Another little trick for the 900

[danduvall]

whats all this "hose block off" "selinoid" mumbo-jumbo you guys are talkin about? this mod looks like something i wanna do! but i feel kinda lost here!

 

[BIGGDAWG]

whats all this "hose block off" "selinoid" mumbo-jumbo you guys are talkin about? this mod looks like something i wanna do! but i feel kinda lost here!

there were a couple of threads last year. but here it is.

quite a few of us have disconnected the ev solenoid : the hoses that go to the exhaust valves and plugged the port on the exhaust valves. What this does is let your valves work on cylinder pressure only and not snap open at 6500 rpm. so the valves open more gradually and earlier increasing midrange. you dial them in by playing with the ev springs but my 975 is working with the purple stock springs. basically it makes it like the first generation exhaust valves on the 2002-2005 700 and 800 twins.

 

[Danbot]

So what size bit are we to drill the angled hole, for us plugged hoses guys?
I suspect this is well worth doing even if a guy doesn't feel like adding the seal, it's still going to be an increase in signal to the bellows.

A thought.....
If the valve bushing is prone to leakage, since it is open to the exhaust port area underneath.... wouldn't it leak more exhaust pressure up into the bellows?? rather than leaking signal back into the exhaust? or is there a venturi effect in there

 

[Danbot]

I thought I would mention since it came up that I am also running stock valve springs with my plugged VES hose mod with good results. With my loud mbrp can I can hear quite clearly that it runs with true variable exhaust valves instead of the light switch stock setup. More lower midrange response was my gain from this free trick.

 

[ghostwhite]

Thanks for the info guys, gotta bring these things up when you figure them out, it is part of what makes the tractor community great!

I thought I would mention since it came up that I am also running stock valve springs with my plugged VES hose mod with good results. With my loud mbrp can I can hear quite clearly that it runs with true variable exhaust valves instead of the light switch stock setup. More lower midrange response was my gain from this free trick.

I forget again, what springs do you run when plugged?

 

[guidoxpress]

I forget again, what springs do you run when plugged?

stock they run the "purple" spring..not sure what the rate is..

but i was told by a fellow 900 owner with BIG mod sleds, to use the SLP White Exhaust Valve Spring - Load: 1.6 lbs @ 1" and 2.8 lbs @.63"

here is the link...only $2-3 more then the polaris springs..

http://startinglineproducts.com/catalog.cfm?pageID=detail&catalogID=3&catID=18&productID=155

so these are what i will be using in the 975, and the 900...and keep tehe stocks in the wifes sled

 

[ghostwhite]

I wish I could remember what I put in mine... Wanna swing by my house and check?

 

[guidoxpress]

I wish I could remember what I put in mine... Wanna swing by my house and check?

yeh sure...i need another sled to wreck..ill be on my way to your house..lol.

 

[diamonddave]

Are you guys opening up the feed by 10 or 20% ??

 

[BIGGDAWG]

Are you guys opening up the feed by 10 or 20% ??

i did i drilled mine 3/32

 

[Sxrlar]

So you guys are disconnecting the hoses from the top of the valves to the solenoid, do you then just cut a hose with a plug in the end of it and place over the top of the port coming out of the valve? Do you do anything more with the solenoid? Will this work on a 07 600 rmk also?

 

[BIGGDAWG]

So you guys are disconnecting the hoses from the top of the valves to the solenoid, yes

do you then just cut a hose with a plug in the end of it and place over the top of the port coming out of the valve? yes


Do you do anything more with the solenoid? no just take the hoses off. leave it plugged in to the ecu so you dont set codes


Will this work on a 07 600 rmk also? yes it should[/

 

[Danbot]

I drilled out my feed holes to 3/32" today, but I am going to skip the seal installation (for now anyways, my bushings are in very good shape). I'm excited to see results from this.
I have also changed my hose plugging method for this year. Now I connected a single clear hose from one valve nipple to the other .

 

[Danbot]

I have 2 variations of this mod on the go for testing. I have spare ves valve bodies and so.... one set I drilled according to the instructions above and are awaiting a set of seals.
The second set I simply drilled the original pressure feed holes out to 3/32" for extra signal. This is how I will start the season.
My third set I will leave stock in case something doesn't work out and I need to go back to stock.

Once I have the seal installed set ready I plan to do some swapping in the mountains to see whats up.

 

[sno_mo_racer]

I have my valves off and found the right size seal from a Dynaline O-ring kit my father has. It is size R-20(inside diameter is "3/4 and outside diameter is "1. On the pic uploaded from up top I just made a red circle on the spot it fits. Is thst the right place for the seal? Am just going to drill the holes and just wanted to make sure I have fitted the seal in the right spot or should the seal go on the outside and not in that lip?

 

[sno_mo_racer]

Well just did the 1 angled hole and plugged the valves off and took the solenoid off. My 3/32" bit was broken so used the next size up 7/64". Put the seal on also and went for a ride since we have snow(been riding for a couple weeks now). Boy does it make a difference. Opens up earlier now and makes it more responsive. Haven't gone WOT though as we are just getting over a blizzard and that made some big drifts.

On a side note also- now when I grab the throttle from a stand still has a slight bog. Not all the time but every other time. Did I do something wrong or maybe because I had to go one size drill bit bigger? I went from stock to this mod with the valve stems plugged.

 

[Danbot]

Your valves may be opening too early now, easiest solution would be to install stiffer VES springs, or in a pinch I'm sure one could shim the spring a little somehow.

 

[sno_mo_racer]

Your valves may be opening too early now, easiest solution would be to install stiffer VES springs, or in a pinch I'm sure one could shim the spring a little somehow.

SPRING COLOR LOAD @ 1 INCH(LBS.) LOAD @ .630INCHES (LBS.)


7041704-01 Blue 4.0 6.0
7041704-02 Orange 5.5 8.3
7041704-03 Pink 4.7 7.1
7041704-04 Purple 3.1 4.7
7041704-05 Yellow 2.4 3.6
7041704-06 White 1.6 2.8

So how much stiffer do I need to go? Stock is purple and the local store messed up on my order and sent blue. Would that be too stiff?

 

[Danbot]

If your chart is correct, Blue seems logical to try. Either way... you get to be the test mule! lol thank you sir
Let us know what you find!!

 

[sno_mo_racer]

Thanks Dan. unfortunately they are closed til monday now so maybe tomorrow I will try see if I have the right washers and see if it will work by shimming it a bit.