performance question.

[do-work-son]

Every piston I have seen has a size on it and a series number the 72 is bore size

 

[clrkaw26]

Also while I have the head off I measured the stroke like suggested and I'm getting 57.150 mm. Stock shows 54 and 57.150 is just shy of +4, is this a + 4 crank?

[clrkaw26]

Mine says 100 and that's it. Nothing else

[oldskool]

Since you have head off, measure bore and stroke. If your piston comes above cylinder deck about 2mm, you got a +4mil crank. Wait a minute. Do you see a spacer plate between cylinders and case? A spacer would also indicate a stroked crank

[clrkaw26]

I do not see a spacer. But I did measure approximately 57.150 mm stroke from top to bottom.

[clrkaw26]

Update, I pulled the jug and the inside of the piston says prox31k and the crank has an N on one side and it looks like 28L or 29L on the other, do you know what this means?

[sstaton1983]

take a pic of the top of the piston and post it . I cant find anything with number.

[clrkaw26]

I have tried a few times to post pics but it always say file too large.

[clrkaw26]

Ok, I think what I have is a 1mm bore to 65mm cylinders and pro x pistons on a stock crank with some port work, thanks to all snd if you think this is incorrect please inform.

[2004LEBanshee]

There is either a spacer plate or cut domes. If there is cutdomes the piston will stick out past the deck of the cylinders. Easy to see.