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Discussion Starter #1
I recently bought a 2003 Sportsman 500 (knowing that it didn't run)
I bought it from a trusted friend who had not had the the time to troubleshoot it
So far I have replaced the speedo, adjusted the valves, checked the cam chain, confirmed that I have spark, replaced the plug, ensured that the carb is clean and working correctly and checked all the wiring. It will turn over but will not crank with the electric start or manual start. I've rebuilt V-Twins in the past but I have little experience with this engine. I am going to attempt a leak down test tomorrow. (I know it's supposed to be done at running temp but that isn't possible right now) Soooo... I have a few questions.

First... If the CDI/ECU is bad would I still have spark?
Second... Anyone have any data on leak down on a cold engine? Something to compare my results with.
Third... Any further advice or suggestions?

I would greatly appreciate any help. Thanks in advance
 

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Welcome to the board!:med:
 

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Have you got the carb bowl full yet. It sometimes takes a bit for the diaphragm style pump to fill the bowl. It won't gravity feed any unless the tank is completely full. I don't use it much, but a couple little shots of starting fluid will usually do the trick.
 

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Discussion Starter #4
It's getting fuel to the cylinder. I've tried giving it a shot or two of starting fluid without success. The leak down was at 28% cold (impressive). I has backfired a time or two but that's the best I've gotten out of her.
 

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How many hours and miles on this? You said it would not crank with the electric start or manual how did you get it to back fire? You need a good battery to run everything, check the kill switch, check magneto for timing maybe spun the key way moved exciter. check all connectors for tight remove clean and replace them tight, check for obvious broken or chaffed wires.
 

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Discussion Starter #6
It turns over well. I really don't know how many hours are one it. When I got the bike it had say up a while and the gauges where full of water. I replaced them. I've checked all the connections and it has spark. White spark not blue but it's a brand new plug and I checked the gap just to be sure.
 

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Have you checked the "stupid questions" first...... kill switch, ignition switch, transmission in park or nuetral?
 

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One thing I ran into on mine is the key for the crank trigger had broke and the engine couldn't pick up its timing any more. It would spark but was so far out of time it wouldn't fire.
 

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Have you checked compression? Rings could be stuck and it is not making compression. Put a little oil in the spark plug hole and pull the rope a time or two to lubricate cylinder. Spray some carb cleaner in carb and try to start it.
 

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Discussion Starter #12
Thanks for all the help everyone. I did a compression check and got nada. Less than 28 psi.
Soooo... I ripped off the head and the piston and rings where shot. It appears the the cylinder was bored and the piston was not matched to the cylinder causing some major piston slap. The cylinder itself appears to be ok, just pieces of the piston stuck to the walls. I'll have it checked, polished and measured for a new piston and rings. Hopefully I'll be back on the trails in a couple of weeks.
 
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