Yamaha FZ-1 2001 and up Ivans Jet Kit

Price: £109.99 inc. VAT (£91.66 ex. VAT)
Postage & Packaging Worldwide: £4.99 inc VAT (£4.15 ex VAT)

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Why buy this kit instead of another brand ?

The Yamaha FZ-1 2001 and up Ivans Jet Kit is designed to enable the carburetors to produce the maximum performance and efficiency that can be obtained.
The factory compromises for emissions and fuel economy (stock needles) are replaced with new needles for optimum performance at all rpm and throttle openings.

The FZ-1 has several carburetion problems in it's stock form. My kit takes the approach of fixing all of these problems at their source. There is also no need for any additional 'tuning' after installation. The thorough R&D on the kit makes it truly 'plug and play'. Just install it and go.

Vibration at light steady throttle:
Most noticeable in the 3800 to 5000 rpm range.
This is due to the excessively large spacing of the three pilot bypass holes. The throttle plate has to uncover the next hole before more fuel can flow from this circuit. Fitting larger pilot jets will make no difference to steady state operation at light throttle due to the fact that the next hole is not yet uncovered. Raising the needle does not help because the throttle plates have not been open far enough to expose the needle circuit during light throttle cruise. The result is surging and buzzing that cannot be eliminated without modifications to this circuit.

The solution is to:
Enlarge the pilot bypass holes. Enlarging these holes in the throat of the carb makes available just the proper amount of additional fuel volume at exactly the correct throttle opening.
Adjust the mixture screws for a richer mix.
Synchronize the carburetors.
Dynamically adjust the throttle position sensor. This also contributes to the smoothness and takes care of all the ignition timing issues under 4000 rpm.

Flooding when parked overnight causing the throttle to be partially opened when starting cold with the choke:
This flooding condition is due to excessive fuel in the carburetor's float chambers which overspills slowly when the bike is parked. The cylinders become 'wet' and slightly flooded, causing the rider to be forced to open the throttle slightly on a cold start with the choke. With the Yamaha FZ-1 2001 and up Ivans Jet Kit installation the floats are readjusted to alter the fuel level vastly improving the condition.

Stock jetting causes an overly rich fuel fuel mixture at full throttle above 8000 rpm:
Full throttle operation with stock jetting above 8000 rpm is overly rich. In order to correct this problem, smaller main jets are supplied optimized for use with the needles that come with the kit.
The original main jets that come with the bike are of a different size on cylinders 1&4 as compared to 2&3....
Repeated dyno testing and exhaust gas analysis has shown a higher and wider power peak as well as a more consistent fuel mixture throughout the rpm range at full throttle with these new main jets.
All of these tests were comfirmed by road testing against another bike under controlled conditions.

Excessively lean fuel mixture at part throttle at any rpm:
The area of part throttle lean condition can only be fixed with a different needle taper. The single, very shallow, taper of the stock needles simply cannot cope with the fuel requirements to keep a consistent fuel mixture, making more heat, vibration, and lazy acceleration.
The custom needles have five separate angles in their design to give the most consistent fuel delivery possible. The result is a seamless power delivery, excellent mileage, and smooth driveability in normal everyday use with no sacrifice in top end power or midrange roll-on.
The needles that were chosen are the result of exhaustive testing in all kinds of weather on the road and on the dyno in conjunction with exhaust gas analysis. Over 70 different prototype needles were tested before settling on the ones that come with My kit. Over 900 dyno runs were logged as well during development on carburetion tests alone.

Lazy throttle response throughout the rpm range as compared to the R1:
The stock bike has lazy throttle response due to heavy slide springs that control the vacuum pistons (carburetor slides).
By clipping the springs to the desired tension, throttle response will become instantaneous and the delay on full throttle shifts will be eliminated. The result is a much more responsive engine.
By enlarging the slide's air displacement holes, you will be allowing them to lift and return a little more quickly, and also to match the new spring tension, and provide the desired improved response.

Other kits that use the stock needles with an airbox mod will have excessively lean fuel mixtures at part throttle and at full throttle operation throughout the midrange....
(4500 thru 9500 rpm at throttle openings larger than 20%)
Causing a/f ratios to be leaner than 16-1 and getting as lean as 18-1 in some areas.

This is due to the fact that the stock needles cannot supply enough fuel at part throttle with an un-modified airbox with stock jetting... let alone a modified airbox with reduced main jets.

Installation time for this kit is just 15 minutes more than any other kit.

IMPORTANT NOTE:
Remember!
This is an R1 motor. Ignition advancers are not recommended unless you have significantly raised the compression!

SG Motorsport are the global distributor (excluding the USA) of Ivans Performance Products, these are offered via the inter-bike site for purchase direct from SG Motorsport. (Please read SG Motorsports Terms and Conditions before purchasing).