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Team Bricktucky

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guy its been awhile since I've been here . who is still here ? I still have a predator ,two outlaw 525s a scrambler 400 hybrid(pred front end) and a 2015 scrambler 1000 .
I just turned one of my outlaws from a mxr450 to a 525 . been awhile since ive done work to these atv's but im having some small jetting issues turning the mxr450 to a 525 . I could use some old school ideas . center mount hmf stock cylinder 525 stock piston ,stock cam . changed the needle to the old honda hrc mcvq needle , tried 152 150 148 main , tried stock 450 needle and stock 525 needle but I still have back fires and a stumble from idle to half . I know im close and feel most of this issue is with needle or accelerator timing/ diaphragm. any ideas ? im at a loss because my other outlaw 525 isn't far off on mods and has way different jetting. the other 525 just has a 8/33 cam and kibble white valves and springs .i cant believe my jetting is so far different. same intake same carb ,same piston. I do have the Polaris service man, and matched the slow air and carb settings from 450 to 525.even tried the same jetting as the other 525.
guess im just forgetting something but might AS WELL SHOOT THE SHIT WITH THIS FORUM SINCE IT WAS A BIG PART OF MY LIFE AT ONE TIME.
distraction628

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Reply with quote  #2 
Brick. Have you changed out the accelerator Diaphragm? I fought one for a week , and it had a pin hole, changed it and everything was just tuning after that.   Also  have you tried  any larger mains like  165?  What pilot? 
I check in at least 4 time a week.....
The facebook outlaw and pred  pages I'm part of are busy, But I feel none of the new guys that get there quads second , third, or fourth hand  even try to figure out anything on there own. They can't find anything. Some can't even come here and do research on what works and what doesn't.
Don't get me wrong I like helping, but people really need to try and learn some on there own for the times when you need to figure out how to get out of the bad. Like in the middle of no where and no cell service.  Maybe it just me getting old!
Glad to see you are still around!! 

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07 525, 06 500, 10 525s 09 RZRs, 04 Ram 2500 Cummins 6spd, 08 Fuzion toy-hauler
Team Bricktucky

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Reply with quote  #3 
well I made a mistake , the spark plug gap was way too big . I also reset the valve gap. I will find out tomorrow if my jetting is good. so far so good
70oldsracer

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Reply with quote  #4 
I don't want to hijack your thread, but I'm new to this forum and I really don't see a lot of recent posts. I picked up a 2008 Polaris Outlaw 525S. I put on a HMF competition slip on exhaust, Velocity intake and filter and I had the carb bored to 41mm. I started tuning the idle circuit of the bike with a wide band meter and it seems to be rich. I'm looking for 14-14.5 at idle and with the mixture screw turned almost all the way in, I get about 13. I had a 48 pilot jet in there and went back to the 45, but it still showing rich at idle. I just bought a 42 pilot and have the mixture screw set at 1 1/2 turns out, but haven't had a chance to start the bike. Does it make sense that with a better flowing exhaust and a better filter set up that I would need to go smaller on the pilot jet?

Frank
distraction628

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Reply with quote  #5 
Frank , Sorry you are having trouble.   When testing to get a/f correct at idle is the quad in a open area with fresh air ?  Is the Motor at full temp ?  You wait 30 seconds after a blip of the throttle?
 You are sure the choke is fully seated?  Also have you calibrated the O2 sensor in free air ?  With the bored carbs I have dealt  with I've  I usually find the pilot is down one and main can go down or up a lot.  Under choke you want to see 11.5 to 12.8 for warm up. Then once up to temp you should be close. remember after choke is off it takes a little bit of time to clear exhaust to get a true reading.  I have found a big box fan works great to help keep air moving over the quad. A little rich is fine  down to 13.7 on warm days and 13.2 on really cold days. I always shoot for best idle at 1825 rpm  + or - 50 rpm.  You really need a tach or you will always have trouble with adjustment as at about 1925 rpm your starting to be on the needle ( unless you have a leak )  The slide relation will also have a impact on the mixture setting.   Hope this helps a little.

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07 525, 06 500, 10 525s 09 RZRs, 04 Ram 2500 Cummins 6spd, 08 Fuzion toy-hauler
distraction628

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Reply with quote  #6 
Brick, Let us know  how it worked out.  Do you ever take the scrambler out any more ?
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07 525, 06 500, 10 525s 09 RZRs, 04 Ram 2500 Cummins 6spd, 08 Fuzion toy-hauler
70oldsracer

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Reply with quote  #7 
Quote:
Originally Posted by distraction628
Frank , Sorry you are having trouble.   When testing to get a/f correct at idle is the quad in a open area with fresh air ?  Is the Motor at full temp ?  You wait 30 seconds after a blip of the throttle?
 You are sure the choke is fully seated?  Also have you calibrated the O2 sensor in free air ?  With the bored carbs I have dealt  with I've  I usually find the pilot is down one and main can go down or up a lot.  Under choke you want to see 11.5 to 12.8 for warm up. Then once up to temp you should be close. remember after choke is off it takes a little bit of time to clear exhaust to get a true reading.  I have found a big box fan works great to help keep air moving over the quad. A little rich is fine  down to 13.7 on warm days and 13.2 on really cold days. I always shoot for best idle at 1825 rpm  + or - 50 rpm.  You really need a tach or you will always have trouble with adjustment as at about 1925 rpm your starting to be on the needle ( unless you have a leak )  The slide relation will also have a impact on the mixture setting.   Hope this helps a little.

Bike is in open area and the sensor doesn't need to be calibrated in open air. I have a tach and always keep the RPM just under 1,800. The bike starts right up right now without the choke and I have let it warm up. I'm going to have to start the bike with the smaller 42 pilot and see if that helps. I'll keep you posted, thanks.
Team Bricktucky

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Reply with quote  #8 
I road the stock engine 525 outlaw yesterday and everything worked out great. I ended up with a 45 pilot, stock obdvs needle in 4th clip, with a 150 main, and I wired ac pump, plus I had to adjust the ac pump timing... I had a few issues before because I was trying to use the honda hrc ,ncvq needle , had the wrong slow air jet(because it was a mxr450 carb) ac pump was off timing and my spark plug gap was too big. I still think I can mess around abit more with the mid but this atv is just really a back up atv and the one atvi'd lend to a friend .

Distraction628, You asked about the scrambler , which one I have a old 400 hybrid but the engine needs a rebuild and a pipe. The 2015 scrambler 1000 , I haven't driven it in three weeks . it runs great because it only has 68 hours on it. It is a fun atv but im still a sport atv guy . 
joshr08

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Reply with quote  #9 
I pop in once in a while.  I still have the predator and it now has a 5' wheelie bar on it and waiting for its next trip to the 1/8th mile to see how much time that shaved off.  Other then that I have a few bikes that I am building.
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distraction628

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Reply with quote  #10 
Brick, The Hybrid.... Glad your closer on the jetting on the 525...
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07 525, 06 500, 10 525s 09 RZRs, 04 Ram 2500 Cummins 6spd, 08 Fuzion toy-hauler
polaris bob

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Reply with quote  #11 
Matt, stop tuning your car with a hammer it goes better.
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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
polaris bob

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Reply with quote  #12 
70oldsracer. I tune my carb using the old school listen and feel method for idle and off idle then I use my O2 sensor for anything above that.

somewhere on here I have a detailed write-up on how to go about tuning with an O2 sensor. Don't know if it'll help out or not.

As long as it's idling smooth and has good transition from idle to off idle I would be happy with in the mid 13s. I normally tune my carb to run in the high 12 low 13's across all circuits. in my opinion tuning for anything close to 14.7 is way too lean for max power.

These motors like to run a little rich.

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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
70oldsracer

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Reply with quote  #13 
Quote:
Originally Posted by polaris bob
70oldsracer. I tune my carb using the old school listen and feel method for idle and off idle then I use my O2 sensor for anything above that.

somewhere on here I have a detailed write-up on how to go about tuning with an O2 sensor. Don't know if it'll help out or not.

As long as it's idling smooth and has good transition from idle to off idle I would be happy with in the mid 13s. I normally tune my carb to run in the high 12 low 13's across all circuits. in my opinion tuning for anything close to 14.7 is way too lean for max power.

These motors like to run a little rich.


I saw your write up and it's very good. I should have listened to your write up and only used the wide band meter for tuning the needle and main jet. Should I put the stock 45 pilot jet back in and tune the idle circuit like you suggested? I was only looking for 14 at idle and was going to tune it for 12.7-13.0 for everything else.

Thanks,

Frank
70oldsracer

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Reply with quote  #14 
Bob,

I put the 45 pilot back in the carb, but I can turn the mixture screw all the way in and it still does not want to stall. I even tried lowering the idle and adjusting it, but it does the same thing. Do I put the 42 pilot back in and start all over again?

Thanks,

Frank
70oldsracer

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Reply with quote  #15 
Also, does anyone have a detail on where the hoses go on the carb. I just want to make sure mine are all in the correct spots. Pics would be great.

Thanks,

Frank
polaris bob

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Reply with quote  #16 
Sorry been real busy lately. I would go back to what was working before and start from there again.
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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
polaris bob

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Reply with quote  #17 
I don't know how long pictures get saved on this site but there was pictures showing the hose layout. Any pictures I had were on my old computer which is no longer functional.
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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
polaris bob

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Reply with quote  #18 
A couple of things here real quick like.

Many times improving the air flow through the intake with a better flowing filter setup or improving the air flow through the exhaust with a freer flowing exhaust causes the bike to go rich. the reason for this is you're getting a better air signal through the various jets in the carburetor and it is "carbureteing better" ! (Is that even a word ? ) LOL conversely going to a bored carburetor often times has the opposite effect at idle. The larger diameter slows the air speed down through the carburetor reducing the signal to the jets making it slightly more difficult to get a precise set up dialed in at lower RPMs.

As for you not seeing any changes or not being able to get the motor to die while adjusting the fuel screw, my best guess is either you are mistaking the fuel screw for the mixture screw or something else is going on inside your carb.

You should see, hear, feel a RPM change and or a stumble every time you adjust a fuel screw in 1/8 turn increments. That is why you want to make a slight adjustment in the fuel screw and wait for the motor to stabilize again.

I would pull the carb make sure is absolutely spotless with no pluged Jets and go back to what was originally working and start over.

On an fcr carburetor the fuel screw is on the bottom of the carb right in front of the float bowl. this is the screw your adjusting when trying to adjust the idle mixture, correct?

Are you using a stock fuel screw or are using an aftermarket fuel screw??

back in the day I turned quite a few buddies fcr carburetors on various manufacturers bikes and I never found an aftermarket fuel screw that worked as well as the factory fuel screw.

In fact we always put the factory fuel screw back in before starting any adjustments. You might go as far to say I hate aftermarket fuel screws.

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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
70oldsracer

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Reply with quote  #19 
Unfortunately, I don't know what was ever good from the start. I bought the bike and changed the air filter, exhaust and bored the carb right away without even riding it. I live in Queens, NY, so riding it here is almost impossible. I had my original header pipe ceramic coated, so I bought a used pipe and welded in a bung for the wide band meter sensor. I got the vent hose diagram and will check everything today. As far as the mixture screw is concerned,( I do know which one is the mixture screw) I bought the R&D flex jet, which I can see you're not a fan of. There's just so little room under the carb to adjust the mixture screw, this just made things so much easier. Is it that much out of spec from the original screw that it would cause a problem?  I was out hunting all day yesterday, but have time today to go over everything. So I don't keep hijacking this thread, can I email you directly? My email is olds7d442@aol.com


Just figured i'd put pics for a better understanding of my email address.[smile]

Frank
polaris bob

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Reply with quote  #20 
I don't care if you email me there's probably a link in my profile but if we keep it on the page it'll help other people learn and I don't care about responding here.

I tried one of those fancy flexjet's, I tried three or four different extended length adjustable fuel screws, none of them worked right.

In the end I went back to the factory fuel screw and bought one of those, I believe it's a motion pro, fuel-screw screwdrivers.

Yes they can be a bit of a pain to get to but that screwdriver makes it oh so much easier to get to.

I guess when it comes down to is this, if you are making adjustments to your fuel screw at idle and not seeing / hearing any RPM changes then something is going on.

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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
70oldsracer

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Reply with quote  #21 
Bob,

There is definitely a change in the rpm of the motor when I screw it in or out, but it will not shut the bike off with it screwed all the way in.  I decided to take your advice and I'm going to try to us the stock mixture screw. I made my own small screwdriver on the lathe and mill and I'll use that to adjust the mixture screw when the bike is running. I cut down a small screwdriver and epoxied it into the handle I made. It slides over the mixture screw which locates the tool. I just want to stamp numbers on the side of the tool so I can tell how much I'm turning it. I'll let you know how it works.



70oldsracer

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Reply with quote  #22 
Bob,

I know the pilot jet and mixture screw control the idle circuit, but if I was to change the location of the needle clip, would it have any effect on the idle circuit. Right now it seems like my idle circuit is too rich and I was wondering if I was to raise the clip on the needle to the next notch if it would lean out the idle circuit, even slightly?

Frank
polaris bob

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Reply with quote  #23 
It could. While the needle and needle clip position has the biggest effect in the mid-range it will affect fueling across all positions of the slide moving.

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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
polaris bob

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Reply with quote  #24 
Have you pulled the carb off, took it apart and made sure everything is installed correctly and it is spotlessly clean?

I can't remember but does that velocity intake adapter have the holes machined in it to line up the air vents on the intake bell of the stock carb? Is the adapter lined up properly?

Besides the rich idle how was the bike actually running?


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2003 Polaris Predator / 2004 KTM 525 exc 6 speed motor.

570 Thumper Racing kit w/ 12.5 - 1 CP piston. Head ported by Thumper Racing w/ new intake seats done by Pro-1 racing. Stage 5 cam (Custom design by Thumper Racing). AC bearing mod. Oil system mod by DJH. KW valves (stock size). * #100 CDI dirt bike CDI. 42 mm FCR carb by Walt/Fast64ranchero. (SX carb = No TPS). Trail Tech -10 oz flywheel. (Stock is 30 oz/ trail tech = 21 Oz's)
Mino water pump. Full flow set up, no T-stat. PB Oil cooler. Custom modded intake. Uni filter/ D2 Moto adapter on a modded Predator intake tube.
KTM Bill modded CT racing full exhaust system. Tusk Clutch kit. Honda thumb throttle. Snyder Motorsports adjustable upper A-arms. PP Billet front hubs W/ DLR tapered roller bearings. Custom modded fox suspension. Hidden comfort camo seat cover on a modded stock seat.
70oldsracer

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Reply with quote  #25 
Quote:
Originally Posted by polaris bob
Have you pulled the carb off, took it apart and made sure everything is installed correctly and it is spotlessly clean?

I can't remember but does that velocity intake adapter have the holes machined in it to line up the air vents on the intake bell of the stock carb? Is the adapter lined up properly?

Besides the rich idle how was the bike actually running?



Bob,

Carb has been off, everything is installed correctly and thoroughly cleaned. The adapter does have holes machined in it to line up with the vent holes. I made sure the adapter lined up perfectly and I used "the right stuff" to hold it in place. The bike ran very good, but it was popping through the carb after letting off the throttle. I originally assumed it was due to a lean condition, but after reading up on the bike, I realized it could be a leak in the exhaust. I put the exhaust back on with high temp silicone, but never took it back out for a ride. I live in NYC and driving on the streets tends to be an issue. I was hoping to get the idle circuit perfect first and then work on the mid range and top end.
70oldsracer

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Reply with quote  #26 
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