Official NS50F thread

[motormike]

I think it was ghost who once coined the category of "Shifty Fifties".....
We are now pushing half-a-dozen NS members I guess. And TWO here in Nashville.
Ten years is a long time to look for one specific bike, so I'm real glad your patience has paid off with a cream-puff...
Norm (Black/Jack Buddy scooter) also has a NSR, I think a street-legal one. He will want to ride on Sundays.
Safe trip for the pick-up.... ..... <<<Aero 125 Rules ! !....

[GKinTN]

Thanks Mike!

I'm pretty sure Norm actually has a Yamaha YSR 50. Sadly his was in the big flood and he thinks the motor now needs a rebuild.
He describes it as pretty nice cosmetically, just needs some TLC done to the motor.

Shifty 50s....haha

[motormike]

...yeah, that Norm doesn't know half the time what he's got...YSR is prob right
He said Richard Reeseman has it to rebuild and norm is trying to prompt him to get started.
I dragged out my NS tonight and kiked it off in about 3 tries...smoked like a mosquito fogger...
My vision for it is taking on more of a stocker look and NOT using the KAW. forks and swing-arm...
just selling for budget money on the keeper...
...Maybe I can double my money on the tracker.
With this recent outbreak of NS50F sales, Your purchase will help my sale. Thanx Glen...

[z50r-ghost]

Congrats, GK! Im so freaking happy for ya dude; Thursday is the day!!

-NO one understands the whole "NS50F-love" until they ride one.
(not even MB5 owners...).

The NS is an absolute blast to ride, because you are always shifting thru the gears and actually riding.
Despite always being at the top of the tachometer, Honda built a bike that can take anything you can throw at it, and beg for more.
Some owners have noted that "they only get faster and faster as the miles go up on the odo"
Then there's the fact that they are just fun.

The NS50F / NS50R / NSR has a cult-like following in Japan, so racing parts are of course available...

I finally feel like I've made some progress on my NS50. When I brought her home, I had a plan on the theme of the build; an all Japanese-spec "racer." it's been over 2 years now, and out of all my "Japan-only parts" build projects, the NS50F has proved to be the most challenging (and expensive)

Motormike is right; we have a small group of NS dudes right here on Hondaspree! It definitely seems like the NS50F's have been coming out of the woodwork lately. When I was on the hunt from 2001-2009, they were impossible to find. I placed "wanted" ads in the paper before the days for craigslist. Never turned up even 1 phone call though.

Anyways; maybe us East Coast guys can all hit up True Grits this year! That would be a blast!

Keep us posted, GK... Thursday is less than a day away... Haha! Feel free to call me if you have any questions. 859-806-0506

And yes sir, have a SAFE & fun trip there and back!
People have been driving insane lately here. -must be the heat...

Later, jon

[z50r-ghost]

After getting side-tracked, tempted by other shiny & anodized parts from Japan, and numerous other rarities, my NS is finally getting her "proper pair of rollers."

i.e. MY NS's WHEELS are HERE...HOORAY!.

I know i owe you dudes some pictures, but dam... We have been so busy lately!! Between balancing work, songbird rescue and rehab, and our own pets, my only free time is either at 430 am or 2am.

As soon as I have the chance to remove my black NS wheels and exchange the slicks onto my new wheels, I will take some pics to show you the rims I have been on a 'quest' for.

My next step is to order new, oem Honda NSR - NS50R (HRC/Nissin) brake components.
I will be needing: calipers & brackets, master cylinders F&R, brake lines, rotors, etc.

Any guesses about my wheel choice?

Later guys, j

[GKinTN]

Wow...sound like building a NS here in the USA with Japan only NSR stuff is a cool but costly habit! I bet it will be awesome when it's done. Love to see some pics...

I got my newly acquired NS50F on the road this weekend. At first I cleaned out the tank, pulled the oil injection line, plugged the injection nipple and started it with 32:1 premix. I had also changed the oil and cleaned/oiled the air filter. Started on the 2nd kick! My bet is the bike hadn't been started in about 6-8 years... That said, it wouldn't run without the choke on even when warm. Turned out to have a bunch of gunk in the carb and after two clean out jobs I finally got the carb cleared. I then also verified the oil injection was working so I hooked that back up and put straight gas (non ethanol) in the tank. Bike runs strong, healthy and smooth, and really outdoes the MB5 in so many ways. The sound of the bike and power band really reminds me of the CR125 Elsinores I've had in the past, though obviously a bit more toned down than that and better low end. Still, the stock pipe even has a similar sound to my old Elsinores when it comes on the pipe just not as loud luckily. I tried some top speed runs and it seems to level out around 57-58 mph on level ground, and it does that with authority and isn't nearly as bogged down by hills and wind overall compared to my stock MB5. The NS50 even in stock form feels like it could probably pull a 1 tooth higher countershaft sproket, and maybe pass 60mph... However I'll admit it's scary enough already to push such a light and small bike even passed 50mph so I may just leave the gearing stock for now.

I also adapted the NS50F to a gell cell battery like I had done years ago on my MB5. I found a gell cell in a 2.9 amp hour (stock lead/acid is 3 amp so close enough) that would fit in the stock battery box. The gell cell is a little smaller in height and width (but some depth) but some foam rubber keeps it tight. I love running the gell cell in my MB5 as my first one lasted over 6 years which is way better life than I got out of the stockers which are good for a year or 2 at best. The NS50F definately has a better headlight than the MB5 too, probably a halogen but sadly also discontinued but working for now so that is good.

I have 2 new tires coming for the NS50F. Trying some Michelin Gazelle's in the stock sizes. There aren't many choices out there for tires but it seems the CB100, CB125, CB175 twin guys are having good luck with the Gazelle's.

Thanks again Jon for the help on the NS50F. I now have a few months to practice on it for the True Grits. I've never owned anything close to a sport bike in the layout of it (though my MB5 has low bars) but I can already see it's easier to lean the bike and carve a precise line. Even though it wasn't cheap I'm really glad I picked up this particular NS50F and it's a nice change of pace from my old MB5.

Once I get the new tires on it I'll post some pics with it totally cleaned up and detailed.

GK

[GKinTN]

"No go" trying to obtain Michelin Gazelle tires for the NS50F. Everyone is out of stock on these at least when it comes to 2.75 or 3.00 x 17s, and nobody knows when Michelin will make the next batch. I even found two different retailers that thought they had them, and I placed orders but in a few days they both found out they were indeed out of stock too and had to refund my money. So...I decided to order a set of Pirelli M75 tires in the 90/80 x 17 size and run them both front and rear. Might actually be a better tire, and I'm hoping the size works out well enough.

[motomech]

In 1990, at the advanced age of 39, I bought a new Honda NS 50 with the intent of going racing. I had been eying mini racing, but I didn't want to go with a Yamaha YSR 50, mostly because I didn't fit(6'0" and a svelte 170# at the time), but also I didn't think much of it's antiquated under-square power plant.
The project was inspired by an article I saw in a Japanese Mini-Moto magazine that some thoughtful person in Japan had tossed in a box of Kitaco big-bore scooter kits I had ordered.
The text was in Japanese of course, but the photos showed an stereotypical Japanese technician in a white lab coat standing next to two disassembled engines layed out on a bench. But the two engines were named in English, NS 50 and CR 80.
I was intrigued, and took the article to the local university's language department for translation. When I went back, the person who did it wasn't there, just a note that said, "no fire". Hummm...
Well, I knew one thing though, the CR 80 was air-cooled and that nailed down the years down to a couple of mid '80's models.
With the two engines layed out on my bench(minus the lab coat), it became apparent that there was a lot of interchangeability.
The 80's close ratio tranny and internal rotor ign(including CDI) bolted right on/in the NS crankcase/crankshaft.
The ported cylinder was bored to fit a Kawasaki KX 60 piston, which with the stock NS crank came to 57cc's, well within the class limit for modded 50's, which was 61cc, to accommodate the stroked-crankshaft YSR's. The cylinder head's combustion chamber was reshaped on a lathe, adhering to the 1/3 squish band rule. The squish was real tight, .010" to .015", if I recall right.
All this came together real quick, but the carb and pipe took some development time. The first try was with the CR 80 bits, because I had them. Using the CR80's reed block and manifold, the 28 m/m round slide fitted ok, but cutting and re-welding the CR's up-pipe was a challenge. Lot's of carbon and no MIG welder made for "chicken-s*** welds. Anyhow I got it together and mounted and while the "Frankenpipe" was not pretty, it worked well. Too well. The bike was a rocket from the git-go, until I seized it(ever notice that two stokes run best right up to the point they seize?). Attempts to jet it safe proved fruitless and I came to understand that the pipe wasn't going to work, The center section was too fat, and the resultant steep rear convergent cones created a strong negative pressure pulse that the carb's fuel metering circuitry couldn't deal with.
Next try at a pipe. I ordered some cones from Air Cone and tried to make my own from scratch. Easier said than done as I discovered the problem that plagued all pre cad-cam pipe designers. To make the center cone the diameter I wanted, the cone angles became too steep and became counter-productive. At least the metal was clean and I could get some decent welds.
With a serviceable pipe, it now became clear that the carb was too big and a 26 m/m round slide Mikuni was fitted.
Chassis modifications at his point were zero, but I attended my first race anyway. It was at the old Las Vegas Speedway and was a silly venue for 50's. WOT with one down-shift for the entire lap. The Honda easily ran away from the YSR's and I thought, "this is going to be a piece of cake". Boy, did I have a lot to learn
The next race was at the Adams track, A fast, banked cart track near Bakersfield. I got waxed, but at least I wasn't last. The stock tire and frt. drum brake didn't inspire confidence and I had not a clue what I was doing(I remember scraping the shiney knee pucks on the asphault behind my truck so they didn't look so new). The Pros(who were not at Vegas) were crossing my bow like Nelson's warships "crossing the T" at Trafalgar. Obviously, both the bike and myself needed a lot more work. I did meet a guy who built me a pipe, a beautiful hydro-formed number that really woke the motor up.
Brackets were machined to adapt a YZ 80 caliper up front and the rotor was from an old CB200 mechanical disc brake model. The tire problem was solved when I was able to beg a used set of tires from the Pro RS125 riders(hey, they were only worn out on one side so I flipped them around, it's only a 50 after all ). Tiny Michelin slicks from the front of the RS125's, they were so small, that from a distance, they looked like inter-tubes wre mounted on the rims.
With the addition of clip-ons, this was the basic bike that I raced for four seasons.
I got better(why can't they all be left turns?) and if I could keep the leaders in sight, I had a chance. While the air-cooled YSR's lost power in final laps, the liquid-cooled Honda ran the same, start to finish.
A Kiehin 28 m/m flat slide(PWK) was installed and when I finally got it dialed in, it was like adding a supercharger! It was in this configuration that I was clocked at 74 m.p.h.(By radar) on the slight uphill starting straight at the Streets of Willow track(It was never dyno'ed, I think 15 h.p. at 15.000 r.p.m. would have been close. With a lighter rider and the right gearing, 80 m.p.h. would have been possible). At this particular track, I was able to pull the field by six lenghts at the start, only to have them breathing down my neck by turn three.
I studied Kieth Codes "A Twist Of The Wrist" till my head hurt(why couldn't he just come out and say what he meant? Well I guess he couldn't sell two more volumes if he did). I came to understand the lines(dirt racing didn't prepare me for this) and I managed to wobble to a fifth place Expert for the year.
The Big Wheel did have the advantage of the higher handle bars because nobody wanted to get their knuckles raked over in a turn and they gave me a wide berth. But the skinny tires didn't offer the grip of the YSR's 12" fatty slicks and I couldn't get the drive out of the tight cart track corners.
So I started over and built a "Small Wheel". To keep the front end geometry and wheelbase lenght reasonable with the 12" wheels, I turned the leading axle forks around so the fork tubes were behind the stearing stem, reducing the trail. Fork/tank clearance issues meant losing the stock fuel tank and I mounted an alum. tank from a very rare 1976 Yamaha YZ175X. With the aftermarket spun alum. YSR 50 wheels, it didn't weigh anything. I could pick it up and walk around with it!
The promoter proclaimed "World Mini Championship"( I know, they would murder us in Europe) was at Reno that year and that was where the "Small Wheel's"[now looking much like the NSR50 that would appear the next year] first and last outing took place. The Reno cart track was new and reflected the trend to "square-up" the curbs to keep the cart guys from putting their inside wheels on them and loading up the chassis. It was one of these curbs I clipped and put me into a memorable earth/sky earth/sky experience. I remember calmly watching the late afternoon sun reflect off the spinning frt. wheel as the bike catapulted over my head(The rider behind me, and eventual winner, rode under it, hitting and ruining his helmet in the process).
[Crashes are funny things, some unfold like in slow motion, giving one time to reflect on how much it will hurt and others blind side you].
Crashing always hurts, but the pain of that one lingered. I had won the first heat and was leading the second. But almost as bad, I caved in the side of my beloved YZ 175X fuel tank.
Back in the shop, I tried to blow out the dent with compressed air. I guess I over did it, because it blew up like a balloon

P.S. The little Honda engine was a rock. I only changed the rings once a season(13 or 14 races) and crank brg.s every other season. Never rebuilt the crank, amazing. It could have been taken to an even higher state of tune and remained reliable.

SAM_0757.JPG (62.93 KiB) Viewed 8762 times

I don't have many pic.s, but here are a couple. This appears to me like an early sm. wheel experiment. The pipe looks like a CR80 I cut-up and refitted, but I have not, as yet, mounted the CR80 internal rotor Ign
The wheels are stock YSR and later, when I actually switched to 12" wheels, I turned the tripple tree around so the fork tubes were behind the stem.

[SuprasNsprees]

Treats has 17" tires back in stock!

[z50r-ghost]

Hey motomech,

I read your NS50 article a very long time ago; really good stuff dude; the fact that you went to the dealer and bought a new NS50F is really cool! -I'm 32 now, and can remember going to the Honda dealer and seeing the NS50F in 1990 and thinking it was such a cool bike.
-great to have you on the forum dude; I will be asking you a lot of questions! Haha!
Thanks for sharing pictures of your NS, man!

SuprasNsprees, I saw that Treats has 17's back in stock last week, too! How's your Puch coming along?

Later guys, j

[SuprasNsprees]

Hey motomech,


SuprasNsprees, I saw that Treats has 17's back in stock last week, too! How's your Puch coming along?
j

Still stock at the moment, but that's gonna change real quick.
I've tripled the mileage since picking it up, but the condenser shot craps last time out. So now it runs real good for about 30 seconds lol

After I fab the pipe for my spree, and finish my customers SpreeDio build, I'll do the kit, bars, wheels/tires, and pipe. Got a lot going on

[GKinTN]

Very cool read about racing the then "new" NS50F back in the day!

Just last week I was talking with a friend of mine while racing RC cars at a local track to find out he had bought a Honda NS50F new back in '90. A few days later he saw my bike and it really brought out some memories, and he suspected mine might be one of the cleanest original NS50Fs left in the country. He also did some racing on his back then, and found it quite superior to the YSR50s he ran against.

I'm really liking the Pirelli MT75 tires on my NS50F. It's probably a no no to run two "front tires" (80/90 x 17) but the stress and speed these tires are seeing is so light with the stock engine and under 200lb weight I can't see it being much of an issue. Still I've heard of folks running the MT75 110/80-17 proper "rear" on the back of the NS, which would be stock sizes for an Aprilia RS50 if I'm not mistaken. Still it seems the much larger width tire would actually drag the bike down some. Even the 80/90 ends up being close to 3.5" wide about 1/2" over the stock width for the back and about 3/4" over stock width for the front. Still the 80/90 looks right on the bike and feels right. The MT75s make the bike very stable even towards the bike's top speed and they corner very smooth. I upped the counter shaft to a 15 tooth and I'm hitting about 61-62 in the flat or even on a slight uphill. I have yet to find a screaming downhill to see where it will wind up to. I'm having a great time on the bike and have put close to 250 miles on it since getting it 2 weeks or so back.

GK

[GKinTN]

FYI if there is anyone here looking... There is a repainted (red) Honda NS50F just recently listed for sale ($1000) on the "east texas" craigslist. I do not know the seller but for some reason I still look around for these even though I just bought one!

http://easttexas.craigslist.org/mcy/3213209316.html

[motomech]

Very cool read about racing the then "new" NS50F back in the day!

Just last week I was talking with a friend of mine while racing RC cars at a local track to find out he had bought a Honda NS50F new back in '90. A few days later he saw my bike and it really brought out some memories, and he suspected mine might be one of the cleanest original NS50Fs left in the country. He also did some racing on his back then, and found it quite superior to the YSR50s he ran against.

I'm really liking the Pirelli MT75 tires on my NS50F. It's probably a no no to run two "front tires" (80/90 x 17) but the stress and speed these tires are seeing is so light with the stock engine and under 200lb weight I can't see it being much of an issue. Still I've heard of folks running the MT75 110/80-17 proper "rear" on the back of the NS, which would be stock sizes for an Aprilia RS50 if I'm not mistaken. Still it seems the much larger width tire would actually drag the bike down some. Even the 80/90 ends up being close to 3.5" wide about 1/2" over the stock width for the back and about 3/4" over stock width for the front. Still the 80/90 looks right on the bike and feels right. The MT75s make the bike very stable even towards the bike's top speed and they corner very smooth. I upped the counter shaft to a 15 tooth and I'm hitting about 61-62 in the flat or even on a slight uphill. I have yet to find a screaming downhill to see where it will wind up to. I'm having a great time on the bike and have put close to 250 miles on it since getting it 2 weeks or so back.

GK

He also did some racing on his back then, and found it quite superior to the YSR50s he ran against.

Well maybe if the YSR's were truely stock and the track was long enough to make use of the NS's top speed.
I raced with the Calif. Mini Road Racing Asc[CMRRA] and they were allowed all manor of "tweeks" in the "stock" class, not the least, the use of the Dunlop slicks. The tires alone would be enough for a good rider on a YSR to give a NS fits on a cart track.
Actually, I was never allowed to race with the stockers, even though when I first showed up, my NS was stock
First, some backround.
in 1990, there was no Aprilla RS50, in fact, there were no "big wheel" mini's in the States. While there were NSR50's in Japan, there were none in the US. No DT50's either.
So, the first day I showed up at a race, I received all manor of receptions, from ignoring me, to statements to the effect to let me race in the stock class as it wouldn't make any difference, I would get killed.
Well, the promoter stepped in and decreed that I would have to race in the modified class because the NS was liquid-cooled. That was ok with me because I didn't intend to leave it stock anyway.
So I did meet some resentment from the Prima Dona types[not unlike some scooter forums ], mostly intermediate riders whose YSR's, once I got the NS modified, couldn't catch it.
Once I got the tire problem sorted out, it domninated the intermediate/modified class.
I was quickly moved into the pro class and had my hands full, as I was never a pro/skilled rider and the best end of the year finish I ever had was 5th. expert. But I raced with a team and with one of my mates on it, only the top 2 or 3 YSR's would run with it. These were very special YSR's, built to the hilt to the tune of 1000's of $$. One kid, on one of the" special" YSR's was tough for anyone to catch. His name was John Hopkins[of GP racing fame], although at the time we called him Johnny.
There was no resentment from the pro's, they were above all that and just loved a good race.
By the end of the second season, my NS was so fast that my team would use it against the YSR 80's in the 6 hr. endurance race. While down on top end by 10 or 15 mph, it was super reliable and reliability is the name of the game in endurance racing.

Another thing I might mention is jetting. The top running YSR's were so high strung, that they had to be jetted for each track. Not so with the NS.
Although, when I was still running round slide carbs, I would use the 26 m/m on the short track and then 28 m/m on the long track. Once I switched over to the Kiehin 28 m/m flatside, it was like the best of both round slides and I just left it alone.

[motomech]

Very cool read about racing the then "new" NS50F back in the day!

Just last week I was talking with a friend of mine while racing RC cars at a local track to find out he had bought a Honda NS50F new back in '90. A few days later he saw my bike and it really brought out some memories, and he suspected mine might be one of the cleanest original NS50Fs left in the country. He also did some racing on his back then, and found it quite superior to the YSR50s he ran against.

I'm really liking the Pirelli MT75 tires on my NS50F. It's probably a no no to run two "front tires" (80/90 x 17) but the stress and speed these tires are seeing is so light with the stock engine and under 200lb weight I can't see it being much of an issue. Still I've heard of folks running the MT75 110/80-17 proper "rear" on the back of the NS, which would be stock sizes for an Aprilia RS50 if I'm not mistaken. Still it seems the much larger width tire would actually drag the bike down some. Even the 80/90 ends up being close to 3.5" wide about 1/2" over the stock width for the back and about 3/4" over stock width for the front. Still the 80/90 looks right on the bike and feels right. The MT75s make the bike very stable even towards the bike's top speed and they corner very smooth. I upped the counter shaft to a 15 tooth and I'm hitting about 61-62 in the flat or even on a slight uphill. I have yet to find a screaming downhill to see where it will wind up to. I'm having a great time on the bike and have put close to 250 miles on it since getting it 2 weeks or so back.

GK

Just last week I was talking with a friend of mine while racing RC cars at a local track to find out he had bought a Honda NS50F new back in '90. A few days later he saw my bike and it really brought out some memories, and he suspected mine might be one of the cleanest original NS50Fs left in the country. He also did some racing on his back then, and found it quite superior to the YSR50s he ran against.

Wait a minute, his name wouldn't be James would it? My racing buddy for the first year or so was a computer geek FROM TN. named James Middle-something. The guy was a wildman on the track and would run mid pack against the modd'ed YSR's on his stock NS. Great rider! It would be too funny if it were him.