Long story short I have a 2003 Trailblazer its a 2 stroke if you did not know, It needed a piston in it so I rebuilt the top end with a new piston gaskets all of that stuff it now has compression, it has fuel, and fire. I bypassed the automatic oiling system cause it failed and caused the original failure I bought this bike not running but this thing is driving me crazy and has confused the heck out of me and I was wondering if I was missing something simple that i needed to do such as maybe sensors for the oil or something that might keep it from running. I can make it fire about 3 or 4 times when i shoot starting fluid in it and pull start it but not if i use the electric start?

 

Welcome! You can check stator resistance on the Black/Red to Brown/White going into the cdi module should be 120 ohms. Also remove the wire from the coil and test the coil primary: tab to ground(the frame or any brown wire) should show around 0.3 ohms resistance. The secondary: tab to plug wire(cap removed) 6.3k ohms. The plug cap itself should be between 3.7- 6.3 range. This is from a little older 250 manual,but should be close. Either of these could be the problem on intermittent spark,plus the stator and flywheel might need to be cleaned up if there's a lot of dirt/mud behind the recoil housing. If the stator and coil check out,possible it could be a cdi problem. OPT

 

ok the stator resistance is 120.3 ohms and the plug wire with cap removed is 6.1 ohms and with the cap on it makes my meter go crazy and just fluctuate anywere from an overload to over 300 ohms. also the resistance with just the cap makes it just go crazy but not as high of a resistance it went up to 30 ohms. I think we may be getting closer to the problem.. Also I failed to mention that I do not have the full exhaust system on because I am having all the rust stripped off and painted Only the header is what is on the bike would that cause this problem? due to some odd compression or air to fuel ratio?

 

Resistor caps can short out. Does the cap itself check between the ranges listed??Plus make sure the coil wire doesn't have any cuts or nicks. If not just try a new 90 degree NGK cap. Hope it's simple as this. The exhaust wouldn't have anything to do with the electrical. OPT

 

I'm going to try a new cap and I will let you know. I tested the ohms again and it depends on where i put the prongs from my meter to what resistance i am getting it can read nothing or all the way up to 199 so maybe we found it I would have never replaced the cap since it was getting fire I just assumed everything in the fireing line was working correctly the average reading was 24-27 ohms on the cap.

 

OK I got a new NGK plug cap today but still no start any more ideas?

 

Was hoping that was the problem,but at least I think you've eliminated the stator from being the problem. The coil itself shows 6.1k ohms with the cap off which is in range, so last thing I can think of is to pull the single black wire from the cdi(kill circuit) plus pull the black wire from the reverse limiter module(the only small module with the black wire,the other module is the reg/rectifier) and see if you have spark. If no full spark you may have a bad cdi module. OPT

 

OK sorry it took so long to get back to you i have gotten real busy, I did not pull the wires off the boxes like you said, but i did do another compression test and i was only reading 60 psi. Should I bring the engine back off the bike and do a leakdown test and if so what would be a good psi to pump the engine to i have heard 7psi and 10 psi and 5 and all kinds of numbers.

 

Don't go over 7 psi on leak down test. I had the exhaust block off adapters and the intake gauge and adapters at the shop and used a bicycle pump. IF the cylinder has been bored properly then most likely you have leaking crank seals. This is a common thing that happens on the older machines.The flywheel/stator and front drive clutch has to be removed to replace the seals. #3084581 seal on the stator side, #3082162 seal on the clutch side.
NOTE: on some online sites the #3082162 seal shows to be discontinued,but worst case scenario you can check with a local dealer. As with a lot of atvs,motor cycles,etc 10 years is when parts start showing up NLA as they phase these parts out when an engine line has been discontinued. I was still rebuilding 2 strokes in late 2010 and no problems on parts then,but things can happen pretty quickly. Plus seals can always be matched up at other places if it comes down to that. The ORIGINAL seal number on the old 250 for both sides was #3080006 which had a metal outer casing. Even these should still work if someone had old stock. OPT

 

It is the stock bore on the atv the jug was still very smooth and didnt have any scratches or scaring on it so I just replaced the piston and rings on it with the stock bore. I will probably just use a rubber tube to block off the exhaust and intake then make something to pump air into the engine from the spark plug hole. Should the engine be at TDC or any particular position?