I've been fighting this issue since I had the Tmax installed. I'd originally built and installed the engine and had the S&S IST on it but was convinced by a local indy to install the Tmax. Well, after diagnosing a few issues (regulator died, other fueling issues) I've gotten the bike to more or less work (still playing with why it likes to not idle when its hot, but only sometimes) but am still having a hell of a time getting it to start. So, here's where I am.

The bike has:

• S&S Easy Start cams
• compression releases
• All Ballz starter (which can easily spin the motor without the releases or the easy start cams - I know this because before I rebuilt it, it had neither)

If I use the CR's, the bike starts easily. Then spits out a CR error. So, I disabled the CR's in the menu, and now it takes forever to get it to start.

My theory is that having the CR's open lowers the compression ratio. That, along with the easy start cams, has it quite low. Somehow, the bike's AF ratio is perfect to start on this super low compression ratio, but when the CR's are left close, that compression ratio is raised and the air fuel ratio to start the bike is no longer any good. Now, I have read in some places that compression ratio doesn't affect air fuel ratio. But, I'm still thinking that this issue has something to do with these two factors.

Am I crazy? What could it be? Does anyone have any experience with any of this (yeah, I know, the bike is 20 years old)?

 

I would suggest doing a compression test with CR's on and off. I see no reason why both are needed. Give details of engine build.

I would leave CR's off and add some timing to the cranking. Can be done in the ignition vs engine speed table. I think default is zero. But the zero and 269 (I think ?) rpm can be raised.

 

Yeah, that's what I thought as well, that I didn't need both, but again, shitty indy was just looking for money. And me rebuilding this after my father passed away, having never done it before, left me feeling not 100% confident at what I had done. Thus the reason for taking it to the indy. Turns out, I had done it perfectly only to have them ruin everything and send me home on a bike that ran like a POS. I'm obviously still sore about the whole thing.
It's an S&S 124, with S&S Gear Drive 640 Easy Start Cams and running 10.5 Compression ratio. Standard S&S heads for the 124.
I will give the raising of the timing a shot and report back soon.

 

Why are you running the Easy Start cams AND compression releases?

 

I can't see needing both. Compression is on the lower side of things.

 

I'm a bit confused, what is the CR error? Did they install auto compression releases with the TMax?

 

If you enable the CRs on a Tmax and get a CR error, they are not hooked up.

 

after doing the compression test that hrdtail78 has said, what are the results,,,,this can help make sure that your cam timing is correct from the start. if its good, the next thing to think about is how good is your starting point base map? if its only so so, or not close at all, you need some assistance. If there is not something that is pretty close to your build in the list in the software, contact TMax tech and see if they cant provide you with a base/starting point map that will get you closer.
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sounds like a weak ignition.

 

It was a timing issue. I added some timing to the zero and 269 RPM and it started. I waited a day, tried it again and it started. So, I may have some more fiddling to do, because it never starts on the first crank, only on the second (which I seem to have to hold onto the starter for longer than I would like). Thanks for the help @hrdtail78