Hi chaps,

I have just had my MC21 on the Dyno at MSG/Road and Track. Great bunch of guys there, who really made me feel welcome.

Is this the sort of thing you would expect to see for a bog standard MC21 with wire splice? Fueling seems pretty good, so I don't think there is any need to split the crank cases and replace the seals now. £40 very well spent I think. I have some Tyga pipes to go on and will be doing the airbox mods too, before going back to check everyting is OK.

Any comments welcome from you guys who have seen more curves than me I am sure.

Hi , your graph looks as expected from a standard nsr . You will see a good change when you fit race pipes

Standard (unmodified) airbox lid, by any chance?
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Yep, standard except for the wire splice.

I'd expect to see it closer to 60hp with the airbox modified correctly, and maybe just eek over 60hp if you've got a healthy motor. In the right hands, there could be almost 10hp more in that motor, but there's certainly 6 or 7 more!

Mind you, the dyno could be reading low, but it's about right without it able to breath. The lid is way restrictive.
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Hey mate. Mine looked almost identicle to that when i had it dyno'd. Std bike with wire splice and different mufflers. Std air box lid as well

I cut my lid, and it 'felt' noticably better, especially up top. Have not had it re-dyno'd, so it could be 2hp or 7hp more.
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I have not dynoed mine, but on the track (straight line), it is as fast as a track RD350 YPVS. Similar bikes to this RD have been dynoed at approx the same power as you got. 52. So I guess mine, std 21 with wire splice, is also on this range. I guess next step is open the airbox and rejet (4x 1 in holes?).

Now, question for the experts. Andy is explaining how to reach the 60 Hp range with wire splice and airbox mod. However, Tyga's way to get there starts with wire splice and new expansion chambers. Are these two ways compatible? What would be the outcome of both mods? Which one to select first?

I know there is a lot of knowledge required to fine tune a NSR, and of course there are no hard rules that can be followed. This is just a question from a non highly skilled person to start planning enhancements on his 21.

Ive never had mine dyno'd, just wanted to ask. Does gear ratio affect the readings at all. I have a 14T on the front? I would have assumed id get a stronger power curve.

e dited
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Last edited by Kubira on Mon Oct 18, 2010 5:24 pm; edited 1 time in total

Kubira wrote:
Ive never had mine dyno'd, just wanted to ask. Does gear ratio affect the readings at all. I have a 14T on the back? I would have assumed id get a stronger power curve.

Don't start Fontyyy off!

I'm sure he'll be along in a moment to answer that one in his own colourful way!
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Kubira wrote:Ive never had mine dyno'd, just wanted to ask. Does gear ratio affect the readings at all. I have a 14T on the back? I would have assumed id get a stronger power curve.

WOW, a 14t on the back, once you finnnnaaallly get up to speed you'll be going so fast you wont be able to stop at the dyno shop!!
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javes wrote:
Now, question for the experts. Andy is explaining how to reach the 60 Hp range with wire splice and airbox mod. However, Tyga's way to get there starts with wire splice and new expansion chambers. Are these two ways compatible? What would be the outcome of both mods? Which one to select first?

The standard MC18 and MC21 pipes are good, although the cans are restrictive, but they are of course rather heavy. There is no reason why a well fiddled with MC18 or MC21 can't make mid 60's with standard pipes.

Race pipes not only weigh substantially less, but they also move peak power slightly higher up the rev-range. This can [a] make the bike slightly faster, and [b] potentially help make more power.

4x 20mm holes are better than 4x 25mm (1") holes, in our experience, and better on the front slope of the airbox than on the flat top, believe it or not. We've seen better results with a lid modified like that than with the whole back cut off, but others may tell you different. I can only say what we've witnessed on Steve's dyno.

No disrespect to TYGA (they are great personal friends of mine), but they are selling products! No company in their right mind is going to say "you could buy our product for £500, but do this for free and get similar results", are they?! Not to say there aren't definite benefits to having a race exhaust system though, and you will need a set of chambers before too long for looks, ground clearance, weight saving, and further potential power increases.

It is generally trickier to get good results with stock pipes than with race pipes, but those results are often better with standard pipes than many race pipes! The standard pipes are an extremely good balance of performance and usability, and tend to give a good boost in the mid-range where the race pipes often lose power or at least drop off a little!
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Last edited by Andy on Mon Oct 18, 2010 4:25 pm; edited 1 time in total

Your sprocket choice will not make any difference on the dyno reading .

If you want to keep your standard pipes , it is worth decoking them as they're full of gunge from years of riding .

The race pipes will help but what you gain in one area you could lose in another area .

Thanks, Andy. 4x20 mm plus new jets will be the next mod. And I hope to go on a dyno before and after the mod.

I now see the point about race pipes and engine power curve shape. I guess it will depend on how often I get on a track vs km's on the road. And $$$$'s! (sorry, no pund sign in my keyboard). In any case, Tyga power-up explanation is brilliant, and based not only in pipes, but also on the reed area. For road use, this mod seems pretty interesting.

Neal, I've decocked exhausts before with caustic soda, although I did not like the results. Is this your preferred method?

I recently removed my stock NSR pipes to put on a set of stainless Tyga's and I can't believe how heavy those stock pipes are. It's rediculous.

Gearing......does it make a difference.....?

In my experience, yes, but it's minuscule in terms of power to the rear wheel.

I tested it back to back on a Honda 110, an NSR150 and an NSR250. Basically three different sized sets of sprockets (same or close as possible ratio).

In the tests with all three bikes the outcome was the same. The small sprockets gave over rev, the large sprockets gave bottom end.

Probably many answers as to why this should be, but it was same same result every time we tried it.

This was on a Dynojet150