hi guys

NOT looking for specific jet sizes

I had a mc21 that I foolishly sold and have now picked up one of the last 28 sps

looking to set it up over the next few weeks, pipes etc on the way (have hrc card)

with all the talk about how crap 28s are can someone explain why they have bigger jets std than the 21?

cheers

paul

Different type of carb and secondary air supply compared to a MC21
_________________
If I have to take the carbs off once more...

with an hrc card can i expect similar results to a 21, or are there other hold backs?

An MC28 with an HRC card, and nothing else, will be a few HP down on a delimited MC21... usually around 5hp down on average. Tuned like-for-like, the MC28 always produces slighly less power than both the MC18 and MC21.

We've yet to see any MC28 make more power than an equally tuned MC21, but a well sorted one can get very close. There aren't many who can tune one to that level though!

Expect to see a maximum of around 60~61hp if you run an airbox, and 62~63hp if you are prepared to run open carbs. Take a good 5~7hp off these figures if you run OEM pipes, and 10hp off of you don't modify the headers!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

This is a stock, delimited MC21R vs. an SP-spec MC28SE. SP-spec means race pipes, kitted (open) carbs, HRC card, etc.

You can see how the HRC parts and other mods have made the mid-range rather strong, and the peak power has crept up near the MC21. It's also gained RPM over the MC21, but remember all the MC21 had done was the wiresplice/airbox mod, and a rejet.

That was considered a good MC28. I think we eventually saw it up to just over 62hp on another visit, if I recall correctly, but I don't have that graph.

For most people, the MC28 graph is actually more desireable, but it's a lot of money to get up to a standard MC21! I think I have a standard R5K graph somewhere, that's even better in the middle than that MC28! Again, nothing more than a wire-splice and airbox mod!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

planned set up is

tyga pipes
modded airbox
hrc card
tyga reeds

my mc21 was

modded airbox
splice
pipes (never found out the brand but not std)

assuming the pipes are equal what on the mc28 is left to make it less powerfull?

MC18 R5K kicks ass!



MC21 still makes the most power though, and has the best chassis!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

paul wrote:
assuming the pipes are equal what on the mc28 is left to make it less powerfull?

All else being equal, the MC28 is still down on the other models... the hard truth no MC28 owner wants to hear, but has to accept... the PGM-IV doesn't work!

HRC not only had "special" cards, a reliable source (who raced NSR's against HRC) also told me that he found out a number of years later that they also used "special" PGM-IV's with interchangeable chips.

They used "special" lightweight twin-ring pistons too, but it's the ECU that will always hold an MC28 back.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

thanks

if its 1-2hp as per the graph above I'm not to worried for a road bike

I looked for 3 yrs for a decent mc21 as most of them are fairly nasty and have been chopped up by now

gave up in the end and the 28 became availible

I raced the last one but this ones a show pony for the road, even so I still want it to go close to right

paul

It'll go OK, but it'll never go as well as some will lead you to believe. My MC21 on stock port timing puts another 5hp on top of that 21R, and kicks its ass in the mid-range! It matches the R5k +/- .5hp all the way to 10400rpm, then carries on going where the others tail off. I'm afraid no MC28 is ever going to do that on standard internals and pump fuel. I run filters too... not open carbs. NSR's run well on open carbs, so we could likely expect even more from it if pushed.

What you can be fairly certain of however, is any bike meet that you turn up at, you're pretty much set to have one of, if not the most desireable of bikes there!

The point of those graphs though are to demonstrate that all those expensive parts only bring an MC28 up to where a standard MC18 or MC21 start off! Both the '18 and the '21 had only a wire-splice and 4x 20mm holes in the airbox lid... +17hp almost, or to put it another way, almost 40% extra power, for free!! We've also seen standard pipes on a (heavily modified) MC21 making close to 69hp!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

I think I'll argue that the MC18 has the best motor in non F3 spec but you are right about the chassis Andy
_________________
If I have to take the carbs off once more...

paul wrote:with an hrc card can i expect similar results to a 21, or are there other hold backs?

mc28 barrels aren't quite as good, the CDI is probably a litle bit worse for ultimate power on UK pump fuel if running the 030 card vs a spliced PGM-III (remember neither are intend to run on 95/97 or 98 RON unleaded), carbs are different (I'm not saying better or worse, just different). Ultimately if you take it on track the mc28 chassis is not as good.

Lots of little bits all add up
_________________
Please do not PM me technical questions, if you can't find it on the Forum start a thread

StephenRC45 wrote:
I think I'll argue that the MC18 has the best motor in non F3 spec but you are right about the chassis Andy

The MC18 motor is definitely doing something right, but there are some quite significant differences between it and the MC21... not all of which I would say are better.

The MC21 overall is still the best, and most "tuneable" package.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

So basically the 18 is the quickest, the 21 handles best and the 28 is the prettiest!

What you really need is one of each then

Know anyone who fits that description, Paul?!

Proper fruit salad you have there... two peaches and a lemon!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!