) workshop manual, both original keys, etc.

The owner had even thoughtfully removed the fuel tank and fuel tap several years ago and stored these indoors, along with the belly pan (so grass cutters wouldn't damage it), before leaving the bike under several covers, behind his home. Sensing his sadness at not being able to ride any more, I promised him when it's done, I'd take him riding on the back. I've since also driven him to the Tokyo motorcycle show, and will treat him to a trip to Moto GP this autumn, in one of the camping vehicles we operate as part of our business.

Tyga Performance has kindly agreed to restore the bodywork, and there’s a source of replica Rothmans decals in the US.

I've managed to track down and buy a complete & perfect condition CBR600RR front end, complete with wheel spindle, triples, etc.

Hopefully if I have space in the workshop and time to do it - sometime in the winter I'll restore and modify this NS400R. Should look something like an amalgamation of the two bikes below (which have been Japanese magazine featured) when done.

I'm pretty sure they'll want to feature mine, when it's done too, as it'll probably turn out even better than those below.

Wheel Tire Fuel tank Automotive lighting Automotive tire

Wheel Tire Fuel tank Automotive lighting Automotive tire
 

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2003 Honda RC51 RVT1000R SP-2
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A couple of months ago, I posted a few pictures of my most recent new project. An NSR250 build, I'd bought most of the parts & donor bike for (started off as a cheap, but very neglected MC21). It was stashed away for 7 years.

When I started, it really was in a shocking state. In the last couple of months, during late evenings and the odd day off, I've completely overhauled the engine, including some mild porting, carbs, 2-stroke oil pump, etc. then assembled onto an MC28 frame, complete with single-sided swing arm. The donor bike's engine had leaked oil from several places, so all the oil seals, gaskets, bearings, crank, rings, etc. and original cylinder heads were each replaced.

View attachment 138096

The carbs were ultrasound cleaned and assembled with (should hopefully be very close to perfect, since they're known to work well with Tyga exhausts, etc) larger main jets and all new gaskets, etc. Even the little oil pump was rebuilt from another, as the original had seized and the previous owner had just run it on pre-mix.

View attachment 138100

Suspension is Ohlins at the rear, and forks are from an RVF400, - fitted with modern cartridges, built specifically for my weight, riding style, etc. by Maxton. Brakes are billet Brembos (F&R), with Brembo RCS19 master, and a CBR600RR rear master.

View attachment 138097

Lots of work done in cleaning, plating, replacing bolts with titanium or stainless fasteners, then working out the exact routing of wiring, cables, etc.

View attachment 138101

Last night, I filled the cooling system - then spent some time finding minor leaks and curing them. In the next few days, new Tyga stainless expansion chambers and silencers will go on, then airbox & fuel tank fitted.
She'll be treated to fresh fuel (premix, as an easy way to bleed the rebuilt oil system), and transmission oil, and hopefully the engine will the first time in 7 years.

View attachment 138099
View attachment 138098

Bodywork will then go on. It was all restored replaced & repainted by Tyga years ago. They did a great job.

Just waiting on brake hoses and Diablo Super Corsa tyres, some small pieces, plus a few more bits from Tyga, and it'll be ready to use. No rush - maybe I'll have it ready by summer. I only intend to ride it when it's fully sorted & completed.

Should be a lot of fun. Apparently these feel a lot like RS250 Hondas (Engines are very similar, and the RS250 unit slots straight into the NSR frame) to ride. This one should be quite a lot better than a standard one, with much improved suspension, brakes and roughly 25% more power.
Amazing work Stig! Wish I could just hang out and watch you piece this thing together
 

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Amazing work Stig! Wish I could just hang out and watch you piece this thing together
Thanks Dave,
Progress is pretty slow; I prefer to take it really easy and fo the best job I can, than trying to get as much done as possible.
I wouldn’t want to work out the total amount of hours put into projects like these.
Comparing prices today, compared to 7 years ago - when I bought the donor NSR and upgrade parts, no doubt I’d make a tidy profit if I sold it once it’s completed, but I don’t ever sell my projects.
i paid around $7,000 - $8,000all in 7 years ago and have added a fair bit more for additional New parts for the engine rebuild, etc.
The best of the last NSR250’s are fetching over $50,000 here in Japan these days, though.

Thankfully, I’ve been able to sell nearly all the unwanted parts for around $5000 so far, and still have a few rare and desirable bits left to prepare and advertise. The trick is to recondition and restore parts before selling them. The forks took around $200 in investment into parts for full restoration.
Office supplies Bicycle part Bumper Bicycle fork Nickel

I got around $1000 for them, and double that for the original bodywork. These each took me a full day’s work to prepare.
Human body Glove Sleeve Red Cap


Textile Sleeve Sports equipment Red Outdoor shoe

By comparison, the best modified NS400R’s (similar to those I posted pictures of above) are worth less than half of what a good MC28 is worth, but NS400R’s are on the rise too. They’re also much rarer.

It’ll be interesting to get to know and experience how they each ride, once I complete them.The NS will weigh about 45-50lbs more than the NSR, and make about 15 bhp more with more torque. The NSR’s chassis design is 8 years newer, and it’s chassis design was influenced by a lot of Honda’s (Moto 2 equivalent, back in the day) racing experience.
I suspect I’ll like the NSR more. The NS won’t be as close a race replica, not look as pretty. As a bonus, I’ll be able to easily swap the NSR250’s wheels for the RVF400’s carbon wheels if I want to make it handle and steer even better.
Tire Wheel Vehicle Automotive tire Window

if you’re interested in NSR250’s take a look at Tyga Performance’s collection. They have the most impressive bunch of these bikes, and several other interesting Hondas, including an NR750, etc. They’re the hardest core bike nuts I know and they’ll spend an entire Moto GP race day looking at Honda’s collection hall in Motegi, taking pictures and decal measurements.

 

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Just a little update on the NSR250 MC28 for those that might find it amusing.

It's almost finished. Lots of last small jobs done recently. From making the storage compartment's lock work smoothly, to figuring out routing for brake lines, ordering more titanium bolts (from China - they're cheaper , LOL!), and making up small carbon pieces of trim. The remaining bodywork will go on last, once I know it has no further leaks from the exhaust or cooling system (VHM heads use o'rings, One of which leaked slightly, so replacements are on their way.

Tire Wheel Fuel tank Automotive fuel system Vehicle


I fitted fresh Pirelli Diablo Super Corsa SP tires & balanced the wheels and finally took it off its front stand last night. Started it for all of around 5 seconds, then it died. Couldn't get it going again, but inspection of the front plug showed it had as coating of 2-stroke oil. I'd pre-mixed the contents of the tank with 2-stroke oil some weeks ago (To help prime the newly rebuilt original oil pump), so perhaps the 2T oil had separated & settled into the bottom of the tank.
I tried starting the NSR this morning, after squirting a little engine starter ether via a tube into the air box (not something I want to make a habit of, as it washes off oil from the barrel surfaces).
Started and ran. Idle was too high so I lowered it, but it would bog then finally died when I let the revs drop too much. Felt like it was being starved of fuel when near idle speeds. Maybe the low speed carb circuits aren't quite right. What do those air valves do? I'll find out...

Tire Wheel Fuel tank Automotive fuel system Vehicle

I'd thought dismantling and ultrasound cleaning the carbs would have cleaned them well inside, but I'll take them off soon and run some thin wire through small holes to make sure they're all cleared, then re-assemble.

Tire Wheel Fuel tank Vehicle Automotive fuel system

Hopefully then it'll run right, ready for its first test ride...
Never so much enjoyed the experience being fumigated with toxic fumes before (That's the smoke in the pictures). Sounds sweet!
 

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Just a little update on the NSR250 MC28 for those that might find it amusing.

It's almost finished. Lots of last small jobs done recently. From making the storage compartment's lock work smoothly, to figuring out routing for brake lines, ordering more titanium bolts (from China - they're cheaper , LOL!), and making up small carbon pieces of trim. The remaining bodywork will go on last, once I know it has no further leaks from the exhaust or cooling system (VHM heads use o'rings, One of which leaked slightly, so replacements are on their way.

View attachment 138175

I fitted fresh Pirelli Diablo Super Corsa SP tires & balanced the wheels and finally took it off its front stand last night. Started it for all of around 5 seconds, then it died. Couldn't get it going again, but inspection of the front plug showed it had as coating of 2-stroke oil. I'd pre-mixed the contents of the tank with 2-stroke oil some weeks ago (To help prime the newly rebuilt original oil pump), so perhaps the 2T oil had separated & settled into the bottom of the tank.
I tried starting the NSR this morning, after squirting a little engine starter ether via a tube into the air box (not something I want to make a habit of, as it washes off oil from the barrel surfaces).
Started and ran. Idle was too high so I lowered it, but it would bog then finally died when I let the revs drop too much. Felt like it was being starved of fuel when near idle speeds. Maybe the low speed carb circuits aren't quite right. What do those air valves do? I'll find out...

View attachment 138177
I'd thought dismantling and ultrasound cleaning the carbs would have cleaned them well inside, but I'll take them off soon and run some thin wire through small holes to make sure they're all cleared, then re-assemble.

View attachment 138178
Hopefully then it'll run right, ready for its first test ride...
Never so much enjoyed the experience being fumigated with toxic fumes before (That's the smoke in the pictures). Sounds sweet!
Love it! The pictures look great with that 2 stroke haze in the air. Please strap on a GoPro once it's sorted and screaming down the road
 

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Stig,
Yes, you have to get some thin wire and run it through the air passages in the carb bodies to get all the crap out of there. Especially if the bike sat for a long period of time. Sometimes you will chase out some of the white powdery corrosion residue that gets in there tight and won’t come out with ultrasonic cleaner. The clogged air passages will definitely wreak havoc with the idle circuit.
Bike looks fantastic, those pipes are really nice. Man, it would be awesome to ride one of those old school 250 two strokes! Good luck.
 

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Stig,
Yes, you have to get some thin wire and run it through the air passages in the carb bodies to get all the crap out of there. Especially if the bike sat for a long period of time. Sometimes you will chase out some of the white powdery corrosion residue that gets in there tight and won’t come out with ultrasonic cleaner. The clogged air passages will definitely wreak havoc with the idle circuit.
Bike looks fantastic, those pipes are really nice. Man, it would be awesome to ride one of those old school 250 two strokes! Good luck.
Thanks emlupi. Yeah, I kinda figured what you're saying, as soon as it failed to idle.
I'll take the carbs off and clean them up using an old cable - which I'll cit to get the wire I need. Maybe I'll do it this weekend.
Tyga shipped a few small bits I need earlier this week, so they should arrive soon I guess.
Got a few more small jobs to do once its running sweetly, then the rest of the bodywork will go on.
It's been seven years since building this bike started out as an idea, and taken about three months to build. A few more weeks won't hurt, but I am looking forward to making myself stink of 2-stroke oil fumes. 😆

@Davebraham - I left my GoPro inside my car in Portugal last time we were there, and now it's in a garage 5 storeys under, on a different continent LOL.
I've got a decent phone holder for bikes that fixes a phone rigidly, so maybe I'll try to position it pointing forwards and shoot a short video. Won't see much of the bike, but hopefully it'll be alright.

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