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Jetting size - BHP or engine size?
bricheun - 1/4/07 at 10:45 AM

I have a 1600 engine with CVK 37X4 carbs.

The main jets are 165 drilled by BB and after fitting pipercross filter the top end is feeling rather weak.

BB said that 165 should be ok since some 2 litre engines are also using 160-170 they make 130bhp.

My car should be putting down around 140bhp but does not feel like it...

I was thinking, do you use jet sizes for similar cars BHP rating or do you rejet to similar engine CC size?

1.6-1.7mm main jets ~ 120BHP?
1.7-1.8mm main jets ~ 140BHP?
1.8-2.0mm main jets ~ 160BHP?

Air jet is not blocked (does not run right with it blocked).

Thanks in advance.

[Edited on 1/4/07 by bricheun]

[Edited on 1/4/07 by bricheun]

bricheun - 1/4/07 at 12:20 PM

NGK - BCP6ES


jacko - 1/4/07 at 12:43 PM

Can i ask do you meen bogg brothers if so my car is a pinto 20l the jets are 1.7mm and on bogg r/road 140bhp at the wheels are you saying you car should have 140 at the rear wheels or the fly wheel

bricheun - 1/4/07 at 05:12 PM

Yeah mine is Bogg brothers manifold and carburettors (ZX6R).
Did you have the air jet blocked off or open?

My air jets which were blocked before did not run right. I suppose with the air jet blocked at 170 maybe = 200 with the air jet unblocked.

My car should be putting down around 130-140 at the flywheel. By looking at the spark plug "fuel ring" it looks very very white.

I might try to drill to 1.9mm later in a few days and see if there is any improvements. I have already raised the needle 1 mm (2 washers) and it helped the low to mid range already.

Thanks.

jacko - 1/4/07 at 06:22 PM

Hi my air jets are blocked off . can you lift the needles with a washer i have 2 washers on each needles
Graham

BenB - 1/4/07 at 07:27 PM

quote:
Originally posted by bricheun
NGK - BCP6ES




Wow! That shows just how rich my engine is running!!!! Mine are soot black after about 10!!!!! LOL!!!!!!

bricheun - 2/4/07 at 01:07 AM

The needles are raised about 1mm each. (2 model shop washers 0.5mm each)

I might try a larger jet and see what happens..

Andy S - 2/4/07 at 04:54 PM

Plugs look OK for 6's on an engine of that spec - I would have 7's or 8's fitted

For mixture you look at the outer rim for plug heat you look at the insulator go for a cooler plug.

Andrew

bricheun - 5/4/07 at 03:13 AM

After many trial and error, I have finally found the perfect setting for excellent idle, strong mid range and powerful top end with a pipercross sausage filter.

Engine : Honda D16A6 w/ delta 272 cam running on ZX6R carbs.


Pilot jets - 35
( I did try 40s, it was way too rich even 1/4 turn out, exhaust stinks and runs strong but crap idle.)

Idle mixture screw (2-3/4 turns out)

Needle : 1mm up (raised 1mm)

Main jet - 165 - weak top end , stops revving at 6800rpm

Changed to 190 - revs keep going and feel peak power ~ 7200rpm.

Main air jet unblocked.

Hope that helps others...