Hi experts, I have seen many posts but none quite like what I have going on. My Big Bear will crank strong, has a good battery, new spark plug, clean carb, and fresh gas. I have checked the ignition coil, spark plug cap, pick up coil, stator, and source coil. They are all in spec. I have cut about 1/4 inch off the plug lead too. Valves are opening and closing fine and properly gapped. I have 150lb compression when cranking with throttle wide open. I have checked timing and the chain is tight and spot on according to the timing marks. It still doesn't even try to start. Have sprayed a little starting fluid in to the carb, very little as I don't like using the stuff in the first place, and it doesn't even sound like it is going to catch. I put my hand over the exhaust while cranking and can feel exhaust flowing out, but I haven't pulled the baffle out to check it. I don't know where else to look? It appears as though I have fuel, spark and compression so at this point I am lost...

 

Have seen a couple like this that actually loose spark when the plug is installed. Plug grounds the spark out. If stating fluid gets no response,valve timing is good,should at least pop back even if it's off a little. Try pulling the plug cap up and just set it on the plug loosely. See if spark can jump this distance to the plug and try to crank. If this doesn't help,I'd recheck your electronics with the factory specs. Plus you might even do like we did on some old Hondas that wouldn't crank. We'd pull the cdi,drop it on the floor and reinstall it. Some would actually run awhile. Then we'd order a new cdi.

 

Well, rather than pulling out the cdi and dropping it, I tapped on it with a hammer. I figured that would suffice. Still nothing. It does act like it wants to start, as in it will catch every once in a while but not strong enough to consistently fire. Is there any way of testing the cdi other than what you suggested. I hate what the manual says. If everything else checks out, it must be the cdi...

 

"If everything else checks out, it must be the cdi..." Yep that's about it in every manual,OR as in Polaris manuals its says for you to replace with a "known good one" to eliminate the cdi as the problem.. Ok for most shops as the techs usually have new ones in stock they can test,but not for the average owner..

 

A couple final thoughts/ questions, and thank you for the info so far. I have the service manual downloaded which covers 87-97. The manual gives everything I need for the 87, then follows up with supplemental manuals. Am I correct to assume that everything would be the same for the 89 as it is for the 87 unless it is noted in the supplemental for that year (1989)? Secondly, the manual is a little unclear on the pickup coil testing. On stator side of the connector I have green, yellow, blue and on the other side I have green, yellow, blue, and gray. I don't know what the gray does as it is not connected to anything. Am I looking for the factory specs across all combinations of g/y/b or are there different values for say g to y, and y to b. Sorry if this is getting to specific but as I mentioned I hate the "if everything else checks out, X is bad." Especially on an exorbitantly expensive part.

 

one more thing, is cdi failure a somewhat common problem on these

 

Cdi modules can go out,but if you can figure the stator specs out in the manual and can either rule it out or confirm it's the problem,this is better than just guessing and ordering a cdi.Plus a simple cheap coil can break down or short out also. There should be a small resistance reading on the coil tab to ground,plus most plug caps are resistor caps and should be around 5k ohms or a tad less. Could simply be a bad plug cap.

 

Hate to brig up old wounds but did you ever find out what the problem was? I have a 1994 Big Bear doing the exact same thing..