1200 bike carbs for 1200 nova?

[DR Kauffman]

can this be done without rejetting??

[shed-on-wheels]

yes but get it setup properly

[mowgli]

a 1200 bike engine produces about 3 times the power of a 1200 nova engine, so i'd hazard a guess at them being a touch too big. maybe 750cc ones or even 600 ones would be better, it all depends on what manifold you can get & what state of tune the 1200 is in.

[pyromaniac_yeti]

i looked at doing this a while back..when i had my ratty mk1

Basicly carbs off a 1200/1000 are just too damn big. Think of it like shoving a set of weber 45DCOES on it - yeah it'll make a lot of noise and use a lot of petrol but from what i learned in the mini world big carbs arent always the best. they'll add the extra power at the top end, rather than the midrange.

However this is where it gets complicated, cause a lot of 600cc sportsbikes have carbs that are just as big, so count them out of it. I ended up finding a set off a 400cc bike, which were about perfect IMO, then i calculated the main jets needed to be around 1.35mm based on how PPC reccomended drilling jets to suit a 2.0 16v. Teddythom may still have them, as i sold them with the nova swearing i'd never have another one.

Take into account though, that a lot of 400/500cc bikes are only actually two cylinders! and as such twin carbs, not the four you'd want.

I'd still love to see a proper budget spec engine build out of a 1200, bike carbs, SR cam, skim the **** out of the head and a 4-2-1 fanimould...bet it'd make a right little screamer and proper good fun to drive!

EDIT: i THINK it was 1.35MM the jets wanted drilling to - i'll check it if your still interested, but i'd highly reccomend calling bogg bros for jetting advice!! http://www.totalvauxhall.co.uk/files/legacy/TOV64.tech60697.pdf

[mowgli]

I think it would be a fascinating little project, but it would need a lot of work before you'd need the bike carbs. Basically, bottom end rebuild, head, cam, solid lifters etc..

[Stuart]

In short, probably cheaper and easier and less money lost come resale to get good ole Weber 40DCOE's fitted....

[pyromaniac_yeti]

Bah. I paid £20 for my carbs, and a tenner for the pipe work to make runners out of?

£35 for a skim on the head, a gasket set....sr cams don't set ya back the earth yet!

Smack it all together on the cheap and learn a thing or two doing it - and if it does blow itself to bits a replacement bottom end can be had for as little as £50. Winner!

[mowgli]

one very important lesson is how to get decent fuel mileage out of it for the performance gain

[turbojolt]

I really wanted to do it with mine when it was a 1.2, but decided against it as I need something that will be better on a long motorway run

[pyromaniac_yeti]

Lol, the fuel consumption would be shocking for the powers gained...but it would sound awesome

[Stuart]

Fuel consumption dosent have to be bad for a gain in power, even with outdated things like carbs :p

[pyromaniac_yeti]

Oh yeah, don't get me wrong if it's set up correctly... But bike carbs on a 1200 is all about the noise for me :d

Sure the performance gains would be less than if the same moneys were put into a decent fast road cam, 4-2-1 manifold and a rr tuneup to get it all cock on.

Can't see a massive bank of carbs doing a lot at all on a stock 1200, but still...you cannot beat the noise of ITB's on full chat!