Anybody who has done the hammer 1250 kit on a rubber mount Sportster, did the vibration go up or stay about the same. I was wondering if the larger pistons will throw it out of balance a little bit. Thanks.

 

If I had to say it did anything, I'd say maybe a bit less vibration. FYI, the new pistons are lighter than the stock pistons.

 

I agree with Charley. The good 1250 kits from folks like NRHS and hammer use lighter than stock pistons even with the bigger bore size so the vibrations actually go down in most cases.

 

Thanks guys, That's what I was hoping.

 

Got this from Hammer...
883's and 1200's share the same crank, literally the same part number, and they're balanced the same. It's been that way since 1995. Yet the stock 1200 piston is about 120 grams heavier than the stock 883 piston. The factory balances the crank for a piston weight that's in between the two.

Well, we have over a dozen different 1250 pistons for different applications, and they vary a little in weight from one dome configuration to the next, but every single one of them is in between the stock 883 and stock 1200 piston in weight. So the balance actually comes out better. Our common reverse dome 883-1250 conversion piston (our best seller, as used in the Basic Conversion Package) sits almost exactly half way between an 883 and a 1200 piston in weight. It's just a little lighter than the halfway point.

http://www.hammerperf.com/883conversions.shtml#balance

 

The info regarding balance is right on regarding the Hammer & NRHS 1250 upgrades.

You should keep two things in mind though-

If you go to a different set of cams, that can have an effect on vibration (usually one of increasing it)

Vibration (or movement of the engine) does not come just from balance. It also comes from the strength of the power stroke.

With the higher compression that comes with either kit, there is more power generated in each stroke, this is something you can feel...not sure I would call it vibration, but it is a stronger feel.

 

Thanks, I would be keeping the stock cams. I don't know what I'm going to do right now. I'm either keeping the sportster and upgrading to the 1250 kit or get a 2015 Dyna Lowrider. haven't made up my mind yet. I am leaning more toward keeping the Sportster and up grading though.

 

sure will be a lot cheaper to do a $700 1250 kit than buying a new bike!!

 

Yeah that's for sure. I just checked on the insurance and the Lowrider would be double the Sportster.

 

Plus the Sporty is, well, more sporty.

AND, with a 1250 and a good tune/ac/exhaust, it will flat walk away from the Dyna Low Rider.