Author Topic: 2019 Sherco 300se r factory. Need info on updated ecu setting/new plug cap  (Read 387 times)

Ninja Garage

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Hi guys, I have just purchased a near new 2019 300 se-r factory. The bike only has 400 km on it and feels like it's making around 30 horsepower. As soon as the bike gets into the high RPM range it starts stuttering and the bike just doesn't hit band properly and doesn't want to sing. I've had a close look at the reed petals and they're absolutely perfect. I have read a couple of times on this forum that the 2019 model 300 2 strokes had to have revised ECU settings and a new spark plug cap. Can someone please help me with any information about this. is this why my bike isn't running right? I'm really unhappy. I literally just purchased it and was expecting the thing to rip and it feels like a postmans bike. It's running the standard rich jetting that the 2019 bikes came with. Any help in the right direction will be hugely appreciated. It's winter here in Sydney Aus. I ride at sea level up to around 500 feet.

JL4049

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The map/plug cap issues causes fouled plugs/flame out. Sounds like you need to rejet. A rich main jet causes the top end to be stuttery and will limit rpm.

Ninja Garage

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Thanks for the reply. I def need to lean out the main jet. Have a Suzuki needle on the way too. Yeah the bike does seem to be jetted quite rich. Has anyone heard of the bad earth between the frame and coil? I've read that removing the paint at the contact point solves the issue. I've also heard that the bad earth could also be the problem. 

BryanZg

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I have found that filing the contact points on the frame for the coil does make a difference.  The bolts also tend to loosen up too sometimes which makes it cut out.  I always file the contact points, grease them, bolt it.  Make sure the screws are long enough also.  Check the bolts every so often.  Jet it right.  I have a '19 300 sc factory with the updated coil, ecu, and plug cap and it is running great. 

Ninja Garage

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Thanks for your reply. I have spoken with a couple of Sherco mechanics about the updated ecu and plug cap and they both said it was rubbish. They said it was just Shercos way of trying to make a problem disappear that they had no idea on how to fix. But I'm relieved to hear you say that your bike is running sweet with the ecu update, the plug cap and the earth to frame fixed. Was your bike running poorly prior to these changes? Just waiting on jets and NECJ needle. Planning on running 38 pilot, 170 main, NECJ on 2nd clip and air screw 1.5 or so out. (Subject to conditions etc) can I ask where you got the updated ecu and plug cap? And did you need to replace the coil?

Gartzza

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I got new coil (new type, Kokusan), plug cap and updated ECU for my SE300 2019. Never since starting or running problems or foiled plugs.

Ninja Garage

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I ended up changing to a 38 piolet jet, a 170 main, NECJ on middle clip, a/s 1.5 out and running a br8es plug. I spoke with the previous owner and he has already had the ECU upgrade along with the new coil and spark plug cap all done at the Sherco dealership I bought the bike from. The bike ran perfectly. All problems solved. Checked the plug after the ride and it looks good. Maybe still a tad rich but that's ok by me.

Strosek

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Re: 2019 Sherco 300se r factory. Need info on updated ecu setting/new plug cap
« Reply #7 on: September 10, 2020, 07:44:02 AM »
So you're running the wrong plug.  This bike takes a 7 not an 8... Gonna run way better with the 7.
Also if your coil is bad you'll know it.  I replaced for piece  of mind you may want to do the same.  The remapped ECU does make a difference also suggest doing it.  I found the bike ran much better after it was done.