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GroupK - High Performance Personal Watercraft

Technical information and updates about high performance personal watercrafts

Group K 4597 Calle Del Media   Fort Mohave, AZ. 86426    928-763-7600

About Group K - Group K is an 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, Kawasaki, Polaris, and Tigershark watercraft.  2000 will be our 14th year building race and recreational personal watercraft. Prior to that, our technicians had 15 years of high performance two-stroke experience with national level road racing and motocross motorcycles, as well as racing ATVs and Super Lites (also known as Honda Odysseys).
What We Do - The engine work by Group K consists primarily of modification to existing pieces. We also build complete race machines. Unlike other aftermarket companies, we do not manufacture or distribute any after market bolt on parts. This gives us the freedom to test all available pieces, and recommend the bolt on parts that offer the best performance and value ... regardless of manufacturer. Since all of our tests are conducted ONLY on machines equipped with our modifications, we cannot confirm which parts will work best on stock machines (or machines modified by other shops). Nonetheless, it has been our general experience that what works best with our kits ... works best on most setups.
Furthermore we do not sponsor any racers or race teams. We find it to be a conflict of interest to hire a professional rider to go out to beat our customers. As an added conflict, paying customers will never believe that they are buying exactly the same equipment as the sponsored rider has. We have pro racers that do most of our high speed test riding. However, to us, they're just test riders and nothing more.
The Purpose of Our Files --  The primary theme of virtually all of our files is the technology, and what it's worth in dollars. At Group K we believe that every kind of technology has to justify its price tag with a real world value. Because we have such an impartial attitude about various aftermarket parts, we get many telephone calls from PWC owners seeking general information about what modifications and parts (for the money spent) will work best on their machine. Unfortunately, our high paced work load permits our technicians only a limited amount of time for phone conversations. Rather than engage in lengthy phone calls, we usually offer to mail our detailed and "model specific" technical pamphlets to the caller.
The purpose of our Internet site is to offer inquisitive owners the full measure of information they want, without a lengthy telephone call. This reduces the customer's phone bill, and saves our technician's valuable time. We prefer that phone calls with our customers be focused on suiting their particular performance needs ... not on lengthy technical dissertations.
About The Files --  Our technical files are broken down in three separate menus.

Menu A contains a group of files that are updated each 30 days (about). These files contain the latest information on current technical issues. Particularly unique is the Between The Lines file which comments on most current magazine technical articles. Be sure to read the introduction first.

Menu B contains the product literature sheets that we mail out to customers. They are all different and exclusive to the particular machines listed

Menu C  contains a collection of technical articles (many have been published in various PWC magazines)

About our Content  --  This site is not a forum, or a soap box, for various causes. The information in these files is the result of our current hands on experiences and on going field tests. It's likely that some individuals may question some of our content ... that's expected.   However the results of our field testing experiences are much harder to question. It is also our intention to avoid political issues except where they directly effect relevant technical issues. There are already enough folks involved in the political mud slinging business.
We ask that you forgive the occasional "typos" that have escaped our spell-checker and proof reads.  We hope that the quality of our text will compensate for our lack of editorial perfection.
About Responding --  We certainly appreciate your comments and input with regards to the technical information in all our files. Unfortunately, time does not permit us to respond to all e-mail inquiries. Our e mail address is <groupklemm@aol.com> We'll periodically try to respond to as many as possible, whether by direct response or an added entry to our Menu A files. For customers who have additional questions about the Group K modifications or engine kits outlined in Menu C, please feel free to contact one of our technicians by phone at 928-763-7600. Happy Reading.

     MENU A


Between The Lines Preface
Between The Lines  Jan-Dec 97
Between The Lines Jan-Dec 96
Group K Garage Sale Page June 1999



     MENU B


Kawasaki Ultra 1350cc Big Bore Kit

Yamaha 2000 GRP/XL Recreational Modifications

Sea Doo 951 Y2K Engine Kits

Sea Doo Jet Boat Performance Modifications - Single Engine

Yamaha 1999 XL Limited 1200 Modifications

Yamaha Super Jet Racing Modification - All Years

Kawasaki Ultra 150

Yamaha GP 800 Single Pipe Modification Kits

Racing Carburetors 1999

Yamaha 1200 Hammer Kits w/FPP Triple Pipes

Kawasaki 1100 Big Bore Hammer

Polaris 96/97 SLTX 1050 Sleeper & Triple Pipe Kits







June 1999

March 1999

Feb 1999

Oct. 1998

Oct. 1998

Oct. 1998

Sea Doo 785 Recreational Engines Sept. 1997
Sea Doo 785 Race Engines Sept. 1997
Sea Doo 785 Technical Updates March 1998
Sea Doo 720 Race Engines

Sea Doo 720 Recreational Engines  

Sea Doo 950 Technical Updates

Yamaha 1100/1200 Triples

Feb. '99

Oct. '98

Dec 1997

Oct 1998

Yam 633/701 '90-'95 Oct. 1998
Yam 701 Dual Carb Models Oct. 1997
Yamaha WaveBlaster 2 April 1997
Big Bore Kits for 701 Yamahas
Yamaha Triples Updates December 1998
Kawasaki Modifications July 1997
Tigershark 650 all
Polaris 750 all



     MENU C


Competition and High Performance PWCs for 1998 Jan. 1998
Carb Tuning '98 Nov. 1997
Carb Tuning '95
About Rear Cylinder Piston Seizures
About Piston Seizures
Gasolines '96-'97
Gasolines '95-'96
About Air Leaks
About Compression
About Instruments
About PWC Modification
About Yamaha Strokers
Technical Letters Dec. 1996
New Testing & New Stuff Nov. 1996
Off Shore Racing '97 March 1997
Off Shore Racing '96 Aug. 1996
Tech Currents Racing May 1996