You've got my interest, I might have to try a 1/8th mile run. The local drag strip has open Mondays for anyone who want to run the track. How doesa 1200 hold up against local guys running suped-up street legal cars, the run of the mill guys just goofing off? Does it help a bunch tochange theignition module to get the rev limit above stock5,200 rpm?

Please post your times.

 

The 'rev limiter' in your stock 2006 1200C kicks in at 5,200 RPM?

Mine kicks in right at 6,000 RPM (2005 1200C), and I believe that is where it's 'set' from the factory on all the 2004+ 1200's.

Far as how well your 1200 will run against the guys with modified street legal cars, it just depends on the specific car and it's performance potential.

Most of the verified time slips I've heard about from guys running their 1200's at the track (most in the Tulsa area) show quarter mile times in thelow 13 second range.

 

I'll be interested in the performance results shown at the track.

Increasing the displacement from 883cc to 1200cc will no doubt provide a very noticeable power increase, but unlessyou usebetter flowing heads and higher lift and duration cams you will will still be limited to the amount of a/f mixture entering the cylinders.

As most known, the difference between the factory 2004+ 883's and 1200's is more than the displacement. The 1200's also have a better flowing head/cam setup, which flow much better than the stock 883 heads and cams.

 

Key statement here. I'm guessing 9.3 at 60 mph.

 

OFG, I've seen it published several places that the later model 1200's have a 5200 rpm rev limit due to the increased weight of the larger stock cast pistons, to protect the lower end from excess wear & tear. My 04 1200 limited out at 5200 with the stock ignition module.

 

Never heard that, in fact they went with lighter pistons on the 2004+ engines. When a tach was hooked up to my '05 1200C when I first got it to do some tests, the rev-limiter kicked in at 5,975 (or right in that area).. I have the exact information somewhere, but I'd have to dig through my notes to find it.

Here is information directly from HD when they were talking to the press about the new 2004+ engines:

"To enhance engine cooling, new cylinders and heads have larger fins while new oil jets are directed at the bottom of both pistons. New pistons have an improved high-speed ring pack designed to help extend upper-end life. Lighter pistons and connecting rods boost the Evolution 1200 redline from 5500 rpm to 6000 rpm. Many engine covers and gaskets have been changed to improve sealing. A new timing system uses the flywheel to determine engine speed timing, reducing engine complexity and enhancing calibration and spark delivery. The traditional XL Evolution timing cover is retained for styling purposes."

 

My chopper is an 80" w/S&S E, Crane 316B cam and drag pipes. Not super hot but the bike weighs in at 530 lbs wet. My best is 8.24 sec/84mphon the 1/8 mi. Good enough to beat the tweaked(315hp) Camaros. It's great fun and a chance for some real time tuning. A decent sporty should do atleast this well. Have noted that the short wheelbase makes them more likely to pull the front wheel up, if you're not into wheelies, some clutch slipping off the line makes for a better(smoother) launch. Because of the power curve there is no benefit to hitting over 5500 rpm unless you have the cam/carb combo to make use of it.
Have fun, Good Luck!

[IMG]local://upfiles/36103/7E5BDF4FD5F34C4BA7C108A203FFD4AA.jpg[/IMG]

[IMG]local://upfiles/36103/E2D65A486A824A89B5EB84F5F744C179.jpg[/IMG]

 

OFG, I can't vouch for the info in this article but it's one of several I've come across.
https://www.hdforums.com.au/Default....amp;view=topic

Maybe it's bad info?????

 

I'd say it's bad information, especially since HD themselves state that the pistons/rods in the later engines (along with the ring pack) were lightened to increase the 'redline' to 6,000 RPM.

I do know for a fact that my 2005 1200C, with stock ignition, doesn't hit the rev-limiter until right before 6,000 RPM, so it seems to agree with the published info from the HD engineers.

I'll talk to my Harley mechanic friend and see what he has to say, as he also owns a late model 1200C and has run many dyno tests, etc., on his bike.

By the way, last I heard he had right at 92,000 miles on the stock engine.

 

All new Sportster engines, 883 and 1200, are redlined at 6,000 rpms from HD. Unless it's a 1200 in a Buell, then it's redlined at 7,000 rpms. The Buells also have a rev limiter that kicks in at 6,300 rpms after a few seconds so 7,000 rpms is only good for drag racing, not top speed runs around Daytona.

It's all a question of Ave. Piston Speed and therefor the stroke determines the redline. HD uses 4,000 ft/minute ave. piston speed and that means that all sportsters can be reved to 6,300 rpms safely. 88" (and 95")big twins can rev to 6,000 rpms and 96" (and 103" and 110")big twins can rev to about 5500 rpms with HD factory parts.

If you take 24,000 and divide it by the stroke (in inches)you'll get HD's factory stock redline for any new HD engine (or at least you'll be close).