I'd like to get my MC21 NSR to make roughly 70hp, somewhat reliably. I'm currently making 60hp to the wheels with most of the standard mods (I probably would make a little more, but i'm running 112 leaded fuel for safety and it's lack of ethanol as ethanal free unleaded race fuel is basically unobtainable here in CA). I'm willing to go to the next level of performance, whatever it takes, so long as I don't have to rebuild the motor every few track days. How are you guys getting these high hp figures out of your bikes? I'm pretty sure it's time to find the porting master now!!
Michael _________________ 1993 NSR MC21 SE 1990 NSR MC21 SP
Andy wrote:You're not going to get a 70hp 250 that doesn't need rebuilding every couple of track days, simple.
Andy, what would be your suggestion to get some more ponies out of her without having to rebuild every couple track days? Maybe somewhere in the mid to high 60's then? Do I dare say 300 kit If I get someone to do some porting, will that severely increase the rebuilding process? What would I actually have to rebuild? Are we just talking pistons and rings? I don't think that that would be such a big deal. I have my other MC21 as my streetbike which puts out a solid 60hp as well. I'm just sick of having those 600's creep away from me down the straights, though it's not too big of a deal once we get to the braking zones . What would be the best way to shave some lbs of her? Not really sure where I can get anymore weight savings besides putting in a lithium battery. I already have some billet calipers getting mounting next week. _________________ 1993 NSR MC21 SE 1990 NSR MC21 SP
Easy power can be had by reducing rotating mass. Get a lightened rotor, lighter chain, lighter rims, etc. For the engine, what have you done in terms of "standard mods"?
I had my wife's NSR250 Race bike making a good 63hp with very little effort (HRC Jetting, Exhaust, Open Airbox, HRC Wiring Harness). I should have retarded the damn thing, she had an issue with keeping it on two wheels
A good port job won't adversely effect the [new] rebuild schedule, although any increased state of tune necessitates an increased level of [preventitive] maintenance.
Our SS tune will give you around 65~66hp using stock components, and the proper 250 rush you would expect... it transforms the bike! A 300 kit will give about 65hp and a bit more torque than our tune, making it more like a 4-stroke. No comment about reliability though. You can read all about what we've experienced with them in the 300 section. Just don't expect a 20% capacity increase to give a 20% power increase. It's not all about the top-end though, as the cases need to be modified too.
The basic 300 kit is more expensive than our basic SS tune, but you do get a lot of new parts for your money. A 300 with Wiseco's and VHM's is getting on for double the price of our SS motor, and still won't give you 70hp, in our experience.
NSR250 pistons are approximately £85 in the UK, and rings are about £50, so in that alone you are looking at around £300 for a basic top-end rebuild. You should allow £350~400 for parts though. You may be able to source cheaper in the States/elsewhere, or you may not. A standard 300 piston kit is considerably cheaper, but you're not getting Honda quality components, and you will be replacing them far more often!
As Charles rightly says too though, there are plenty of other areas that can also be looked at. Weight savings, suspension, and brakes all need to be looked at. It's about optimising what you have, not about trying to compete with something in a completely different class, with 20~25 years of additional development, and over double the capacity.
At the end of the day, modern 600's are fast bikes. You only have to watch them at the TT now; they look like "thou's" of less than a decade ago, and besides, the NSR250 has never been about straightline speed anyway. Any idiot can open the throttle in a straight line, even me! A well-built F-III will kick a 600's ass still, but you're looking at thousands for a motor, and then doubling it, for all the other bits! Then you're looking at an HRC RS250 rebuild schedule. You only had to watch Jim Hob on his 125 or Moto3 round Donington at our last track day to see how power isn't everything, however. He was blitzed down the home straight by the the 1000's, and by the time they came round again, he'd exit the last corner ahead of them all again, just to be blitzed down the straight once more. Or to see Matt on Watfordhorn's NX5 chase down Shane on Steve's NSR500V... He made up a good half a lap on Shane in a 10 minute session, and chose not to overtake him! And Shane's not slow by any means!
If you're like the majority of us, and can't ride at a professional level, the simple fact is "performance costs". Some have sold NSR's for [usually] faster HRC RSs, some have sold them for 600s and 1000s... one even sold his for a 500 GP bike! _________________ Andy.
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I couldn't keep up with the 600's on my 1996 Fireblade at Donington since the new ones make more power and weigh less.
I couildn't keep up with the F3 NSR's either, since their corner speed was so high that it took a whole straight for me to build up to the same speed as they exited the previous corner!
Could you lose a few pounds? Most of us could, and they're free!
Better brakes and suspension will knock more off your lap times than all the performance hikes in the world, as you feel more confident and therefore carry more corner speed onto the straights.
Last idea is to pick tracks with lots of corners and no long straights!
Neal wrote:Get a 300 kit or sell the track bike and buy a RS
I was thinking about both. I don't think I am going to go the 300 route as I like having the kick of the 250 and have no problem keeping her in the power band. Getting an RS is on the list, but may be a little while. May even go to the dark side and pickup a TZ 250 if a well sorted good deal comes my way
cgallant wrote:Michael,
Easy power can be had by reducing rotating mass. Get a lightened rotor, lighter chain, lighter rims, etc. For the engine, what have you done in terms of "standard mods"?
I had my wife's NSR250 Race bike making a good 63hp with very little effort (HRC Jetting, Exhaust, Open Airbox, HRC Wiring Harness). I should have retarded the damn thing, she had an issue with keeping it on two wheels
I have a Magnesium front Marchesini wheel, currently running a DID non O ring chain. For the engine, standard mods would be HRC rear head conversion, RS Coils, shorty race plugs, High Flow Reeds, Tyga Exhaust, HRC Jet kit, Pod Air Filters, and a Tyga Airbox, and of course the wire splice. The bike has been dyno tuned and runs a solid 13:1 ratio, makes 60hp, though does go a little rich in the higher rpm's. I probably would make somewhere around 62-63 hp also if I wasn't running 112 Leaded, but my mechanic insists that I don't put the crap unleaded ethanal fuel we have here in CA.
Andy wrote:A good port job won't adversely effect the [new] rebuild schedule, although any increased state of tune necessitates an increased level of [preventitive] maintenance.
Our SS tune will give you around 65~66hp using stock components, and the proper 250 rush you would expect... it transforms the bike! A 300 kit will give about 65hp and a bit more torque than our tune, making it more like a 4-stroke. No comment about reliability though. You can read all about what we've experienced with them in the 300 section. Just don't expect a 20% capacity increase to give a 20% power increase. It's not all about the top-end though, as the cases need to be modified too.
The basic 300 kit is more expensive than our basic SS tune, but you do get a lot of new parts for your money. A 300 with Wiseco's and VHM's is getting on for double the price of our SS motor, and still won't give you 70hp, in our experience.
NSR250 pistons are approximately £85 in the UK, and rings are about £50, so in that alone you are looking at around £300 for a basic top-end rebuild. You should allow £350~400 for parts though. You may be able to source cheaper in the States/elsewhere, or you may not. A standard 300 piston kit is considerably cheaper, but you're not getting Honda quality components, and you will be replacing them far more often!
As Charles rightly says too though, there are plenty of other areas that can also be looked at. Weight savings, suspension, and brakes all need to be looked at. It's about optimising what you have, not about trying to compete with something in a completely different class, with 20~25 years of additional development, and over double the capacity.
At the end of the day, modern 600's are fast bikes. You only have to watch them at the TT now; they look like "thou's" of less than a decade ago, and besides, the NSR250 has never been about straightline speed anyway. Any idiot can open the throttle in a straight line, even me! A well-built F-III will kick a 600's ass still, but you're looking at thousands for a motor, and then doubling it, for all the other bits! Then you're looking at an HRC RS250 rebuild schedule. You only had to watch Jim Hob on his 125 or Moto3 round Donington at our last track day to see how power isn't everything, however. He was blitzed down the home straight by the the 1000's, and by the time they came round again, he'd exit the last corner ahead of them all again, just to be blitzed down the straight once more. Or to see Matt on Watfordhorn's NX5 chase down Shane on Steve's NSR500V... He made up a good half a lap on Shane in a 10 minute session, and chose not to overtake him! And Shane's not slow by any means!
If you're like the majority of us, and can't ride at a professional level, the simple fact is "performance costs". Some have sold NSR's for [usually] faster HRC RSs, some have sold them for 600s and 1000s... one even sold his for a 500 GP bike!
I'm working on other areas to share some weight, suspension is completely dialed in for me and feels great. Had the USD RS250 front end completely revalved and sprung for my weight, as well as the rear set up by Lindemann Engineering. I currently have Brembo Rotors and am running standard OEM Cast P30/34 Calipers on there, she stops amazing I must say, and I have a set of CNC Billet Brembo P30/34's going on this week which should shave a few lb's. I know I'm never going to blast by a newer 600 or 1000 down a straightaway, but I just want to not give up as much. Not that I am a "professional" racer by any means, but I can ride the girl pretty well. I just want to be as competitive as I can be on what I'm running with. I don't care about doing 140mph down a straightaway, I'd get a litre bike if I wanted that and definitely realize that power is not everything. I like braking and corner speed, and would just like to be as fast as possible without constantly rebuilding. I have a few sets of pistons and rings and gasket sets, and a top end rebuild in my eyes is not really that big of a deal as long as I don't have to do it every 3-4 trackdays. What exactly consists of your SS tuning? I'm definitely interested in hearing more about it! Like I said earlier, I definitely am looking to obtain an RS or TZ one of these days, just not now. I'm happy with the NSR, it is by far the most fun bike I have ever ridden and I've had quite a few bikes.
Dave Ett wrote:I couldn't keep up with the 600's on my 1996 Fireblade at Donington since the new ones make more power and weigh less.
I couildn't keep up with the F3 NSR's either, since their corner speed was so high that it took a whole straight for me to build up to the same speed as they exited the previous corner!
Could you lose a few pounds? Most of us could, and they're free!
Better brakes and suspension will knock more off your lap times than all the performance hikes in the world, as you feel more confident and therefore carry more corner speed onto the straights.
Last idea is to pick tracks with lots of corners and no long straights!
Could I lose a few lbs? Unfortunately not, I'm only 5'8" and am pretty fit at 140lbs. My suspension and brakes are dialed, I love corner speed . I do try and pick tracks that don't have ridiculously long straights too. _________________ 1993 NSR MC21 SE 1990 NSR MC21 SP
When you ride a 300 back to back against a 250 you will notice the difference . Like for like state of tune . If a 300 pulls like a fourstroke then that is how the person set it up , thats moving away from the feeling a two stroke gives .
If a F3 250 can smoke a 600 , then a F3 300 will make it easier .
I change pistons on my 300 after using 200l of avgas and the bike is used for racing and track days . For me , it was a case of money well spent doing the conversion and in my case the grin factor has been worth it .
But you could get a gp bike by selling the nsr and adding the money needed to make the nsr faster _________________ NSR300
I've thrown everything at my bike and it was making a legit 76.2bhp on MCE Racing's dyno. I mean everything..... +2mm overbore (268cc), custom heads with inserts, PJ38 carbs, porting, stuffing, on and on...... And I was replacing the single ring pistons every 10-12 hours of run time. Obviously Master Patterson should chime in but if you want a real 70bhp, you're going to need to pay to play.
With my stock MC28SP engine and all the HRC goodies I could get my hands on, it made 62.3bhp.
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If I get someone to do some porting, will that severely increase the rebuilding process? What would I actually have to rebuild? Are we just talking pistons and rings? I don't think that that would be such a big deal. I have my other MC21 as my streetbike which puts out a solid 60hp as well. I'm just sick of having those 600's creep away from me down the straights, though it's not too big of a deal once we get to the braking zones 
. What would be the best way to shave some lbs of her? Not really sure where I can get anymore weight savings besides putting in a lithium battery. I already have some billet calipers getting mounting next week. 
