I picked up a new 500 yesterday and took it out for about 10 miles last night. I noticed that when I accelerated hard and then backed off the gas it backfired. I recall seeing something about this being a trait the 500's have. Does anyone have the rememdy figured out to this problem. If the fix is simple I'll do it myself since the dealer is better than 120 miles away. It is a manual shift if that makes any difference. Thanks in advance for any advice.

 

all fourwheeler do that when tere gas is low but my beartracker dose that when i let go of the gas when im going almost full speed

 

I have an auto and it does it sometimes. Usually when it does it, it's not very loud. Just once in a while it'll do it kind of loud. I'm not worried about it.

 

I don't have experience with Arctic Cats but try fiddling with your mixture screw. You shouldn't need to change the jetting with a stock carb unless you are at extremely high elevations. Backfiring means your mixture is too lean i.e. too much air, not enough fuel. Hope this helps.

 

Bahnerman:
Congrats on the new 'Cat purchase! Aside from the backfiring, how is it working out for you-what do you think??? Both of our 'Cats had a slight backfire when we first got them, when running at 3/4 throttle or better, then letting off immediately it would pop-sometimes louder than others. It went away after we had put quite a few miles on them, don't remember how many for sure, but it was around 100 or so, so maybe it is around the breakin period, who knows. I had heard though of somebody having this problem quite a bit and all they did was change the spark plug, then it went away. I changed my plug from the stock 6 to an 8 and it backfired the first couple miles, but now works better than ever. I don't know alot about them, but it depends on the type of climate you ride in. Out here, it has been very hot (over 100 degrees) so the colder plug has worked better for me. I think AC used to run a 7 standard in all models, then switched to a 6 which is a hotter plug. Could be something to think about, but at 4000' I wouldn't know for sure.

Best of luck, definately follow the break-in procedure like AC recommends. It is kind of a pain in the butt, but the drawback to not doing it could result in a bad engine. Also, the breaks may not work too well at first, but if you follow the proper burnishing procedures listed towards the back of the AC manual, they'll work great!

Good luck!

Mike

 

Its a normal thing for it to do this.My AC 500a does it, My Lakota did it and my Honda 200x did it. Enjoy your new ride!!!

 

bahnerman. My 400 Ac did this right from day one but it got worse over time. The bike was taken back to the dealer and he found an exhaust leak at the clamp on the inlet side of the muffler. This has completely cured the problem. One other thing to watch out for is running low on fuel, if the backfire occurs when you are at the 1/2 tank level or less try switching to the reserve. I discovered this by accident one day. It is caused by the fuel pick-up for the normal position being quite high in the tank.

Cheers Jim

 

The fuel tank was full so that isn't the problem. The elevation we were at was about 7500 and I'd guess the air temp at the time at about 65-70 degrees. I'll get a new plug and see if it makes it better or worse. So far I'm happy with my new ride as well as the 300 I got for the wife, but 10 miles is not much to judge from. If I get the backfire calmed down a little and get my winches istalled I'll be even happier(I was to cheap to pay $90.00 per machine to have the winches installed, it can't be that hard).

 

Glad to hear you got the winches, they're what I consider to be the best investment you can make for a quad. I know mine has more than paid for itself several times over. Course I had the $69 deal so that wasn't hard to do. Actually, the AC's have a great winch mounting access position. Installing them is rather easy infact if you've got all the parts. Hardest thing is running all the wires properly, up high and tight so that there is no slack and nothing will catch on sticks or brush that you'll encounter in the rough. The solenoid fits nice and snug in the battery box, and all the wires can be affixed to the upper frame rail, zip tied down. Haven't had a single problem at all with my setup. Only thing I wish I would have done different is the switch. I've got the rotary switch, and would rather prefer the hand held switch that comes standard with the 2500 lbs. Warn. Course you can upgrade the A2000 to the 2500 and get that switch for an additional $180 but I'm too cheap to do that.

Good luck with the installation, hope you enjoy the ride!

Mike

 

The easiest thing to do is check the spark plug gap. The service manual calls for .028-.032. If it is extremely narrow it will usually show up as an intermittent miss on acceleration. This is a long shot but worth checking. My '99 500 has a Mikuni carb with a 145 main jet with the needle jet set at position 4 (second notch from the bottom). This is dead on for my altitude of 1300'. When I take it to the high country in Colorado (8000-13000')I install a 140 main jet and set the needle at position 2 (the second fron the top). I would doubt that AC changes the jetting depending on what part of the country that they are sending the units to, so I would imagine that you are not too lean for your altitude, if anything maybe a little rich. You can look at the color of the insulator on the inside of your plug to determine this. If it is dark brown to black you are too rich. If it is light brown to white you are too lean. If you have the 145 you might try a 147.5 (richer) or 142.5 (leaner). They continued to use the same carb for the 2000 500 gear. My (or I should say my wife's) 500 auto uses a Keihin in which the needle jet is not adjustable so I use a 138 at high altitudes. For 2001 both the 500 auto and gear use the Keihin.
The 2000 500 auto had the muffler problem that was described above. I had to turn the clamp over to get enough room to seal it up.
I hope this helps.