Hi FM team.

PV purchased from FuleMoto.
2015 Sportster Iron


I'm running a new 1250 kit from Hammer Performance (HP). 10:1 compression, stock heads and cams. 4" Figure Machine/K&N intake and Spitfire Hi N' Tight Exhaust.


Since the first runs after heat cycles, the bike runs hot, it slowly creeps up to 420+ after 20 minutes of riding. Oddly, it starts to cool slightly at stoplight and other idle situations.


So, I first used the FM map based on the same parameters above. This is when I noticed the high temps. They kept creeping up past 420+, but I shut it down before it got too far. The bike also ran pretty rough starting at about 3200-3500 rpm.


After reading the HP info, they say that they will create special maps due to the high compression. Apparently their theory is that less spark advance is better for higher compression. I figured this must be the issue.


I loaded the HP map but had the same results.


HP then suggested that I enrich the A/F mix to a 13:1 across the board, but keep all the other parameters from their map. Then, autotune with the PV. This helped, but temps still creep up to 420+, just slightly slower and with some minor cooling on deceleration at low speeds. Also, the bike clearly runs rich even after a few autotune sessions.


Now, I'm wondering what I can try next.

1. Even less spark advance?
2. I'm changing the exhaust to the D&D Bobcat in a week or so. Should this help cooling?
3. Would I be better off with bigger valves/ports to control temps?
4. What is considered to be the max head temp? The PV manual suggests 410, I've seen 420 in my Dakota Digital standard settings for Sportsters, but I can't seem to find any official max temp.

Thanks for your help.


In the meantime I will continue to fine tune with the PV and hope something comes from it.

 

The first thing to note is that Sportster engine temp is scaled differently than Big Twin. Even on stock 883/1200 models ET will get in the 400's, if you have a 1250 kit with stock heads & cams it will be higher yet. I would need to see some datalogs to see if anything his abnormal with your tune, your exhuast system choice is not going to exactly be cool running next to your leg as well. For best technical info you can email info@fuelmotousa.com