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2004 CRF 450 wont start when hot


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Alright my 04 CRF 450R won't start when it gets hot. If you run the bike for 5 to 15 minutes if you turn it of it wont start until it's cold. I was told I need to check the valves. They are fine. I cleaned the air filter and air box. The guy I bought it from had it serviced and they spray 1/2 a can or more of filter oil. I cleaned the it out and let it dry over night. Lightly oiled it and cleaned the carb up good. Still it will start and when cold but wont start when it is hot.

New Plug - NGK IRF8H 11

My Valve

Decompressor Clearance 0.014 in.

Valve Clearance

Intake 0.005 in. (Both)

Exhaust 0.012

Carb

Main Jet 165

Pilot Jet 42

Leak Jet 55

Pilot Screw 1 1/2 turn

Here's the plug

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I'm having the same issue.I put a moose lighting coil on and the bike did some cracking and popping but it started.Now the bike will only start when its cooled down.I'm going to put the stock ign back on and I'll let you know how I make out.

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So I started the bike a few minutes ago. Rode it up and down the block.. My buddy was laughing at me. He stopped by to help me trouble shoot it.. My NGK IFR8H11 was gapped at 0.044 so I gapped it to 0.047. Started it and if fired right up. 5 minutes after he left I can't get it to start again. When we pulled the plug it was running a little rich. My pilot screw is 1 1/2 turns out. Not sure what I'm doing wrong. I miss my 2 stroke..

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Alright I did so much I'm not 100% sure what fixed it. It started running better after I went threw the carb for the third time.. I stayed with the 165 main jet and adjusted the pilot screw 1 1/2 turns out. I turn my throttle up 1/2 turn and gapped the plug to .47.. I ran it 3 times in the last 2 day. 1 hour each time. It started first kick everytime. I did so much I'm not sure what exactly fixed it but something worked. I also noticed when I replaced the fuel lines that the was back pressure from the petcock on the tank. I cleaned out the cap and notice the breather vent had sand in it.. I have learned alot in the last week. These bikes need to be well maintained.. Still miss my 2 stroke..

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Remember that if you are using a feeler guage type spark plug gapper, you are ruining the plug. These iridium plugs are pre gapped from the factory and if you stick something in there to check the gap it wipes the iridium off the plug and essentially ruins the plug. If you did that, I would get a new plug asap or risk being stranded when it quits working.

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I took the coil and plug cab off today. I'm startign to think I have a bad plug cap..

Primany Coil Resistance 00.3 (OHMS Meter 200)

Secondary Winding resistance 19.8 (OHMS Meter 200k)

Plug Cap 14.6 to 15.2 (Fluxuating) (OHMS Meter 200k)

Secondary Winding Resistance 5.44 (OHMS Meter 20k)

(Without the plug cap)

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