I have the SERF installed on my 06 Dyna Low Rider. It has a stage I done with a K&N air filter and SEII exhaust w/ Big City Thunder Monster baffles installed almost the same as no baffle. While researching the various lower cost tuners. I read that the low fuel setting would be overridden by the O2 sensors so I installed the Daytona O2 sensor eliminator kit.

There is not a lot of information out there on tuning with the the SERF. For the most part it is pretty straight forward but for some reason I can't grasp the low to mid range rpm cutover setting. I found several different settings recommended but they were for different size engines and years. The instructions that came with my SERF has 2500rpm as the start point but that is all that is said about it. Just to use it as the starting point. The instruction are useless for how to tune the SERF. The thread that has been the most helpful (copied below) was I believe from a Sportster 1200 and he had it set at 1800rpm. Not sure why or if that's where I should set it for my bike with the larger engine in it.

Could anyone help explain how the low to mid range cutoff setting would actually effect the way the bike runs at different setting or where I should set if for my bike? If I set it at 2500rpm as a starting point, which way do I go from there and why?


For reference below is the contents of the thread that I copied and have been using as a guide to help me tune my bike. Only copied the contents to print out at the time. So sorry no link to paste instead. I also pasted it below because there is one other thread (https://www.hdforums.com/forum/elect...eler-long.html)
in the this forum that starts out with this information but then is gets cut off before any important help is given.

Dave63's Avatar

Join Date: Jun 2008
Location: USA
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Quote:
Originally Posted by Richie M View Post
ok thanks dave, I don't recall it coming with any "CD" or anything like that just a screw adjustment for the right mix i guess? new to all this sorry if this brings back old post memories! the part no of the fueler is: 32136-06A
The cover comes off and there's LED lights and "screws" that you adjust.
I found this on another site, when searching for information for you....I didn't write it.
Fitting is very straightforward but it is a bit awkward getting the connectors off and on the injectors under the tank. A well trained 5 year old is very handy for this as they can get their hands in the small space under the tank. Also the wire colours in the instructions were not quite the same as the wire colours on the bike but it was pretty obvious where they went. (White instead of Grey if I remember correctly). I taped the unit to the tank while I was setting it up, it made life much easier. Once finished I slipped it in next to the ECU under the seat, not next the battery as in the instructions (acid and electronics don't get on)
Setting up
------------
I used a frequency counter on my multimeter to check the rpm settings, see the table lower down for the values.

________| 1 |____| 2 |____| 3 |____
_____________R___Y___G_________ Fueler Layout
________| 4 |____| 5 |____| 6 |____

LED's
------
R = Red LED Low rpm range
Y = Yellow LED Mid rpm range
G = Green LED High rpm range
What the dial does (earlier models are different)
---------------------
1 Low rpm range fuel adjuster ______ -10% to +40% fuel correction
2 Mid rpm range fuel adjuster ______ -10% to +40% fuel correction
3 High rpm range fuel adjuster _____ -10% to +40% fuel correction
4 Low to Mid rpm cutover range _____ 900 to 3500 rpm
5 Mid to High rpm cutover range ____ 4500 to 7100 rpm
6 Accelerator fuel enrichment _______ 0 to 100%
The dials are marked 0 to 10
0 = Fully Anti-Clockwise position on all dials
10 = Fully Clockwise position on all dials
Note these figures represent the position of the dial only, not the value of fuel or rpm. For example Position 2 on Dials 1, 2 & 3 roughly equates to no fuel correction. See the table below for the values.

Initial Settings
-----------------
These are the positions I started at.
_Dial __ Position_
Dial 1 ___ 2
Dial 2 ___ 2
Dial 3 ___ 2
Dial 4 ___ 3.5 - (Low to Mid rpm needs to be set at around 1800 rpm which is appx 3.5 on the dial)
Dial 5 ___ 0 - (Mid to High rpm needs to be set to 4500 rpm which is 0 on the dial)
Dial 6 ___ 0

Now go for a 10 minute ride to warm the bike up. don't worry if it pops and crackles a bit we just need the bike warm. When you get back take the lid off the fueler as we need to make some adjustments.
Dial 1
------
Start the engine up and slowly increase the rpm until the red led goes out (about 1800rpm) and the yellow led comes on then bring it down a bit until the led's swap back over and we have the red one lit again. You need to hold this rpm really steady (the lock on the handle bar throttle is useful for this). Now very slowly increase dial 1 (clockwise), the engine should start to speed up (if the yellow led comes on then set the throttle back a little so we are back on red). You will get to a point where the rpm no longer rises and then you can turn the dial back down to a point where the rpm just starts to reduce.
Dial 2
------
Now we do the same again but at about 4000 rpm. So this time we raise the rpm until the green (third) led comes on and then throttle back very slowly until it goes out and the yellow led comes back on. Then we slowly increase dial 2 until the engine no longer increases in speed and then dial it back slightly.
In both the above exercises we are looking for the point where the engine runs fastest and smoothest with the dials set as low as possible. you may need to stop and let the bike cool during these adjustments. If the engine gets too hot then the EFI will run slightly richer to compensate and this will mess with your results.
Dial 3
-------
This is the hardest to set up manually but unless you are screaming the bike above 4500 rpm a lot you won't need to worry. The only way to set this is to get the bike pulling hard above 4500 and the increase the dial a bit at a time until it runs about right. I set dial 3 to position 4 which is probably too rich but on the safe side. I don't tend to go above 4500 rpm all that much anyway.
Dial 4 & 5
-----------
Need no further adjusting.
Dial 6
------
This is set by snapping the throttle open from idle. If the engine stutters before picking up then you need to increase the setting on the dial. Eventually you find a point where the engine responds straight away and there is no stutter. Again you need to aim to keep the setting as low as you can without the stuttering.

This table shows approximate dial settings
------------------------------------------------
Position____Fuel% (1,2,3)____rpm(4)____rpm(5)
0 ................ -10 ................. 900 ....... 4500 (fully anti-clockwise)
1 ................ -5 ................ 1160 ....... 4760
2 ................. 0 ................ 1420 ....... 5020
3 ................. 5 ................ 1680 ....... 5280
4 ................ 10 ............... 1940 ....... 5540
5 ................ 15 ............... 2200 ....... 5800 (12 o'clock, half way)
6 ................ 20 ............... 2460 ....... 6060
7 ................ 25 ............... 2720 ....... 6320
8 ................ 30 ............... 2980 ....... 6580
9 ................ 35 ............... 3240 ....... 6840
10 ............... 40 ................ 3500 ....... 7100 (fully clockwise)
-----------------------------------------------------
Earlier models have a different rpm range:
Low to Mid Adjuster Range 600 to 2000 RPM
Mid to High Adjuster Range 3000 to 7000 RPM
-----------------------------------------------------
At my next service I will get the bike on the dyno and it will be interesting to see how close I got but in the mean time this is what my settings are.
Dial___Position____Value
Dial 1 .... 3 ....... +5% fuel (modified to 3.5 (7.5%) after test ride due to popping exhaust)
Dial 2 .... 3 ....... +5% fuel (modified to 4 (10%) after test ride due to popping exhaust)
Dial 3 .... 4 ....... +10% fuel
Dial 4 .... 3.5 ..... 1800 rpm
Dial 5 .... 0 ........ 4500 rpm
Dial 6 .... 6 ........ 60% (of whatever extra fuel it throws in)
__________________

 

It's looking like no one is running this old dinosaur anymore. Anyone have a good memory that once had one installed? Does the bike have to be running in the RPM range of the POT you are adjusting to have any effect or can you make a small adjustment to the POT while the bike is off?