should I bore this?

atx360

New Member
So this is a cb 360 ported polished and freshly buttoned up....The jug, combustion sufaces and all head parts have been ceramic-coated. I just recieved my vm 30's and the corresponding boots. I noticed that the intake work we did is a much smaller bore than the boot size. Should I widen it??

As we all know the better the air gets to combustion the better the power.

any inputs would be appreciated....
 

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teazer

Well-Known Member
DTT BOTM WINNER
What size are the intake ports at the flange face? They should be 30mm to match your carbs and can then taper down to teh appropriate size at the critical port diameter around the valve guide area. Who ported the head and what did they do to it and how did they port it without matching it to the intended carb size? Or did they and the manifolds are deceptively large or wrong?
 

atx360

New Member
I still have to get exact measurements. But the headwork was all done before I decided on getting larger carbs.
 

teazer

Well-Known Member
DTT BOTM WINNER
Blend it to the carb diameter. If the boot is larger than the carb, ignore the step.
 

Tim

Administrator
Staff member
It looks like the intake size should closely match the carb body. The boot should be bigger than the intake hole - it's the carb body / head that need to match.
 

jimmer

New Member
I have 36mm carbs which mount in 36/38mm boots.I then made a sleave to stuff in the boot to eliminate any steps.So, 36mm carb,sleeved boot at 36mm,and then the intake port is 36mm.
 

overdraft

New Member
Tim said:
It looks like the intake size should closely match the carb body. The boot should be bigger than the intake hole - it's the carb body / head that need to match.
FTW! when you look down the carb boots with no carb mounted you see past dimension B to dimension A and think omg, it's so restricted! But the relevant dimension is A... throat of the carb matching port size... sorry for the msword art.

 

atx360

New Member
Thanks guys. Once I mocked it up it all looked flush. Nice illustration too.

Sent from my SAMSUNG-SGH-I997 using Tapatalk
 

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