Plugged Exhaust Valves?

[thefullmonte]

Running at altitude I would start with the pink spring. If you are above 8000ft all the time you may need to go with the yellow, but I would start with the pink.

Thanks for chiming in Ron. Everything you stated is correct from what I understand.
I'm not here to argue any point, and I'm not even sure this is worth noting. I just wanted to state my interest in this in the first place. Note, these are just my thoughts open for discussion.

As we all know, what the dyno says and what happens on the snow are two entirely different things. However, I found this interesting. FYI Dynotech is in New York at sea level.

According to the dyno, the surge is quite possibly being caused by the valves opening too soon! This would be in conflict of what we are seeing from the guys who have actually tested this on the snow. The dyno showed a drop in HP and then it quickly started to rebuild when the valve timing was off. Note the surge. My concern is of the opposite. If the valves are being held completely closed until X rpm it is keeping too much heat around the exhaust valve and port area. Going back to the old way allows the valves to operate gradually from exhaust pressure working against spring pressure.

The more important issue was letting off at WOT the valves really needed to be held open longer. Again, this is accomplished the old way. When they closed immediately it caused a rich condition and the possible burble/stumble some people experienced when getting back on the gas.

The hole thing just seems buggered to me. Who came up with this darn diaphragm operated thing anyway? Japanese two strokes have been using mechanical exhaust valves for ever. Yamaha was using them before they retired the two stoke sled too. I remember dirt bikes in the 80's all using mechanical systems. This system just seems kinda flawed to me, but again I have been exposed to a lot of different two strokes over the years. I've never been in a position until now that I even thought about changing how it worked. Sorta tells a story right there huh.

 

[Kraven]

Electronically controlled exhaust valves

Running at altitude I would start with the pink spring. If you are above 8000ft all the time you may need to go with the yellow, but I would start with the pink.

Thanks for chiming in Ron. Everything you stated is correct from what I understand.
I'm not here to argue any point, and I'm not even sure this is worth noting. I just wanted to state my interest in this in the first place. Note, these are just my thoughts open for discussion.

As we all know, what the dyno says and what happens on the snow are two entirely different things. However, I found this interesting. FYI Dynotech is in New York at sea level.

According to the dyno, the surge is quite possibly being caused by the valves opening too soon! This would be in conflict of what we are seeing from the guys who have actually tested this on the snow. The dyno showed a drop in HP and then it quickly started to rebuild when the valve timing was off. Note the surge. My concern is of the opposite. If the valves are being held completely closed until X rpm it is keeping too much heat around the exhaust valve and port area. Going back to the old way allows the valves to operate gradually from exhaust pressure working against spring pressure.

The more important issue was letting off at WOT the valves really needed to be held open longer. Again, this is accomplished the old way. When they closed immediately it caused a rich condition and the possible burble/stumble some people experienced when getting back on the gas.

The hole thing just seems buggered to me. Who came up with this darn diaphragm operated thing anyway? Japanese two strokes have been using mechanical exhaust valves for ever. Yamaha was using them before they retired the two stoke sled too. I remember dirt bikes in the 80's all using mechanical systems. This system just seems kinda flawed to me, but again I have been exposed to a lot of different two strokes over the years. I've never been in a position until now that I even thought about changing how it worked. Sorta tells a story right there huh.

Monte,

On an interesting note, my 1997 POLARIS 785 PRO Factory Triple Piped Jet Ski had computer controlled, servo box with cables that opened and closed the exhaust valves.

POLARIS offered this ski from 1997-99, engine was Fuji, just disappointed that technology didn't find it's way into the sleds.

 

[Kraven]

I haven't read the whole thread but will chime in anyway. Here's my understanding of how the EV's work in the Cleanfire's:

A. There are only two options for the EV's- 1. Closed with lower exhaust port timing for more bottom end. 2. Open with higher exhaust port timing for more top end.
B. The exhaust springs control the transition from closed to open. You can test that opening RPM on the trail by easing R's up gradually...you will feel a surge when the EV's open.
C. The solenoid opens to let the EV's return to open sooner. Without the solenoid & with the lines plugged you have EV's that function like they did on the Edge 6, 7 & 8's, etc. The advantage of the sloenoid is that the engine gains bottom end quicker when you let off the throttle since the solenoid releases pressure and the valves open instantly. Without the solenoid the valves stay open longer because of latent engine pressure. When does all this matter? example-climbing a hill, go over a log, let off the trigger, back on the trigger. The valves will open in this scenario to get more bottom end power, wouldn't open with the solenoid removed because it takes longer than that to bleed off cylinder pressure.
D. The solenoid drain line lets some excess oil drain, with the solenoid removed you will get more goo build up. Not a big deal, it's there to some extent and the EV's should be cleaned at least every 400-500 miles IMO.
Edit: I fail to see how plugging the valves will open the valves sooner, the solenoid is closed unless R's and TPS dictates that the solenoid should open letting the valves close. There seems to be some misinformation floating around.

Ron,

On the bold, @ 3000 miles on my D7, that "drain line" purge line was bone dry.

On the underlined, it takes all of 10 minutes to plug the "T" with a 5/16" stud and test this for your self.

The sled with the plugged valves accelerates quicker, PERIOD.

If I was trying to sell a pipe mod or a clutch kit I could understand the skepticism, but for a mod that costs ZERO$$$ why all the rhetoric and negativity?

Let each sledder try it for themselves, and if they feel it doesn't benefit them, all they've lost is probably less time than it took to read this thread.

'nuff said.

 

[beefspots]

Ron,

On the bold, @ 3000 miles on my D7, that "drain line" purge line was bone dry.

On the underlined, it takes all of 10 minutes to plug the "T" with a 5/16" stud and test this for your self.

The sled with the plugged valves accelerates quicker, PERIOD.

If I was trying to sell a pipe mod or a clutch kit I could understand the skepticism, but for a mod that costs ZERO$$$ why all the rhetoric and negativity?

Let each sledder try it for themselves, and if they feel it doesn't benefit them, all they've lost is probably less time than it took to read this thread.

'nuff said.

I am defiantly going to try this when I'm able thanks for the input.
Beef

 

[milehighassassin]

Polaris has quite a few options, but since I can't unlock the file to post it I will just give you the popular ones. Springs are measured by Load/lbs @ 1" and Load/lbs @ .630". All the part #'s begin with 7041704-
-1 Blue 4 6
-2 Orange 5.5 8.3
-3 Pink 4.7 7.1
-4 Purple 3.1 4.7
-5 Yellow 2.4 3.6
-6 White 1.6 2.8

I am trying to find the Polaris part number for the YELLOW spring.

7041704-5
and 70417045
Does not work.

Anyone have the complete Yellow part number?

thanks

 

[GMCRMK]

If nothing else this has all been very informative. Thanks for everyone's input.

 

[Kraven]

I am trying to find the Polaris part number for the YELLOW spring.

7041704-5
and 70417045
Does not work.

Anyone have the complete Yellow part number?

thanks

Mile High,

I purchased the yellow springs years ago for my '02 edge, still have 'em, but I may have obtained them from SLP, not POLARIS, I thought I saw a previous post stating that SLP and POLARIS were the same, but not sure??????????

SLP PART #'s (from the 2010 Catalog)

PINK 14-117

YELLOW 14-113

WHITE 14- 118

Hope this helps.

 

[Rich07Dragon700]

I am trying to find the Polaris part number for the YELLOW spring.
7041704-5
and 70417045
Does not work.
Anyone have the complete Yellow part number?
thanks

From HCS racerdave post:
Here's the chart, courtsey of Rogerbzxcr:
http://98.118.8.119:8080/RogerBzXCR/Polaris_Springs.htm

Part Number Color Load @1.0" @.63" Free Length Wire Dia

7041786-01 Red/White 3.0 4.3 1.854 0.0410
7041786-02 Blue/White 4.0 6.0 1.740 0.0450
7041786-03 Green/White 5.0 7.0 1.930 0.0450
--- 7041786-04 Yellow/White 5.0 8.0 1.620 0.0450
7041786-05 Orange/White 7.0 9.0 2.300 0.0460
7041786-06 Pink/White 6.0 8.0 2.110 0.0460
7041786-07 Purple/White 9.0 11.0 2.670 0.0490
7041786-08 Green/Yellow 8.0 10.0 2.400 0.0490
7041786-09 Red/Yellow 3.0 3.7 2.586 0.0370
7041704-01 Blue/White 4.0 6.0 1.752 0.0475
7041704-02 Orange/White 5.5 8.3 1.792 0.0475
7041704-03 Pink/White 4.7 7.1 1.734 0.0460
7041704-04 Purple/White 3.1 4.7 1.726 0.0400
--- 7041704-05 Yellow/White 2.4 3.6 1.734 0.0370
7041704-06 White 1.6 2.8 1.537 0.0360

This may be a older chart, as I have also had this for a while in shop manuals. The colors may be different now?
xxxxxx
Good luck; Rich

 

[SD Coyote]

I am trying to find the Polaris part number for the YELLOW spring.

7041704-5
and 70417045
Does not work.

Anyone have the complete Yellow part number?

thanks

The polaris # is 7041704-05 for the yellow spring.

 

[adam5187]

I have a 2007 dragon rmk, and I was having issues with the exuast valves sticking, giving me a bog. I was using ves gold polaris oil and was told that it is terrible for gumming up the actual slide. I have since swithed to shell synthetic(just what I use) and the valves stay alot cleaner, and don't stick. You should clean the valves at the beginning of the season.

 

[milehighassassin]

Man

I still can't get any of those part numbers to work.

 

[Flange509]

Just checked mine and their the orange ones,look new so they were more then likely changed with the update. Going to try the pink ones, number I found for the pink was 7041704-03.I ride at 9-12k so I think I could use lighter ones, getting 8100 rpms but takes a while to get there and needs a little more. 08' D8

 

[Danbot]

Ive been following this topic and decide to plug mine at the T and try it with stock springs. While I was setting it up I found a rubbed through hole in one of the hoses underneath where it couldn't be seen. Who knows how much power I could have been missing last year.... or the year before,

 

[Ron]

Sorry but some of us have tested head to head on your (see bold) with plugged valves and there is zero diff in acceleration. Now if your solenoid isn't working then sure. I have my sled stock and it pulls hard at any speed.
I also have a drip bottle and there is oil that drains from the valves. It enters the EV's from the hole in the cyclinder and has no where to go unless you let it drain. Have a little experience with the non solenoid sleds since I owned an 02, 03 & 05 Edge. If you want some performance gain there may be some keyboard tuning but the old less sophisticated methods still seem to work too. If you don't do head to head comparisons then you really haven't tested.

Ron,

On the bold, @ 3000 miles on my D7, that "drain line" purge line was bone dry.

On the underlined, it takes all of 10 minutes to plug the "T" with a 5/16" stud and test this for your self.

The sled with the plugged valves accelerates quicker, PERIOD.

If I was trying to sell a pipe mod or a clutch kit I could understand the skepticism, but for a mod that costs ZERO$$$ why all the rhetoric and negativity?

Let each sledder try it for themselves, and if they feel it doesn't benefit them, all they've lost is probably less time than it took to read this thread.

'nuff said.

 

[Ron]

So for those with the 800 motor, what is the color you should use at higher elevations? Seems white is the lightest spring rate, but I keep hearing yellow. What is the FULL POLARIS part number?

Say 8000' +

Just a thought here....maybe compare light springs to taller gears in a car. There is no right answer it depends on some other factors. The lighter springs let the EV's open quicker, good for drag racing, lower altitudes where you have more power, lake racing, trail riding etc. But at higher altitude you lose HP, and running in deep snow have more "drag" from rolling resistance from snow. You need to be in "low gear longer", will likely get a bog if the valves open too soon. Clutching comes into play but the reason for the valves is to let you run higher port timing= more top end power and still have enough low end power when the valves are closed.
A weak analogy would be running a drag race with a manual tranny in a car and shifting from first to third or forth, by passing second gear. It's a no brainer in a vehicle so why do you want to shift up too soon with your sled. If all you do is ride trails sure go for the light sping, but in deep snow you need the low end grunt a little longer. That's the balancing act with when EV's open because it also affects when they close and how soon you get the torque back again.

 

[Kraven]

Real world testing

Sorry but some of us have tested head to head on your (see bold) with plugged valves and there is zero diff in acceleration. Now if your solenoid isn't working then sure. I have my sled stock and it pulls hard at any speed.
I also have a drip bottle and there is oil that drains from the valves. It enters the EV's from the hole in the cyclinder and has no where to go unless you let it drain. Have a little experience with the non solenoid sleds since I owned an 02, 03 & 05 Edge. If you want some performance gain there may be some keyboard tuning but the old less sophisticated methods still seem to work too. If you don't do head to head comparisons then you really haven't tested.

Ron ,
(on the bold) I've tested my D7 back to back with my bud's D7, clamped off the hoses with vise grips, the plugged hose sled accelerates quicer, PERIOD (as previously stated) other riders have p.m.'d me last season with similar results. Casey , Team Bayport Racing also plugs his as well.

I might know a little bit about fast accelerating toys and real world testing.

Way back in 1984 when I was 22, I built a '72 Dodge Colt, Full Tube Chassis car in my garage, another in a series of 1/4 mile drag cars, Strange Struts, 4-link rear, Koni Coil Overs externally adjustable, 15" x 33"s, Did all my own Fabricating, including Aluminum Motor Plates, Mid-Plates to Accomodate a 426 Wedge Motor, Trans mounts, set-up the Narrowed Dana 60, built the Torqueflite Trans, Engine, etc, Lexan Widows, Quick Release Dzus Fasteners and Quick Release Pins Everywhere, 2220 lbs, with driver.

Leaving the starting line plastered to the back on my seat carrying the front wheels in the air and stopping it from 137+ m.p.h. by pulling the parachute, PRICELESS!!!

I know what it takes to be fast, and know what it takes to make and build things right.

And I might have even learned a few things since then.









Circa 1982, 71 Dodge Demon, Mild 426 Wedge, Aluminum 4-speed, Narrowed Dana 4.56, 12.2 x 31.25 Firestones, Polished Centerlines, Aluminum wheel tubs, Super Stock springs located inside the frame rails, Alston Ladder Bars and Floater, Alston 10 point Roll Cage, Fiber Glass Hood, Fenders, Deck Lid. 3070 lbs. w/o driver. ALL fabrication done by me in my garage back when I was 19 & 20 years old. Drove it on the Street as well as the track.



Sorry, what was that about keyboard tuning?????????? lol

 

[RookieTurboGuy]

I do not see how this could improve accelleration on a WOT drag race. It may affect holeshot in some way but that's it. An improved holeshot may actually be because of reduced hp with the valves opening sooner, resulting in the track not blowing out as easily. I tend to agree with Ron on this one.

 

[Ron]

Why all the bragging about non sledding toys, didn't criticize your knowledge, just don't agree with your conclusions. I could list all my experience and accomplishments but doubt the readers are interested, they come to this forum for info.
Lets put this in perspective....You ride low elevation, maybe want a drag race sled at least that seems to follow your logic? SW has a high percentage of high elevation riders and most of us could care squat about building a lake racer or drag race sled. We know that when you do that your sled won't work very well in deep snow or climbing hills.
For the sake of argument let's say you are correct and you gain a sled length bypassing the solenoid. What do you lose? Does SLP or Carl's rec. plugging the EV's for better performance? Why don't they? This came up in 08 and we tested two sleds-plugging the EV drain lines made no difference in performance...at our altitude around 7000 feet.
If your sled run's better for you then that's great. But this isn't necessarily good for everyone else, and it's not a revelation either. It was one of the early mods tested in 08.

Ron ,
(on the bold) I've tested my D7 back to back with my bud's D7, clamped off the hoses with vise grips, the plugged hose sled accelerates quicer, PERIOD (as previously stated) other riders have p.m.'d me last se ason with similar results. Casey , Team Bayport Racing also plugs his as well.

I might know a little bit about fast accelerating toys and real world testing.

Way back in 1984 when I was 22, I built a '72 Dodge Colt, Full Tube Chassis car in my garage, another in a series of 1/4 mile drag cars, Strange Struts, 4-link rear, Koni Coil Overs externally adjustable, 15" x 33"s, Did all my own Fabricating, including Aluminum Motor Plates, Mid-Plates to Accomodate a 426 Wedge Motor, Trans mounts, set-up the Narrowed Dana 60, built the Torqueflite Trans, Engine, etc, Lexan Widows, Quick Release Dzus Fasteners and Quick Release Pins Everywhere, 2220 lbs, with driver.

Leaving the starting line plastered to the back on my seat carrying the front wheels in the air and stopping it from 137+ m.p.h. by pulling the parachute, PRICELESS!!!

I know what it takes to be fast, and know what it takes to make and build things right.

And I might have even learned a few things since then.









Circa 1982, 71 Dodge Demon, Mild 426 Wedge, Aluminum 4-speed, Narrowed Dana 4.56, 12.2 x 31.25 Firestones, Polished Centerlines, Aluminum wheel tubs, Super Stock springs located inside the frame rails, Alston Ladder Bars and Floater, Alston 10 point Roll Cage, Fiber Glass Hood, Fenders, Deck Lid. 3070 lbs. w/o driver. ALL fabrication done by me in my garage back when I was 19 & 20 years old. Drove it on the Street as well as the track.



Sorry, what was that about keyboard tuning?????????? lol

 

[thefullmonte]

Ron and Kraven, I just want to say you both have very valid points with this topic. With your input it helps members make better informed decisions on such things. Remember, there are often times multiple ways of getting to the same result. As well, different variables in riding styles and riding location. Just keep a smile in there guys it keeps everyone happy
All I can say is that it is a simple test and not an extravagant modification to your sled. So, it is probably worth testing personally if this thread has struck your interest.
Lost rpm and valves not opening completely may call for a different spring whether you plug the lines or leave them connected. The more I research this the less likely I think it is that the orange spring can be working right at high altitude. JMO If the spring is too stiff for your altitude it either won't open completely or has the potential to flutter.
As I mentioned before my complaint is that the valves are either open or closed. The majority of two stroke exhaust valve systems still in use today function as a variable type more like the old way. A person doing a lot of crawling through the trees with these valves completely closed is going to create a lot of heat in the valve and exhaust port area. Probably not an issue if climbing at WOT, but variable low RPM has me concerned.
A person would have to tap into the signal wire to the solenoid with a volt meter or light and run the sled to see exactly what rpm they are opening at. A simple process if someones sled wasn't tore down.
FYI, I already found some interesting stuff that I can't believe was never mentioned on here. I will be posting pics soon.

 

[Flange509]

Thats what I was thinking, I ride at 9-12k and it has the orange spring which has the highest rate.My rpms vary from day to day at at the same altitude,what im hoping is going to a lighter spring will make it more consistant with rpms.
My KTM came with three differant springs for the valve and an adjustment preload, changing these made a big differance on power output,lots of fun to play with.