I am wondering if there is any way to tell if a bike has been bored out without pulling the heads? I just got an 89 883 sportster and I do not know the history of what has been done to the bike but I suspect it has a big bore kit.

Thanks,

Mike

 

Look at the base of the cylinders where they meet the block. If your engine has the black wrinkle finish or any type of paint, you might see some chips in that area which indicate the jugs have been pulled off, POSSSIBLY for boring.

Depending on how it was done, a compression test could provide an answer as some 883 to 1200 conversions result in higher compression.

You could also have it dyno'd if you like throwing money away.

You could also find a friend with a sportster and race him.

 

Just ride an 883. You'll know right away.

 

if you can find out what kind of piston top came stock on that years 883 you could compare it to whats in the bike by peering into the cylinder with a borescope. For example ... if the bike came from the factory with a flap top piston, and you peer into the bore and see a domed piston i think it would be a pretty good bet that in addition to a different piston the previous owner took it out to 1200cc

 

Unless there's a record of it being done, the only way is to pull the head and measure the cylinder bore.