NC29 Race engine project

[greggo]

I currently don't have a spare engine, so i'll be freshening up the old stocker into a nice hot engine, and figured I would put it on here. It's going to take a fair old while as the pocket money is running low but I intend to have it finished by chrissie. The engine in my race bike at the moment is pretty fresh, so I should be okay. Touch wood.

I'll be reusing the pieces I can, and replacing what is beyond service limit. Here are the planned mods - but this may change as I rebuild her;
Lightened, balanced, knife edged crank.
RVF pistons (balanced).
Rods - Balanced.
VFR 1st, 2nd and 3rd Gear to make a close ratio box.
CBR600 clutch (I read a post here someone uses it in their race bike).
Ported head (plus she needs a complete set of inlet valves) - I'm also hoping to get my hands on an NC23 head to use but we'll see.
Lightened fly wheel - and I plan to remove 2 of the windings, leaving only one.
Remove tensioner gears from the Cams.

I'll be putting my trials and tribulations on here. I'll spare you too much detail as it is all in the Haynes manual. However i'll share with you the modification parts in as much detail as I can.

If you want some HI-RES pictures of anything along the way, or can think of a mod I have missed, feel free to speak up!

[greggo]

So I brought the engine home today and started pulling everything apart. I got as far as the clutch basket, and was defeated by a lack of a 27mm socket. So splitting the cases will wait for tomorrow.
This was my start point


Everything is going into nicely labeled boxes...


Managed to get the head off nice and easy


and this is where play ended - tomorrow i'll split her wide open once I've got my 27mm socket

[CMSMJ1]

Gonna be interesting this one

[domski]

Good luck Greg, I'm looking forward to reading your updates

[piston]

Why do you want to use a NC23 cylinder head???.

[greggo]

The NC23 head has smaller exhaust ports, so you get higher velocity exhaust gas flow. At the very least you get a better start point for the porting. My current engine runs an NC23 head for that very reason - it has massaged inlets and stock outlets with a degreed inlet cam (which I think has been set too far one way - but thats another story). I may even end out using that head on this engine when it is complete. We shall see.

I got the engine completely stripped today. Getting the clutch basket off was a bugger. Ended out with vice grips on the output shaft and giving the breaker bar a belt with the hammer to free the centre nut. Other than that it was all quite easy and as per the Haynes manual.

This piccie is the bottom of the crank with the sump off. All the rods are marked with twink (liquid paper). I checked all the side clearances for the rods and everything was within service limits. Bonus.


Haynes recommends putting all the crank bolts in a cardboard cut out of the crank case. Good idea!


Just in case you want to know how much a stock crank weighs....I'll be curious to know how much the lightening and knife edging takes off...as will you all i'm sure


The pistons are all in reasonable shape. One of my cylinders has some minor pitting so I'll have to seek a second opinion on whether just cylinder honing will be suitable, or whether to source a new upper crank case. Shit balls.



Somehow I damaged my lightened flywheel, so i'll have to source another. Bugger. Other than that everything is ok, i've yet to measure the bearings, shells, running surfaces etc, but there is no need yet. Not much will happen in this space for a few weeks. I won't have the VFR gearbox for another couple of weeks, nor will I see the engineer who i'm asking to do the crank till early July. Plus I need to repaint my race bike after the crash last month. So all i'll be doing is looking out for the parts I know I need, and scrubbing the buggery out of the crank cases and bolt heads with WD40 and scouring pads. That isn't for a clean fetish (unless I do it in a latex gimp suit), that is so the engine is clean on assembly and I avoid transfering any dust, dirt or manky substance into the important bits on assembly.

Anyone want some second hand CBR pistons cheap?

[yeurman]

greggo,
I've taken over a kilo (1.5 i think but I'll have to check my notes) off by lightening and knife edging the crank... down side is for me, not getting off the line as fast as the engine has less spinning mass so looses inertia ... but maybe that’s just me and how i launch off the line.
Col

[greggo]

Out of curiousity Yeurman, do you run total loss or do you still have the flywheel on?

[yeurman]

total loss..

[GF Racing]

Looking interesting - am currently in the middle of 3 full race NC29 engines - varying specs - reached 71 rear wheel BHP so far - hope for more.

Mind you - slight change in direction as we comprehensively damaged our no 2 race NC29 at Cadwell over the weekend so have had to ask for some engineering help - we are are out again in 2 weeks !