If i convert my 883 to a 1200 or a 1250 do i HAVE to change the cam or can i do that later. Im also wanting to run the 883 heads

 

No, you don't have to change the cams.

 

You can change the cams later but you'll have to tune the bike twice. What year is the bike? Carb or EFI? Also, your 883 heads will work fine but I'd consider, at minimum, a competition valve job from NRHS or Hammer Performance. If I remember correctly, a competition valve job is recommended, as a minimum, on 883 heads if changing cams. 883 heads are rather inefficient without the valve job. Here's an excellent write-up from Hammer Performance on 883 conversions: http://hammerperf.com/883conversions.shtml.

-Beer

EDIT: Guess you have a 92 Sporty. I missed that the first time.

 

Thanks for the link thats the best info ive found on a conversion all in one place

 

If you go to the NRHS website they have a graph showing engine performance comparing stock 883 engine, with 1250 kit plus stock heads and various stages of head porting. The noteworthy thing is that performance of all 1250s is very similar in the rev range most of us will ride. I am sure most of us will be thrilled by a 1250 kit and stock 883 heads with stock cams. Further changes improve performance mostly in the upper rev range.

 

+1

Even with a 100+ HP Sporty vs a simple 70 HP conversion, most of the extra power comes above 4500 RPM. Most riders will shift at or before then.

Unless you'll be dragging the bike or want to post great dyno numbers, you probably won't need the extra ponies. Also remember, the more power you add, the more expensive it gets and you sacrifice some reliability.

If you're going to have cams and head work done, it should be done while you do the conversion. 100 HP seems like a great idea when you're already doing the conversion to begin with. Just realize that it won't be cheap and it won't run as reliably.

 

I agree to disagree

 

Or unless you want a killer engine with tons of power that's reliable. Nobody needs the extra ponies, if that was the case they would all be 883s


There can be a lot more power made at 3 grand, not 4500. Why do all you guys think these sportys with some port work cams are so unreliable. Please don't fear the unknown of a beefed up 1200

 

No you don't have to change the cam. If you want performance. The more you do at once the better. Simply because the engine is apart. Good luck

 

Upper rev range....how about 3000 to 3500 as a starting point. Like stated above, I don't think you realize the fun factor and power of a worked over 1200 has in the 3000 to 6000 range.