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Raising the Jet Needle
- daveo
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My KZ1100 engine is completely stock, except for a V&H header with the street baffle (no glass wrap), and Dynatek 2000/mini-coil ignition.
I've opted to use the stock air box with a K&N washable filter, rather than convert to pods.
Here is the BS34 carburetor set up: main jets 125 (stock spec is 120) with the original jet needles raised 1mm, and the pilot jets 37.5 (stock spec)
The modifications are confined to the main jets (two steps up) and raised needles. I'm planing to change the main jets to 122.5, and am wondering...
Is it necessary to raise the needles?
1982 KZ1100-A2
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- baldy110
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- koolaid_kid
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When you go larger on the main, it has the effect of raising the needle already due to the larger diameter opening at any point you are on the needle. No need to do it twice.
1983 GPz 750
810 Wiseco, Kerker, K&N, DynoJet S3, Accel, Progressive, etc.
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- Haybus
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- Big Al
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www.Sudco.com/Carburetor02.html
Alan
1976 KZ900 LTD (sort of)
2005 FJR
2009 Hayabusa
www.kzrider.com/forum/11-projects/557845...-streetfighter-build
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- daveo
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- daveo
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I dropped the needles back down to the (non-adjustable?) stock position, and put in the 122.5 main jets. All it needed was to up one size on the main jet...and that's it!
Thanks a Trillion for the push!
1982 KZ1100-A2
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
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koolaid_kid wrote: +1.
When you go larger on the main, it has the effect of raising the needle already due to the larger diameter opening at any point you are on the needle. No need to do it twice.
Must be referring to the Needle Jet/ Emulsion tube, not the Main Jet there. The Needle goes into the Needle Jet. Changing the main will have the most effect on 3/4 throttle and up, although it can map across more of the throttle opening.
1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- koolaid_kid
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On a Mikuni BS34? The main has a direct effect on the needle, which is why you tune the main first, then the needle.Motor Head wrote:
koolaid_kid wrote: +1.
When you go larger on the main, it has the effect of raising the needle already due to the larger diameter opening at any point you are on the needle. No need to do it twice.
Must be referring to the Needle Jet/ Emulsion tube, not the Main Jet there. The Needle goes into the Needle Jet. Changing the main will have the most effect on 3/4 throttle and up, although it can map across more of the throttle opening.
1983 GPz 750
810 Wiseco, Kerker, K&N, DynoJet S3, Accel, Progressive, etc.
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