Hi Guys, just wondering if anyone knows if it's a big job to change my 2003 fatboy 88ci over to a 96 ci ? I have a brand new set of 96ci cylinders and pistons, What else do I need and is it a good idea or am I just asking for problems ?

Thanks

 

The 96 " pistons and cylinders are for a 4.38" stroke, yours is 4". That's why the 96 is no longer an 88. So no, they won't work.

However, a 95" upgrade ( pistons and cylinders,) for your 88 is relatively inexpensive, and will work

 

Exactly! Unless you want to spend a lot of money for a new flywheel, just have your current cylinders bored and get the corresponding pistons to bump it up to 95 cubic inches,

 

"The 96 " pistons and cylinders are for a 4.38" stroke, yours is 4". That's why the 96 is no longer an 88. So no, they won't work."

About says it all. If you're looking for increased performance, consider a 95", or if you prefer more cubes, 98" big bore kit. Both will kick a 96" motor squarely in the nuts.
Many good shops offer both 95" & 98" big bore conversion kits, comes with everything you need, or you can send them your cylinders and heads for boring and headwork.
Hillside Cycles, a forum sponsor, does both. Or just google 95" or 98" Big Bore kits.