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Discussion Starter #1
Just bought a trx450r about a week ago. It started fine, test drove it got it through all the gears etc. I put my hand on the exhaust before he started it so I know he didn't have it warmed up on me. Well I get it off the trailer go about 300feet pull in the clutch downshift and it dies. I can't get it started since. I put the battery on a tender overnight and still nothing. Bought a new plug and also cleaned the injector. Its getting fuel and spark but still nothing. It backfires when starting sometimes. I cant figure it out
 

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Discussion Starter #3
Someone said I should check decompression spring on exhaust cam.. Ig ill be checking that when i get home tn.
 

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Sorry idk why i said trx
OK!
So it ran fine motor cold when you rode it & started to warm up it quit running...?...common valve clearance being too close of gap..

Check & adjust your valve clearance...
Valve Clearance: between cam and valve lifter
Standard:
Exhaust 0.17 ∼ 0.22 mm (0.0067 ∼ 0.0087 in.) best at 0.21mm
Inlet 0.10 ∼ 0.15 mm (0.0039 ∼ 0.0059 in.) best at 0.14mm

Valve clearance is in range & the symptoms continue...?

Is your ECU OEM/stock or a Procom...? OEM see picture

Does your KFX have any modifications...?..List your mods...Like fuel controller, cams, full exhaust, Fuel custom intake

With a stock ECU...Does your F.I dash light remain ON or flashing when trying to start...?..If yes...it stays on & doesn't turn off after 3 second..
Check for error code...orange wire in black pouch by the headlights..see pictures

Make sure your battery is fully charged...12.8v standard...!!

Make sure your throttle cable has a little bit of slack to fully close to idle position...!!
 

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Discussion Starter #8
Looked at it more today. It appears to have somehow jumped timing. He was definitely in it not long ago cause the valve cover bolts we're lose af. I bet he couldn't get it to stay timed. I'm thinking it's maybe a bad tensioner?
 

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Discussion Starter #10
He's not getting back to me so I might attempt to do it myself. Anyone have a diagram or instructions? I've changed a timing chain on my car before so it can't be much more difficult then that. my email is [email protected]
 

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Discussion Starter #11
Will I also have to relash valves? I was doing a little research so far it looks like I need to remove valve cover, camshafts, alternator rotor, then 2 lower guides and front guide?
 

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Will I also have to relash valves? I was doing a little research so far it looks like I need to remove valve cover, camshafts, alternator rotor, then 2 lower guides and front guide?
Here's the cam chain diagram

Valve Clearance: between cam and valve lifter
Standard:
Exhaust 0.17 ∼ 0.22 mm (0.0067 ∼ 0.0087 in.)
Inlet 0.10 ∼ 0.15 mm (0.0039 ∼ 0.0059 in.)
If the valve clearance is not within the specified range,
adjust it.
 

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Discussion Starter #14
I see that you tried sending it. I got your message but it was blank? Nothing in it. Plz try resending when u get a chance
 

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Discussion Starter #15
I ordered a new chain as well just to be safe. Who knows if the old one stretched or not. When I took the valve cover off the chain seemed pretty tight thought? Looks like it should be here this weekend. I actually got a service manual. Thx though man appreciate your help!
 

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Discussion Starter #17
Alright so I took the stator off and it looks like one of the wires are bad? I know on cars the crankshaft position sensor pulses to the ecu and ecu pulses back to keep the engine in time. Do you think the crankshaft postion sensor wire could have burned up and that's why it jumped timing? Timing chain guides look fairly new and chain is pretty tight on top and bottom. I wish I could just order the new wires for the stator. I cant seem to find them alone. Looks like Ill have to order a whole new stator
 

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the pulse coil/crank sensor can not cause it to jump time..But will cause an DFI error code & lock the advance timing into limp mode ...only a loose cam chain can cause it...!

Can you solder the wire together & isolate with shrink tube...??
 

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Discussion Starter #20
I'm really bad at soldering I just ordered a whole new stator and gasket. It should be here sometime next week. Along with chain and flywheel pull tool.
 
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