GT750 - New Piston Problem

[speedblock]

After weeks and weeks of delays in getting my top end redone, I finally have all the parts in hand and had a few hours today for reassembly. I have a newly bored 2nd over cylinder and the pistons to match - or so I thought.

I grab the first left piston (from a box marked Suzuki 12103-31870-100) and to make a long story short, it won't fit over the small end bearing with the thrust washers in place. I immediately check the other left (same part number) and then the right piston and of course they are fine.

Looking at the 2 left pistons, one is clearly different. It's marked "S1.0" while the other is simply "1.0." The clearance inside is about 26mm on the good piston, and 24mm on the bad. The good one has a hammered look on the inside, while the other does not.

What the heck? This mystery piston is for some other bike and was maybe in the wrong box? I had them dropped shipped to the machine shop so I am assuming (maybe incorrectly) that one of my new bores matches this piston, which it now appears I can't use. I will contact the vendor tomorrow - anyone else ever run into this? Looks like more annoying delays in store for me.

This is frustrating.

[speedblock]

Just did a little reading and I am guess I have 1 old style piston (designed for big end thrust washers) and 2 new ones. Guess I need to see if I can get the vendor to send me the right one.

- Chris

[oldjapanesebikes]

Just did a little reading and I am guess I have 1 old style piston (designed for big end thrust washers) and 2 new ones. Guess I need to see if I can get the vendor to send me the right one. - Chris

Correct - really annoying, but hopefully you will be able to get the correct part.