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Discussion Starter #1
Hello all, I wanted to pick some nerd brains here. My F4 has been consistently turning off at 85-90 mph riding on the highways. Initially I thought it it overheating issue. But no, as I switched to Motul MoCool. I was returning from Bike night, 10 PM (OAT was around 70F) the bike coolant was 3-4 bars (way below the mark). I am not sure what happens. It is really scary as it happens on the freeway. Any suggestions.
I took it to the dealer, new SW was flashed last year.
 

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Electronics or fuel? Is it a sudden cut like no spark, or more gradual like fuel shortage?
 

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Any mods on your bike?
 

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Like an alarm?

The end result of this tread: alarm wiring
 

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Does the engine turn back on as normal when the speed drops below 80mph? It sounds like you have accidentally set the speed limiter. I've accidentally got myself into this function a few times when trying to zero the trip meter or switch between trip 1 and trip 2 while on the move.
 

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Discussion Starter #6
Hello, the cut is sudden. Like I know I can’t use throttle anymore. And then never starts back. But once I take the key to ignition off and then turn it back on. Then start the engine, it comes back on and I am able to ride it as normal.
There are no mods on the bike. Just the brake and clutch levers are aftermarket.
 

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Does it happen under acceleration (open throttle) or on closed throttle during deceleration?
 

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@sajmani: When this occurs, does your engine continue to run...? (Just not respond to throttle input?)
 

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Discussion Starter #11
@silentservice703 No the engine goes off as well. Electronics and dash is running though.
 

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Discussion Starter #12
So I try the trick to press the clutch and slightly release it to see if I can do a rolling start back on but that does not happen. Just turn bike off and on and the bike starts in an instant and runs fine. No codes nothing at all.
 

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If the yellow check engine light does NOT light when this happens, then most likely your ignition switch base is faulty. There was a service bulletin on that.

If you do have a check engine and the dash stays lit, it's likely its the twist grip. In this case the throttle would not respond, you would be in limp mode and engine would go down to idle. Key off/on resets this.

Another possibility if NO check engine light is that there's a place where the wire harness could be routed incorrectly and be passing over a sharp edge. That would affect the IMU (tip over switch) and make the bike think it had tipped over. Key off/on resets that.

Last option would be the crank angle sensor. Clues are no check engine, dash stays lit and tach drops to zero with clutch out. Engine turns but tach quits. This is usually bike temp and time related, not related to ambient temp.
 

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Discussion Starter #14

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Discussion Starter #15
Does it happen under acceleration (open throttle) or on closed throttle during deceleration?
It happens on open throttle or regular cruising at 85mph
 

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Bet it is the switch as covered by the bulletin sleiper1 mentioned.
 
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Discussion Starter #17
Bet it is the switch as covered by the bulletin sleiper1 mentioned.
Hi @esq'z me Do you have this previous discussion thread about the ignition base faulty. I can look into it and order the parts needed.
 

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If it is an issue with the throttle a fix maybe to clean the connecting plugs for the throttle and right hand switch block which includes the map switch. Follow the leads for these, they plug into the main harness on the right side of the steering head. There is a black plastic panel to remove to access the plugs. Unfasten the plugs and spray the plugs and sockets with contact cleaner. I use Wurth contact OL but there are lots of alternatives. Spray the contacts and let them drain and dry off then repeat. A spray of dielectric grease before reassembling can help. I've had a few of these types of incidents, one where the engine cut completely. It would then start and idle but with any movement of the throttle the engine would die. The routine above cured it which was just as well because I was 400km from home at the end of day one of a five day trip.

Also check the condition of the two leads, look for any impact or rubbing damage. They can get trapped by the forks if they are not secured properly. It is a balancing act between securing them so they stay in place and not securing them so rigidly they cant flex smoothly with movement of the handlebars. HTH.
 

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Discussion Starter #20
Thanks @Tony F . I really appreciate this advise. Started looking into it.
 
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