Dead Sherco

[Bushy Matt]

Bike - 2019 Sherco 300 SEF-R.

As some of you bike talkers already know, my bike totally died on the Grand Final ride last Friday.
To give some background - I pulled out of a side road onto Main Mtn Rd, accelerated moderately up to about 4th or 5th gear then the engine just cut out (like if you turn off the ignition) and rolled to a stop.
I rode the bike the previous Tuesday and Wednesday with no issues and it started Friday morning ok. Only rode about 15 min into the ride (maybe less), switched it off a couple of times on corners and it re-started all as normal.

So far this is what has been checked or somewhat diagnosed;

Fuel pressure out of the tank - ok
Fuel spraying out of the injector - ok but not like a jet, more of a mist.
Power to the plug cap / coil - ok
Spark at the spark plug but only tested by holding the plug against the frame. New plug, gap at 0.9 on both electrodes, Good blue spark.
Compression feels ok, I don't have screw in tester but it will push my hand up off the spark plug hole and can feel suction also. It will make little exhaust puffs out the muffler too.
Tried putting petrol straight into the barrel and as a last resort even tried some 'start ya bas$&#@' spray, both through the throttle body and straight into the barrel too. On many other internal combustion engines if there's been spark this stuff will fire. Not even hearing a slight kick from this.
Drained the battery down a bit turning it over and over testing stuff but have recharged the battery and it's spinning up plenty fast enough now.

So now I'm open to suggestions or if anyone has had the same issues and fixed it by replacing part A or whatever, please feel free to reply.

My gut feel is the plug cap shorting once inserted into the head but seems a bit of a long shot. I'm at 90% that it's ignition related but haven't done a proper compression test so that's the other 10%.
Have read that Sherco's are notorious for crapping ECU's or some of the ignition hardware but that was "meant" to be on pre 2017 models. By 2019 the issues were resolved........maybe.

This is the plug cap

[Brownballs]

CDI


Sent from my iPhone using Tapatalk

[Toysrus]

Get a compression tester, if its ok and Aerostart wont make it kick your at ignition.

[Dann]

Sounds to me like you've ruled out the fuel system.
Compression imo isn't worth looking at because it wouldn't just suddenly stop. Say even if you had a bit of shit holding a valve open but you've got spark, cranking it with areostart surely you'd get some kind of fire or backfire.
I had a loose female connector in my YZ, caused a misfire that would start happening every 3 rides. That took ages to diagnose, I eventually noticed that electrical plug was a bit burnt after going over everything 10 times.
You're suspect on the spark plug cap, you had spark earthing it out on the frame but it wasn't sitting in it's natural position. If you can, try cranking it while pushig up and down on the wires and the plug and see if it fires. Go over other plugs and earths and look for something stupid.
Try a new spark plug cap.
If you still can't find anything it's time to consider cdi or stator.
It would be fantastic if you could get another bike to swap bits and see what it is.

[Walkahz]

How did you go Bushy?