So far it looks like we have 4- 2009 170's that do backfire, a 2010 170 that does not, and 3 2011 170's that do.

 

I have a 2009 and a 2011 (and four kids). If you mod the air-box with an after-market intake you'll need to play with jetting, needle position(maybe) and A/F mix. The 2011 is stock with the new style air-box and runs fine. The 2009 has the UTV intake with jets and I had to tweak the A/F mix a bit, but it hauls pretty good especially compared to the 2011. I will probably end up doing something homemade for that one with all the lessons learned on the other one.
Oh and don't forget, adding a engine air filter set up is mandatory before you even hit the dirt for the first time on these!

 

2011, Yes, & now NO, thanks to ^ exactly [screw/needle settings, I just started tweaking it until it was perfect]

 

I just got the airbox update done on my kids 2009. Is there a general starting point on the needle and A/F screws that you'd recommend starting at? I realize elevation and temperature are going to have an effect on those, but I'm just looking for a good baseline.

 

With the airbox update from Polaris you may not need to do anything.
How does it run now, does it still backfire, etc?
I have a 2011 and it runs fine.
When you snorkel them and open up the aire flow, like when using a K&N type filter, you'll need to jet and maybe play with needle clip position.

 

Still backfires a little. Maybe not as bad, but still does on decel.

 

I would just try adjusting the D-shaped air/fuel mix screw, I ended up with only about a 1/4 turn, but then again, each one is going to be different.
You'll need to play around, but remember, small, individual tweaks one at a time and give the machine plenty of time to warm up or you might end up with a bigger mess than when you started.

 

1/4 turn out from closed is Richer than the factory position correct?

 

Yes, I believe so, but I think if it's backfiring on decel it might be running to rich, so you might want to start with a slight turn in. IMO

 

Today was the second time out with my sons 2011 170 and it backfired alot on decel Plus everytime we would go through some water it would die and be very hard to start, had to choke it everytime which leads me to believe it is leaning out. Lean or rich? I'm confused! Are they connected?

 

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

 

rwillden

what is your elevation please?

 

4000' but the changes I suggested would probably be adequate at any elevation since the jetting in my 170 was stock jetting, not adjusted for altitude. Made a huge difference.

 

Rwillden if I have the dealer put a 40 in and ajdust the screws it I wont have to chock it eveytime we start it ? How many turns does it usally take to get it set right ? what about after it get warmed up willl it still run good ? I dont want to get out on the dunes and have to keep playing with it to get it right.

 

I did this on mine. Installed the 40 pilot and went up 1 size on the main and it is amazing at how easy it starts up now. I would always have to start if for my daughter and get it warmed up because she couldnt keep it running workning the choke. Now if i leave it in the garage the choke is not needed even after sitting a week. And i got rid of the backfiring and it just seems to run better all together. I also bypassed the switch on the gas pedal assembley as that is what started me with the jetting because it was missing real bad and i could not get it to go away. Now i just have to fix the stupid broken swing arm.

 

I have and extra OEM RZR 170 sway bar for sale. It's the newest version with the extra reinforcing. It's essentially brand new.

Here's the ad for it:

http://www.rzrforums.net/polaris-rzr-parts-sale/35618-fs-rzr-170-swingarm-mint-w-futv-uhmw-skid.html

 

40 pilot and 110 main night and day difference. Runs like a singer sewing machine. No backfires no hick-ups. Fires right up no choke.

 

What year is yours? We just bought a 2012 and wondering if I should order these jets to switch out before we take it out?

Anybody know if these are the size jets I should use in my 2012? Thanks much!

 

so if its sits for a few weeks or a month you still have to choke it ?

 

No choke. Turn key and go.

 

is the swing arm still for sale ? who made it ? FUTV or is that the stock one ?

 

Depending on your location (altitude, humidity, temps) will have some effect on your jetting. The 40 pilot should be good regardless of location. The main may need to be played with a bit but the 40/110 set up will definitely be better than the stock 35/100 (I believe Polaris jets them lean to get thru emissions requirements). The 2011 and the 2012 are the same motor/aspiration wise anyway.......

 

OK thanks..Ill pick one up then!

And we ride east of San Diego..Ocotillo, Superstition, the dunes..not sure of the elevation there

 

You should be fine with the 40/110 here in Cali at low elevations............Going up in elevation like over 5,000 feet you will need to lower the main......

 

would that work good in texas you think ?

 

Not familiar with Texas and the climate there however if you are experiencing the lean condition as as I did after the purchase this will be a step for the better.

I would assume Texas to be dryer than California so maybe even fatter on the main. Bigger wont hurt in fact I have run as big as a 135 in the main with a 40 pilot and while it was too fat at top, it wont hurt the motor like too lean would. You should always go a little fat first and adjust lean if needed.

Make your adjustments in small increments and track what you do. It can take several to many assembly-disassembly of the carb to make changes and get dialed in but one you do it will be worth it.

Instead of me re-typing the pages of info, google "how to adjust a keihn 22mm carb" or "how to adjust a keihn carb" and you should get some useful info on the correct steps to take to verify the correct jetting. OR better yet here ya go

http://www.keihincarbs.com/tips/gate.html

One last thing keep in mind if you make drastic elevation changes you will need to make changes again..........

I need F.I.and a turbo on my 170. Better get to it.............

 

Almost forgot, currently I have made no changes to the stock needle position of 3rd from the top (middle notch). All jetting changes were in main and pilot.