Group K has been building Race and Recreational Watercraft since 1986. Our Professional Aftermarket High Performance Shop specializes in Engine Modification Kits for Yamaha • Sea …

The porting mods used in all our 550 kits is the result of many months of performance and wear evaluation testing. We confidently claim that GROUP K cylinder porting will yield a wider …

Group K is a professional aftermarket high performance shop in Fort Mohave Arizona (about 50 miles north of Lake Havasu) that specializes in engine modification kits for Yamaha, Sea Doo, …

To start viewing messages, select the forum that you want to visit from the selection below. PWC advice, by Harry Klemm, Owner of GroupK, a professional aftermarket high performance …

2006年10月3日 · Has anyone done the Group K Retro mod (stock pipe) to their 650sx??? They have presented the information in a very easy to understand form and the price of the machine …

Experience big fun on the water with our exciting lineup of Jet Ski® personal watercraft. With industry-leading performance and technology across the board, you’ll be sure to make waves …

2008年1月17日 · Group K offers the same throat boring mod for these as the singles. These bored 40mm(and 38mm) Keihins can easily meet the fuel demands of the most heavily …

We confidently claim that Group K cylinder porting will yield a wider power band and longer piston life than any other porting modification available anywhere. All Group K porting includes …

Coming from a Yamaha perspective, I can't say enough good things about Group K. My 97GP1200 has 206 hours on the Group K pump gas Sleeper kit. I still have good compression …

The JS550 was the flagship stand-up jet ski in Kawasaki’s fleet from 1982 through 1989. It was built on the proven JS hull and featured a 2-stroke, 530cc, vertical twin engine rated at 36/41 …