I just purchased a 1996 ultra sp with psi pipes and am having a problem with a really bad off idle bog I have cleaned the carbs several times put new main jets in it tried several different size pilots in it and still can't clear it up I am running 400/400/410 mains, 25 pilots, needle second from top, and air screw 1 full turn out. I am now thinking it might be clutch related I just ordered a new red epi primary spring I got some 10/ 55gram weights and then I ordered a 42/34 helix and a purple epi secondary spring and also new super slippery slp buttons for the secondary. I haven't taken the clutches apart yet but I might replace all the bushings in both clutches also depending what they look like.

 

Both of you guys' pilots are too small. Try larger and your problems will go away. @5500 are you even on the needle yet? (less than 1/4 throttle)

 

I've tried pilots all the way up to 30's, 35's, and 40's and it doesn't do anything other than make the sledd easier to flood out when starting. 50's are stock PSI pipes recommends a 25 pilot

Both of you guys' pilots are too small. Try larger and your problems will go away. @5500 are you even on the needle yet? (less than 1/4 throttle)[/b]

 

35s on asphalt and 40s on ice for me. 4500 engagement. Ground off SLP needles ( I don't know what they are) in the middle clip. 350 to 380 mains It's almost as fast as a twin out of the hole...

 

I have a set of Boswell modifed 38 mm roundslides with Cyclers and special reed plates with 44 mm boots for a 1996 Ultra with PSI pipes. This solves all the typical carb problems experienced on the Ultras with pipes. $350 shipped. Includes throttle cables and choke cable.
248-889-1046

 

I have a 96 Ultra which I recently put SLP pipes on.
I am having a little problem tuning it.
Sled runs great and pulls hard from 5500 on but has a hesitation or bog off idle untill that point.

2200 feet elevation
dropped my pilots to 30 as SLP suggests.
I am running the SLP needles dropped all the way down as I was getting some loading up when I had the needles at the second or more position. Concerns me a little to have the needles on the leanest setting for my altitude, but as of now that is all I can do to clean up the midrange.
I have taken the carbs apart and sync'd them.
Seems it either idles at 1200rpm or with a slight adjustment it wants to idle at 3000rpm. So I'll take the 1200rpm.

Compression is good in all 3 cylinders.

I purchased some 35 pilots, but was unsure if I should throw them in.
Any suggestions to get rid of my off idle bog would be much appreciated.
thanx in advance.[/b]

What's the belt to sheave clearance on the primary?

 

Drill out the pilot air bypass (remove the pilot jet and drill straight down through where it threads into) to 1.0 mm (.040"). Start with 30 pilots, air screw at 1/2 turn, the slp 14-101 low elevation needles and stock 247 P-4 nozzles. 380/360/380 mains. Run BR10ES plugs, only good fuel, and if you are 1500ft. elevation, stock timing of 16 degrees at 8000 rpm. Take the weights out of the primary clutch and run the engine up to that rpm to check with a timing light. As said, belt to sheave clearance must not be more than .020", and deflection 1 1/8" to 1 1/4".

 

Pockets, if I have my flow paths correct this drill out modification will lessen an overfuelling/loading issue at low throttle openings with the sled under load? (heavy snow, 1/8 to 1/4 throttle opening). Or does this richen that circuit? I need leaner!

I have 30 pilots already but seems to load up if I creep along in heavy snow ie. maneuvering through the bush etc.

 

Sheave clearance is .020 to .025 with a new belt
timing is still stock so if you think thats ok at 2200' I'll leave it
It is an RMK which means it has 1.5 slides, but I have replaced the heads with sp/sks heads
air screw is at 1/2 now
needle jets are stock
Thing is I purchased the pipes used last year and they came with the SLP needles and helix
I don't know if I have the low or high elevation needles

I had 390/370/390 mains, I had tried 400/380/400 and was loading up a bit, I will drop them to 380/360/380
I will drill out the pilots
and change the plugs

I appreciate the help everyone
The sled only has 600 miles on it and I'm hoping to get it to perform like I've read about

 

( have an ultra with PSI pipes. PSI recommends 25 pilot 1.5 turns air screw, 2.0 slide, 247p-8 needle jet, psi custom needle 2nd pos. and 410 410 420 mag for jets. You must make sure timing is 12 to 14 degrees at 8500 rpm. I have bored carbs so i am higher. 430 430 450. and a Q2. )

This is info from another post on here do you guys really think the pipes are that different between SLP and PSI?? I am running basically this setup except my mains are slightly leaner at 400,400,410 I haven't checked timing yet? I went through my clutchs today and my belt to sheave clearence on the primary was probably .035 or maybe more so that is my first stop on monday at the dealer and get a shim put in to get that to spec I think i'm going to have them check all the busshing also in both clutches cause to me they seem like they are worn to much the machine has a little over 5000 miles on it

why run a colder plug BR10ES wouldn't you want to run a hotter plug BR8ES

Drill out the pilot air bypass (remove the pilot jet and drill straight down through where it threads into) to 1.0 mm (.040"). Start with 30 pilots, air screw at 1/2 turn, the slp 14-101 low elevation needles and stock 247 P-4 nozzles. 380/360/380 mains. Run BR10ES plugs, only good fuel, and if you are 1500ft. elevation, stock timing of 16 degrees at 8000 rpm. Take the weights out of the primary clutch and run the engine up to that rpm to check with a timing light. As said, belt to sheave clearance must not be more than .020", and deflection 1 1/8" to 1 1/4".[/b]

 

l

 

PSI pipes do require different jetting. When changing heads, you actually should either put on aftermarket ones, or those from a Ultra SPX or 98 700 XCR. Polaris even came out with a team tips stating this when adding aftermarket triple pipes to the ultra engine to prevent deto.

 

we never talked about changing heads??? what are you talking about???

PSI pipes do require different jetting. When changing heads, you actually should either put on aftermarket ones, or those from a Ultra SPX or 98 700 XCR. Polaris even came out with a team tips stating this when adding aftermarket triple pipes to the ultra engine to prevent deto.[/b]

 

PSI pipes do require different jetting. When changing heads, you actually should either put on aftermarket ones, or those from a Ultra SPX or 98 700 XCR. Polaris even came out with a team tips stating this when adding aftermarket triple pipes to the ultra engine to prevent deto.[/b]

lol
Wish I knew that before I purchased new sp heads to lower the compression from the rmk ones
I'll keep an eye open for those heads
thanx for the tip

 

I got it all back together today 1996 Polaris Ultra 680 SP with PSI pipes. I have 400 pto 400 center 410 mag side main jets needle set at second from top clip pilots are 25 and air screws 1/2 turn out. primary clutch is red EPI spring and 10A/55 gram weights secondary has new super slippery SLP buttons a 42/34 helix and a purple EPI spring. This thing fricken flys now my fiance has a 2000 Yamaha SRX700 with triple pipes and a aftermarket can and it has been clutched also and my Ultra will run right with it if not beat it. I LOVE IT!!!

( have an ultra with PSI pipes. PSI recommends 25 pilot 1.5 turns air screw, 2.0 slide, 247p-8 needle jet, psi custom needle 2nd pos. and 410 410 420 mag for jets. You must make sure timing is 12 to 14 degrees at 8500 rpm. I have bored carbs so i am higher. 430 430 450. and a Q2. )

This is info from another post on here do you guys really think the pipes are that different between SLP and PSI?? I am running basically this setup except my mains are slightly leaner at 400,400,410 I haven't checked timing yet? I went through my clutchs today and my belt to sheave clearence on the primary was probably .035 or maybe more so that is my first stop on monday at the dealer and get a shim put in to get that to spec I think i'm going to have them check all the busshing also in both clutches cause to me they seem like they are worn to much the machine has a little over 5000 miles on it

why run a colder plug BR10ES wouldn't you want to run a hotter plug BR8ES[/b]

 

I forgot to mention my primary belt to sheave clearance was way of I had to take two shims out of it to get it right

I got it all back together today 1996 Polaris Ultra 680 SP with PSI pipes. I have 400 pto 400 center 410 mag side main jets needle set at second from top clip pilots are 25 and air screws 1/2 turn out. primary clutch is red EPI spring and 10A/55 gram weights secondary has new super slippery SLP buttons a 42/34 helix and a purple EPI spring. This thing fricken flys now my fiance has a 2000 Yamaha SRX700 with triple pipes and a aftermarket can and it has been clutched also and my Ultra will run right with it if not beat it. I LOVE IT!!![/b]

 

I forgot to mention my primary belt to sheave clearance was way of I had to take two shims out of it to get it right[/b]

Taking mine out this weekend
I hope my results are as successful as yours

 

went to a radar run today with the Yamaha and the Ultra. The Yamaha has brand new studs in it and it did 81mph in 500 feet on a poor track. My Ultra did 77mph in 500 feet with worn out studs it probably spun the first 75 to 100 feet. I am happy with the results but I'm ordering new studs monday for the Ultra. Fast mph of the day in any class was a heavily modded Artic Cat F7 he pulled 90mph in 500 feet.

I got it all back together today 1996 Polaris Ultra 680 SP with PSI pipes. I have 400 pto 400 center 410 mag side main jets needle set at second from top clip pilots are 25 and air screws 1/2 turn out. primary clutch is red EPI spring and 10A/55 gram weights secondary has new super slippery SLP buttons a 42/34 helix and a purple EPI spring. This thing fricken flys now my fiance has a 2000 Yamaha SRX700 with triple pipes and a aftermarket can and it has been clutched also and my Ultra will run right with it if not beat it. I LOVE IT!!![/b]

 

Drill out the pilot air bypass (remove the pilot jet and drill straight down through where it threads into) to 1.0 mm (.040"). Start with 30 pilots, air screw at 1/2 turn, the slp 14-101 low elevation needles and stock 247 P-4 nozzles. 380/360/380 mains. Run BR10ES plugs, only good fuel, and if you are 1500ft. elevation, stock timing of 16 degrees at 8000 rpm. Take the weights out of the primary clutch and run the engine up to that rpm to check with a timing light. As said, belt to sheave clearance must not be more than .020", and deflection 1 1/8" to 1 1/4".[/b]

Drilled out the pilots and dropped my jets as you suggested.
Seems better, still have a bit of bog from 4500-5500 but I am going to tighten up my sheave clearance this week when I get a puller. I am hopping it takes care of it.
I am really having problems with the needles I have with the pipes.
At position 2 they cause the mid range to load up, when I drop the needles to the first position it is better but it still loads up a bit.
I don't think it will be possible to find some new low elevation slp needles anymore.
Is it possible to run the stock needles and perhaps change the needle jet to compensate?

thanx in advance

 

I couldn't get the SLP needles to work, still too rich even with needles dropped all the way.
So I put the stock needles back in and set them at position 2 as 3 was loading up a bit.
Perhaps the reason is because my cut away is only 1.5 as opposed to 2 of the SP which makes it run a little richer.

Adjusted my belt to sheave clearance to .015.

Sled runs awsome now, almost all hesitaion around 5k is gone, pulls hard right till redline now.

Just wanted to thank everyone for there help.
Pockets, you know your ultras

 

I got it all back together today 1996 Polaris Ultra 680 SP with PSI pipes. I have 400 pto 400 center 410 mag side main jets needle set at second from top clip pilots are 25 and air screws 1/2 turn out. primary clutch is red EPI spring and 10A/55 gram weights secondary has new super slippery SLP buttons a 42/34 helix and a purple EPI spring. This thing fricken flys now my fiance has a 2000 Yamaha SRX700 with triple pipes and a aftermarket can and it has been clutched also and my Ultra will run right with it if not beat it. I LOVE IT!!![/b]

Hi there. I found this thread and got some anwsers to my jetting questions. Did you go with the P-8 needle jets and PSI needles?

Are you still getting 9 MPG

I am still averaging around 3 if lucky

 

yeah I'm still getting around 9mpg with mine it is still running alittle rich on bottom and mid I think i may even drop it down to 20 pilots then I have to figure out a good needle and needle jet combo to clear up my mid range as I have the needle all the way down in its leanest position and it still is a little rich in mid range

Hi there. I found this thread and got some anwsers to my jetting questions. Did you go with the P-8 needle jets and PSI needles?

Are you still getting 9 MPG

I am still averaging around 3 if lucky[/b]

 

The SLP needles for low elevation were designed to run with P-4 tubes not P-8's. The stock 6DH8's were pigs on gas, that's why they cut their own. If you were to try and mic them, I think they were fairly close to the stock SPX needles, if I remember correctly. HTG uses the stock 6DH8's, you'ld need to at least run 3.0 slides and Q-2 tubes. With P-4's, I've never had a problem with the SLP needles. I even used 45 pilots for the throttle response, but had backed off to 40 pilots for trail riding. No plug fouling what so ever.

 

huge difference between SLP and PSI pipes not even close to each other in the carb set up

The SLP needles for low elevation were designed to run with P-4 tubes not P-8's. The stock 6DH8's were pigs on gas, that's why they cut their own. If you were to try and mic them, I think they were fairly close to the stock SPX needles, if I remember correctly. HTG uses the stock 6DH8's, you'ld need to at least run 3.0 slides and Q-2 tubes. With P-4's, I've never had a problem with the SLP needles. I even used 45 pilots for the throttle response, but had backed off to 40 pilots for trail riding. No plug fouling what so ever.[/b]

 

You could try the SPX 6CEY06 needles, with Q2 247 nozzles.

 

is that for PSI pipes or SLP pipes?

You could try the SPX 6CEY06 needles, with Q2 247 nozzles.[/b]