The 2001 Honda NSR150SP - Repsol 2-Stroke

I have a new toy.

A 2001 Honda NSR150SP 2-Stroke with REPSOL Paint scheme.

It has just over 17,000 km's on the clock.
It has been dropped on the right side - lightly.
I have started to fix her up a bit already.

So what else but to Blog its attributes.
Nothing fancy, just about the model, rebuilding, tuning, maintenance, etc.
And a few pics ... of course.

The BIKE:
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The Engine is 150cc original capacity 2-Stroke.
It is stock Honda Piston and Crank.
I am told you can take this to about 170cc with a new crank and Piston.
There is a very good option from Taiwan 'KiWAV Motors' for the Crank called Royal Rods.
And TYGA Performance has Higher Performance Heads.

It has about a 40 horsepower (30Kw) Engine - at peak.
I assume if it is tuned absolutely correctly.
My aim is to tune it to a 50hp (37.5Kw) Engine !
Note: I think Moto3 are about 55hp Engine.

It only has a redline of 11,000 rpm, and has a cut-out at 13,000 rpm so you wont bugger it.
It spins to over 11,000 rpm very easily in every gear.
It is a 6-speed gearbox.
6th is geared to 16 kph / 1000 rpm.
5th is geared to 14 kph / 1000 rpm.
4th is geared to 12 kph / 1000 rpm.

So... you are doing 112kph at 7000 rpm. (in 6th)
And at that speed, you can feed in the power in 6th, or drop a gear and snap it on.
The bike shoots to 140 kph without hesitating... and keeps on pulling.
At 140 kph the engine is now on the boil (in 6th) and feels strong.
Or in 5th you are at 10,000 rpm with power to burn.
This is where the difference between a tiny 4-stroke 250cc and your 2-stroke becomes more evident.
You are not revving at 14000, and have to get up 19,000 rpm just to make some power.
 - Don't get me wrong, I really like the Tech that goes into bikes like ZXR2, CBR250RR, etc.
-  They handle great and look great, but you need to work the engine and gears a fair bit.
-  And I am told the wear-and-tear on the Engine is reasonably high. And maintenance too.
-  Although if I had one of those I dont think it would be a Daily ride, so it wouldn't matter.
The NSR actually feels like a 'big-bike' power delivery profile. With similar rev range.
And with the weight being low, and a small rigid frame.
It all really works well.
I would say you could feel very safe and stable at 160 kph (100 mph) on one of these.
But I haven't done that yet.
The Aerodynamics are also pretty good.

You have to get the bike warm before it will settle and run without spluttering a bit.
And when you ride it, you need to be above 8000rpm before you feel that great burst of power.
And when it does start to accelerate, it feels great.
Just like the pull of a big bike, only smaller.
But actually pretty damn quick.

Remember, it is only 122 kg dry weight. (132kg kerb weight)

It has a stock 28mm Keihin PE  2-Stroke Carburettor.
I note that the NSR Manual says it is a PE 30mm - so I will let you know.
I already have new Keihin OEM jets and needle for this.
Std Main #152 , I have #155, #157 and #160 to try.
So I need to give it a rebuild, to cater for the airbox and pipe modifications.

I have already bought a Keihin 39mm PWM (new) as a replacement.
However this will require a bit of plumbing, and remove the original Airbox.
I would use a POD filter, and a 90 deg Stainless Steel or 2mm (thick) Aluminium Intake
tubing at least 54mm maybe slightly larger upto 62mm in diameter.
Although I might go back a step to about a 33mm Keihin PWK Air-Striker.
(maybe a better choice)
I can modify all the current original Airbox and intake setup to accomodate this size.

It has stock plastic Reeds at the moment.
I will get some Carbon  Fibre Reed valves, and slightly open-up the Reed Valve housing and intake.

New Pirelli Demon tyres.
- Front 100/80/17
- Rear  130/70/17
These are one size bigger than the OEM fitting, but have the correct profile.
They ride really stable, and neutral handing, with plenty of grip and feel.
The bike feels like it has a bigger footprint, than it actually has.
With these tyres it is not so flightly.
It is solid as a rock at 140kph on a freeway burst.
And now changes lanes easily without any drifting or pulling.
At 80-100kph the bike sticks to the road and changes direction well.

New Honda NISSIN original metal-sintered brake pads are installed.
Honda products are pretty good.
Dont under-estimate their quality.
I bled out the brake line, but still need to do a full flush.
The Front Disk is still at 3.9mm thick (4mm is new), and no warping.
And I bought a great 2nd hand replacement, just in case, for $17:50 aud, from Tasmania.
The Disk is a huge 300mm with a Twin piston NISSIN caliper.
It stops hard. And the lever is 'one-finger' light. Very sensitive.
Great feel and progressive stopping.
Tremendous power for a Single disk.

Clutch is a manual cable operated by the Lever, and now adjusted.

Throttle is a single cable, single return spring at the Carburettor.
It is reasonably Light, and returns well.

The Wheels are good.
The Front has a few scrapes on one part of the right side rim, otherwise perfect.
The Rear is perfect.
Note: The Rear is a ELF designed for Honda single-side Hub Wheel.

New K&N High-flow lifetime Air-filter, as usual in all my bikes and cars.
- Love K&N Air and Oil filter products.

New NGK Iridium Spark Plug - boy, that makes a difference.
Also supposed to last 60,000 km's before replacement.

Tank is Good.
Although I managed to put a small ding in it already !
The only drawback is 10.5 litre capacity.
I get about 180 kms before I need to fill. (ie: to reserve)
Reserve is supposed to be about 2.7 litres of that.
So the range is not quite what I am used to.

Replaced the Fuel lines.
Checked the Fuel Tap.

Replaced the Oil with Synthetics.
I like Castrol, and Motul, - and used it again this time.
I also like Penzoil, Shell, and Valvoline, and other good brands.

Above:

CRC Clean-R-Carb the best stuff for cleaning out Carbies. And almost anything else you want to get rid of sticky gunk and leave just clean metal.

CRC TAC2 is a pretty good high-pressure Chain Lube. Low oil fling, and Good protection.

Motul Chain Lube is White, sticky, low-fling, and also coats the O-ring chains well.

Motul 510 Synth Oil for 2-Strokes - this is my choice for the pre-mix Oil tank for the NSR.

Castro EDGE - Titanium full Synth Oil for Gearbox for the NSR. And in my ZZR and GPz.


I replaced the chain with a Nice tough O-ring RK chain. 520 size I think.
Because the previous chain had perished O-rings.
The sprockets were not worn at all, I checked and measured the teeth.
No burrs. No bends. They are fine.
This chain will bed in on these sprockets.

I use either Motul or CRC chain lube. Both are very good.

I also fixed a small Fork leak (right fork) with the 'Seal Mate' Fork Seal Cleaner tool.
Basically just a piece of hooked plastic to get any gunk and grit out of the seals.
You then Bounce the forks a few times after cleaning. To make sure the Oil has stopped.
The surfaces of the installed fork seal, and the fork tube, re-mate and no more leaks.
It works a treat.
Purchased through Amazon from Motion-Pro for $46 Aud - for a 12pack.
Part No. 08-0356.

The head lights are a strange H4R bulb.
Same as the H4 style, but the lugs are wider, so H4 does not fit.
- There is a trick which I will add to this blog later.
The rating is 30W low, 55W high, in a Twin headlight setup.
It is Yellow light, and does make the bike seen.
However, I am investigating a bright option, with High-Bright H4's, and also LED's.
I like Philips X-treme series bulbs. The light penetrates well.
And they are not those annoying Super-Bright Bluish lights that some people use.
Motorbikes need to be seen, and I believe a study has shown a Yellow-ish light is the most visible for bikes during the daytime.
The yellow light tends not blend into the background, so you remain more visible.
There is also a HID option you could probably kit out, using 35W HID bulbs.
HID are extremely bright and are not always legal.
I will advise later.

Note: The whole electrics runs at Only 188 Watts.
I got myself a NSR150 manual, that was available Online.

I will also, add additional Tail lighting, as this is one of the weaker points in most Street bikes.
Small tail lights just cannot be seen well enough by Cars and Trucks approaching from the rear.
Especially at highway speeds at night.
I have got some very bright 3W LED point lights, about the size of 5 cent coin, or a Nickel.
These will wire into the existing rear tail lights, as DRL - or Daytime Running Lights.
That means they will come on with the Rear lights, but will not act as Brake Lights.
Making a lighting 'spread' over a greater area will allow the Bike to be Seen far far better.
The point lights will be mounted down further, near the Number plate and Blinkers, and mounted slightly wider.
It is all about the 'frame of reference' you create.
The common example is a rear-window brake light in a car.
This effectively creates a brake light 'triangle' frame-of-reference, rather than just 2 brake lights at each side of the car.
Your mind fills in the whole frame-of-reference as the brake lights come on, and you see the car stop. It's a BIGGER area that you percieve is lit up, even though it is only 3 lights.

And even though it's a Kick Start unit, I replaced the battery with another great battery from SSB PowerSport in Melbourne. They have really good products, and good support, and fast delivery.

It has a TYGA tuned Performance Exhaust System, and Muffler.
Not sure of the power gain here, but it is lighter, and sounds good.
I am sure it is a little more free flowing.

It also has some TYGA Rearsets which look good but are just a bit high for my legs.
I did put the passenger rearsets back on the bike, to brace the exhaust, and in case anyone 'small' wanted to go for a ride.

I will have to look into the Suspension.

The Rear shock seems ok - for my use.
Stiff with good rebound and soaks up road bumps ok.
Seat is a bit tough. I might put a leather cover and soften it a tad.
There maybe a fully adjustable aftermarket rear shock available.

But the Front needs a little work.
Too much dive and sponge for me.
Forks are 35mm standard Telescopic Tubes.
I'll do the fork Oil first, and maybe Pressurise the sealed units.
I need to get air-valve fork top plugs.
And I might need to increase the pre-load a little.
TYGA performance has an adjustable pre-load kit available at cost.
May be worth it.

Cheers.




This is my 2001 Honda NSR150SP - Repsol - 2-Stroke - October 2014

And a few fuzzy Garage shots...