what do the stock pistons for a 1974 z1 900 engine look like?

i was told my bike had a kit in it but i dont know for sure

also could someone decode these vin #'s for me

kzt00g-500087

and my engine vin

z1e048438

Not much to decode on the motor, looks like a 75 Z1B 900cc engine, the 80 number I have no clue about but they were all 1000's. Id guess thats a frame number which tells you nothing but the serial number

The frame VIN tells me that you have an early Z1 Classic frame 1980 KZ1000G1. Look at www.zedder.com to confirm. The stock pistons are a shade under 70mm (69.7mm I think) and have ART stamped on them with an arrow pointing towards the front if memory serves. The OEM piston will have a slightly domed top that is smooth. If you have aftermarket pistons there is usually something stamped on the piston that will indicate the manufacturer AND the domes will not be smooth and only slightly domed. They will usually have more pronounced domes and a non-symmetrical shape. The piston pins will be retained by thin wire clips if they are stock and generally be retained by thicker wire clips or circlips or buttons if aftermarket is used. If there is a kit in a 903 block, it can be no more than 1015cc (70mm diameter) unless new sleeves are used (I think this is true but I am old and my memory bad).

Id say thats probably right, my 900 motor is sleeved to 1105. It belonged to a friend who let the bike set up and go to crap in the Fla salt air so I got it for free & paid $600 to have it shipped from Fla to Mt. He originally paid Superbike Mike close to $4500 for it back in the late 70s. I cleaned it up and went thru the top end and put it in a 78 frame I had

i went and measured the pistons turns out my bike has the stock pistons in it

thanks for the website with the vin numbers that was a big help i thought my engine was a 74 z1 but it is a 1975 z1-b engine

cutmesomeslackjk wrote:

i went and measured the pistons turns out my bike has the stock pistons in it

We can fix that. We can turn that:( into a :woohoo:

Jay

APE Jay wrote:

cutmesomeslackjk wrote:

i went and measured the pistons turns out my bike has the stock pistons in it

We can fix that. We can turn that:( into a :woohoo:

Jay

:woohoo:

lol yeah i bet you could change that...but i dont have the $$$$ for you to do so...all the project money i have for this bike is about $200 and that would not even buy me a stock kit