question about 1200 conversion..

ratfink · #1 13th January 2008

when you go from an 883 to a 1200 conversion i understand how the displacement is increased, but what about the gear ratio and such?...my 883 has a stage two kit and it runs good and i can feel the higher rpms arounnd 80 mph or so....question...with the 1200 kit will i still feel the same rpm feeling at 80 mph? ...i may have more power and get to 80 faster with the 1200 kit ,but wont i still have the same drive train and the bike will still have the same rpm ratios thru the gears?...

Gone · #2 13th January 2008

Yep, same rpm at the same speed unless you change the gear ratio. Changing the front sprocket to a larger diameter will drop the rpm. I considered the 27-tooth to 29-tooth sprocket change ('03 and earlier; 30-tooth, I believe for '04 and later) as an extra gear.

bigrabo · #3 13th January 2008

not sure i understand this question very well.....but the guy that lives across the street did his 883 to a 1200 and he has no problems.......his bike runs beautifully..........i wish i could help....good luck man

Folkie · #4 13th January 2008

Yes, you will, and some see this as an advantage because you'll still have the lower gearing of an 883, which will make the bike accelerate faster than a stock 1200 could.

The downside is that you'll be turning higher rpms at highway speeds, which stresses the engine more. There are questions as to whether this causes higher oil temps and higher oil consumption. Some folks who convert their 883s to 1200s also change the gearing to be more like the 1200 ratios.

To get exactly the same gearing as a 1200 would need the engine sprocket and the primary chain to be changed, as well as the transmission sprocket. I think most people just change the transmisison sprocket.

ed_in_az · #5 13th January 2008

All that changes with a basic conversion is the cylinders are bored larger and matching larger pistons are installed. Everything else on the bike remains as it was.

I like mine with 883 gearing. It goes as fast as I want (115mph) and maintains a low 1st gear for slow going when needed. I can cruise at 90mph, but 70-80mph is my usual highway speed so it's fine.

If you have somewhere you can comfortably or legally cruise at 90+ then a re-gear might be in order. I don't want to lose my license to drive and ride so lower gearing is another plus for me, and the acceleration is GREAT!

ratfink · #6 13th January 2008

thanks for the feedback...i think i would have to ride one for comparision before i would make the change..in the meantime i will do the front pully change...

Desertfox · #7 13th January 2008

Quote:

Originally Posted by ed_in_az

All that changes with a basic conversion is the cylinders are bored larger and matching larger pistons are installed. Everything else on the bike remains as it was.

I like mine with 883 gearing. It goes as fast as I want (115mph) and maintains a low 1st gear for slow going when needed. I can cruise at 90mph, but 70-80mph is my usual highway speed so it's fine.

!

True that. My conversion plus has all the power and roar I can use in every day riding. I cruise at 70- 80 mph on the freeway. But even that doesn't last long . The wind will beat you to death if you sustain much over 70mph. anyway. Most of the guys I know with performance Sportys gear them DOWN.

ed_in_az · #8 13th January 2008

Quote:

Originally Posted by Desertfox

True that. My conversion plus has all the power and roar I can use in every day riding. I cruise at 70- 80 mph on the freeway. But even that doesn't last long . The wind will beat you to death if you sustain much over 70mph. anyway. Most of the guys I know with performance Sportys gear them DOWN.

Desertfox, I noticed you have a solid mount. What did the conversoin do to your motor's vibrations? I assume you went with light weight forged alloy pistons as I and most do. The vibes didn't increase on my rubbermount.

Desertfox · #9 13th January 2008

Quote:

Originally Posted by ed_in_az

Desertfox, I noticed you have a solid mount. What did the conversoin do to your motor's vibrations? I assume you went with light weight forged alloy pistons as I and most do. The vibes didn't increase on my rubbermount.

Vibration, at least percieved vibration actually seemed to decrease somewhat. Especially at freeway speeds. When it was an 883 anything over 70 mph had vision blurring vibration. Seems to run MUCH smoother especially at 70mph+. Yep, I went with forged reverse dish pistons.

JayFL459 · #10 16th January 2008

Went to the 29T after the 1200 conversion ... Was fun for a couple weeks stoplight to stoplight but got old quick...