is a bigger jet needed when porting manifold and exaust, increasing air flow

[069Toolman]

A quick question, should i enlarge the jet if i have increased the airflow through the head. I Have increased manifold diameter with dremel and roughly ported out manifolds where they meet the head.

thanks in advance

 

[069Toolman]

if so what size jet and i am at 450 metres above sea level.

Cheers

 

[Venice Motor Bikes]

You won't know if you need a bigger jet until you actually ride the bike.
Re-jetting isn't always needed just because you changed something on the engine.

I explained a little bit of how to tell the right jet size in this thread... http://motorbicycling.com/showthread.php?p=439187#post439187

 

[Carlbaker]

But its feels very nice while riding a bike.

 

[Carlbaker]

Oh its good that you have reached at this level.

 

[Carlbaker]

But I'll suggest that you should not enlarge the jet even if you have increased the airflow through the head.

 

[maniac57]

These kits are usually too rich to start with so I doubt you will need to rejet with these modifications.

 

[CTripps]

Most likely you'll just need to play with the needle's clip until it runs the way you want it to. Move the clip down for richer, up for leaner.