Took the Sportster to the Harley Dealer to have it upgraded from 883 to 1200. All I am doing is boriing out the cylinders. No head work.I already have pipes and Screamin Eagle air cleaner along with a carb rejet. They are telling me that I will not realize any increase in power unless I do head work. Everything I've read says I will have increased torque in the low and mid range but will not have an increaseor at least not as much on top end.I thoughts on this.

 

I had my 883 converted to a 1250 by just changing cylinders and pistons, basically the same thing you are doing and I ended up with 65 hp and 70 torque. If that ain't an increase then I don't know what to say except I must have had a helluva powerful 883

 

I just had my 883l upgraded at my local indie. Same deal, just bored out the cylinders, new pistons and rings. I haven't gotten it back yet as it's still in winter storage, but I am told, by them, that I will definitely feel the increased power. Your harley dealer is probably just trying to get you to spend some more $$.

Rob

 

A co worker of mine did his 2005 carb'd 883.He bought new cylinders (on ebay!), and reused the 883 heads and used the 1200 dished pistons.He had a large hp increase.

jon

 

Tha 883 heads do not flow as much as the 1200 heads do. You will notice an increase in power but notas much as with the1200 heads. Switchingto the 1200 heads and you'll get even more.

 

that is bull you do not need head work....the 883 head will make plenty of power..bigger is not alwasy better....you will smoke any 1200 with that upgrade

 

towboattrash, you are right, you don't need any head work, however, a 1200 upgrade with 883 heads will not out run a 1200 with 1200 heads. The 1200 heads flow more, meaning more power. True, doing the upgrade without heads will get you more power, just not as much as you will get with the heads. As far as it smoking a regular 1200, I'd have to see that, and so far, I haven't seen it.

 

it should smoke a stock 1200 due to the lower gearing on the 883. top end the stock 1200 will win. Light to light? I think the 883 conversion would win.

Rob

 

so if you can make a 1200 by either, borring the barrels out, or by changing the heads, how many CC's can you get by doing both?

 

same amount of cc's, just more power by changing out the heads. not sure by how much.. it would be nice to see numbers regarding hp/torque just doing the cylinders and pistons vs cylinders, pistons, heads, cams....

anyone?????