o.k. things have slowed down and now I am ready to give this machine one last shot at getting it running. I bought it not running, no I didnt give much. It is a 1996 magnum 425 4x2. I have tried everything suggested above and still no luck. I want to know if there is any way to test the coil and stater? I just dont think the spark is strong enough. anyone Please?? Thanks ,Dave

 

Well after today I am finally going to throw in the towel on my 425. It has totally kicked my a__! I have tried it all and still nothing. I have tried every suggestion offered and short of hauling it to a dealer or repair shop still cant even get the thing to remotely try to start. Thanks for all the help you guys have been great!! Thx, Dave

 

Im back! Cant walk past that thing without thinking of something else to try. I did tear it down to the point that I Pulled the stater off and the valve cover on the cam sprocket cover. I just had to make sure that things looked the way they did in the picture, Thanks Wes. I think it is possible that maybe the the cam chain could be a tooth or two off from where they should be. The reason I pulled it this far down is because with the flywheel on and the machine at TDC, with all valves loose, the manual makes it sound like you should see the timing mark lined up through the inspection hole if all is well. Mine seems to be to the right of the hole / pointer. On my flywheel I found a single mark and on the the same section I could see 3 lines. Wich ones need to be visible through the timinig hole?? Thanks For everyones help.. If timing IS NOT the problem, How bout the box??

 

stil no luck

Things I have tried, Set crank /cam timing, cleaned carb, checked all resitance on coil and stator, looked good. Cleaned all electrical connections, tried several new plugs. still cant make this damn thing run. I have thrown in the towel once but just cant give up. It does seem to pop out the back of the carb but will just not run. Any and all advice appreciated. Thanks, Dave

 

You have me confused about your problem. Is it a firing or a fuel problem.
Do you have good spark?
Have you tried this: Disconnecting the ground wire from the CDI box?

 

I wish I knew.

I wish I knew if it was a fuel problem or something else. I did have it running once. I put it all back togather and went to start it to show the wife, then it wouldnt start. I have a coil comming but my old one tested good. Wes sent me a manual so I have tore it down, checked timing, all the ohm checks from the stator etc.. everthing checks within tolorances. All she gives me is some backfireing out of the carb. just wont start. I am confused. Are there any checks a person can run on the cdi box to test if it is good? yes, I did unplug the black wire with no luck. Thanks for any and all help. Dave

 

I guess the spark looks good but I have nothing to compare it to. I know you loose spark under compression and that is why I ordered a new coil... Dave

 

If it's backfiring out the carb, then it's a timing issue.
Did you check the cam shaft? They're notorious for going bad.

 

I I know the camshaft, crankshaft is in time. With the thing at TDC everything is aligned and looks good. I guess I didnt think it could be the cam since I have good comprssion and it appears that the rockers have good motion with the valves set at .006. How do I tell if the cam is wore? I am sure you have to make measurements etc.. Could you shed some light on this? Thanks for all your help. Dave

 

i would rehook up the fuel pump than clean the carborator and check the timing,also the valve clearance.

 

Carb has been cleaned,Timing is on. Thanks, Dave Valves are at .006

 

The exhaust lobe is what usually wears off on the camshaft. It is the lobe in the middle. It will have severe scoring on it. There is a post on this forum within the past few months with photos of a worn out camshaft. With the oil being thin and smelling like gas it would be a good idea to change the oil. Use 0W-40 synthetic oil

 

Thanks, I will pull the valve cover and see what I can See. This thing just isnt making sence so It has to be something wierd. Thanks, Dave

 

I wish I knew how to post a pic, but I got down to the camshaft and really dont see severe scoring or deteriaton on the exhaust lobe. But Im not a mechanic .. Thanks, keep the ideas comming. Dave

 

Do all of the lobes look the same?

 

yes, had a pretty knowledgable guy look at it today and he didnt see anything that looked abnormal. I guess I have a question. What roll if any does the CDI box play in the roll of timing? I know the crank, cam timing is on the money but the thing still acts like a timing issue, any coralation if that CDI box or brain box is faulty??Any tests I can perform to troubleshoot that thing? Thanks, Dave

 

It will be late when I get home 2nite but I will do more reading in the service manual. I will let you know what I find. I think by disconnecting the black(?) wire from the cdi unit is the way to test it. I will also bring the book to work with me 2moro. We will figure this thing out sooner or later. I hope not later than sooner.

 

Here are things I do know about the machine. 1. looks nice 2. gave the guy a 100.00 for it. 3.drained stinky gas and rinsed tank. 4. Discovered the fuel pump had been bypassed. 5. Removed carb and cleaned with aresol carb cleaner and compressed air. 6. Yes, diaphram looks swelled and had a couple micro tears. 7. after hours of finagaling I did get it running. sounded good. actually drove it in and out of garage. 8. shut it down and installed tank and plastic etc... 9. Wife got home and I went to show her that I got it running and it wouldnt start. 10. Fly wheel cover has a hole toward the top, must have happened when recoil assembly gernanded. 11. Stator, flywheel and everthing in case very rusty. Cleaned it all up. 12. Starter rusted solid. Got it broke loose and free and working. 13. Actually reset the crankshaft/ camshaft timing as per the polaris manual. Did discover a green wire comming off the top black box not hooked up, I believe it is the reverse limiter. Now for the thing that I have tried. I believe the carb is clean and free of any gunk. I did buy another used coil and tried it but it ohmed out the same as my old one. I did most of the resistance tests recommmended and found nothing out of the ordinanry. I tried several different new plugs, Tore down and made sure the cam and crank timing where o.k. Crank at TDC while cam gear is alinged and all valves loose. Seems on the money.Took rockers off to inspect cam it looks like normal wear, nothing alarming. Did work on cleaning electrical connections and used a thin film of dialectric grease on them. I have tried to start by spraying carb cleaning directly into the plug hole, I have tried fogging oil, gas etc and all I can seem to get is a good backfire out of the carb. I did find the green wire off the reverse module off and found that it belongs on the yellow/red spade so I will put that back on tomorrow after I install the rockers and readjust the valves and see if that green wire makes any differance. I just cant believe it is anything that big. I have tried disconnecting the black wire and that does nothing. Hope this helps explain what I have tried and what I am up against. Thanks for all your help. Dave

 

The hole in the diaphram in the top of the carb is the culpret of all your troubles. It needs to be replaced. I know they are expensive. Or it has something to do with the routing of the fuel lines/vent lines.

 

really, I am not doubting you but was told that it would run but terrible . Could it be that easy?? Dave

 

The carb system on a Polaris is kinda different than most things. The engine creates a vacum pulled thru the carb then to the fuel pump. So therefore if it has a hole in the diaphram you create an air leak. Then you deprive the engine of fuel. You should have mentioned those holes in the carb earlier. Someone spray carb cleaner on the diaphram and ruined it. I have seen it happen many times. I have been there and done that. The reason I kept pointing you elsewhere is because you said carb was clean and componets are good. I hope this will solve your problem. If you need more help I will be glad to help. Send me a PM. That part is about $70.00. I had a carb a few months ago and sold it. I don't remember who thou. Post an ad in the parts wanted section. I would request a close up pic of this part and if the insure you that it's in great shape. But you might want to buy a new part thou. I am looking at the service manual now. It states in the troubleshooting section backfire,pops=Ruptured vacum slide diaphram;Vacum slide stuck closed or sticky.

 

First of all I want to say thanks for all and any help you folks have sent my way on trying to get this 425 running again. I guess I would have given up a long time ago if it wasnt for the help and ides you folks have passed my way. tt425 I want to give you a special thanks for all the info and ideas you have given me. I guess I have it nailed down to two possibilities! It has to be the carb diaphram or the CDI box. I guess either way you look at it I could install both and still have a quad that doesnt run. If it where you folks what would be your first purchase, A diaphram or a CDI box?? Has anyone had a no start condition on a polaris magnum that ended up being a CDI box? how common is it for that box to go bad and is a not start condition usually the case? Also, if the rubber diaphram is swelled and in bad condition how many times does that cause a no start condiotion?? Just trying to figure out what will give me the greatest chance of getting this thing running for the money!! Thanks again, Dave

 

If you have spark I would think the cdi is good. With the diaphram described as you are saying it needs to be replaced either way. When you cleaned the carb did you remove the jets and run a wire thru all of the passageways.
Another thing is that out of all the people on the forum very few people have any ideas. They might not know alot about the older models like I do tho. I can't offer very much advice on things that are fuel injected or on some of the newer atv's. I hope you get it repaired soon. Thanks

 

This has to be the damndest thing I have ever worked on. tt425 I hope you can help me!! I was putting the old quad back togather today to make room in the garage and to maybe sell the thing on CL or to part it out. I tried to start it one last time and all she would do is click. I figured starter or selinoid. When I bought the thing the starter was rusted and wouldnt turn so I pulled it out and sprayed some penetrating oil down the gear end and worked it back and fourth till I got it to turn. I grounded it on the frame and it spun so I put her back in and never thought about it again until today. Well today with the thing just clicking I thought I would just give the starter a wrap with a long bar while I was holding the starter button. I about shit myself when she fired right up. I mean the thing didnt even hesitate. I let her run for a bit but was filling the garage with oil smoke that was buring off the head pipe so I reluctantly shut her down to clean things up. It did start several more times without any hesitation but now Im back to nothing but clicking and whacking on the starter isnt working!! What do you think and why?? Thanks again, Dave.

 

It's gonna be the starter shorted out,the switch on the handlebar is bad, or the starter itself is not grounded or loosing ground. Use a test light to see if you are getting power to the starter. After you determine that it's not a ground problem look at the starter. dbelectrical sells an aftermarket starter at a good price. If the brushes and armarature(spelling ?) are rusted bad they will rob the electricial system of voltage needed to start the atv. I hope this helps you. Be sure and charge your battery because a weak battery will cause problems. Never try to start it without a battery connected to it or it will blow every bulb on it.

 

Prettyn much looks like the brushes are gone. I will see if I can find brushes tomorrow just to try and get me started again and if she goes will invest in a starter. Thanks again, keep your fingers crossed. Dave