[Thirstyb37]

Hey DGordon,

I guess yours is still running good since motor swap? I have not been on here much lately, but do have a question for you...
I have the vent intake and big gun pipe on ours and it sure seems to be backfiring quite a bit. I can't remember what jest that I have in it now as I have changed several times. I did order about 4 of each when I did order them. Going out to try and check tonight if I get a chance but thought I wiuld pick your brain while I was on here.
It only pops or backfires at about mid throttle. WOT seems to run pretty fair but we really have not had a chance to go actual riding other than around the house here.
Would appreciate anyone's thoughts and I will post back with the jets that I have in it now.

It almost time to go riding!

 

[dgordon]

The 300cc was awesome at little Sahara way exceeded my expectations, we put my carb an intake on my buddies little girls stock Rzr an it has been running great! It's jetted 120 main, 40 pilot and about 1 3/4 rounds out on mixture screw, haven't had any problems with that set-up. Give that a try and let me know what happens.

 

[BoondockSaint]

Yes, it does...sub'd

 

[gobucks85]

Just wanted to update everyone on this issue. I will also post a new thread with my solution. I went up to a size 40 pilot jet today after diagnosing the issue with the carburetor. The problem is Polaris installs too small of a pilot jet from the factory (almost makes you wonder if they pulled this carb off of a lawnmower and slapped it on the RZR without testing it.) Based on the number of 170 owners who have this issue, I can almost guarantee that this is the issue.

When testing the pilot circuit, you are supposed to turn the Pilot jet in (richens the fuel mixture) until the engine starts to cut out. If you turn it all the way in, and there is no change in the idle condition, then your pilot is too small. I did this test with both a 35, 38, and 40 pilot jet. The 38 pilot jet had to be turned all the way closed, and then brought back a 1/4 turn to achieve the correct fuel mixture. This is not ideal, because it doesn't leave you room for further adjustment, and it's not as efficient. The 40 Pilot is set where you want your pilot circuit to usually sit, which is 2 1/2 turns out from closed. When doing this, I put everything back together, and had my son ride it up and down the street, with several WOT runs with coming to a dead stop, and where it would typically sputter, spit, and backfire with the stock pilot, it did not with the 40 Pilot.

So, if you want your RZR170 to run the way it should, and not too lean on the pilot circuit from idle to 1/4 throttle, you should pick one of these Pilot jets up from your dealer and swap it out. It will make a huge difference in the way these little guys run.

http://www.rzrforums.net/rzr-170-specific-disccusion/50914-solution-backfiring-170-issue.html

Was the stock.jet the 35?? I bought a 40 and will.install.it here soon. Did the 40 give u more power that u can notice

 

[dgordon]

The 40 is the pilot jet which controls idle and low end take off, you will not see a power gain from this but when you replace the main jet with a 110-120 you should see a small increase in power, mainly more torque

 

[gobucks85]

Ok I think that be great I need more low end on take off.

 

[Natekurtz22]

So I tried the 40/110 jet combo and am still getting a good bit of backfire although I have noticed the 170 to start easier. I also tried putting a 125 main in but its seem to sputter to much when fully accelerated. I'm here in pa sitting at 1301 ft above sea level. I would appreciate any input on where I'm going wrong. Also the rzr is stock besides snorkeled CVT and uni air filter, I also tried adjusting D shape screw in carb but still get backfiring. Thanks in advance.

Sent from my Nexus 7 using Tapatalk 2

 

[dgordon]

I have had that problem on my buddy's little girls Rzr, we tried the carb only without a larger intake and it didn't work, it was starving for air so we installed my vent racing intake for the 170 and it has ran flawless ever since, sorry about that, I know there is not much mention of larger intakes on this thread in addition to jetting the carb bigger but it was a must for us, our elevation is about 900 and we ride up to 1500ft. Kids sure are expensive, lol. But I think we bring it on our selves.

 

[chipster314]

We are located in North Texas and ride in Oklahoma dunes and Arkansas moutains, so we also fight elevation changes, I just happened to have some left over jets that i found in my tool box, the pilot jet is the same one as a YFZ 450, i believe it is the keihin 21 series size 40, the main jet i found was in my raptor 660 pile, which I used a 120, 100 is stock, I'm almost certain that if you jetted your stock rzr170 with this same set-up it should make a world of a difference, also remember to adjust the air-fuel mixture screw at the back of the carb when you get done and the machine is at operating temp. The way I did it was we went to our pasture and found a long stretch of flat ground and I kept adjusting 1/4 turn until hesitation on take off was gone and was clean sounding all the way through the RPM's. Hope this helps as it did with ours, good luck!

What screw? The only adjustment screw on my carb is the idle screw at the back of carb.

 

[dgordon]

There is a "D" shaped screw on the back of the carb that adjusts fuel mixture, I think there are a couple of pics on this forum that talks about it

 

[gobucks85]

I replaced the jets and I had to screw them.in all.yhe way otherwise they felt loose if not

 

[chipster314]

Don't see it. And I had it off at and at motor cycle shop to get correct jets and they didn't notice any other screws to adjust either. I'll go look again

 

[Natekurtz22]

Its on the top left side of the carb. It just looks like a small round brass piece, but at a closer look it is indeed a d shaped screw.

Sent from my Nexus 7 using Tapatalk 2

 

[chipster314]

OK got it thanks

 

[gobucks85]

I replaced the 35 with 40 and it seem to help with backfiring so a 42 would defently help bc I still get an ocassional backfire

 

[Papasaki]

Just picked up a 2013 from Westfield and nkticed it backfires / sputters at partial throttle cleans up when you give it more but it sure is a pain. Ordering a 40 pilot jet today see if it helps. Machine is all stock so far and only 5 hours on it.

 

[chipster314]

Just picked up a 2013 from Westfield and nkticed it backfires / sputters at partial throttle cleans up when you give it more but it sure is a pain. Ordering a 40 pilot jet today see if it helps. Machine is all stock so far and only 5 hours on it.

Bad or poorly setup limit switch on gas pedal assembly Cannot adjust it. Pull connector apart that hooks up to it and short it out to see if it goes away

 

[Papasaki]

Unplugged the safety swith on the accelerator and cured my sputter issue!! Thanks Chipster ! Only backfires after a full throttle run on decel. Otherwise it runs good.

 

[larryw.3]

my '09 has an issue with starting. i have a feeling it's either an electrical issue or an engine issue

 

[sandgoat]

I got my boys a 2014 rzr170 it back fires all the time rough ground it will spit and spunder hit the breaks hard it will die and its allways on the rev limiter when they're out playing in the field or in the sand