Very Sick NC30 - Major heart surgery underway

[Johnny Wishbone]

Unlucky mate but it looks like you have the job of sorting it under control.

Love the way you've just cracked on, dropped the motor, ripped it apart and got stuck in!

I'd offer my assistance but I don't know my left handed screwdrivers from my right handed screwdrivers so instead I'll just wish you good luck.

[NGneer]

Thanks to all for the supportive words and offers - i may well call on some of you.

Anyway on with the strip. Had a lot on at work recently so not been able to crack on as much as i would like to and when i did had the obligtory few bolts that just rounded off and delayed me. Some top notch help (you know who you are) and i have finaly manged to get everything off and split the crank case. How did Mr Honda squeeze so many pieces into such a small space????



At last i could get to the pistons and remove the offending article. Previously (with the heads off) the crowns of the pistons could be seen and looked like the engine had been fitted with RVF pistons at some point in its history. Managed to get hold of x3 RVF pistons in good nick so decided i would just clean up all my old ones (all the bores are fine) and match the best one of mine, by weight, to the new three to make a full set.

On the old pistons there is the number MR8 but on the replacement items it is simply 8. Cant be that much difference thought i, they are both RVF pistons after all. Oh how wrong was i. I had been advised to be quite anal about matching the piston weights after all these things are wanging around at a fair old pace and a couple of gramms out of balence at 14500RPM could make for a bad day! So i had got the pistons free and had one in each hand, old and new, took a while for my brain to catch up and work out the difference(s) .


So if the replacement items are RVF, and the old ones are not NC30 (high crown and valve dimples etc - where i though NC30 ones were flatter)...what the f**k have i had fitted in the engine to date??? Anyone any ideas

[G-MAN]

According to this pic in a 1989 mag about the NC30 (RWB colour) those pistons are NC30

[NGneer]

Hmm Cheers G-Man (you got mail).

I was so convinced that my origonal pistons were RVF i hadn't checked stock NC30 piston profiles - Dohh . I think you are correct and they are just standard NC30 ones (http://www.akhara.com/nc30/pistonrod1/index.html) - at least i know what i am looking for now part No 13101-MR*-000 (superceded by 13101-MR8-010)

[G-MAN]

Ian reply sent , happy reading and enjoy the pics

[NGneer]

Anyone got a spare NC30 piston in half decent nick lying around?

[vfrman]

I may have one.

I plan on tearing my shed apart tomorrow to take pictures of all my spare stuff. I will see then. I am pretty sure I still have an HRC piston or two as well...

[vfrman]

I just found three used NC30 pistons and rods, as well as a mismatched set of never used HRC rods (3 rear, 1 front) and one used HRC RVF piston. God knows what else I have laying around in there!

[NGneer]

I just found three used NC30 pistons and rods, as well as a mismatched set of never used HRC rods (3 rear, 1 front) and one used HRC RVF piston. God knows what else I have laying around in there!

LOL - sounds like the sort of clear out i need to have after this re-build. Many thanks for the offer but managed to get some bits from Geoff yesterday (chers Geoff), so i have been busy using all the aqua washes etc at work cleaning up all the components before the rebuild actually begins. More to follow...

[vfrman]

Sounds like fun. I enjoyed building my motor... twice. Long story. Lesson learned is don't ever trust the machine shop to do the job correctly. Always verify!