looking at uping the missus sporty 07/883 and came across this , verry interesting as i would of gone 1200 heads

There's no difference in the bottom part of '95-later
883 and 1200 engines... it's all the same from the
cylinders on down, including the starter, primary,
clutch, and transmission.

The only difference between a factory 1200 cylinder
and one that's been bored to 3.498" is the casting
mark on the front of the jug. One says 883, the
other 1200. The outer diameter of the steel liner,
as well as it's thickness, is the same. Harley DOES
inspect all new cylinders for porosity to a depth
of .030" to ensure they can take 3 overbores. Some
say that it's better to buy new 1200 cylinders than
to bore 883 cylinders to avoid possible porosity.
I've never even heard of a porosity problem with
bored 883 cylinders. All this being said, if new
1200 cylinders are used in a conversion, even the
casting stamp will be the same.

The 1200 cast pistons weigh a whopping 517 grams with
rings, wrist pins, and circlips. Because of this
weight, they can't be revved as high as lighter
pistons, such as the 425 gram 883, or Wiseco 883/1200
pistons, without cracking, or overstressing the rods,
main bearings, and crankpin. This also causes engine
vibration to occur at lower engine speeds, which
would be at a lower road speed. So to get the
vibrations back up to the same road speed as the 883's,
higher gearing (a 29 tooth front belt sprocket vs the
27 on an 883) has to be used. This sacrifices
acceleration.

Also because of the much heavier pistons, the factory
1200 has a lower rev limit (5,200 rpm) in the
ignition module than the 883 (6,000 rpm). Certainly
either engine can be revved to 6,800 with a SE
replacment module, but the heavier pistons produce
more wear and tear on the factory 1200 lower end.
The modules also have different advance curves that
suits the combustion chamber they are used with.
That's why a stock 883 module works well with the
883/1200 conversion.

Wiseco 883/1200 pistons weigh about the same as the
stock 883 pistons, so they don't have the vibration
problems of the heavy factory 1200 pistons and
require you to sacrifice acceleration with higher
gearing. And as forged pistons, they're MUCH stronger
than the factory cast pistons.

While the factory 1200 heads do have larger valves,
they have a huge, 3.5" wide inefficient combustion
chamber with no quench (squish) area above the piston.
IMO they are the poorest design put on a Sportster in
recent years. To improve upon them for performance
requires welding in a lot of metal and then machining
it, while with the 883 heads require only machining
to remove material, and they also provide a 1/4" wide
quench ring all around the top of a 1200 piston,
resulting in very efficient combustion. The SE heads
used on the 1200 Sport are much better than the
factory 1200 heads, which couldn't tolerate the
higher compression.

It IS possible to do an 883/1200 conversion using
factory 1200 pistons, but this brings with it the
vibration problems, and it requires grinding out
the quench area of the 883 head to lower compression,
making them as poor as the factory 1200 heads in that
respect. And it is even possible to acquire used
1200 heads additionally. Those who've tried this
route eventually have to sacrifice acceleration with
the larger front belt sprocket to raise vibration
speed.

Ignoring the 7% torque multiplication advantage of the
883 gearing, a Wiseco 883/1200 conversion has a 9.6:1
compression ratio with stock HD 1200 gaskets, and over
10:1 with thinner aftermarket head gaskets. This
added compression produces significantly more torque
at lower and midrange rpms than a 9.0:1 factory 1200,
and the additional compression of the conversion almost
exactly offsets the advantage of the larger factory
valves at higher rpms. The 883/1200 and factory 1200
engines make the same hp at higher rpms.

Combine this stronger 883/1200 engine with the 883's
7% torque multiplication advantage in the belt drive,
and the conversion easily outperforms a factory 1200
on the street. Put Andrews N4 cams or SE bolt-in cams
in the 883/1200 and you have better acceleration than
even a factory 1200 Sport.

In summary, the only differences between the 883/1200
and a factory 1200 are the pistons and the heads... and
the conversion has better ones, resulting in better
performance, even when gearing isn't considered.

Mick,

This is really good info, as I mentioned to you when we met up on the ride I've enquired about getting mine done. Kit with wiseco pistons can be bought off US ebay for around $400 US plus shipping. Then you need either a Thundermax or apparently I've read you can get the ECU calibrated via a remap to suit the 1200 upgrade.

wiseco k1655 piston kit is suitable for the 07 on. approx $375 aus from most shops.
The piston, pin clips and rings weigh 82 grams heavier than the factory piston assembly on balancing scales, and there is not enough area to take 80 grams of weight out so i didn't bother. (and there is no notable vibration over idle)
The standard ECM will not operate the engine properly even with a race tuner fitted. and a 1200 ECM is no good niether becase of the difference in geometry of the reverse dome pistons and closed chamber 883 std heads.(but i did try to use it)
Thundermax ECM is the bees nees of all ECM's on the aftermarket and HD stealers will tell you they are very good.
The sportster has now travelled over 4000 klms after the conversion and does not rattle, burn oil or show any sign of problems.
If any one needs info on how or what i done just ask. Once you ride them after the conversion you would never go back.
Cheers and ride safe, Bretho.

I had the conversion done about 12 months ago. Used reverse dome Wisecos. Kept the same heads and the combination of the reverse dome pistons and the smaller head chamber equated to a big increase in power. I rode a stock 1200 just after the conversion and felt my conversion had more grunt off the mark. Something about the smaller heads (combustion space) from the 883 and the r/d pistons that leads to a freaky combination.

what's the go with fitting a Thundermax to a 883, then going the conversion to 1200? Will the Tmax adapt itself, or is a different map/whatever required? I'm tossing up a Tmax for this winter's spending spree, and the 1200 conversion next winter when the bikes 2 yrs old and I can get the extra warranty from HD....

The Thundermax will do fine on the 883, have heard of a few people fitting them to the 883's with good results.  All you need to do when you do the 1200 conversion is load the 1200 map into the TMAX and start tuning again from there.

there is no base map for 883 sportster on thundermax. i would think it would overfuel on the 1200 map so my suggestion is not to fit the thundermax until the conversion is done.

i have just traded my 07 883/1200 custom in on a new 09 softail and i am a little dissapointed in the initial power in the 96b engine but it is far smoother at high speeds.

ps i got 12,500 trade in and the dealer said if it had not had the engine work it would have been 10,500.

Rodders,

The Harley kit is a good way to go as it brings your bike up to 1200 factory specs, ie both heads and barrels.  I remeber when the dollar was good I priced it at $1200 delivered from Zanotti's.  Although now you will most likely pay more.  With that option who ever fits it should be able to flash your ECU to 1200 specs and the bike should run fine.

Q: "Will this give quicker exceleration and more mid range power/torque?"

A: You will be amazed at the difference compared to the 883, much better accelleration and torque.

Q: "If keeping the standard 883 front pully, what effect will this have on performance?"

A: Due to the 883 gearing and pulley, you will get better off the line and low end accelleration than a factory 1200.  It will rev higher at higher speeds though.

Q: Will the SERT accomodate the 1200 conversion?

A: I don't have a SERT but I did eventually get my bike to run fine with the 1200 stage 1 Harley ECU.  I got my 883 ECU flashed with the 1200 stage 1 map.  But as you probably know I ended up getting a Thundermax which has worked out well but not without it's problems.  It generally works well but I've had some issues with pinging and the like, which I am still to fully work out.

As I don't live in Melb I can't help you out with any suggestions on who is best to do the work but I would say any good shop will be able to help you out.

 

Sounds pretty expensive, my whole conversion cost me just over $2000, and almost half that cost was the Thundermax. Labour on mine was just over $600, so I think getting quoted $1200 is way too high. I'd shop around, when it comes down to it installing new barrels and heads is a fairly simple job for someone qualified. Not too sure how the revs differ to the 883 but I have heard that the pulley makes them rev a bit harder at high speeds.

hi just about purchase a iron 883  and want to have the engine up garde to 1200 , saw this on ebay and in discussion with the people at north side motor cycle on all the ins and out of the process , they were advertising the pistons for $275 , seems like a cheap price, what you think these pistons do the trick? heres the link to the item ..

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=320415728497&ssPageName=STRK:MEWAX:IT

 

 

 

ok let say i found a kit from the usa for this project , could you recomend a mechanic for me to do the work plz ??

 

oh in sydney

ok looks like you have completed a successful up grade now , in your conclusion , what would you now recommend ? in a nut shell ? could you send me the sites in the usa where you purchased the kit . and a basic shopping list id need to start my project in the new year . oh and what is ECU ? any help would be great . ya have a msn ?many thanks

Try Mandm cycles they will give you about a 30 percent discount on any genuine HD stuff. and they have like the TTS mastertune for 440 USD so about 500 delivered to your door AUssie.
also lick cycles have a 1200 upgrade kit that includes wiseco (i think) pistons for like 550 USD so about600 aus plus postage about another 70 to 80 then fitting.

so regarding revving at higher speeds what kinda speeds we talking? i want to do longer runs on my bike and im a little concerned if its revving higher that there will eventually be some kinda over heat or other long term wear not good for the engine.

I'm not sure what speeds people are saying is high?

Arnie, was your bike EFI? If so what did you for a ECU? Reflash to 1200?

How is it now still happy with it?

 Anyone used these Revtech cylinder and Wiseco piston kits on ebay for US$475?

The "no returns under any circumstances" and "need honing to fit piston" concern me...

http://cgi.ebay.com/ebaymotors/BIG-BORE-KIT-04-10-HARLEY-SPORTSTER-1200-CONVERSION-/200538487971?pt=Motorcycles_Parts_Accessories&hash=item2eb1067ca3#ht_1634wt_1165

What cylinders and pistons are used in the 883 to 1200 conversions? A few I looked at evelbay use Wiseco and other no name brand pistons with after market cylinders. Is there somewhere I can get origional HD brand cylinders with Wiseco pistons?

If I buy Barrels and pistons or just pistons, What else beside gaskets do I need? Just a turner? I've different thing for people. Some say you don't need to change the front pulley on the final drive as the wiseco pistons are lighter and don't cause the vibration like the factory ones do. I have also read there is a 1200cc clutch kit. Is there a difference in the clutches in the Aust bikes? I do a lot of K's and don't want to make the bike unreliable.

  Cheers. 

What do you think the most cost effective way to go with a tuner is, HD race tuner ? Or aftermarket?  Can dealers just remap  the 883 ECU to 1200 spec?

I just bought a 1200conversion sporty and am noticing alot of engine noise, is this normal?
Sorry Im a first time harley owner???