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Discussion Starter · #1 ·
Picked up a 99 400ex two days ago with 416 kit and a lot more.

Wasn't running kid said needs timed. It was way off, after timing was set right bike wouldn't start turns out decomp plunger and spring were gone. Took decomp off stock cam and it takes a while to start but does only with the choke. If I turn choke off it dies. Also tried to ride it down the road and it falls flat on it's face after about 1/4 throttle and almost wants to die.

Could it be carb is dirty?
Any help is appreciated thank you.
 

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Discussion Starter · #4 ·
It doesn't have the hot cam. The kid took the hot cam out and put stock back in but lost the plunger and spring. Puzzled me for a day or so. Just took decomp lobes off stock cam and it started. But turns over for like 10 sec before it fires.
 

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My guess is carb - timing is set by the crankshaft and can only be off if the flywheel key sheared

Cam timing is either right or wrong, but tight valves can cause hard starting when all else is right

Falling flat above 1/4 throttle is classic carb issue - get it up to the point of falling flat and put the choke on - if it runs better even momentarily, it's the carb causing the problem.
 

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Discussion Starter · #11 ·
I know it's getting fuel, it has good compression, I checked spark from another plug and,it has a strong spark. So I'm thinking the plug thats in there is fouled out. Haven't got a new plug yet, kinda a pia to get the plug out without proper tool.
 

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Yeah - that's the reason Honda (and all the other manufacturers) includes a tool kit and an owner's manual with each vehicle. Although I do not need them, I always ask for them when someone is trying to sell me a machine. There have been times that I walked away form a "good deal" because the owner did not have the manual or the tool kit. It usually means they have not done any basic maintenance and if they claim they have I ask them how they did it without the tools and instructions.

Call me an A-hole, but that's me being me.
 

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Discussion Starter · #13 ·
Makes perfect sense. I know this machine was taken care of because the kid raced it. Yes I know how hard it may have been abused, but at the same time he needed it to race so he kept up with maintenance. I can get the plug out with a very skinny socket. But gonna buy the tool kit.
 
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