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Discussion Starter · #1 ·
Picked up this quad from an estate sale that someone had started a cam swap and was apart. Put it all back together and it won't start; won't even try. Here's what's been done or observed.
1. Timed (It was off)
2. Valves adjusted (they needed shimmed)
3. Good spark; new plug
4. Compression at 60psi
5. Don't know condition of carb but sprayed carb spray in intake while cranking with throttle wide open

Not sure on what the cam is, but should that really matter?

What the heck am I missing?
 

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Discussion Starter · #3 ·
Welcome to the forum.

You are missing compression - need at least 120 psi with the throttle held wide open - if the cam timing was off and you cranked the engine over without first turning the engine by hand to check for interference, it's likely the valves contacted each other or the piston and are bent.

I does not make a great deal of difference on the cam installed, as long as it is correct for the application.

Did you adjust the valves because they were too loose or too tight?
I was using the manual for this quad that states the compression should be 58 psi @360 RPM.
The motor has always turned over by hand (as long as we've had it at least). Guess PO could've bent the valves?
I'm pretty sure the valves were too tight; had to take mm's out.
Could I see the valves through the exhaust port with a bore camera? Don't think I can see them through the spark plug hole since my camera points down only.
 

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Discussion Starter · #4 ·
Welcome to the forum.

You are missing compression - need at least 120 psi with the throttle held wide open - if the cam timing was off and you cranked the engine over without first turning the engine by hand to check for interference, it's likely the valves contacted each other or the piston and are bent.

I does not make a great deal of difference on the cam installed, as long as it is correct for the application.

Did you adjust the valves because they were too loose or too tight?
Doing some reading on the compression and since it's an ER version, it's supposed to be 60psi while cranking.....
 
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