Plugged Exhaust Valves?

[Danbot]

I had the chance to do some testing with this yesterday, here's my findings:
06 900 rmk, 4000 - 6000', stock VES springs
My engine revs up quicker with the valves plugged for sure, I tried it in several situations back to back, and no matter where I was or what I was doing the RPM's built up noticeably quicker with the hoses plugged ( stud between the 2 hoses ) Additionally, when using 1/2 throttle and below, judging by the exhaust note, the valves seem to be fully capable of being truly variable.

I will be leaving my hoses plugged, and I see no reason to try any different springs. The valves work awesome now!

I have had time to swap from plugged hoses and solenoid control in many different situations and elevations from 3000 - 8000 feet all still on my stock springs. My feeling about this is still the same... the sled just seems to run crisper and build up from low to high rpm faster with the hoses plugged.
Rolling into the throttle on a packed trail it is noticeable that they open sooner, and judging by exhaust note they really seem to be at partial opening at times.
cheers

 

[thefullmonte]

I had been meaning to post some pics of this. After talking with a couple of professional Polaris engine builders I am more convinced than ever about this. Here is how I did mine.
FYI, this requires the use of some steady hands. There are much easier ways of doing this.

I used a 5mm-0.80 tap and set screw. The size was right and commonly available. A #19 drill bit is recommended for this. I also suggest you tape off the bit to the length of the set screw. This way you will only tap it so far and you can bottom the set screw.

The set screw is flush with the tube for easy access. I chose blue loctite for this just in case it has to be removed. I will also put a rubber automotive cap over the end. I try not to take any chances. Better to be thorough right.
All hoses are removed and I zip tied flow right material over the ends of the solenoid. Figured it would be good to filter some air through it so it doesn't fail from condensation or belt dust building up in it. Who knows, but again that's just me being cautious.

 

[pager]

Valve maint.

Lots of good info...gonna definately try it out... curious how often should valves be cleaned run VES gold and valves seem to always be cakes with thick black oil, is this the norm i know the valve opens and closes properly and the solenoid functions or am i just not on the throttle enough. Also when servicing i notice the moisture traps in the black cover rusting the spring how often should they be replaced

 

[just-pinch-it]

I had been meaning to post some pics of this. After talking with a couple of professional Polaris engine builders I am more convinced than ever about this. Here is how I did mine.
FYI, this requires the use of some steady hands. There are much easier ways of doing this.

I used a 5mm-0.80 tap and set screw. The size was right and commonly available. A #19 drill bit is recommended for this. I also suggest you tape off the bit to the length of the set screw. This way you will only tap it so far and you can bottom the set screw.

The set screw is flush with the tube for easy access. I chose blue loctite for this just in case it has to be removed. I will also put a rubber automotive cap over the end. I try not to take any chances. Better to be thorough right.
All hoses are removed and I zip tied flow right material over the ends of the solenoid. Figured it would be good to filter some air through it so it doesn't fail from condensation or belt dust building up in it. Who knows, but again that's just me being cautious.

Works just like described. Good HTD post!

 

[otterpoo]

When I plugged the hoses on my 05 900 I cut the hex end off of a 1/2 inch bolt and attached them together held even more secure with some O clamps.
With new bellows, gaskets, purple springs, and a good cleaning I managed to snap a few picks clean off and get a 115 track speed. I was also impressed with it getting up to speed more quickly and a better throttle response. Before this I was having issues of track speed topping at 92 and low and mid response.

 

[600xc4me]

Well I tried this on my D8 as well. At 1500'. with stock springs this time. Not a good idea. Mid range is all over the place, bogs in the mid range quite badly. Put them back on and problem solved. So at low elevation don't try it unless you put in stiffer springs, then it works great here.

 

[sledneck_03]

i did this and its awesome at 1500 feet, stock springs. it screams now and accelerates faster.

 

[600xc4me]

i did this and its awesome at 1500 feet, stock springs. it screams now and accelerates faster.

Mine did as well for two rides. After that it sucked. NO idea why it would get worse with time, but that's what it did with mine.

 

[thefullmonte]

Just did my first break in ride on the new motor. EV plugged with the SLP PC V map installed. So I have the two working together.
Unbelievable, noticeable increase in throttle response at all positions. Much improved through the mid range. I'm lifting skis on ice when it could barely do it before on packed snow. This was on a lake in MN with about 6-8" of soft snow. Sounded much healthier too. I can't wait to get it out where I can let the auto tune do it's thing. I think it's only going to get better yet.

 

[metallicat]

are you guys plugging the leftover solenoid hoses also?? I see monte just put flo rite material over them. is there a reason they still need to breathe? when i tried this, i plugged all of them off and it did not help just as 600xc4me said. it made it worse. i'm at low elevation also.

 

[beefspots]

I had been meaning to post some pics of this. After talking with a couple of professional Polaris engine builders I am more convinced than ever about this.

Monte,
So please elaborate about your conversations with the polaris engine builders. If you would please.
BS

 

[thefullmonte]

I had been meaning to post some pics of this. After talking with a couple of professional Polaris engine builders I am more convinced than ever about this.

Monte,
So please elaborate about your conversations with the polaris engine builders. If you would please.
BS

Well, the one gentleman builds some of the motors for the Polaris snow cross team. I noticed on his test mule sled that they were capped. Which we can probably assume all the race sleds are. So, I asked him why he did that. He said the solenoid control is nice IF you actually had the ability to control it. Meaning if you could tap into the ECU and control when it opens and closes it would be nice. In it's current state it isn't working to it's potential (or properly). I think we can all agree it is only there as a means for Polaris to meet EPA regulations.
Remember, exhaust valves on two strokes are just a means of increasing low end response so manufactures can create pipes that focus on higher RPM horsepower. Most applications dirt or snow open almost immediately.
The other conversation was about the lack of cooling around the exhaust port. This lead into how the valves are being held closed too long and retaining excessive heat around the exhaust port. So with the solenoid holding the valves closed it is aggravating a cooling issue that is already inherent to the guillotine style exhaust valve.
Although, it is no question in my mind that they should get plugged. Many factors do come into play. Riding style might dictate that the valves are hardly ever ever closed anyway. Thus never having a worry or issue. My concern was always slower speed boon docking or even trail running where you might be around 6000 RPM for a length of time. This would obviously build quite a bit of heat with the smaller port opening and lean fuel mapping. God forbid if you ever had to tow out another sled. That could be catastrophic. Plus I really like the side effect of the increased throttle response.
Hope that answers the question. I was surprised they had the same thoughts and concerns I was having. Guess I'm not a total idiot after all.

 

[skibreeze]

This thread is worthless after 75 posts!

 

[otterpoo]

Living in the flat lands I search out any and all varieties of riding and terrain(trails, lakes, goat paths, logging roads) that the area has to offer. With my riding style I really like a good throttle response and low-mid RPM range power. In an instant I find myself riding pack trail to the unbroken trails and roads for some fresh tracks. I plugged my valves mid way through this season and noticed a difference instantly in every situation of riding. Again I ride in very low altitude for most of the season and am an on/off throttle rider and WOT on the trails and lakes. Gunning the throttle to bang a mogul(bump) or a fallen tree was made even easier and more fun. Since the plug, my skis tend to lift from the ground with very little effort and I reach top track speed and RPM range in a shorter distance, and also have noticed lower temperature on the gauge.
This was done on my 05 900 Switchback which is bone stock minus a few free mods I learned about from this forum.
When testing and comparing differences in mods I don't see the point of running against a test sled. There are way to many variables when comparing how 2 different sleds are running with one another. The gauges and the feel of the sled seem to be the most accurate when you don't have the access to a dyno test.
Go buy a cheap small set of Vise Grips, plug the valves, and make an opinion on your own.

 

[Kraven]

Living in the flat lands I search out any and all varieties of riding and terrain(trails, lakes, goat paths, logging roads) that the area has to offer. With my riding style I really like a good throttle response and low-mid RPM range power. In an instant I find myself riding pack trail to the unbroken trails and roads for some fresh tracks. I plugged my valves mid way through this season and noticed a difference instantly in every situation of riding. Again I ride in very low altitude for most of the season and am an on/off throttle rider and WOT on the trails and lakes. Gunning the throttle to bang a mogul(bump) or a fallen tree was made even easier and more fun. Since the plug, my skis tend to lift from the ground with very little effort and I reach top track speed and RPM range in a shorter distance, and also have noticed lower temperature on the gauge.
This was done on my 05 900 Switchback which is bone stock minus a few free mods I learned about from this forum.
When testing and comparing differences in mods I don't see the point of running against a test sled. There are way to many variables when comparing how 2 different sleds are running with one another. The gauges and the feel of the sled seem to be the most accurate when you don't have the access to a dyno test.
Go buy a cheap small set of Vise Grips, plug the valves, and make an opinion on your own.

Exactly!!

 

[Kraven]

Mine did as well for two rides. After that it sucked. NO idea why it would get worse with time, but that's what it did with mine.

I suspect there's something else going on

1) LEAN at mid-range and the earlier opening leans it out further

2) Torn exhaust bellow

 

[600xc4me]

I suspect there's something else going on

1) LEAN at mid-range and the earlier opening leans it out further

2) Torn exhaust bellow

That's what I thought, But I have a PC5, and I checked my VES bellows. When I put them back on it fixed the problem. Have 200 miles since and still working good since I put them back on.

 

[Kraven]

That's what I thought, But I have a PC5, and I checked my VES bellows. When I put them back on it fixed the problem. Have 200 miles since and still working good since I put them back on.

600 XC,

Thanks for the feed back

Is your PC-5 richened up in the mid-range??

Or did you try installing some positive #'s in the mid range w/hoses plugged??

My D7 is 7-10% RICHER starting at 5250 R.P.M. and up in the 40% Throttle opening.

My bud's 2007 D7, NO PC-3, and we just plugged his exhaust valves last weekend, same positive results AT 600' elevation, warmer weather

Another guy that doesn't ride with us just did his STOCK 2006 600, POSITIVE results on performance, however at 1200' in the U.P. over 100+ miles of trail riding, claims gas mileage suffered.

In all cases, we kept the SAME exhaust valve springs and they were tested at the lower (1200') elevation

I'd like to get to the bottom of your set-up as to why you were experiencing those problems.

Any other thoughts/possibilities?????????

 

[Grizzly Mtn]

oil coming out the discharge tube??

09 800 dragon RMK I just noticed alot of oil in my belly pan coming from the exhaust valve discharge tube? Any ideas why? The exhaust billows look good. Could that control valve not be working?? Looking for ideas....

 

[psyfox]

Hi
Bringing this old thread up a bit cause im a little dumb
so i have a -06 SB 900 and was thinking of plugging the exhaust valve, that wont cause any future problems or danger of braking stuff right? (im riding mostly flatlands ) so as i understand it the easiest way of plugging it is in the T between the VES and also do i have to change springs or will it work plugged without springchange

hope you guys get what i mean

thanks a lot