Author Topic: 450 Factory stuttering at low load  (Read 378 times)

Mongobear

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450 Factory stuttering at low load
« on: October 25, 2020, 09:38:40 PM »
Afternoon guys and gals,

First post here and starting off right with a problem :)

Bought a '16 450 Factory a couple of weeks ago and really like the bike. First injected bike after two WR250F and a 300 2-smoker. Bike has done 61hrs, just under 2000km and I'm located in Queensland, Australia.

I only had a chance to take her out twice and noticed on the last ride that she is stuttering and coughing a fair bit under low load. Seems to come and go but is more present than not. Starts fine for what I can tell (2-4 cranks), idles fine and moves quick as it should when you twist the throttle. She however misfires and coughs heavily when just roaming along. At some stage she completely stalled on me and wouldn't want to start again. I just let her have a break and 5mins later she started and ran just fine, was still coughing along but did not stall again.

As it's the first injected bike, I don't quite know where to start troubleshooting. Understand there is a TPS somewhere and the throttle body may need a clean but then there is nothing about either in the manual and I don't know if the issue can relate to any of those parts.

Fuel pump maybe? But how would one troubleshoot that? I don't have another Sherco to swap parts with (anyone here from the Sunshine Coast?) and would really want to avoid shelling out 600 bucks for a new pump not knowing if that's the actual issue.

Thanks in advance guys
Pete




Trailrider383

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Re: 450 Factory stuttering at low load
« Reply #1 on: October 29, 2020, 05:31:02 PM »
Water in the gas maybe? Dump it and try new gas.

Mongobear

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Re: 450 Factory stuttering at low load
« Reply #2 on: October 29, 2020, 05:36:44 PM »
Thanks mate, good tip. Fuel was fresh from the pump but I'll give it a shot.

I'm gonna rip her apart on the weekend and disconnect and spray all connectors. Have a new spark plug on order as well.

Still hoping it's something simple.

Cheers

VxZeroKnots

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Re: 450 Factory stuttering at low load
« Reply #3 on: October 30, 2020, 09:22:32 AM »
Sounds to me like a dirty injector. Pull it out and use a 9V  and pigtails to hold it open and liberally spray it out with carb or injector cleaner. you can get crafty with the plastic spray hose and a vaccum plug to rig a setup to back flush it. I bet some crap comes out if you spray it onto a towel.

Mongobear

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Re: 450 Factory stuttering at low load
« Reply #4 on: October 30, 2020, 01:43:08 PM »
Thanks mate, great tip. Will give that a go. Does it only take 9v? Couldn't just use the bike battery?

Cheers :o

VxZeroKnots

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Re: 450 Factory stuttering at low load
« Reply #5 on: November 01, 2020, 05:25:17 AM »
Bike battery with jumpers from alligator clips should be fine. 9V is a little smaller is all and is enough to activate the solenoid

possiblytoofast4you

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Re: 450 Factory stuttering at low load
« Reply #6 on: November 02, 2020, 01:41:06 PM »
Check the stepper motor in the throttle body is full of air filter oil.

possiblytoofast4you

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Re: 450 Factory stuttering at low load
« Reply #7 on: November 02, 2020, 01:41:28 PM »
isnt* full of air filter oil

Mongobear

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Re: 450 Factory stuttering at low load
« Reply #8 on: November 02, 2020, 05:55:25 PM »
Thanks mate, will keep that in mind.

Made a start on the weekend and may have found the issue already. Previous owner replaced the battery just before I bought it and the positive cable was only attached loosely to the battery. Still need to run a full test but looked good on a short run down the road. Will update again once I can throw her into the dirt.

Supernova666

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Re: 450 Factory stuttering at low load
« Reply #9 on: November 03, 2020, 06:49:03 AM »
That would for sure cause run-ability issues.
You will only sound insane if you try to explain reality