Hey everyone,

Just joined the forum as you might know. I have currently owned a 2002 NSR150SP for 2 years and still is my 1st bike and I will never get rid of it. Also have an interest in racing it later on down the track and was just wondering if this bike would be worth racing?

I plan on working on it for now as I have found some performance parts from Tyga performance. :D

Hope to hear from everyone. :mrgreen:

Seth

i raced my one at eastern creek(NSW) heaps, its a real blast
all i can recomend is exhaust, reeds, and a cr125 carby and pod filter, an tune it properly,and some rear sets wouldnt go astray as the stock ones hit the road easly

i use to carve up the bigger bikes every where except the straight
its really good when a new gsxr1000 goes past you at 260+ then you catch and pass him everylap

High

I once also owned a 150sp, good laugh for sure, I used it a few times on track days and the like, If your going to track it I would recommend that you strip the front forks dig out the piston/valve youll see a large hole to flow the oil through the best thing you can do is weld that up and drill it back out to half its original size, now you will have a little bit of damping.

The carb route is the best bolt on power mod you can do either a 32mm flatside or a Cr later being more fun but both rewarding, also a tyga pipe.

I used Bridgstone BT39 tyres in the super sport copound in 100 front and 130 rear i think excellent choice, but the rims will take gp 125 slicks if you like for real action. Oh dont forget the braided front line apert from that i found the brakes quite good.

Of course a little porting work never goes amiss.

have fun i did

luke f
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Farting is funny

Thanks for the reply's

Sounds fun can't wait to get out on the race track. With the carby is the one from Tyga Performance from a cr125 or are they both different? If they are which one would be best at gaining the maximum power?

Also another probably silly question can you use a forge piston with a polished and ported head? :|

Regards

Seth

TYGA's carb kit is based on an NSR250 32mm carb; the CR carb is a 38 or 39mm.

Unless things start getting really serious, the 32mm TYGA kit would be the most flexible and easy to install, as they supply everything you need to bolt the carb straight on.

Andy.
NSR-WORLD.COM

i would like an nsr150sp saw a load of real trick ones in thailand but never seen one anywhere else, and never in blighty. shame really
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MC21SP - Roth-tax
CBR400 - track
MC21R - sold
MC21SP - sold

There's at least one in the UK... it was at the Llandow trackday!



Andy.
NSR-WORLD.COM

cr125 bolts almost straight in, email tyga as i think they have done it, my local performace shop did it for me, said it was a snap to do, my theory is bigger the better, if you dissagree with me then why do ppl put rs250carbs on nsr's

oh and it made a massive differance to power n torque(dyno proven) but made it a sh*t load better to ride

The best plan for any NSR150SP owners out there is to, at the very least, fit a pipe. the stock pipe is restrictive (It's got a cat don't ya know) and weighs a ridiculous amount.

Our carb kit is basically a modified NSR250 MC21 carb and manifold block. It bolts on with the minimum of grief and gives a couple of ponies.

More power can be had with a bigger carb for sure. Any of the PJ or PWK series Keihin carbs will work, but remember that the bigger you go the more bottom end you'll lose. throttle response at low rpm will also be noticeably worse.

Go above a 34mm carb and you'll have to start considering crank case modifications to increase the inlet area, so as to take full advantage of the bigger juicer.

Matt@TYGA wrote:Go above a 34mm carb and you'll have to start considering crank case modifications to increase the inlet area, so as to take full advantage of the bigger juicer.

Is that when porting the cylinder and skimmed head comes in or is there more to it than that?

Just to make things more clear is the carb off a 2002 cr125r model same year as the NSR150SP?
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/\/SR-150 SP Its Special

The NSR150SP has a reasonably small exhaust port, although it's timing figures are quite clsoe to the NSR250. It struggles to flow enough gas over 10000rpm to make decent power so to be honest it needs a bit of modification all through the motor to make respectable power.

If you pull out the reed valve you'll see that the shap of the inlet is a tad on the small side. have a look at an RS125 or CR125 motor and you'll immediately see the difference. The latter two are high hp, high revving motors. The 150 is not. Take the intake of either of the race machines as a guide to modifying the NSR150SP. In fact the older NF4 RS125 is a very good place to collect data with a view to modifying either the NSR150SP or the NSR250.

The 150SP exhaust port doesn't need any more duration, but it does need more area. Consider thinning down the centre bridge and lifting the outside edges. The transfers are on the same boat. They don't really need more duration, but you can increase area. The nikasil on the edges of the ports is also rather nasty on the 150SP, so clean this up. Remember to leave a nice chamfer on the ports to give the rings an easy life.

The actual exit of the exhaust port into the pipe is also too small for big revs. A fraction more area here works well at the top.

The head is designed for low rpm torque, but still gives good top power. Consider less squish area (NOT to be confused with clearance) for more top end.

I can't give you solid numbers to work to, but by having a good look at any race engine will give you a good idea of where you should be heading when you want to up the hp of a two stroke motor.

Thanks Matt some very good information. :)

I'm going to take the engine to my nearest Honda shop and see if they can fit the cr125 carb and to do any other modifications that are necessary. Also going to fit a Tyga Performance exhaust sooner or later.
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/\/SR-150 SP Its Special

although honda is good at fixing honda's find a speciallized bike shop to do the work, i would suggest a dirt bike shop as they do lots of 2stroke tuning

"Guest" is spot on here. Don't just go trusting any one with your pride and joy. fitting a carb is easy, but getting it to work properly is not.

Crosser shops seem to be far more at home messing with strokers than your average high street bike shop. They've always got the bikes in bits fettling this and fiddling with that, so they're a good place to go for info and assistance.

They won't even mind if you ride your NSR through a muddy field on the way to the shop........maybe!