Power Valve: How to tell if it's fully open and "rounded scraper"

Yiotta

New member
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Feb 26, 2021
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Location
New Hampshire
Hello...noob here...thanks for the excellent resource. I'll contribute what I can but owning a 2002 I'd think most everything is sufficiently covered here already.

I just bought a 2002 SXV with 5K+ miles and I'm geeking out this morning reading up on it's tech and maintenance.
I'm not actually performing maintenance now because the previous owner was meticulous with it so I'm just making sure I know exactly how to do common tasks before I undertake them.

I've been looking for over an hour here, google and youtube and can't find the answer so here goes.

1. Regarding YPVS adjustment: I found the Service Manual Supplement and some PV posts that mentions when adjusting "...the YPVS valve should be fully open"
But no where has anything told me how to determine if it's fully open or not.

My assumption is that when the 2.5mm allen keys are snug behind the valve housing, assume the port is fully open so button up that YPVS and move on to the next one.

I hate assumptions, so is this all I need to do or is there a way of actually verifying the valve is fully open that I haven't come across yet?

2. 'Rounded scraper': when cleaning up the PVs, the manual mentions to use a rounded scraper. The manual diagram makes it look like a wood chisel. OUCH...not on curved aluminum.
Consensus seems to say use some carb cleaner on a scotchbrite...DON'T LET THE CARB CLEANER DRIP INSIDE THE VALVE HOUSING AND MESS UP THE GASKET AND ORING. DON'T EVER USE OVEN CLEANER or other harsh cleaners....PV is coated aluminum so care needs to be taken not to remove the coating. Wipe down with clean rag. Any remaining deposits need to be scraped off. What is the best tool for this job? I see people using screwdrivers, razor blades, etc....not ideal if you ask me. I'm thinking like my spark plug gapper...the one like a swiss army knife, unlike other tools I see others using, it's got rounded edges and is somewhat flexible. is this ideal? If not, anyone else have a tool that better matches the curvature of the valve?

Like this:

bladed_spark_plug_gapper.jpg

Comments much appreciated.
 

For cleaning scrape off what ya can with a razor blade then carb cleaner and scotch brite pad. As far as valves they are either open or closed if I remember right. When running just hit the choke and get sled to idle down, once below 900 rpm it will open valves and shut sled off! Then simply mark this position on servo so you know where it’s at. Great write up in tech section. https://totallyamaha.com/snowmobile...ng Power Valves/Setting Your Power Valves.htm
 


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