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Hey guys, got a 97 ZRT 600.Bought it used last year.I am currently getting it ready for the season.Gotta couple bugs from last season to work out and , naturally , that led to more probs right now.

Last year it was getting boggy on the bottom end , it would idle perfect but if you nailed it, there was no power till she built up some RPM.On the trail it would keep working the same.Really sluggish from closed to half throttle.

Another thing was that at times it would not shut off.I hit the kill or the key and it would run on .Ocassionally it would backfire(PTO side cyl. ,every time.)Kept blowing the pipe off that cyl.

I figured it was running real rich.So I went all over the Carbs, choke cables and plungers.No prob there.Replaced the PTO side crankseal and installed new plugs.Still no improvement.The base gaskets were drooling a wee bit , so I figured new gaskets were the next step.Didn't get around to it till this year

That's where it gets interesting.Turns out this sled's been messed with before I got it .Someone shaved the top of the cylinders and put aluminum spacer plates at the bases.I've heard tell of advancing third port timing this way, but I'm not very educated here.

Now , I also see that the tops of the pistons are washed clean.2 are extremely clean, NO carbon at all.PTO side cyl had a little carbon on the top, but still washed quite a bit.

The jets are already 2 sizes smaller than stock, but in my opinion the engine must be running too rich.Will the advanced third port timing cause the richer condition????

And what the heck is making it keep running after I shut it?off.The sled only does this once it has run enough to get hot

Any and all help is greatly appreciated.Thanx in advance, guys.
 

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i assume that the start of the year the machine ran good? as for the engine getting boggy maybe the clutches need rebuilding. you say you went all over the carbs. how about float height? did you replace the needle and seat? by the sounds of things you are deffinately rich (clean pistons) is it hard on fuel? if the float is way too high or the needle is not seating it will run very rich even with a small mj in it.if it idles ok i would go to the float height first. im not too sure by what you mean by third port height. when you raise the cylinders up you raise all the port heights equally.it also lowers compression so that is why they shave the head .generally a taller port height(exhaust) will let the engine rev higher.im no expert but that is my understanding. do you have stock pipes on this sled? how thick are these spacers?have you done a compression test on this engine? i would check over all your grounds and make sure all connectors are tight . what needle jets needle and pilots are in the carbs?
 

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Discussion Starter #3
The carbs were the very first things I went over.They are definately OK.Needles and seats are like new and holding fine.Float height is perfect.I didn't do compression test yet.It worked good when I started last year, I only put 500 miles on it.If it was compressionI would expect the change to be more gradual.
When I use the term "third port"I am refering to all the transfer ports.There are 3 ports in a 2 stroke cyl-intake , exhaust, and transfer.I think some ol timers called that the thirdport.My knowledge in this department is very general and very limited. :confused:Please feel free to correct me;) ;)
I do intend to clean all grounds and I might disconnect the throttle safety when I get everything back together.I've heard tell of them causind odd probs before.

Thanx 1000ml, let me knoow if you think of anything else I'm missing.
 

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Kingmort,
I have a 99ZR 500 and i am having the same problem with the sled not shutting down. The ignition or kill switch will not shut down the sled, I have to pull the plug wire. I`m also going to try the throttle safety ,it seems to be related somehow. My problems started when I found that the slide needle was bent and the sled kept backfiring. Had to unpugged the throttle safety because the sled was idleing fine, but soon as throttle was applied it would bog and would barely move. After the throttle safety was unplugged it ran fine, but know the sled will not shut down unless you pull the plug wire. I tried to crossover the throttle safety and still no luck. I have checked all the wire harness and can`t seem to find anything. Almost everyone I talked to had trouble with the throttle safety and had to disconnect it. This feature was not one of Artic Cat`s best ideas.
If I happen to find the problem I will be sure to let you know

camarrow :confused:
 

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kingmort,
The problem with my sled is the CDI unit, that is why my sled will not shut down using the kill switch or ignition. I`m glad I found the problem, but the CDI unit sells for $534.00 CDN. I`m trying to locate one elsewhere, to try and save some money, but no luck so far. Hope this helps
camarrow
 

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catdog

Good news. Had this sled,had this problem with not shutting down. Easy fix though, when the sled gets hot its burping up small amounts of antifreeze which is a conductor of electricity! Pull all of your connectors to your ignition apart, dry them and put dielectric grease in all the plugs, presto fixed. I ran mine for three weeks shutting it down with the choke every time. tons of wasted plugs. The only reason I found it was because I had enough and was by-passing the ignition when I found all the antifreeze. As for the motor, that motor is awsome when its set up right, but you bought it after someone else messed with it as did my cousin who could never make it run right. good luck.
 

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Discussion Starter #7
ZRTease, that's a new one!!sounds very promising.Gonna look into that antifreeze thing tomorrow, I expect I should see some green in the connectors if that is the prob??If its that simple to fix I'm gonna be kicking myself in the a$$ !
 

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backfires

I had a 98 zl500 and now own a 99 zl 600 that would backfire as soon as you would turn the key off when it was hot.Solution was simple .When you come to a stop let your idle come down to normal idling speed before turning off the ignition.It give the motor a chance to burn off excess fuel brought in by the execessive revs.Hope this works for you
 

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Discussion Starter #9
catlover, I appreciate the advice , but I think zrtease had the answer.The engine didn't only backfire, but wouldn't shut off, either.
 

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I've got a 96 ZRT 600, have had all the same problems. Not shutting down was moisture in some of the connections. I have also raised my ports to change the timing, however I just got done lowering them back down to factory specs, but ported and polished it. Sled runs 10x better.
 

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You will also notice a huge difference when you replace those base gaskets, at least most of the time. With your cylinders raised your gonna have problems with the base gaskets.
 
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