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Discussion Starter #21
Greetings,

It's been a month of riding in 40+ degree weather, after spraying the ignition switch with electronics cleaner the no crank, silent response when starter button depressed, has not show up. A fix, maybe?. But the plot thickens with recent developments. Here are two starting conditions that have shown up recently. At start up while cranking the engine for 2-3 seconds the starter disengages. This has happened three times in about a dozen starts. Secondly, at start up once the starter switch is depressed and released,the starter runs continuously. Turning the ignition key to off stops the starter. Turning the key back to "on", press the starter button and the bike starts. Considering the Remus exhaust note and the clutch rattling it's difficult to detect if the starter has disengaged. Not a pleasant thought to sit with while suiting up. This has happened twice in the last month. My first guess is the starter solenoid. I could use some help on how to test the circuit before purchasing parts. What are the choices? Can the solenoid be disassembled and contacts cleaned? I don't want to ignore the warning signs. The goal is to have a reliable starting bike that can be turned off and started anywhere, anytime.
Thanks in advance for your experience based advise.
 

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most of the 5am ecu file have what they call "servo ignition" which means if you press and release the start button quite quickly it will crank until it fires and reaches a certain rpm. if you press and hold for a couple of seconds that usually disables it. if it fires and doesn't reach the cut off rpm the starter will keep running, but it's quite low - 900 rpm or so from memory.
 

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"At start up while cranking the engine for 2-3 seconds the starter disengages. This has happened three times in about a dozen starts." This is indicative of the starter sprag or freewheel going bad. It will just get worse until it doesn't crank the engine whatsoever, but just spins. Needs replacement. Not too expesive, but a bit of effort to get to it.
 

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Discussion Starter #24
Thank you, thank you. A bit of knowledge accurately placed has saved me from myself. A continuous start....who would have thought. I'll try to figure out how to use it to my advantage. Personally, I like being able to have a thumb on the starter button. Speaking of which, in general, is there a preferred cold starting protocol for the ST4's? I have gotten to the point of moving the "choke" lever full on, crank the bike 2-3x (has yet to start at this point), 1/2 choke until it starts. Does that sound about right? Previous liter bikes, (Japan, Germany) started like a light being switch on. Since the bike is new to me i'm somewhere low on the learning curve.

In closing thanks belter for the heads up on the starter. Thanks steve_d, I'll start looking into the starter sprag and see if it's a repair I can do myself.

Ciao....
 

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Please note that on the ST4s, the "choke" lever is merely a high-idle cam that you're adjusting -- it's built into the throttle linkage. For my 2003 ST4s, it seems to start the best at closed throttle, but with a slight opening of the throttle when it fires, and then I set the high-idle with the "choke" lever. But do note, it is not a choke, and it doesn't richen the mixture at all. It just opens the throttle plates a bit.
 

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Also note that ST3 machines have an AIC valve and are totally idle controlled by the ECU. I believe your bike is an ST4s ?
 

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Discussion Starter #28
Yup, an "03" ST4s in apparently the second fastest color. With left hand on full "choke" lever, right hand on the starter button, crank the engine, feather the choke back a tad and bam!!! A bike ready to ride. Thanks. I don't know whats more fun, learning about/working on the bike or riding it? 100+ miles on twisty back roads yesterday pretty much says it all......riding of course. Silly boy.
Thanks again for the helpful tips. At this point on the learning curve there is no such thing as a silly question.
And I've the Desmo Times manual in hand. Looks like a good way to get yourself an education. I am curious as to what is the fastest color. Up to this point I thought it was red.
 

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Fastest color= BBG(bat barf gray, stealth gray, matte gray), always up for discussion!😂
 
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