I have a 2000 Fatboy FLSTF twin cam 88. Well it started that way. It has been rebuilt wth machine work done by Dave Mackie (95 megasphere) assemble by trustworthy and knowledgeable machanic in my home town of Ventura Ca. The bike runs great. It has 10.5:1 compression so I have to be sure to use my compression release valves upon starting. However I have put on about 3,500 miles on it and its starting to ping a little bit. My mechanic and friend said this would happen after carbon build up and we would eventually have to get a better ignition module. It has a screaming eagle ignition module now and sarts fine. I have purchased a Daytona Twin Tec TC-88 ignition module and set the peramiters and the bike wont start. Put the screaming eagle back in and it starts. Put the TC-88 back in and its starts if its warm. Bike cools down and it wont start. Tried anthor off the shelf Tc-88 wont start. My mechanic put in a different manufactures module and it wont start. You name it we tried it cam sensors etc.. I NEED HELP!!! NEW IDEAS!!! ADVICE!!!

 

I'm using the same module on a 2000 Deuce - 95" with about 9.75 compression ratio. Which TwinTec module did you get and what settings have you tried? I'm assuming your bike is carbed, right?

 

yes carbed and its the tc-88 module settings where 2 and 2 and tried 5 and 5

 

First, I need to correct my prior post. I'm actually running a theoretical CR of 10:1 so we're not that far apart. I'm not running compression releases but don't really seem to need them.

I'm assuming you selected multi-spark (Mode 1) since this is the typical choice. I was running 5 (initial timing) and 5 (advance slope) for a while but even with my lower compression, I tended to get kickback when starting and a little pinging under load at around 2500 RPM (using Premium gas). So I reduced the initial timing down to 3 and left the advance at 5. I did notice that setting the initial timing at 3 tended to make it harder to start (cold) so I'd guess that 2 might make it even worse. I'll probably move the initial to 4 and leave the advance curve at 5 to see how that works.

Here's a thought: compression releases effectively lower the starting compression to a level at or below stock so unless you were getting kickback on starting (at the 5 / 5 setting), I'd think about advancing the initial timing to 6 and giving that a try.

On the advance slope, did you notice any pinging when you had it at 5? If not, I'd suggest you leave it there or move it down to 4 only if you need to eliminate some high RPM pinging.

 

Something else occurred to me and this is a bit of a reach but a thought none-the-less. Since the elimination of the cam position sensor, the ignition modules determine the compression stroke for firing by detecting the subtle slow-down of the flywheel as it compresses on each cylinder. Here is my thought: If the combo of a strong starter and the compression releases doesn't slow down the flywheel enough, maybe the module isn't detecting the compression stroke so no spark - and no go.

If nothing else has worked, try one of these approaches to see if this might be the problem. Crack open your throttle a little during start so more air enters and the starting compression effectively goes up. Alternatively, try not using one or both of the compression releases and see what happens.

Good luck.

Doug

 

When you crank with the DTT, do you have spark? If no spark on a cold start I would start looking at the voltage supplied to the module during cranking, low voltage can equal no spark. I really suspect that if it starts warm, a little easier cranking, higher cranking voltage. Have you called or emailed DTT? I suspect they might have some insight into this.