883 to 1200cc conversion. Buy 1200 heads or bore 883 heads?
#1
02-03-2010, 08:47 PM
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#4
02-03-2010, 11:44 PM
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#5
02-04-2010, 12:53 AM
Are the valves a problem on the 883 heads?
No!
Also, what sort of gain would there be by buying stock 1200 heads vs bore the 883 heads?
The only gain would be that you would then own a set of stock 1200 heads and a set of stock 883 heads. I have never heard of anyone upgrading their motorcycle to use and then putting it back to stock just to sell it. It would be most cost effective to have your 883 heads worked over by Branch 'O Keefe or NRHS or Headquarters or Zippers or any of a number of recognized professional high performance shops. Good luck with your project and ride safe out there.
No!
Also, what sort of gain would there be by buying stock 1200 heads vs bore the 883 heads?
The only gain would be that you would then own a set of stock 1200 heads and a set of stock 883 heads. I have never heard of anyone upgrading their motorcycle to use and then putting it back to stock just to sell it. It would be most cost effective to have your 883 heads worked over by Branch 'O Keefe or NRHS or Headquarters or Zippers or any of a number of recognized professional high performance shops. Good luck with your project and ride safe out there.
#7
02-04-2010, 05:47 AM
Ultimate HDF Member
Here is what I posted in another thread. I did a stage 2 to my 883 heads and that left me the money for cams and ignition. This may pertain to you but you didn't give us any specs for your bike. 
Heres a dyno sheet off of NRHS Web site for 883 heads.
This provides an idea of what to expect from the NRHS/Axtell Street Dominator conversion kit when used with your 883 heads and supporting components*. Only the head preparation level was changed between the top three pulls, all other components remained the same. The original stock 883 result is also shown for reference, in purple. That's right, with the bolt-on 1250 kit and these supporting parts, you can more than DOUBLE the power of your stock 883. You won't believe how much more fun your bike will be!
Yes I did the build in march I think. I did 1250 Jugs, 10.5.1 Compression Pistons, Stage 2 883 Heads, Shorter push rods, Screaming Eagle .497 Cams, Screaming Eagle Programmable Race Ignition, Ness Big Sucker II and a complete Cometec Gasket kit. The Cams, jugs, Gasket kit, shorter push rods and head work I got from NRHS. I have about $2800 in it. I did all the work and the install was smooth as silk. I modded my carb and intake myself, plus a couple things that I wont say but will tell you that they didn't cost a dime. I'm pleased to say it runs like a raped ape now. No leaks, no coughing or backfires ever, accelerates real hard. Once I change out my pipes this spring I'll be in the century mark with torque in the upper 90's instead of the lower 90's.
I don't have $6500 in the bike total including the price of the bike....I think it was worth every dam dime.
I don't have $6500 in the bike total including the price of the bike....I think it was worth every dam dime.
Heres a dyno sheet off of NRHS Web site for 883 heads.
This provides an idea of what to expect from the NRHS/Axtell Street Dominator conversion kit when used with your 883 heads and supporting components*. Only the head preparation level was changed between the top three pulls, all other components remained the same. The original stock 883 result is also shown for reference, in purple. That's right, with the bolt-on 1250 kit and these supporting parts, you can more than DOUBLE the power of your stock 883. You won't believe how much more fun your bike will be!
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#8
02-04-2010, 11:27 AM
Most head builders love the 883 head because they have a not more material in the right places to port. I have a set of ported 883 heads on both of my Sporties one make about 75 HP the other 85 HP and that's at the rear wheel and both use the stock cams.
The pictures I put up show the 85HP heads that HeadQuarters did for me, they are a work of art almost to pretty to close up so no one can see them.
The main advantage of using ported 883 heads over the 1200 heads of any kind is they move the power range down lower in the more usable RPM ranges, in other words you don't have to be standing on it all the time to make HP or Torque.
The pictures I put up show the 85HP heads that HeadQuarters did for me, they are a work of art almost to pretty to close up so no one can see them.
The main advantage of using ported 883 heads over the 1200 heads of any kind is they move the power range down lower in the more usable RPM ranges, in other words you don't have to be standing on it all the time to make HP or Torque.
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#9
09-29-2010, 09:13 PM
COmpression area is different
I hear it is good to use the 883 heads because they have a smaller compression area. Supposedly mine has been "bored out" to 1200, but it seems to have the power of an 883. The jugs have "883" cast into them, and it seems to need more power. My big bike buddies blow past me when we ride. Hmmm. The dealership that sold the bike on consignment to my sister 8 years ago said it had been converted. How can you bore a cylinder out .250" and have any cylinder left????
I think she (and thus I) was bamboozled. If I find that is the case, I will post the seller's name, because I have it. I will now take some solder and try to ascertain the width of the bore. 3.0" for an 883 vs. 3.5" for the 1200, right? I suspect a guy in Virginia might be hearing from me........
I think she (and thus I) was bamboozled. If I find that is the case, I will post the seller's name, because I have it. I will now take some solder and try to ascertain the width of the bore. 3.0" for an 883 vs. 3.5" for the 1200, right? I suspect a guy in Virginia might be hearing from me........
#10
10-03-2010, 01:51 PM
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