Hi everyone!
if i want to blueprint my mc21 which are the areas that i should give major attention and have the best gains?

Not sure what you mean by "blueprinting". Most engine builders "blueprint" by making each and every cylinder/valve/spring/port specs match as close as possible so the engine runs at a better state of tune. Not easy on an NSR, when the intake tracts are entirely different on each cyiinder of an NSR.

Here are some things you can do internally:
-weld the pins on the crank
-port/epoxy the cases
-gasket-match the cylinders to the cases
-map the ports, clean them up, and open the exhaust port closer to RS specs (best bang for your buck!)
-run the .5mm base gasket on the upper cylinder, .6mm on lower cylinder

Do all that and run all the Tyga bits, and you wont get a much better NSR unless you go overbore.
_________________
Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

Follow what Paul says and you won't go far wrong.

Just be sure that you have the right tools for the job though, and don't just go hacking away blindly.

The nasty overhanging Nikasil on the ports is a good area to start. Just cleaning that up can net you a couple of ponies. You don't even have to cut any aluminum to get good results.

If you've got the cases open then just look at the jagged lumps and sharp corners. They're crying out to be cleaned up. Nice radii is what you're after, not sharp corners.

Wrench. wrote:
-port/epoxy the cases

Can you get into more detail about this?
_________________
james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm

j911brick wrote:

Wrench. wrote:
-port/epoxy the cases

Can you get into more detail about this?

I have a good series of pics of the requested cylinder/case/port mods that I got while in Japan. Maybe Andy would be kind enough to post them up in his Technical section with a good narration of what to do some day. If you want the pics, email me at "the5herrs at charter dot net".
_________________
Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

Pics sent. Did you get them all, James?
_________________
Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

I got them Paul. Thanks. Been working on a reply but its been a busy day.
_________________
james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm