Add timing?

[wavlovr1]

Using TTS on my 09 bike I see a spark table separate from the regular front and rear called closed throttle spark. I have no idea when this table is used but when I tried 25 I got kick back and changing these values to 22 seemed to stop it.

It is hard to track down however because a bad comp will cause the same problem. I am now on my 4th compensator. Probably a result of maxing out the throttle blade control table and developing too much TQ at too low of an rpm. but, I am no tuner for sure...

jb

[stro1965]

Yeah, I actually have a brand new ('14) compensator.  Kicked back on me on the very first hot start after the install.  Kinda rules out a bad compensator in my case.

[rbabos]

It happens because the starter can't over come the pressure in the chamber before the piston OR better yet. The rod angle pass's TDC.  igniting the gases at 4 degrees BTDC only makes this worse.

Looking at carbs. Most ignitions are set to fire at 0.  Make a hotrod out of it and for the most part. Ignition is retarded.  Putting starting spark ATDC.

So , you ever try that -4 in the kpa area to see it's effects on startup. I'm beginning to think even if there's a hidden table for startup only, the cts and kpa seems to influence it's values. All I know for sure is it don't start on the cts table, even if the throttle is closed. It's bypassed until the engine starts, then transitions over.
Ron

[Y2KRKNG]

I've heard about a setting to delay spark for one rev. Is this something that's out there?

[rbabos]

I've heard about a setting to delay spark for one rev. Is this something that's out there?

I think that's non existant in the Delphi EFI. I've not seen that delay when checking for spark. I've always attributed the slight delay in engine light up to available cranking fuel.
Ron

[saddle tramp]

T-max has a timing delay you can set for 2 or 3 revolutions before spark kicks in, for bikes with compression releases.

[hrdtail78]

I remember when I found out about delay spark.  It was with a crane hi4 and a kick only 78 hard tail.  Lessoned learned in the hardest worn out way.

I didn't try the -4, Ron.  But I know I have a 08 96 with 255 running out there set at -2. 

[07heri]

I've cured this on a few bikes by richening up the start up fuel.  Same thing happens with carb'd bikes here when the Texas summers heat up.  A carb bike won't kick back with full choke, no throttle, then push choke back in right after it fires.  Bumping up the starting fuel reacts the same way.  The 255's in my bike never kick back after I bumped up the starting fuel.  Doesn't matter how hit it is, no kick back.  I'd give it a try before getting too cosmic.  It's a free experiment.

[Y2KRKNG]

I propose that even if you pulled the S plug wires off the plugs it would still kick back!
Has anyone figured out exactly WHY the hot soak kickback occurs? My theory(and I treat the symptom accordingly) is that the kick back is actually a "dieseling effect" due to the superheated charge in the one cylinder that happens to be resting with the valves closed. Dieseling being a combustion explosion NOT Ignition from spark plug.
So check this out. You've got a bike that will kickback every time you stop for gas after a long hot run. Then try this. When your ready to fire it back up and you're cringing because you know she's going to turn heads for all the wrong reasons. run the shifter up to 5th then roll the motor though once, this will let the trapped hot gas charge out. Now start it up as you normally would, Guarantied it will not kickback!
Pain in the ass, but it works. So now let's get lazy and modify the procedure. Forget about manually rolling over the motor, and just tap the starter button as quicklie as possible then start it normally that WILL work also.

Not dieseling because there's no previous fuel in there from an injected system but the amount of spray or lack of fuel in the cycle prior to compression might contribute to detonation when the spark occurs BTDC.  That will stop the slow moving piston. Rules should be the same. Reduce timing or add fuel to create normal burn. Injected engines need sightly more fuel when hot then cool due to heat evaporation to counter this hot start issue. Generally even if timing is a tad high, more cranking fuel will cure the condition. At least from my limited experience.
In your example of running the engine through a couple of strokes, it will purge the heat out of the cyl inducing a cooler charge of air. Less heat, even with slightly less then desirable mixture will be less prone to detonate at startup.
Ron

I stumble across this while shopping new IGN mods, Though it was interesting and pertinent;

TWIN CAM 88 HOT STARTING
PROBLEMS
Some Twin Cam 88 engines are prone to hot
starting problems. When cranked after a short hot
soak, the engine may "kick back." Over time, this will
cause damage to the ring gear and starter pinion.
The TC88 module uses an improved starting
algorithm that includes a programmable cranking
delay. The TC88 module is shipped with a zero
cranking delay: it fires on the first recognized
compression stroke. This works best on stock and
mildly modified engines.
High compression engines may exhibit a
"dieseling" phenomena after a hot soak. This can be
verified by temporarily disconnecting the 3 terminal coil
primary connector to disable the ignition. If the engine
still kicks back or runs for several revolutions after
cranking, the problem is dieseling. The only solution is
to install compression releases. When compression
releases are installed, best starting results will be
obtained by programming the TC88 module for a 1-2
revolution cranking delay. This can be done by means
of the PC Link software and optional interface cable

[stro1965]

I installed a new "Big Crank" battery today, we'll know this spring if it just needed a little more spin power.

[stro1965]

Just to update this thread...ZERO kickbacks in the 500 miles or so since installing the new battery.

[Y2KRKNG]

 

[rageglide]

Glad the battery fixed it. also as FYI...
Latest WinPV exposes three additional Timing tables (air, engine, head temp) Joe referenced in Jan. 

[stro1965]

Good to know, I'll have to update.