so this is just a general question i have in regards to timing, or more specifically timing MAPS.

since my 883 to 1250 conversion, i've received probably a half dozen different maps for my PowerVision. some say you should use a 1200 base map to tune from since your bike is NOW a 1250, some say stick with an 883 base map since your bike started that way. i noticed on every base map i was sent (from Hammer, DynoJet, Fuelmoto, and others on the forums), ALL of them had different timing tables. some had similar or same AFR tables, but none matched with the timing. i found this curious...

my question(s):
*how are the timing tables calculated? i know the PV doesn't auto-adjust timing for Sportsters so all of those tables must have been populated manually but based off of what data? why are they all different? i understand some maps are based off of different bikes (model years, parts, upgrades, etc.) but they are all SO different. i just do not know which one to use with my setup as a base.

*in addition, what is the concensus: should you start with a 1200 base map or an 883 base map for an 883 to 1250 conversion?

as per usual, i always appreciate the feedback and help!!!

 

If you have used a Hammer conversion I suggest you pick up the phone and talk to them. They have more expertise than we do! They sell PV tuners, so must know all the answers - I hope!!!!

 

The increase from idle to max can vary greatly depending on your setup, but for a 1250 you should run it no higher than 28 degrees max timing.

 

i have spoken to them but their tuning experience is somewhat limited to their "house" 883 to 1250 2007 conversion bike. i did get a host of great info from them and i highly recommend Hammer but i am looking for "other" opinions and expertise as well.

this is interesting considering ALL of the canned maps i received had timing tables with values over 40 towards the higher RPM's.

 

What kit have you used and what more can you tell us, so we can be more helpful. If you hold info back we can't help you very much!

 

The maps I run on a (basically stock) Stage 1 1200 have a max timing of 33 - 35*.

That said, the OP didn't say what heads he's running. Are the heads stock 883? There's a big difference between 883 and 1200 heads.

 

That's probably under low vacuum (light load) situations. That's perfectly normal. I was referring to heavy load (i.e. full throttle), which is commonly the problem area.

 

sorry, my bike:

2013 XL883N converted to 1250 with STOCK heads and cams. i have V&H Big Radius exhaust and V&H VO2 air cleaner

i'm not necessarily looking for a "handout" of a new map, i am more curious in learning about how timing works and why they are set the way they are on different maps...if that makes any sense. basically just looking to expand my knowledge base and hopefully find the perfect base map in the process. i've been told too little timing can cause excessive heat and adversely, i've been told too much timing can do the same. how do you find the right balance?

 

Honestly, Jamie at Fuel Moto would be your best bet.....its what he does for a living. no issues at all (and none to change) the tune he sent for my Sporty when I bought my PV from him.

 

what's funny to me is that he sent me 2 completely different maps. one via email exchange with him and 1 via the Map Request Form on their site. both times i gave them the same info regarding my bike yet 2 different maps both sent by Jamie, completely different timings and AFR's. i may call him though to chat. i appreciate the response.