Monday, 12 January 2015

Glass blasting and boring T250J cylinders

My T250J cylinders were in a pretty bad condition when I bought the bike. Other cylinder had deep grooves inside the cylinder sleeve which had to be removed by boring the cylinder to the next oversize. Bore was 55.00 mm (stock is 54.00 mm) before so the next step would be 55.50 mm.

Before I dropped the cylinders to my local machine shop to get bored I glass blasted them. I covered all the holes and ports in the cylinders were I didn't want the glass get into with a masking tape. I also removed rubber cushions from the cylinder heads. Both of them had 11 cushions between the cooling fins. Before blasting I used diesel fuel to get all the excess dirt out. Glass blasting is usually used for surface finishing so it might be necessary to sandblast the parts you are cleaning first. My cylinders had thick oil and dirt stains which needed to be sandblasted to get rid off. Below are some pictures of my overhauled Suzuki T250J cylinders and heads.






Suzuki T250J cylinder sleeve. Bore is 55.50 mm
(+1.50 mm/0.060" oversize).
Intake port of Suzuki T250J cylinder.
Exhaust port of Suzuki T250J cylinder.
Left side port of Suzuki T250J cylinder.
Right side port of Suzuki T250J cylinder.

Wednesday, 7 January 2015

NOS Wiseco piston set for T250 and GT250 - Suzuki T250J

T250's, GT250's and T350's have different size connecting rods which affects your piston choice. I choosed to use T350, GT 250 K/L connecting rods which have 21 mm small end eye diameter. Piston pin diameter in this case is 16 mm. T250's con rods normally have 18 mm small end eye diameter and the piston pin diameter is 14 mm. Other measurements in connecting rods are the same. T305' and T350's pistons have 16 mm piston pins. That is also one reason why I decided to go with GT250 K/L connecting rods.

Pair of NOS Wiseco piston sets for Suzuki T250 and GT250
(55.50 mm, +1.50 mm/0.060" oversize).

One set includes piston, piston rings and piston pin clips.
Piston pins and small end bearing are not included.

Part one of installation instructions for
Suzuki T250 and GT250 Wiseco pistons. 

Part two of installation instructions for
Suzuki T250 and GT250 Wiseco pistons.

Piston speed in relation to crank angle at different rotation speeds.

Piston acceleration in relation to crank angle at different rotation speeds.