How do you check to see if the power valve (exhaust valve) is working properly?

M

mx100

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Jun 16, 2010

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Livingston, MT.

• Dec 11, 2012

• #1

When you wack the throttle on the trail, the rpm's jump to 8000,(track spinning?) then fall to 7000 very quickly. In the deep snow is only pulls 7000ish. Both clutches are freshened up with all new parts and springs. A reliable source says it's the secondary not back shifting, or the exhaust valve is not opening properly. I believe the secondary is ok, but I will pull it apart just to double check the spring has been wound 1/3 of a turn. I am wondering the best way to check the powervalve? And any other ideas? Thanks.

 

B

BU1

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Jun 9, 2002

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MN

• Dec 12, 2012

• #2

Need more info.

What sled?
What helix and spring in secondary?
Pin weight, ramps and spring in primary?

Classic symptom of needing a shallower angle helix for starters.

 

M

mx100

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Livingston, MT.

• Dec 12, 2012

• #3

01 summit 800. Both clutches are totally stock, and just rebuilt. Stock helix and springs.

 

R

Red-eye

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Dec 3, 2008

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Sparwood, B.C. Can.

• Dec 12, 2012

• #4

Pull the covers off and rev the sled. They should react both the same.

 

R

rstephen0424

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Mar 5, 2012

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• Dec 13, 2012

• #5

check / replace the big bushing in your secondary when they start getting worn out the secondary wont shift proper,

 

M

mx100

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Livingston, MT.

• Dec 13, 2012

• #6

rstephen0424 said:

check / replace the big bushing in your secondary when they start getting worn out the secondary wont shift proper,

Click to expand...

I will check the bushing. The clutches were fairly worn out when I rebuilt them, so the bushing could be worn out.

I pulled the caps off the exhaust valves, and they both move at the same time, when the throttle is hit. I can pull on the white plastic caps and pull the valve out a little way, but it is a little stiff. I am sure I cleaned them when I installed new pistons last year, but I will pull them out just to check. Where should the red caps that put tension on the spring be set? They are 11 clicks from being bottomed out.

Any other idea's? Thanks.

 

B

BU1

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MN

• Dec 14, 2012

• #7

Caps should be screwed in all the way. Keeps the rave from opening too soon.