It is generally not our policy to release actual dyno test numbers. But as a part of researching our new drop in cams for the ZRX we did an extensive test series and we'd like to share that with our customers. A cautionary note: These numbers are for our bike, on our dyno, on a given day. Please use them for comparative purposes only, Your actual numbers may vary but the percentages of change should be very close, given the same equipment.

The following definitions and conditions apply to this test series:

"Box stock" This is a 1999 ZRX-1100C3 with 5500 miles of fairly aggressive use.

"Stage 1" This refers to a DynoJet jet kit utilizing new slide springs, needles and main jets with the stock Kawasaki air filter.

"Stage 3" This is a DynoJet jet kit with new slide springs, needles and main jets and four K&N paper air filters.

"Air Box Mod" This is simply the removal of the stock air inlet silencer.

"Muzzy Bolt-on" This is the Muzzy oval carbon bolt-on muffler attached to the stock head pipe system.

"Muzzy Full Exhaust" This is a standard stainless steel Muzzy 4-2-1 exhaust with any of the standard round, oval or megaphone muffler configurations. ("Quiet" muffler options will reduce peak power numbers slightly).

"Muzzy Drop-In Cams" These are the new Muzzy camshafts (P/N 1199-OZR) with identical timing to stock ZX-11D camshafts. They were installed utilizing the stock ZRX sprockets, without any "degreeing". The stock ZRX lobe centers are 100 deg. on both inlet and exhaust.

"Cost Factor or "CF" This is what each 1% of HP gain will cost you at Muzzys' suggested retail price.

Jetting was optimized for each configuration and the test was carried out on our Schenk Eddy Current Dynamometer. The engine was stabilized at wide open throttle at each rpm increment and held for approximately 10 seconds, power was reduced, the RPM reset and power re-applied and held at the next level. Numbers are rear wheel power, corrected to standard day, sea level conditions. An analysis of the dyno charts will show the following percentages of increase or decrease in peak power and torque over the stock bike as well as a relative cost / benefit factor.

A little digging on the full charts turns up some interesting points.

The best thing to do from a cost/ benefit standpoint is also the least expensive. This is the stage 1 jet kit on the stock bike.

The next best "CF" requires the largest expenditure which is the cam / full exhaust / jet kit combination which gives you a huge 29% increase in peak power. In between, the best deal seems to be the full exhaust and the stage 1 jet which gives you a 14% increase in peak power.

Equally apparent is what you don't want to do, which is install the drop in cams without the full exhaust system and jet kit / air box to allow them to work. You actually end up losing torque and gain very little power. If you want to install the cams, do so with the full exhaust and stage 1 jetting. Something to keep in mind is that the ZRX was designed to be "torquey" and when you install the cams, exhaust, and jets the torque peak moves from 6500 RPM on the stocker up to 8500 RPM. The bike will feel very different. The torque at 6500 is still slightly higher than stock but it takes off from there and doesn't drop off until after 10,000 RPM.

The bolt on muffler with the stage 3 jet and K&Ns works pretty well at a 9% increase in peak power but for only a few dollars ($63) more for the full exhaust system you get 5% more power at 14%.

The ZRX with the drop in cams, full exhaust and appropriate jetting is a gas to ride and for the dollars spent, gives one of the best rides around.

We believe in an educated consumer, we hope this helps. Feel free to E-mail us with specific questions.