best way to go on a honda powered mini?

[Andy Smith]

Hi Ade

Working on this equation:

2.2* cfm X bhp expected = total cfm needed 

A 130bhp engine will need to flow 286 cfm but this is the total the engine
needs so you'll need something that'll flow 70 cfm per cylinder. A Weber
40 flows 175/barrel so one will be plenty, even an HS4 flows 142 cfm so
you could run a pair of HIF44's and still have plenty spare.

If we look to bike carbs (if you really want a carb for each cylinder) and
work the equation backwards a GSX-R1100 makes about 150bhp, that
gives 68 cfm/barrel so that's about right. However, a set of 36mm
flatslides will set you back 250ukp but carbs from a GSX (no R) 1100 are
125ukp and from a GSF1200 are 145ukp. So there are possibilities from
the bike world, K&N sell cone filters for most bikes so the airbox is not a
worry and the air under the bonnet will be relatively still (unless you want to
ram charge the engine  :-)), the manifold will probably need to be custom
built but someone like Mike the Pipe (somewhere in Surrey) could so that
easy enough. 

Although bikes do run an ECU/black box thingy, it normally isn't
connected to the carbs and when it is it only senses vacuum but doesn't
control the carb at all. Very modern bikes run fuel injection so you'll need
a set of slightly out of date carbs which is better for price.

(*  the actual equation is between 2 and 2.2 cfm but I used 2.2 to give
some leeway for further tuning. Prices quoted from Straightline Racing,
Kings Lynn - 01553 811855).

Bike breaker web sites:

www.powersport.co.uk  
www.ebley-motorcycle-breakers.co.uk
www.motorcycle-uk.com/abe 
www.colchestermotorcycles.co.uk 
www.elymotorcyclespares.co.uk 
www.fastline.co.uk
www.lm-spares.co.uk  
www.biker.net 
www.pitstop90.co.uk 
www.m1salvageandbreakers.co.uk 
www.japanesebikespares.com 
www.yamahaperformance.co.uk 

Hope that helps

AndyS
www.montecarlo.demon.co.uk 



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