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Lurches forward and instantly dies

4K views 13 replies 6 participants last post by  wiesshund 
#1 ·
I have an 06 vstar 650 that was fine a month ago but today it does not want to go into gear without dieing. I know the kickstand switch will cause this but I have bypassed it a couple months ago. I bypassed the clutch switch also. I have checked both and even hooked them back into their switches and nothing happened. Since it lurches forward then maybe it's the clutch? Maybe it only lurches forward because it dies? I revved it up and put it in gear but no change.

What all would kill the ignition on this bike?
Are there any more safety switches besides the two?
 
#2 ·
sometimes the clutch will stick after sitting for a few days - certainly if it sat for a month

you start it up in neutral and when you pull the clutch in and kick it into gear the bike jumps forward. Its because the plates are in the oil, and after sitting for a while the film is pressed very thin between the plates, and they stick together.

If the bike is jumping when you kick it into gear, that is whats happening. Try giving the bike a bit of a push with your feet to get it moving then kick it into gear with the clutch pulled in. If its really stuck you may have to pump the clutch lever and get on the gas a bit to break it loose while the bike is moving.

If you get the bike moving and then kick it into gear, and its still stalling, then something else is going on.

How are you dealing with the choke?

all the way out to start when cold
push half way in when it starts
push it the rest of the way in about half a mile down the road
 
#3 ·
Pushing the bike and shifting into first or second did not change anything. You can't feel it jumping forward or anything when you put it in gear while it's rolling it just dies.
Shouldn't I be able to start the bike while it's in gear? I'm pretty sure I've done that many times but now after it dies I can't get the starter to engage unless it's in neutral. Some safety switch is keeping it from running while in gear.
 
#6 · (Edited)
.Shouldn't I be able to start the bike while it's in gear? ...
only if the kickstand is up and the clutch is pulled in

if the kickstand switch or clutch switch is failed or bypassed wrong it will do exactly what you are seeing.

It could be the wire to the switch, or the connector pin from the switch going back to the ECM.
 
#7 ·
With the key on and engine off I can hold in the clutch and slowly push the shifter down and I hear it clicking a relay off and keeping it from turning over(ignition relay?) and when I slowly let off the shifter the relay clicks back on. I never actually locked it in gear while doing that.
I'll try to find a wiring schematic for it later unless someone already has a link to one.
 
#8 · (Edited)
if you google Yamaha service manual V star 650 you can find the entire manual online as a free PDF download

the wiring diagrams are near the back of the manual

it sounds like you have the kickstand switch wired so the ecm always thinks the kickstand is down
 
#9 ·
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#10 ·
Alright, I figured it out. There is a relay module between the back tire and the battery box that has two relays and 6 diodes. One of the diodes is used on the sidestand switch circuit and it tested bad. I found a suitable replacement diode (1N4001). After soldering in the new diode I plugged it back in and the bike no longer dies after putting it in gear and it also starts in gear now with the clutch pulled in how it's supposed to.

Thanks for all the help everyone.
Maybe I can finally get this thing on the street for the first time ever.
 
#11 ·
that is a very impressive repair - I did not know the kickstand circuit uses diode logic like that

that is one of the weaknesses of the service manual schematics: they show you how all the switches and modules are connected together, but they do not show you what is inside each module or relay box

Nicely done!
 
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#12 ·
Great news, good job on reading wiring diagram.
 
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