I want to first start by thanking everyone for reading and viewing my post.
I will let you know that where I am NOT new to engines, or fixing them, I am new to this site (although I have been browsing it for years) this ISSUE I have never seen before and I am very curious how to fix it - this machine WILL NOT beat me!
So to explain, I used to ride this trike many years ago, when I was a kid we had one and there are still many family stories about how I rode it into the Mississippi River (I just cleared up the facts on the telling of this story last year). So I had driven by this guys house for 3 years (at least) and had seen this machine sitting in their yard. I finally got up the courage to pull into there driveway and ask the guy if he was looking or willing to sell it. Obviously, I bought it from him ready to knock a small project, clean it up, getting her back in shape and ride the hell out of her.
I have to admit, where at first I was disappointed because it seemed to be a simple fix (head bolt stripped) of drilling out and installing a heli coil, and reinstalling the head and orginal copper head gasket. I had 120 psi compression, spark at .040 on the gap (moved the gap back to factory or .028), ultra-sonic cleaning the carb & reinstalled.
I discovered the pepcock was stuck on (open) so I removed, broke it down and cleaned and lubed, tested and reinstalled = fuel flowed good, and shut of completely on OFF.
After reinstalling the carb (air box off/exhaust pipe installed) I pulled to start it, took a couple of pulls but she fired up at a high idle - not reving out but high. I turned to pick up the screw driver to adjust the AirFlow intake and she died on me.
HERE's where it get's sticky....
I try to restart it and the engine kicks back on me yanking the starter cable out of my hand, I figure "fluke" pull on it a couple more times and same damn thing, except this time it breaks the old rubber handle in half!
So off with the starter, at this point I am thinking >timing< right? NOPE-> I recalled that these are 2 stroke and non adjustable stators (fixed).
So it has to be the sheer key right? NOPE->sheer key was fine, intact: I removed it to inspect it, not a mark on it. reinstalled and retorqued the flywheel nut to specs. I did notice that the starter wheel was mangled and broken. I did some repairs and reinforment with the small welder; basically I used thin gauged flat metal sheet cut into 7/8in strips, by 1in folded in half and insterted on the pully engaged side of the starter wheel. Spot welded them into place, ground smooth = starter get's it right now!
So it has to be the Trigger Coil right? NOPE-> Trigger coil test at 10.4 ohms (little high but good enough)
So it has to be the Charger Coil right? NOPE-> Charger coil test at Brown Wire = 283.9 ohms (right in range)
So it has to be the Ignition Coil right? NOPE-> Ignition coil test at: Primary = 1.0 ohms (right in range), Secondary = 5642 ohms
Out of ideas, I am back at the crank case, maybe there is TOO much fluid (oil, gas, water) in the crank case causing it to back fire? I used an electric fuel pump and 1/4in line to suck out the crank case. Got to tell you, there wasn't alot in there, maybe 10oz, although there was some, but I wouldn't think it was enough to cause this "backfire."
So back to the Carburator: it has to too much fuel... I remove the carb, remove the plug (run another compression test just to be sure = 120psi: still holding strong). I removed the carb bowl, nothing out of the ordinary; no dirt, sand, tank debris, gas smelled clean. For all intent and purposes the carb still looked clean. I checked the float adjustment; shuts off at level with carb: I re-adjusted it a little tighter to close out just A LITTLE SOONER.
So I had read some where that a clogged exhaust pipe >might< be the issue, So I uninstalled the pipe and reinstalled the carb, gas line on=check and away we go ....
Again, a few pulls to start and the thing fires up! I give it gas and it throttles up nice, then back down to a high idle. AGAIN, i turn to reach for the screw drive to adjust the idle with this beast screaming at the top of her lungs and it shuts off. I go to start it again, and she yanks BACK hard and here the backfire out of the exhaust port. I remove the plug and it's oiley wet with a tinge of gas smell.
Now here are the new waters for me - I am not sure that excessive OIL would cause it to backfire, whats more - I'm not sure how to adjust the oil delivery (if it can be adjusted). So again - taking out the plug (NGK-R=BR8ES) and taking a shot in the dark to replace it with Manufacture recommended Champion Copper Plus 801cN3C (replaces N10Y), to no avail - still BackFires and yanks the pull starter.
SO in conclusion - I have ruled out EVERYTHING that I can possibly imagine. If I am missing something - please let me know. As a last ditch effort, I have already ordered a new CDI praying that this MIGHT fix it. I can not think of anything else that it could be. Thoughts?