what is the secret to making SLP twin pipes work

[terryqyh]

I picked up some SLP twin pipes last year for my 04 RMK 800 Edge. I installed the intake airflow kit and rebuilt my clutches to the specs that SLP recommended. I also jeted the carbs according to their charts and installed a Holtzman ATACC. I started out with jets that were two sizes to big and have worked my way to smaller jets inspecting the spark plugs and pistons as I leaned it out. It runs great in the mid range but falls flat on its face on the top end. I get about 7800 rpm instead of 8300 as i expected. The local polaris guru tolled me to get rid of the SLP pipes says he has never seen them work very well, and go with CPI or PSI pipes I forgot which he said. He said that there is something about the SLP pipes that would not tune very well. SLP's have been around for a while I would think that someone out there would have worked this out by now. any suggestions?

 

[Jay]

SLP makes an outstanding product. Carls 910 and UBR 900 and more BB 800's than you can imagine run SLP twins with excellent results. What elevation and clutching are you running? What jets? There are a bunch of guys on here that can help you out better than I, someone will speak up.

 

[BB454]

SLP pipes

They like to be hot to make power. Usually you need to run them a couple of minutes at half throttle to build heat in them before you work them hard especially after stopping for a break from riding. If you are that lean on top end, I bet you have gone too far. Go back closer to the SLP spec and get them good and hot and see if they run better. I ran the single because it was more forgiving but the twins make more power.

 

[theultrarider]

Start by getting rid of the aatac until you get them dialed for your elevation ect. They do run very very well, but slp's jetting chart is way off. You are most likely running about 4 sizes too fat on your mains. Maybe more. Their clutching chart is quite good however. Good luck. It will rip once you get it setup.

 

[sled_guy]

As others have said, pull the ATACC and get it dialed in first.

You need LOTS of intake air for the twins. I run 2 florites in the dash as well as both gauges replaced with speedo florites (I have an Avenger gauge).

Were the pipes new or used? The first Edge 800 twins built in early 2002 were junk. They wouldn't run. By late 2002 SLP had redone them and since then they have been spot on. If you bought used, maybe you got a set of those early pipes.

Your local Polaris guru is wrong, CPI and PSI don't make better pipes than the SLPs.

Start with the removal of the ATACC and post up your jetting and altitude you ride at and you'll get some good feedback from guys on here as to the setup that will work.

sled_guy

 

[terryqyh]

These are used pipes off ebay. As i recall, someone was parting out a 04 RMK. They look like fairly new pipes. They still have a clean finish on them, no rust or rub marks, though that probably means nothing. Is there any way to tell the difference between the older pipes and the newer ones? I ride between 7 to 11 thousand feet, 5000 at the house. I am currently running 420 on the main jets with the needles in the #3 position and I have 2 florites in the dash also. My drive clutch has the SLP black/pink spring with 68g weights no rivets. Driven clutch has red/black spring and a 58/38 Helix.

 

[SHERMAN]

I had slp twins on a 04 Polaris and my jetting was 2nd clip from the lean side 390 and 400, I forget which for mag and pto, stock pilots. mods were air horn with flow rites boost bottle slp clutching vforce reeds @ 4 - 6000 ft. Sled ripped. One problem I did have was motor getting heat soaked and would only pull 7600-7800 rpm, put a lexan hood (gave more room under hood and venting) and problem solved. Don't give up I believe the twins to be worth it!

 

[SHERMAN]

Just finished reading your post, those 68 gr weights seem really heavy, I'm pretty sure I was running 64 gr. but can't remember the spring rate or secondary setup. Hopefully someone else with chime in and let you know for sure.

 

[winter brew]

As said.... Get rid of the atacc to get it dialed in. Then once you know how it should run you can try the atacc.
Jet down to 390's no atacc and needles in the middle. Probably end up at 380's but do plug checks first.
Those arms are likely too heavy. Leave the secondary alone.

 

[sled_guy]

I believe there is a little tab welded to the pipes right where the cylinder flanges are that has a part number stamped on it.

My 910 runs 390/400 mains from 8-11k feet. I don't know what the ATACC does for jetting, but it sounds rich.

I assume you are using MTX weights... your probably 3-4 grams heavy for that elevation.

And you want to target 8100-8200rpm... above that and the timing is pulled out of the motor.

sled_guy

 

[terryqyh]

Went out with some friends yesterday at sunup for a quick four hour ride in a new local, we got lost, made it back to the trucks about sunset,out of gas, and dead tired. Man, I love this sport!!! The sled ran ok in the morning. 7200 was about all I could get out of it. By noon it was hitting 8K and running good. maybe just needed some break-in time or something. Still could not go full throttle with out bogging. I just put smaller jets in it today. I think I am getting there.

 

[Twostroke]

if it runs good then falls on it face high in the rpms or underload your too rich on your mains.

 

[terryqyh]

I guess I'm a little gun shy when it comes to main jets. The first thing i did when I put the twin pipes on was run out in the field behind the house for a quick test run. Less than five minutes later I was dragging it back with a four wheeler and ordering new pistons and doing a lot of reading. I have done a lot of work on it since then... air box, drive clutch, driven clutch, flow rite vents and a few other things. I'm sure your right I just need smaller mains.... and MORE TIME TO RIDE!

 

[big_wally81]

it sounds like it is rich. I don't run much bigger jets on my 800 in minnesota (low elevation).