Maximizing Performance on Your Kawasaki Ultra 150: Head Modifications, Impellers, and Pump Upgrades

My favorite part of your Ezine is the question and answer portion. I always learn something new and now I have a question. I have a 2002 Kawasaki Ultra 150 with aftermarket reeds as the only add-on. I want more speed/quickness and wonder what you would suggest to get the best performance per dollar?

I was thinking of a new prop, but don't know what size. Will an intake grate help? What about a ride plate? What will each do to help performance? Would an aftermarket head be too hard on the engine? I don't want to shorten the life or reliability.

​Bill Oneal'

RESPONSE
​​Many Ultra owners have asked similar questions before. While the reeds you have added are a nice touch, they don't really result in significant power gains for the money spent.
The best value for money upgrade for Ultra 150s is a head modification to slightly increase compression ($190), and an aftermarket Solas impeller with shimming. While there are various aftermarket heads available for purchase, many owners prefer to modify the stock heads to a 91-octane-safe specification as it is a functional and less expensive option. This upgrade doesn't require any jetting changes and significantly improves overall acceleration.

The Solas 16/20 Dynafly impeller is the most popular Jet Ski impeller for your Ultra, offering better hook-up and peak speeds. However, it alone does not address all the jet pump issues. The jet pump bearings and seals are the Ultra's Achilles heel, with seals failing every 40-50 operating hours, causing water to compromise the bearings. Since the Ultra has a tapered impeller and outer housing that must be precisely shimmed, a compromised pump bearing is a significant problem.

Most Ultra owners opt to send their pump to an experienced shop to address the collective pump issues. At Impellers.com, we break down the entire pump assembly, install new bearings and seals, install the new Solas Impeller, and precisely shim it. This upgrade costs $490 for parts and labor and significantly improves overall performance.

A scoop grate is a good addition if you do a lot of high-speed riding in rough water, but it will cause a slight loss of smooth-water peak speeds. I hope this helps.

​Impellers.com