RS 250 carbs

**Wed Dec 22, 2004 5:31 pm » Post: #1 » Download Post**

how much extra power is there to be had with RS250 carbs on an MC21 NSR250?
i wonder how much they would add to an NSR300 kitted bike?

whats a typical price for RS carbs, and what years are desired / work for the MC21?

Thanks
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Koren
2 Strokes and I'm Off Rolling Eyes

**Thu Dec 23, 2004 2:48 am » Post: #2 » Download Post**

You will sacrifice a bit of low-end power and the bike will no longer idle (RS carbs have no idle circuit).
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

**Thu Dec 23, 2004 3:44 am » Post: #3 » Download Post**

On your next order get the carbon fiber reeds and Hi-flow cages, then mod your airbox. With those pipe you think it's a different bike.
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**Thu Dec 23, 2004 1:31 pm » Post: #4 » Download Post**

already have the carbon reeds installed when i purchased the bike.

might drill a few holes in the airbox, and then rejet the bike
or i might just see how it goes with the pipes first..

maybe you can give me some good base setting for jetting Jeff,
similar location and such, would probably be spot on
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Koren
2 Strokes and I'm Off Rolling Eyes

**Thu Dec 23, 2004 6:33 pm » Post: #5 » Download Post**

hi maine2stroker,
how much extra power will give the rs carbs on a 300cc nsr? you know?
in this winter im going to build 38er keihins on my nsr300.. im intrested in how much power it will give....

**Fri Dec 24, 2004 2:36 am » Post: #6 » Download Post**

The 300 works very well with stock carbs. Better with bored out stock carbs, and better still with big and juicy 38's!

However, the jump from bored stock to the 38's is not as good as it sounds without some more mods to the porting. Basically the port timing and area are more aimed at use with the stock parts.

I've got a pair of cylinders in production with porting worked out for BIG carbs and higher rpm. We'll just have to see what happens.

**Thu Dec 30, 2004 9:46 am » Post: #7 » Download Post**

where I have to start to jetting the 38er Keihins from a 92 RS on the 300cc kit? I have to buy some jets, which size (of course on the safety side to go then smaller) i need maybe?

**Sat Jan 01, 2005 8:33 am » Post: #8 » Download Post**

My 300 has HRC 38mm carbs (not standard PJ38) and is jetted as below:

MJ - #175/#178
JN - 1271 clip 3
SJ - #40/#40
AS - 2 turns out

Don't take it that these settings will be perfect on every bike. Plug chops need to be done to be sure.

**Sat Jan 01, 2005 2:54 pm » Post: #9 » Download Post**

thanks

**Mon Jan 03, 2005 10:20 pm » Post: #10 » Download Post**

G'day
I raced a NSR for a couple of years, a 1989 MC18 with various MC16 and 18 engine bits.
I put some racepipes on it, and was impressed.
Then I got an Aprilia RS250.
I put Tyga's on it. Impressive.
I put PJ38's on it, off a 1990 Honda RS250. Shocked

Mate. I wish I had done that to the NSR!!
They give at least as much as putting the pipes on did, and its a heap easier to work on them. (They're in a enclosed fibreglass airbox)
Sorry for hijacking this thread, but it is relevant
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The Chopster