2023-03-01 KZ1300 - Top End Rebuild Thoughts

My 79 A1 was rebuilt by Ray Slocomb, RIP, approx 2014. The build was fraught with issues. 

• The head gasket, bought in a kit from Cruizin Image immediately leaked upon installation, engine cold, no cooling system pressure!

• Ray phooked up when installing rings on a piston, later found scoring, so new liner from LA Sleeve was procured.

• The bike ran 'hot' all the time. 

• It burned oil, about 1/2 quart every 120 miles or so as shown on spark plugs (this pic not the worst pic of oily plugs, just the first I found) Also, oil consumption has improved with miles and time, but still not right... 

• Water pump leaks

• Base gasket leaks

• During break in procces, some idiot left the petcock on, the crankcases filled with gas, and the bike was run that way... with diluted oil

Long of short, thinking of rebuilding the top end, of returning to stock bore to reduce, slightly, the heat load on the marginal cooling system. BUT, that requires new liners.

Some issues though…

1. Cylinder Bore

   • ​The Cruizin Image kit runs 64 mm pistons, stock is 62 mm. 

• • So I called LA Sleeve, who made a liner for Ray Slocomb after the upside-down ring was found that scored the cylinder wall.l.

  • Spoke with ‘Dave’. He remembered and actually found the work order from the sleeve Ray purchased. The breakdown is this:

  • $160 per sleeve

  • $225 labor per sleeve

  • Up to 3 months to make them

  • Doing the math, (225+160) * 6 equals a staggering $2,310

2. Pistons

   • ​Kawboy, from KZ1300.com, discovered/confirmed that a KZ650 uses identical pistons!

• • A PartZilla search shows the following:

    This Kawasaki 13027-069 PISTON,0.040in.,O.S. fits the following models and components: Kawasaki Motorcycle 1980 LTD - KZ650-E1 Cylinder/Pistons Kawasaki Motorcycle 1980 KZ650-F1 Cylinder/Pistons Kawasaki Motorcycle 1983 CSR - KZ650-H3 CYLINDER/PISTONS ('81-'82 H1/H2) Kawasaki Motorcycle 1982 CSR - KZ650-H2 CYLINDER/PISTONS ('81-'82 H1/H2) Kawasaki Motorcycle 1981 CSR - KZ650-H1 CYLINDER/PISTONS ('81-'82 H1/H2) Kawasaki Motorcycle 1979 SR - KZ650-D2 CYLINDER/PISTONS/CRANKSHAFT Kawasaki Motorcycle 1978 SR - KZ650-D1 CYLINDER/PISTONS/CRANKSHAFT Kawasaki Motorcycle 1977 KZ650-B1 CYLINDER/PISTONS/CRANKSHAFT Kawasaki Motorcycle 1979 KZ650-B3 CYLINDER/PISTONS/CRANKSHAFT Kawasaki Motorcycle 1978 SR - KZ650-D1A CYLINDER/PISTONS/CRANKSHAFT Kawasaki Motorcycle 1978 KZ650-B2 CYLINDER/PISTONS/CRANKSHAFT

     

  • Called Wiseco, spoke with 'Alan', he sounds like a long time employee and gear head..
    Yes indeed the:

• Wiseco part is 4037M06400

• The pic on the website is incorrect (new website, still applying lipstick, including correct pics and a 'cart' to purchase

• Wiseco price is 192.38 USD, they have 6 in stock, will take 6 - 12 weeks to mfr new IF orders come in

• eBay has many vendors at ~153 USD

• Alan confirmed that these have previously been sold to KZ1300 customers

• He also stated that forged pistons are much stronger than cast and, more importantly, that

• Ring material and quality is vastly improved over ~1980 technology *especially the oil rings

​SUMMARY

My thinking is to purchase the Wiseco forged pistons, hope they match well to current bore size. If not, well, liners might be needed...