The following link is to a thread on the XL Forum involving a Very Common Problem with Rubber Mount Sportsters. A lot of us are fighting this and now wondering if the Factory ECM Profile is a big part of the problem.. Especially starting to deaply question this at and after reply # 20 on page 2. Please, breeze over the whole thing so you can get the full story though.

Your help will be greatly appreciated...

http://xlforum.net/vbportal/forums/showthread.php?t=23248

Sincerely,
SGO

Hi SGO.

Ok, I have a 03, But I make a Living fixing car computers.

Ok, from what i have seen of the Harley system, it's just timing control, it has very little to do with Idle speed.
For it to control Idle speed. It would need a IAC (Idle air control) valve, and some type of Mixture control, and a O2 in the exhaust stream to monitor the outflow.

From your description, it sounds like you are raising the idle speed to the point that you are taking the carb out of the Idle circuit into the Off Idle circuit.
The Off idle circuit is a transitional fuel enrichment circuit design to fatten the mix up between the Main and Idle circuits.
Two thing can cause this, lager then stock cams and to lean of Idle mixture.
If you are running big cams, then you may need to drill a small hole through the throttle blade to let more air in to compensate for the higher air demands of the cams.
Now, when I say small, I mean .030 to .060 hole, Not a bloody 1/4 hole. You want to start small and work up as needed to get the throttle closed enough to keep it out of the off idle circuit.

Since you have done the stage one, this should not be the issue here.
You are running a 42 slow jet, that is too lean, go to a 45 or even a 48.
Wile your in there, replace the main jet with a 175, and pull out the shims.

?? I already have a #48 in mine. No big cams. I have stayed with in the 950 to 1050 RPM adjustment range. What I am looking for is a possible timing crossover where the timing is advancing within that range that creates a very lean condition causing the idle speed to hang high. What I need is a read out of the updated stock ECM profile for a Rubber Mount, if anyone has that....
Thanx
SGO

The below photo is what the stock 04-06 883 ignition MAP looks like. It is very similar to the 04-06 1200 MAP. Look at the idle timing at 1,000 rpm. It's set to 10 degrees. Now look at it at 1,500 rpm. It's 20 degrees. That's a big jump of 10 degrees in timing in only 500 rpm. I think that may be causing some of your problems with high idle speeds once in awhile. As rpm decreases down once the throttle is closed, it hangs at a higher than normal speed do to the high timing.

http://images.picpile.com/uploads/484705526.jpg



Now look at the idle timing in the photo below. This is one of the MAP programs I wrote for the TC88A adjustable ignition modules. The idle timing is 15 degrees at 1,000 rpm (which gives a smoother idle than the stock 10 degrees) ... but, the timing only increases to 19 degrees at 1,500 rpm. So, we now have only an increase of only 4 degrees vs the difference of 10 degrees in the stock MAP program. This may keep the idle speed from hanging high when the throttle is reduced to idle after driving at higher revs.

http://images.picpile.com/uploads/243700602.jpg

That is what we were beginning to suspect. You have given us the Holy Grail. Thank You for the time and effort. We appreciate it....
SGO

Hey Ron,

Your map looks great, one of these days when I get my gearing dialed in I will get a cable and load it up. In the mean time what switch settings do you think come the closest to approximating you maps. I'm currently running 5,6 on my 05 883 with Stage 1 carb settings, pipes, and Big Sucker air cleaner.

I think that your bike should be the Featured Sportster of the Month!!, it would get my vote.

Stan .... I am going to have to look at those various switch positions tables and let you know later. Thank's for the compliments. Now you gave me a super-ego complex! :)

BTW, here is a link that shows the timing we were talking about above. The timing table is formatted a little differently that what I showed above, but the numbers are the same. They use 1 to 2 degree offset between the front and rear cylinder timing I didn't show above, but that don't effect that 10 degree 1,000 rpm and 20 degree 1,500 rpm that's shown. High vacuum/ idle manifold air pressure (MAP) is shown as 0 MAP in this factory chart.

http://mysite.wanadoo-members.co.uk/hddiagrams/TT_December_06_2004___XL883_Ignition_module_calibr ation_changes.pdf

What you see highlighted in yellow is what the 883 Service Bulletin ECM re-flash calls for. The 'zeros' are replaced with anything from 3 to 5 degrees of advance (but this still won't effect the problem you have since it's done in the area of higher throttle settings) ... Actually, this is done to get rid of the carb farts.

how do i set up my module on my 05 883 i have a screamn eagle module

Son-of-bitch, it looks like I may have been right. But hell, the solution is probably to go to an aftermarket ignition like the TC88 like Turbota did. I don't know if I want to do that. I'm not up on these modern electronic ignitions that need to be programmed via a laptop....I don't even have a laptop! Crap! Damn the EPA! What the hell happened to points? :roflblack How hard is it do put in a TC88? What is needed? Can I screw it up? Ya know, takin apart the top end of my bagger, switchin cams and carbs is one thing, but this newfangled electronic stuff.......just makes me nervous.:doh


SGO......thanks for starting a thread that has zeroed in on our problem. :clap

TC88A is easy to install:

1) Remove seat.
2) Disconnect negative battery terminal at the engine (just a precaution).
3) remove bosch connector on ECM.
4) remove the 2 nuts holding the ECM to the frame.
5) reinstall TC88A in reverse order.

That's it. The only thing is that the switch settings on the TC88A aren't very good for sporties so you are best to upload a MAP like the one Ron showed above. This requires a computer and the cable from Daytona-Twintec. But, I do recommend it, my bike is going much better with the TC88A fitted.

Cheers,

Brett

Uploading the MAP is what I'm worried about. Besides a laptop and cable, is it easy to uplaod a MAP? Can I screw it up? How much better does your bike run with it? More power? Smoother? Are you at Stage1 or beyond? I have to wonder if it's worth the trouble for just a Stage1 bike.

how do i set up my module on my 05 883 i have a screamn eagle module

I responded to the PM you sent me. If all your doing is installing an SE ignition module, you just pull off the seat ... pull off the electrical connector on the stock module ... take the 2 screws out holding the stock module ... and install the new SE module in reverse order.

You may have to do the "security system learn" procedure in order to make the new module work and the bike run.

Do a search here ... the learn procedure has been disscussed more than 1 time before.