Does anyone have any more details about the big bore kit that has been mentioned here? Maybe some details of cost, piston and ring design and weight etc. Maybe some tasty dyno figures.

$20'000, 97bhp at the rear wheel.


So ive heard. LOL

TTS is the only place ive heard of that does the big bore kit. Not sure how reliable it is, theres been stories of the bore size being wrong and massive oil leaks etc.

I think the hamster might be jesting with you slightly with his $20,000. Even if the pistons were made out of RHS they probably wouldnt be that much!

From memory, these kits were going for about £500 several years ago but ive not looked at prices for ages.


You would be far better getting suspension sorted and then thinking about engine mods. You can get a fair amount of power out of the 400 without getting bigger pistons. If you do want a bigger engine, its far eaiser to get a bigger bike.

It may possibly be more than $20'000. Looking on THIS website for the 450cc NC450V EFI Engine, its expected to make around 100bhp at the wheel and it has cost them so far around $20'000 to build and test. That is the price to TEST the engine, to actually get a production one ready to use would probably cost more....

Rick O told me he is develping a bige bore NC30, I would speak to him first, as he is likely to know how to do it properly.


Dave,

Its Ricks post that drew my attn to it, so I guess he will post more details when he is ready. Cubic capacity can be a very cost effective method of gaining power, esp if a suitable donor piston can be found. The G-force kit linked above is a race engine with custom pistons, rods and stroke which explains the price.

My suspension is reasonably well sorted with technoflex rear shock, raised ride height, EBC disks and pads and reasonably sticky rubber and the limiting factor is now my lack of talent - A bit more torque and power would help on the long straights and for overtaking the badly ridden bigger bikes that blast away on the straights then get in the way on the bends.

I have owned bigger and faster bikes like a cbr600rr and Aprilia Falco but get more satisfaction from being on a 20 year old 'baby' bike where my engineering input and learning to ride properly adds to the fun

Yes,
I like riding my NC30 hard but I never feel like my RC30 is at its limit.

Dave.

The engine in my bike was built by TTS but not for me - I acquired it as a finished unit and just bolted it in.

It had been a pretty costly project for its previous owner and had gone back to TTS a couple of times to cure a problem with the liners shifting and causing head gasket leaks. Once finally sorted it ran a seasons racing with no reliability issues.

It uses JE pistons which are a good deal heavier than you would ideally want them so I run a fairly conservative rev limit on it in the interests of bottom end longevity.

I did speak to TTS a while before this engine came my way about the possibility of building me one - they seemed less than keen on the prospect and were talking a cost of £1500 plus...

The Hamster wrote:It may possibly be more than $20'000. Looking on THIS website for the 450cc NC450V EFI Engine, its expected to make around 100bhp at the wheel and it has cost them so far around $20'000 to build and test. That is the price to TEST the engine, to actually get a production one ready to use would probably cost more....

You're comparing apples and oranges here. G-forces engine above is not simply a big bore nc30 engine!

Your average nc30 big bore won't be putting out more than 75hp and if you were handy you could probably string one together for under a grand.

I've got a set of the G-force pistons and I'm just waiting for the carillo rods to arrive. Cost around $3400 and with the exchange rate for Danish kroner that works out to about £1700.
If you think about what a full system plus PC costs for most bikes today, it's cheap hp.

428 cc high comp cosworth pistons (+3mm pin hieght)
+3mm Carillo rods
Balanced standard crank.

Should give over 80 hp at the back wheel without any other mods. The peak stesses on the crank/rods if anything should be lower as the forces are greatest at TDC on the exhaust stroke. The pistons alone wiegh about 20gr less than standard. Reliabilty and power I hope.