Originally Posted by 03custom883
Now on the same bike with a 1250 will that hp and tq value be any higher since its
Better quality stuff and slightly bigger displacement. Sorry to hijack just asking since
I have an 03 rigid as well except with se a/c and v&h pipes(straight shots)
Madnss is correct ...
The 1250 kit is about 4% more displacement than a 1200, and to the extent displacement is limiting power, that means about 4% more power. However, they tend to give more on the order of 5-7% due to the bump in compression, and also due to the unshrouding effect of a larger bore. With stock 883 heads those gains will also tend to be down low, as the heads constrain the motor at higher rpm's anyway, i.e. the displacement isn't what constrains it.
Where the 1250 kit really shines is at higher horsepower levels. Additional power gets quite a bit more expensive as you move up the scale, and the 1250 kit becomes some of the cheapest power you can buy.
That said, if you're converting from an 883, it can make a lot more sense, as it's only a couple hundred bucks more than the 1200 conversion, and you get much better cylinders
in the process. Now you're talking 3-5 more hp for an additional $200 which is a much more reasonable proposition.
makes sense for 2009 and newer 883's as their cylinders can't be bored, and therefore you need to buy new cylinders to do a conversion anyway.
One thing about the conversion pistons, they lock you into 883 heads. That's why in the other thread I recommended a competition valve job on 883 heads
, to both fix the major restriction in those heads and make the chamber bigger, and a set of flat top pistons instead. That makes an enormous difference in those heads. We've had multiple customers make mid 80's for torque and power both, using a flat top 1250 kit, a competition valve job on their 883 heads, and a set of cams
. They're real arm stretchers. A competition valve job costs less than half what even the lowest cost porting job costs, too.
Your bike, being a solid mount, would especially benefit from the ultra lightweight pistons
that come in the HAMMER 1250 kit
. Less reciprocating weight reduces vibration, reduces wear and tear on the lower end, and makes more power. Ours will come closer to matching the weight of your stock 883 pistons than any other pistons on the market. They've been 100% reliable for us, too.