TZ-250G YAMAHA (1980) Cylinder 4A100.   Used, very good condition.  

Bores have been Nikasil'd.  

Good cross hatch except for port corners.  No Modified Porting, No detonation damage.  

Fastest Trap Speed @ Daytona with this item with TZ250G Pipes and 34mm Lectron carbs.
(carbs and pipes not included, cylinder only being sold.)

Note,, the article I attached says I was riding a TZ250G in the picture but that is incorrect the 
bike in the picture is a "H" model...  I really liked that bike and did well on it...