I have a Thundermax on an 07 Softail, and have problems starting the motor while it's hot. It sounds like there simply is too much pressure in the cylinder and it becomes very hard for the starter to even turn the motor over. Any guesses as to what is going on? When it's cold, the bike starts perfect.

 

I'm having the same problem since I put on the 103" kit and a set of Andrews 37H cams. Running Thunder-Max map #398. Starts great when cold but doesn't want to start easily when hot. Hope someone has suggestions for you. I'll be watching, or if you find out something please let me know. I made the mistake of not putting compression releases in when I had the heads off, may have to redo that, but there may be a change that can be made to the timing in the Thunder-Max that may help without going to the trouble of taking in heads off again. Feels like it is too far advanced in the start mode.

 

If you feel it's kicking back, in the timing vrs tps map, drop the 0 and 256 rpms down to 1-3 degrees. Generally if you imediately try a hot start after shut down cylinder pressures will be high and the starter is somewhat wimpy. The other problem is with tmax it fires immediately compared to stock ecm that takes a couple of revs to light the fire and timing at startup has less influence to to engine already spinnng. 103 with no comp releases you say? Bummer.
Ron

 

I realize this is an old post, but before I try the timing change are there any other suggestions? I'm having this issue with and occasional back fire when the motor is 170*+

I really tense up when I have to start the hot motor. It will sometimes spudded and the sound like a fart when I let off the starter. The ECM will recharge and when I fire it up it's a very soft start, not the usual power with a cold start.

BTW, I have a 96 with Andrews 48h, big sucker, D&D fat cats, and the tmax

Looking for advice,

Jesse

 

I too have had the same problem. Two things have helped me and one was a weak battery. I replaced my battery due to the bike would crank over and over then start but would sputter and die then when i started again it would fire right up. The second thing is that when the bike is hot I click the run button and as soon as the engine light illuminates I hit the start button. It seems that if I wait this the light goes out I get back kicks and snorting through the intake and it dies.

 

I did a 103" conversion over the winter along with P&P on the heads and I too experienced a problem with hot starts. It turns out that in my case with the electric compression releases the T-Max holds them open as long as the starter button is pressed. On the stock ECM the computer backs off the CRs. I spoke with Zippers and brought this software glitch to their attention. They claim they will come out with a firmware update to correct that. In the meantime I disconnected the connector to the rear cylinder, so the engine is started on #2, while #1 CR stays open as long is the motor is cranking.