TZ750 Cylinder, Head, Pistons and Sundries For-Sale

For Sale: TZ750A (#40900 - 347cc) Cylinder, Head, 2 NOS Pistons and Rings, 2 Good Used Pistons and Rings, 2 Reed Blocks, the Water Inlet Fitting, and 2 Brass Drain Plugs.


Very little wear in the quite nice barrel, but with issues - there are several visible 'bumps' in the plating; they can barely be felt so may hone out. I cannot tell if plating is chrome or Nikasil, but it looks like it's been replated because of how nice it is. Worst case it will need replating with no damage repair. If crucial to the buyer, the cylinders could be bored to 66.4mm before a replate. (castings are the same).

The displacement difference between the 40900-64mm and the later 40970-66.4mm bores is 26.5cc. If you race, these cylinders will pass a 350cc protest. Performance is similar; 40900 and 40970 port-maps are identical. There is a little more meat for transfer port mods if desired with the 64mm barrels.

The head is the proper 64mm diameter. The combustion chambers look near-new, being freshly polished and with no damage or detonation marks. This is the proper head for the 64mm 40900 barrel with 11-degree squish-band angle - stock.

Both pair of pistons have had the typical period modification - the intake window areas of the skirts have been removed and smoothed ala 1X2 because the window-bridges tended to crack or break. Racers also did this to increase intake flow by removing the obstruction caused by the long, windowed skirts. The final version of the 66.4mm 1X2 pistons have short non-windowed intake skirts with similar port timing to the modified windowed pistons.

Piston skirt loading is more an issue with the forward-spinning cranks of the twins than the backward-spinning TZ750 cranks; loads on the power stroke are intake-side instead of exhaust-side like on the 750. Wristpin offset is opposite too. Wonder if it's possible to retro-fit RD350 pistons? That would solve a couple issues!
Back in TD1 days, racers would use YDS3 pistons in a pinch, and only run a single ring to reduce friction; the TD1A originally used the standard 2-ring YDS2 pistons with both rings installed.

Sundries include the inlet spigot: P.N. 383-12498 and the 2 coolant drain-plugs: P.N. 383-11374. I'll also include a full set of used head bolts: 8 blue alloy 'nuts' and 3 steel bolts (not pictured), plus any extra O-rings and seals I can find - just ask.

$1000 / ONO plus shipping (large Priority box) from Phoenix - 85375. PM through the site, or call Warren at 60Two- 653-One876 for additional pictures or info. Thanks for looking!

 

Price Drop: $800/OBO.

 

SOLD