2018 Husqvarna FX350 - no start

Cary Kellum
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Cary Kellum
Help, I’ve installed a new battery on this bike, and a new spark plug, check for spark it is good. Installed new fuel pump and filter’s, and checked it and
Injector is spraying fuel. Main harness fuse is good. If I have fuel, Good air and take, I installed a new air filter. Shouldn’t the problem be electrical, and has anyone run into this problem before. Can a sensor like the throttle position sensor, map sensor, coolant temp sensor and thingsSuch as this burn out. And has anyone run into this problem before? Please help
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weland28
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weland28 5/23/2020 8:28pm
5/23/2020 8:28pm
If it has good spark and is turning over when you press the button what makes you think it’s electrical? How many hours does the bike have, could the valves be off or your timing? Is the top end super old and you have bad rings and no compression?
Cary Kellum
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Cary Kellum 5/24/2020 4:27am
5/24/2020 4:27am
The bike has 93 hours on it. Last time the valves were checked at a shop they said the gap was perfect on intake and exhaust. It was not a gradual
Decline in performance, it was a instant shutdown
Of the engine and then would not restart.
I have had no loss of oil or blow by in exhaust.
I have a compression tester but no adapter to
Fit this cylinder head . I guy at the track with a KTM
Said when he hit 90 hours on his bike his fuel pump
Quit. I got a fuel pressure gauge, after installing a new pump and the pressure is at 54 psi. And installed a new battery, l finished off the old
Lithium ion battery trying to start the bike.
Does anyone know where I can get hose
Adapter for a compression tester to fit this
Cylinder head?
I talked to another guy at their track and he
Has a 150 on his 350, and never did a top end
Or shimm the valves.
It’s a learning curve for me ,it’s my first fuel injected
Bike!! I am just trying my best to repair it myself,
My local shop wants a 120.00 per hour just to
Diagnose it . Thanks for your advice..
soggy
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soggy 5/24/2020 6:37am
5/24/2020 6:37am
look into the tps sensor voltage. if set incorrectly ive seen them be hard to start.
kb228
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kb228 5/24/2020 8:09am
5/24/2020 8:09am
Go get a leak down tester and use it. If you own a 4 stroke you should have one anyway. Compression testers do not tell the whole story with 4 strokes.

96 hours is enough to where id highly suspect some kind of top end issue.

The Shop

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Cary Kellum
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Cary Kellum 5/24/2020 8:45am
5/24/2020 8:45am
Hey guys, thank you very much for the advice I will check out the TPS, and check into a leak down tester, that should tell me if I have compression and or the valves are ceiling and the piston rings
Are good. Do you know if motion pro sales leak down tester’s?
Cary Kellum
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Cary Kellum 5/24/2020 6:58pm
5/24/2020 6:58pm
Hey, On average does anyone know what it cost to get a top and down on a 2018 FX 350, piston and rings and a valve job if I get it done in the shop?
kb228
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kb228 5/25/2020 5:02pm
5/25/2020 5:02pm
Cary Kellum wrote:
Hey, On average does anyone know what it cost to get a top and down on a 2018 FX 350, piston and rings and a valve...
Hey, On average does anyone know what it cost to get a top and down on a 2018 FX 350, piston and rings and a valve job if I get it done in the shop?
I charge $200 labor plus parts for a top end rebuild. That doesnt include any head machining - something that would need sent out. Usually those are $40-$80 per valve depending on the shop.

But im just a guy doing this on the side. A real shop would charge much more.
Cary Kellum
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Cary Kellum 5/25/2020 7:48pm
5/25/2020 7:48pm
Hey thanks for the info KB228. I’m still trying to decide what to do.
kb228
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kb228 5/26/2020 3:12am
5/26/2020 3:12am
Harbor freight sells a leak down tester thats not crazy expensive and it does the job. Its cheaper to buy one and test your engine than to pay for a shop to do it for you.
Cary Kellum
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Cary Kellum 5/26/2020 6:04am
5/26/2020 6:04am
Thanks KB 228, I’ll check it out!
Cary Kellum
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Cary Kellum 5/26/2020 6:17am
5/26/2020 6:17am
If I get that leak down tester, I need to put the bike engine at top dead center on the compression stroke? And if there’s no leakage, I have clear intake passage, the pump and injectors spraying fuel, and I know that the plug is sparking. Would that Indicate that one of the sensors for the engine has failed, GPS, map sensor type deal?
kb228
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kb228 5/26/2020 6:36am
5/26/2020 6:36am
Cary Kellum wrote:
If I get that leak down tester, I need to put the bike engine at top dead center on the compression stroke? And if there’s no...
If I get that leak down tester, I need to put the bike engine at top dead center on the compression stroke? And if there’s no leakage, I have clear intake passage, the pump and injectors spraying fuel, and I know that the plug is sparking. Would that Indicate that one of the sensors for the engine has failed, GPS, map sensor type deal?
Yes if the engine is in good condition and youre getting fuel and spark, it should run. Generally if a sensor is bad it will either not allow spark or not allow fuel or it will put the bike into a type of “limp mode”.

Its best to start with the simple stuff like fresh gas, plug, clean filter thats not over oiled, and verifying engine condition with a leak down test, and checking timing and valve clearance.
Cary Kellum
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Cary Kellum 5/26/2020 7:05am
5/26/2020 7:05am
Thank u,KB228 - will do
Cary Kellum
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Cary Kellum 5/26/2020 7:13am
5/26/2020 7:13am
Cary Kellum wrote:
Thank u,KB228 - will do
Good advice

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