Group K Modifications
Sleeper Engine Modification Kit – The 300 Sleeper engine kit, by Group K, is a quiet and reliable engine modification package that offers a totally stock looking engine compartment together with acceleration and peak speeds that will let you easily run with any stock 550. The wide powerband gives snappy acceleration at all waterspeeds, and the top speed increase is enough to let you go riding with the “big boys” and not get left behind. Our careful upgrading of the top end, cooling system, and intake system will make your 300 operate consistently and reliably on 92 octane pump gas. The detailed installation, maintenance, and tuning instructions will assure that you’ll have all the information you need to make your 300 everything that it can be. The Sleeper kit can also be suited to accommodate any aftermarket bolt-on parts that you may already have.
Peak water speed (with pump kit) smooth water; (js hull)-37.1 mph (sx) • hull-35.6mph
Sleeper pump blueprinting- For the 300 owner who wants a pump that’s up to par with a high output engine, Group K offers blueprinting and finishing of the pump vain case along with scoop grate matching. The end result is a ready to install pump assy that can process significantly more water per impeller revolution, and cavitates less in rough water. The result is better peak waterspeeds and acceleration in rough water conditions. (note: pump nozzle boring is not included since it’s part of our engine modif. kit)
Sleeper cylinder & head mod. only – The heart of the Sleeper kit is available separately, for the owner who has other bolt-on modifications already in place.
Ignition flywheel lightening – your flywheel loses .8 lb. To permit much quicker throttle response and better overall acceleration. Your engine will still retain full charging capabilities and smooth idling characteristics.
Cylinder boring – The top and bottom of your cylinder are prepped to assure flat locating surfaces. Then we bore, hone to size, and chamfer the ports of the cylinder. (piston is required for proper clearance setup, supplied by customer or Group K)
“Air Leak” Pressure test kit – The lower end of your engine should be totally air tight up to 8 psi. New engines pass this test with no problems. However engines with deteriorated crank seals or brittle intake gaskets can allow outside air to leak into the lower end during operation. This “air leak” can make the fuel mixture lean enough, at high rpms, to cause a piston seizure. Air leaks, not engine modifications, are by far the number one cause of watercraft engine piston seizures. Group K offers a simple to use pressure test kit that allows you to quickly test for any air leaks that your engine may have. This kit comes with block offs that will allow you to pressure test any Kawasaki, Yamaha, or Sea Doo model watercraft engine.
Package / Upgrade / Parts
Group K Price
Includes: cylinder Porting/decking and exhaust manifold matching, head milling and dome re-shape, carb boring and circuit modification, arrestor case matching and arrestor element, additional water bypass, exhaust resonator modification, pump nozzle bore, and ignition flywheel lightening.
Stock parts required for modification: cylinder, cylinder head, exhaust manifold and resonator,ccarb with brace, flame arrestor assembly, ignition Flywheel & aluminum pump nozzle
Separate Labor Prices
Group K Price
300 SLEEPER PORTING & MANIFOLD MATCH
MILL & SQUISH CUT CYLINDER HEAD
CARB BORE & INTERNAL CIRCUIT MODS
LIGHTEN FLYWHEEL- (.9 lb. reduction)
TOP END GASKET SET
BLUEPRINT PUMP-300 – (send pump & grate)
PUMP NOZZLE BORING
CYLINDER BORING HONING & CHAMFER (SINGLE)
AIR LEAK PRESSURE TEST KIT
Recommended Bolt On Parts
Group K Price
38mm Mikuni carburetor
Westcoast velocity stack flame arrestor
Skat Trak stainless steel impeller
Westcoast scoop grate
ORDER INFORMATION: SEND ALL PARTS REQUIRED FOR MODIFICATION VIA UPS TO:
GROUP K • 4597 CALLE DEL MEDIA • FORT MOHAVE, AZ. 86426 • (928) 763-7600
GETTING THE WORK DONE – Most customers send GROUP K the parts needed for modification via UPS, and then do the engine assembly work themselves. We also do complete engine and pump assemblies for customers who want a finished unit ready for installation. The 150-lb. UPS weight limit makes engine shipping practical and affordable. NOTE: Group K will bill an additional $25.00 handling charge for complete engine assemblies. All orders prepaid with a cashiers check or money order will be returned freight free via ups ground service anywhere in the continental United States. All other orders will be billed to a visa/master card or sent freight collect cod cash. If you would like to pay additional for 3 day, 2 day, or 1 day return shipment, please specify your preference in a cover letter with your parts. Be sure to include your return address and day phone information in case we have any questions regarding your order. PACK YOUR PARTS CAREFULLY !!