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Engine Starting (Read 1198 times)
sign216
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Engine Starting
10/06/17 at 08:52:13
 
With MyECU my bikes runs like a champ.  Better than factory.
Except for starting.  It takes two tries of several seconds each, and is embarrassing. 

I recall other people had this, and were going to research the issue. 
Any progress?
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Re: Engine Starting
Reply #1 - 10/07/17 at 07:48:03
 
Cold or warm starts?

You need to determine which stage is causing the issue. See the last section on http://www.myecu.biz/MyECU/FirstSteps.htm

I find the prime value to be the biggest player, just a change of 1 can make the difference between starting first go and looking like it wont start. It's easy to flood. Sometimes I'll crank with open throttle and then drop the throttle and it starts right up.

It will take a bit of experimentation. I'd start lean and richen it up.
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Re: Engine Starting
Reply #2 - 10/08/17 at 00:40:17
 
It's cold starts that are reluctant.  Hot starts are okay.  For hot, I give 3/4 throttle and it starts up fine.  Cold I just open the throttle stop lever and crank.

Am I right, that for starts you crank with an open throttle, and close it while cranking?  Interesting.  Is this for hot or cold starts?
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Re: Engine Starting
Reply #3 - 10/08/17 at 07:43:01
 
That's correct but that's only for my Cali and was before my latest changes because I had too much prime.

The throttle is ignored while starting so it is possible to clear flooding by opening it up.

I don't use fast idle until after starting.
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Re: Engine Starting
Reply #4 - 10/08/17 at 09:28:26
 
I'm slightly confused (or greatly confused, according to my ex-wife).

I understand that throttle is ignored on start-up, but 3/4 throttle really seems to work on hot starts.  Am I deluding myself?
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Re: Engine Starting
Reply #5 - 10/08/17 at 11:08:51
 
Whatever works.
I don't use any throttle for a warm start. No throttle and it immediately starts and idles.
Perhaps you have two wrongs.
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Re: Engine Starting
Reply #6 - 10/08/17 at 11:44:16
 
Throttle works for me on hot starts, so I don't want to mess with that.

You said "Sometimes I'll crank with open throttle and then drop the throttle and it starts right up."

So you do that for cold starts?
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Re: Engine Starting
Reply #7 - 10/08/17 at 18:17:46
 
sign216 wrote on 10/08/17 at 09:28:26:
I'm slightly confused (or greatly confused, according to my ex-wife).

I understand that throttle is ignored on start-up, but 3/4 throttle really seems to work on hot starts. Am I deluding myself?


Perhaps stating the obvious but please note that "ignoring throttle" only means that the injector durations wont depend on throttle. You are still letting more or less air in, that's purely mechanical.
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Re: Engine Starting
Reply #8 - 10/09/17 at 00:27:30
 
raz wrote on 10/08/17 at 18:17:46:
sign216 wrote on 10/08/17 at 09:28:26:
I'm slightly confused (or greatly confused, according to my ex-wife).

I understand that throttle is ignored on start-up, but 3/4 throttle really seems to work on hot starts. Am I deluding myself?


Perhaps stating the obvious but please note that "ignoring throttle" only means that the injector durations wont depend on throttle. You are still letting more or less air in, that's purely mechanical.


Raz, you're right.  Sometimes the obvious needs to be said.  And this explains why 3/4 throttle works on hot starts. 

Also, I cold start w the throttle stop (fast idle lever) engaged.  Let me try it the way Admin suggested, and use the fast idle only after starting.

If that doesn't help cold starts, then I'll adjust the prime value on the map, and see what that does.
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Re: Engine Starting
Reply #9 - 10/09/17 at 06:49:39
 
The fact that you use 3/4 throttle may mean that your prime is too much for warm start and you need to lean it with throttle.

"Sometimes I'll crank with open throttle and then drop the throttle and it starts right up."

Since last adjustment I usually crank with no throttle. It will fire and I'll tease it to idle with throttle.
If it doesn't fire I'll do the crank with throttle. It probably means I need to lower the prime also.
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Re: Engine Starting
Reply #10 - 10/11/17 at 07:36:47
 
Not engaging the fast idle lever until after the bike is started, did help starts.  Thanks for that, I didn't know that throttle position was ignored on initial starting.

Starting is better, incrementally, but I'll play w prime until I get it really starting well.  I'll let everyone know my results.
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Re: Engine Starting
Reply #11 - 10/16/17 at 10:55:36
 
Thank you all for the good advice.  I ended up leaning the prime by two points, and starting is quick now.

A word of your wisdom is worth a month of fussing in the garage.

Thanks again.
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