My first Suzuki finally!!!!!!

[James Mason]

Congrats on an awesome looking bike hope you figure out its demons

[Frank Angerano]

Thank you @James Mason.  I pretty much for the most part will always  find the problem and to be honest I'm a little excited that its giving me a hard time. I think for the most part the quads i find are more straight forward repairs and find myself doing more cosmetic/body work. Don't get me wrong i love all that stuff but a real problem for a change is something good and i think keeps us all sharp learning about new problems, especially for the next guy.  So we will see!  
 

A ton of very good reply's to this topic so a big shout out to our members that commented on this.  Keep em coming. Always grateful! 

[Frank Angerano]

Well timing is spot on so its on too the next thing!! The valves and head look brand new. This is a tough one!
Everything else tested good electrically. I may pull the flywheel and maybe replace it.

It could possibly be a bad cdi but im going to hold off until the last minute before i pull the trigger on that.  

[Jim Denton]

I bet it's the sparkulator in confabulation with thethingamabobber.

[06kfx440]

I’m thinking the CDI. Flywheel. Or maybe a bad carb. Why else would it be choppy?


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[Frank Angerano]

No clue.
Carb (You know me) is good! Its either a flywheel or cdi which is a pricey item for this atv!  

[Jim Denton]

Carbon arcing with the spark plug maybe. KFZ has to have hit one of em. Checked rectifier output?

[06kfx440]

Yeah. I say carb because maybe a vacuum line in the carb has a small hole in it somewhere. I’ve had my Mojave’s and a few warriors that did this.


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[Frank Angerano]

I hear ya but i went through it all.  My last item im going to swap is the flywheel. After that its only leaving the cdi! 😳

[Jim Denton]

I'll send you one of my cdi units to try if you like. Don't know if the KQ 300 is useful or not.

[Frank Angerano]

That's awesome and  would be very helpful and i would pay for shipping etc and get it right back to you.

Im going to get into it later on today and rule everything else out first. 

Here are a few pics of mine.  If it matches then we can arrange something. 
 

[Jim Denton]

Sorry we had a lazy snowy day on the farm, just saw your reply Frank. I've read that the regulator could be the culprit with your symptoms. Output above 15.5 v can cause the cdi to loose it. I've just about got the front fender off the lowest millage machine. Shouldn't be much to get the piece out for you. Unfortunately I'd not be able to say it's for sure good. 

[Frank Angerano]

Brother i hope your right. I am going to swap the regulator and see what happens.  Sit tight and stay tuned.  

[Jim Denton]

Frank looked my cdi up in the manual. Doesn't look doable. 

[Frank Angerano]

Nope definitely not but thanks anyway. Going to do a few more tests. 

[quadnut20]

Damm U still chasing that ghost ?? Id like to know what it is when u find it !!

[Frank Angerano]

I haven't really had time honestly since i put the new harness in and checked the timing.  I should get an hour or two in this afternoon. 

[Ministry Deadwolf]

great deal for that price.

 

hope you'll find the best

[northernmi]

Without a factory service manual in front of me,  I'm just throwing this as an idea to a possible cause? or it could be some other related safety switch inline the ignition circuit harness.

Just curious if the your quad was equipped with some form of (ETC) Electronic Throttle Control switch, like a Polaris product would be equipped with. Or some form of 1? used by Suzuki. In the advent the throttle cable breaks or becomes stuck  or out of adjustment the ETC kicks in, Grounding the CDI BOX out.  I had this problem before on my 01 trailboss because the cable needed adjusted. normally it should of just killed the engine going from idle into "mid range" throttle. but the switch contacted ground intermittedly (causing backfiring) when it should of just killed the CDI box all together at mid range throttle if adjusted correctly.

Knowing you already checked the ,  1) In & Ex Valve clearances, 2)Spark Plug resistor cap (Rx Value), 3) Spark plug, even though new? got some out the box that were bad. Flywheel Key half sheared  due to the back firing, Flywheel Magnets (magnetic poles become unstable to be not useable). Even if a ignition coil tested good, seen them also cut-out when accelerated due to a internal crack inside the field windings which you can or cannot see. The Stator plate and alternator windings for shorts?  After the wiring harness being cooked, your lucky to have spark, depending how good of condition the CDI box and pick-up coil in the stator are? after the fire. Finding were the previous owner left off?, is real treat or sometimes a real headache.

 

[Frank Angerano]

All very good  points and have checked out all except the flywheel and the possibilities of the ignition coil being bad.  The flywheel and pick up coil is on my list. 
 

I managed to grab a used cdi from a reliable source for $50 bucks. Its on the way. 
The rev limiter was on the top of my list and i tore into it looking for one but there's nothing connected to the throttle to indicate that the engine would react on over throttle condition. Nothing on the handle bars going into the throttle either so unless it's electronically picked up through the cdi that its reving high then i would say no. But i am double checking the spec on that. 
 

As far as the burnt wires: I can't verify if the fire happened on the atv like something or someone caused the fire OR if there was a fore near the atv.  None of the wires were cooked from the inside like you would suspect.

Some really good points you hit on though and its great info! 
Thanks @northernmi   

[Jim Denton]

Crazy man.  Curiouser and curiouser. 

[northernmi]

Frank

Just 1 last thought, you using an (analog ohm meter) instead of digital 1 for the (pick-up coil and stator & voltage regulator)  Engine Off tests.

I know on most older and some newer Honda's,  Kaw's, Suzuki's required a non digital meter for these types of test to get good solid reading measurement,

due to the sensitivity of some of the digital meters.   I'm Hoping the CDI box solves your problem, it will be interesting what your future posts will

reveal for the fix. Good luck!  

 

[Frank Angerano]

I actually use both and the readings  are spot on surprisingly. My father had every type of tester possible and i have very good digitals.  So yes thats all good there.  New cdi will be here tomorrow so we will see how that goes.  
 

[Sudsy]

Hello..just bought my first Suzuki quadrunner...got you beat in price but yours is alot prettier lol...curious to know if you solved the problem..hello to all

[Frank Angerano]

Welcome to Quadcrazy @Sudsy 

Cant say you got me beat if mine is a lot cleaner then yours.  
Buy anyway post some pics and lets see that thang! 

[Ajmboy]

@Frank Angerano, great topic! Did the CDI do the trick? Like @Jim Denton mentioned, maybe a bad voltage regulator? Any major fluctuation with lights on/load?

[Frank Angerano]

Hey @Ajmboy thanks.   So here's an update on tis PITA! CDI was a complete failure and it did not do the trick. Valve lash was good, timing spot on. Carburetor is perfect and she runs great to half throttle and starts backfiring like hell.  Regulator is on the way, i am stalking the stator, pick up and flywheel! Just about gone over everything else. 
Stay tuned.  

I was actually going to search the archives to see if anyone else had this problem. 

[Ajmboy]

@Frank Angerano any chance someone was in that carb and tried jetting it incorrectly?

[Frank Angerano]

I bought and installed new jets stamped with the numbers on them. They are what matches the spec exactly. 

[Dra O]

for my knowledge - two questions while thinking about stator:

1) you're checking stator to see if any of the coils are bad/burned, checking the pulse generator and testing the voltage/ohm readings on the stator and i guess the pulse generator as well to see if w/in specs?

2) when you take off the cover to get to the stator, does the oil need to be drained first?  asking because I eventually wanna check the stator on the 1986 honda trx 250 I picked up - the wires coming out of it are loose - someone has been in the case before, apparently (no surprise)