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Discussion Starter #1
Hello all,

I just got a 2003 trail boss 330 the other day, today when i took her out she was running GREAT for a couple hours, im very happy with this quad!! That being said i did encounter a little problem. toward the end of my ride she started bogging down and backfiring (bad) if i got on the throttle anymore than 25%, at 50% throttle it would really start to backfire and felt like it was going to die off. I managed to limp her back home and shes running fine at idle. A few things to know are
1: the battery was getting pretty weak even befor this :thinking:
2: i swamped her out pretty good but theres no mud/water/debris in exhaust or airbox
3: the guy i got her from supposidly "cleaned the carb" (whether or not he reassembled it correctly i havent checked yet)

This all being said I would like to add that Im a heavy equipment mechanic but would just like to see if anyone has had to deal with this and knows a good place to start. I figure ill start goin thru her tommarro but if anyone can give me a good lead Id greatly appreciate it as im not familiar with this model (yet:)) not to mention two heads are always better than one!

thanks in advance for any help! :beerchug:
 

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Discussion Starter #2
ok so now that shes cold and dry, the problem seems to have gone away. Im kinda leaning towards electical, does the rev limiter on these only inact on reverse? I dont have the manual yet so id really appreciate the help from any of the seasoned veterans out there
 

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i would probably start and check the carb anyway, especially if you are a mechanic. you just never know. check and make sure the jets look clean, bowl, ect is all clean and free of debris, and reassembled correctly.

could you tell if it was a lean or rich backfire? on possible senerio is that the fuel vent line is plugged or pinch to where as the machine was using fuel, it wasnt able to equalize the pressure inside, basically creating a vacuum as you continued to ride to the point where it couldnt suck enough fuel to run at higher RPM, but now that it has sat for awhile, it was slowly able to equalize pressure again to run right.

they do have a throttle safety switch on the throttle cable that will cause sputtering and backfiring if the proper play isnt set, but it doesnt sound like its that.

i would pull the plug and see what it looks like too
 

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Discussion Starter #4
Thank you blueline
yeah im def gonna tear down the carb (thinking i might just as well stick a stage 1 in while im in there:D) As far as the backfire being lean or rich i couldnt begin to tell you :unknw: It was an exhaust backfire but thats all i know.
As for the vent line I just figured it used a vented cap, guess ill actually look next time stead of just assuming :) Thats great news about the rev limiter tho.

Thank you again for your help! i definatly appreciate it!

Also how come they dont make many performance upgrades for this machine? I was originally supposed to get a sportsman and those seem to have TONS by comparison. I really do like this machine, it could just use a little more grunt off the line is all
 

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as far as i know, polaris has never used a vented fuel cap. they always seem to have a vent line up by the neck. im going to bet all your problems probably lie inside the carb. and i think a stage 1 will certainly help. haha

i think the big reason you dont see too many parts for the trail boss is it tends to be a machine that a) people dont want to put any more money into because its their farm workhorse or b) its a machine most people buy because its not as powerful....

with that said, they do have potential, and speedwerx has some parts for it
 

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Discussion Starter #6
So good news turns out after checking it all out the battery was the culprit :pat: Id checked the plug the other night and it was perfect as you can hope for. Checked the vent line and that was fine too. So I charged the battery last night, took her out today and she rode GREAT all day. Once i got her back to the trailhead I shut her down to drain the clutch housing (went REAL deep today :)) when i started her again the battery was really weak, then she started with the backfiring again, i shut her down, checked all my electrical connections, plug, air filter, vent line, anything i could acces with a trail tool set. When i went to crank her up again i couldnt get her to pull start so i jumped it with my truck and PRESTO! she runs like a champ, take off the cables and problem returns. I checked the battery and the acid was SERIOSLY low so im gonna see if i can refill and salvage this one (just till pay day:sad2: ) Oh and I found a .50 piston kit for it so she may be getting a few more horses soon too :biggthumpup:
 
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