Just thought I would say Hello…

Just bought a MC28SE after years on GSXR Suzuki’s, always promised myself I would get another two stroke road bike after spending over 10 years racing TZ Yamaha’s in the late 80’s and early 90’s.

The last two stroke I owned was a TZR250 3MA SP with a full formula 3 race kit fitted, I bought the kit new in Japan and fitted it myself.

Never blew up in 8,000 miles of abuse and I sold It for just £1700.00….. I know.... don’t even go there, but it was 1998

Anyway after reading this forum it seems that I have bought the latest, but hardest NSR Honda to derestrict and tune to get some proper BHP out of.

Apart from the usual stuff like fitting some Tyga chambers and doing the wire splice, is there anything else you guys would recommend I can do to the bike to get some more BHP?

The bike is in really nice condition, but I would like to get 60-70BHP out of it, if at all possible, or any of you guys have anything that you want to sell to get me there please contact me.

I own a company that produce tuning parts for a Japanese super car so small production runs are possible too, if I can help with anything…… just PM me and I will see what we can do?

I would really like to get this bike flying and if I can give you guy’s something back for the excellent info on here, I am all for it.

Please let me know if I can help you, as I am sure you guys can help me

Best Regards

Rob


Last edited by NSR250MC28SE on Wed May 21, 2008 7:16 pm; edited 1 time in total

Hello Rob, and welcome to the forum.

The MC28 is indeed the most difficult, and certainly the most expensive to get high power from, but it's not impossible. A little over 60hp is well within your reach if you are happy with a fairly aggressive setup for the street, which by the sounds of it, won't phase you too much?!

The key to getting anything near 1/2 decent power on the MC28 is an HRC ignition card. The PGM-IV (ECU) on the '28 is seriously restricted, and unless you use the HRC card you are fighting a losing battle right from the start. The wire-splice is useless without the HRC card.

Fontyyy's is pretty much the best "standard" (i.e. no-one's been inside the motor to tune it) MC28 in the UK, and that makes, with a fresh top-end and the right setup, around 61~62hp.



He'll no doubt be more than happy to step in shortly and tell you what's been done to it to get it there. I think it's made more power since this run was made.

To make any more than this will require getting inside the motor.
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It's made a horse of so more than that, just by taking the airbox off though and jetting real lean
It's also made (making ) 10 less than that just from being setup a tad on the too safe side and being ragged round dozens of track days and races for the past 2 years, so don't underestimate the gain from a fresh top end (or more to the point what you'll never make if the top end is 15,000k's old) or jetting for the day.

That graph is pretty much as I got it back from Apex;

Fresh top end, replated, new stock pistons, rings etc. SP barrels and heads, stock (0.5) base gaskets
Open airbox, i.e. no lid, filter wired in place (IMHO it felt better with a modded lid, never proven on the dyno)
HRC 030 card
Tyga pipes
HRC jet kit (2nd clip - i.e. one leaner than middle - B needle, 188/190 mains, no power jets)
Everything else stock, that was close to the edge though and did just seize one cold day.

So 60bhp is easy if you get the HRC card, all but impossible without it;
My current road '28 runs;
Stock (but maybe old) '21 entire engine (inc flywheel), stock derestricted pipes, modded airbox, stock Honda smartcard, bearing in mind I know exactly what 53bhp in a ripped down race/trackbike bike feels like I'd guess the road bike which is probably 20kg heavier is making maybe 50-52.

I'd be impressed if you saw much over 55 with the stock card (on a dyno that shows a stock derestricted '18 at 62) but if it's completely standard it's only making 40, and it's a rubbish 40 too, unlike a nice screaming banshee gp125 40, it'll make 36 of them at about 8000rpm then it just throws the towel in and limps round to the redline.

But all is not lost;

Firstly, get those exhaust pipes off and see if the headers have (what look like) big washers welded in them, they will look like one of these;

The top one on the left is how it should look, the bottom one on the right is stock '28 and not the way forward if you don't want to be whipped by L plated Aprilia RS125's ridden by crazy kids with no gloves.
Loads of time with a dremel or the best part of £400 (+tax, post etc) Tyga's way is the answer here. Jap4Performance probably have the pipes and cans in stock in the UK (hint, become a titanium member of this site and you'll get 10% off at Jap4, more than covers the cost of the membership if you buy the pipes and cans).

Airbox, Tyga mod the lid like this and will sell you one done if you want, nice if you want to keep yours intact. But we've seen good results from 4* 1.5" holes drilled in the top of the lid. Whatever, plain common sense tells you airbox inlets smaller than the carbs isn't helping the cause.

MC21 flywheel, worth a horse or 3, I'll bet Andy will sell you a lightened one if you ask nicely, that'll give it a tad more bing too, which is nice, order a flywheel puller from someone while your there, Tyga do them.

That will (if set up right, don't just do that lot and run stock jetting!) be a lot better, it'll still get spanked senseless on the track by an RS250 Aprilia with some pipes but as a road bike (IMHO) it's enough.
Anyway without taking a Dremel to the porting it's about as good as you'll get running the std Honda card. Tyga did it all here.

Want more?

Then that stock card has got to go, pains of running an HRC card and details of what you have to do here, details of the wiresplice here and here.
Pains of obtaining an HRC card may be more involved, Honda have discontinued them, you may need to track down a matching PGMIV as well (or ditch the lot and run PGM II, III, F3 stuff, RS stuff etc, depends how commited you are).

Sort the ignition out and it's no different to any other NSR to tune, ported, optimized squish, setup carefully and you'll see the best part of 70bhp.
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Last edited by fontyyy on Wed May 21, 2008 7:36 pm; edited 1 time in total

Thanks Andy for the reply....

I take it HRC cards are now almost, if not impossible to obtain too

Does the PGM 000 HRC Card have any use to me?

I hope that Fontyyyy does allow us to know what he has done to engine to get that impressive BHP gain.

Cheers Rob

If you've got one (an 000 card) and a working PGM for it then maybe, it'll be better than stock but may need some crazy fuel to stay alive, Tom listed what he knows about them here.
Anyone know more?
Have you got one?

60 ish bhp is nothing special, just fresh bits bolted togeather, jetted right and all the restriction removed.
Andy's '21 which is pretty stock but very carefully put togeather makes around 66 and pulls a lot stronger, Steve's F3 which is (shockingly) F3 spec make around 71 and is even better still.
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Wow Thank you fontyyy for the informative , if not depresing for me personally post.

I knew i should have bought a MC28 a couple of years ago.

So the hunt begins for a HRC PGM card.

Any one know what a PGM 000 card does to the MC28?

Cheers Rob


Last edited by NSR250MC28SE on Wed May 21, 2008 8:17 pm; edited 1 time in total

Fontyyy's MC28 is effectively SP250 spec. If you looked in a 1994 HRC SP/SS manual, he's just done exactly what Japanese SP regs allowed and Honda says to do, less some clean-up work around the ports/cases, and it works. (The porting and cases had to stay stock for SP250.)

I would expect a simple "cleaning up" of the internals in the right places (and within SP rules) could easily see another couple hp @ peak and a couple hundred rpm over-rev to his MC28 without any losses.
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NSR-WORLD.COM

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...this is why i like my MC28 SP on PGM3!!!!
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Ducati 916 SP
Honda NSR250R MC28 SP
Ferrari 348tb
Mercedes E55 kompressor AMG

Bosch Man wrote:...this is why i like my MC28 SP on PGM3!!!!

How easy is this to do Bosch Man....any problem or limitations to doing this to my MC28

Cheers Rob

None really, you just end up with a better bike, although still not a true MC21...

Come on, I couldn't resist!!
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NSR300R - Why did i ever have a 250...

Fairly easy, but more work than you'd think, especially on a tidy road bike.

From an mc21 you'll need;
Loom inc everything needed for the GPS
PGMIII
Clocks
Clock mount
Flywheel
Top yoke
L/H switch gear
Ignition switch
Petrol cap
Helmet lock (l/h lower fairing mount)
Lock mech from tail cover.
Anything else needed for the steering lock.

Remove the following from the mc28;
PGMIV
Entire wireing harness
Clocks
Clock mount
Flywheel
L/H switchgear
Top yoke
Steering lock mech (forks out, probably oil res out as well just to get there)
Petrol cap
Tail cover lock mech
Helmet lock

Install the bits from an MC21 instead, I think that's about it.

Things to note (apart from the obvious, i.e. no smart card, no fancy dash etc.);
A PGMIII is not located where a PGMIV is, it's attached to the rear subframe. I have no idea if it will happliy sit where it should with all o.e. 28 bodywork and metalwork in place.
Leave the mc21 flywheel out at your peril, an mc28 flywheeled engine on a PGMIII could well be the worst combination of all.
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The HRC 000 card is for use with Avgas. So you will need to run race fuel with it or risk serious detonation.

Fontyyy is that set up you listed above running with a oil pump or on premix ?

cheers.

keith

On the pump.

188/190, middle clip on the B needle was Apex's '28, 030, race pipes, stock engine base setting (blue trace on the graph) and it was a tad fluffy, the red trace is one clip leaner on the needle*


*taking my word for jetting may not be wise, I've seized an NSR250 five times which is I think a record for the regular posters on this board.
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Firstly i want to thank you all for taking the time to write such lengthy replies....

Thank You one and all

watfordhorn wrote:The HRC 000 card is for use with Avgas. So you will need to run race fuel with it or risk serious detonation.

Can you substitute Avgas with octane booster ?

will it still blow up?

What do you guys think?


Cheers Rob