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polarisjunkymike

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Reply with quote  #1 
Hey guys picked up an 04 predator 500 for a steal because it "needs work". It ran and had power but smoked like a two stroke. So i pulled the top end apart to investigate the cause. Turns out it was rings and valve guide seals. So of course it's getting a 12.5:1 piston instead of just rings! My question is does anyone know the valve guide clearance spec? I'd like to measure it before I replace the seals and still have issues. Thanks for the help, mike
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99 scrambler 400
99 trailblazer 250
04 predator 500
polarisjunkymike

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Reply with quote  #2 
Any advise would be great. Was planning on using my dial indicator that I used to set backlash on diffs, was planning on going with the .002-.003 rule of thumb so an overall amount of play no greater than .006. But would rather see if anyone had a spec
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LEOGM5150

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Reply with quote  #3 
Intake .006 (.15 mm) =/- .0019 (.05 mm) 

Exhaust .010 (.27 mm) +/- .0019 (.05 mm) 

Intake not more then .0069 (.20 mm) but not less then .0051 (.10 mm). 

Exhaust not more then .0119 (.32 mm) but not less then .0081 (.22 mm) 

don't just guess on this making these clearances too tight. this will result in piston to valve contact and usually a destroyed top end. i hope this helps.

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FROM: POWELL WYOMING USA

MY GREATEST FEAR IS THAT WHEN I DIE MY WIFE WILL SELL MY TOYS FOR WHAT I TOLD HER I HAVE INTO THEM...

2014 POLARIS RZR 4 900 EPS
2012 POLARIS RZR 4 900 XP
2008 POLARIS RZR 800
2008 POLARIS OUTLAW 525S LE
2007 POLARIS OUTLAW 525 IRS
2000 400 RCR TWO STROKE SCRAMBLER
2001 400 TWO STROKE SCRAMBLER
2005 SKI DOO 1000 TWO STROKE SAND SLED
polarisjunkymike

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Reply with quote  #4 
Isn't that the valve adjust spec? Needed that specs too lol but the first spec I'm looking for was for radial play of the valve in the guide to see if guide replacement is necessary. Appreciate the help leogm5150
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99 scrambler 400
99 trailblazer 250
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Reply with quote  #5 
ah ha ok sorry about that.

here is all the info in the service manual i can find about that.

Valve Stem Diameter:
Intake: .2343-.2348I (5.950-5.965 mm)
Exhaust: .2341-.2346I (5.945-5.960 mm)

NOTE: Valve seat width and point of contact on the
valve face is very important for proper sealing. The
valve must contact the valve seat over the entire
circumference of the seat, and the seat must be the
proper width all the way around. If the seat is uneven,
compression leakage will result. If the seat is too
wide, seat pressure is reduced, causing carbon
accumulation and possible compression loss. If the
seat is too narrow, heat transfer from valve to seat is
reduced and the valve may overheat and warp,
resulting in burnt valves.



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FROM: POWELL WYOMING USA

MY GREATEST FEAR IS THAT WHEN I DIE MY WIFE WILL SELL MY TOYS FOR WHAT I TOLD HER I HAVE INTO THEM...

2014 POLARIS RZR 4 900 EPS
2012 POLARIS RZR 4 900 XP
2008 POLARIS RZR 800
2008 POLARIS OUTLAW 525S LE
2007 POLARIS OUTLAW 525 IRS
2000 400 RCR TWO STROKE SCRAMBLER
2001 400 TWO STROKE SCRAMBLER
2005 SKI DOO 1000 TWO STROKE SAND SLED
LEOGM5150

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Reply with quote  #6 
more info that might help.

Valve Seat Contacting width In Std 1.5255

__________________
FROM: POWELL WYOMING USA

MY GREATEST FEAR IS THAT WHEN I DIE MY WIFE WILL SELL MY TOYS FOR WHAT I TOLD HER I HAVE INTO THEM...

2014 POLARIS RZR 4 900 EPS
2012 POLARIS RZR 4 900 XP
2008 POLARIS RZR 800
2008 POLARIS OUTLAW 525S LE
2007 POLARIS OUTLAW 525 IRS
2000 400 RCR TWO STROKE SCRAMBLER
2001 400 TWO STROKE SCRAMBLER
2005 SKI DOO 1000 TWO STROKE SAND SLED
polarisjunkymike

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Posts: 8
Reply with quote  #7 
Not quite what I was looking for but I don't think I'm gonna be able to find the spec so I might just pop some new guides in to be sure. The problem is the thing smoked terribly and the exhaust valves are tweaked. Not enough to loose a bunch of compression but leak down was 37%. When I tried to lap the valves(total fail) I popped the exhaust valves in the drill and sure enough ever so slightly tweaked. The valve guide seals were old and obviously leaking. When you put the valve in the guide and hold it in the open position(+/- just in the area) I can rock the valve more than I would like and more than I can on the intake valves. When building engines there's something's I do by feel, valve work is not one of them lol. I was just looking for a spec to compare to. I've put a lot of valves in engines before and done a lot of beadwork and I'm probably over analyzing this they are tighter than some of the heads I've put together on budget builds and they were fine and run problem free to this day but I had specs to compare to. This is my first polaris 4stroke build so I'd like to do it by the book to get a feel for it so I know what I can and can't get away with. Might just throw some seals on the guides and see what happens, it only took 45 mins to get the head off with it being the first time I've had one apart, so I'm assuming if it does need guides it will take even less time now that I know how it comes apart. Ill measure the amount of play I have and run it then I can post if that measurement is good or no good lol, thanks for your time and help leogm5150
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99 scrambler 400
99 trailblazer 250
04 predator 500
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Reply with quote  #8 
yeah i am sorry i don't know that spec or where to find it. i would replace them myself if it was mine.
__________________
FROM: POWELL WYOMING USA

MY GREATEST FEAR IS THAT WHEN I DIE MY WIFE WILL SELL MY TOYS FOR WHAT I TOLD HER I HAVE INTO THEM...

2014 POLARIS RZR 4 900 EPS
2012 POLARIS RZR 4 900 XP
2008 POLARIS RZR 800
2008 POLARIS OUTLAW 525S LE
2007 POLARIS OUTLAW 525 IRS
2000 400 RCR TWO STROKE SCRAMBLER
2001 400 TWO STROKE SCRAMBLER
2005 SKI DOO 1000 TWO STROKE SAND SLED
polarisjunkymike

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Posts: 8
Reply with quote  #9 
Im thinking I'm going to measure and run these just for the simple fact of have a measurement to use in the future. Been a pain and I can't believe there isn't a spec on these so I think I will post measurements and results for members future builds. Like I said it takes no time at all to pull these motors apart, that and I've got 3-4 months until riding season. And until this ride is done I rebuilt the scrambler couple months ago and with the new intake, top end pipe, clutch kit, fresh cyl. And wiseco piston, she rips and the 4wd is nice in the snow. So there is no rush to get this thing back together
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99 scrambler 400
99 trailblazer 250
04 predator 500
polarisjunkymike

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Posts: 8
Reply with quote  #10 
So finally had a chance to take a measurement on the valves. Not gonna take a chance on running these guides. I had one intake valve at .007 the other 3 were between .009 and .010. I'm not good with those at all lol so will deff be replacing all the guides. Now just have to decide if I want to buy the $50 reamer or pay the machine shop that my shop uses $50 to do it. Sounds like an easy decision but I really enjoy doing this stuff. We'll see whAt happens
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99 scrambler 400
99 trailblazer 250
04 predator 500
fastkill

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Reply with quote  #11 
Quote:
Originally Posted by polarisjunkymike
So finally had a chance to take a measurement on the valves. Not gonna take a chance on running these guides. I had one intake valve at .007 the other 3 were between .009 and .010. I'm not good with those at all lol so will deff be replacing all the guides. Now just have to decide if I want to buy the $50 reamer or pay the machine shop that my shop uses $50 to do it. Sounds like an easy decision but I really enjoy doing this stuff. We'll see whAt happens

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fastkill

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Reply with quote  #12 
I dunno if this is it but any of those spec's helpful?
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