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Discussion Starter · #1 · (Edited by Moderator)
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Ok450er people, almost done with my build and I’m stumped on my 2007 450er Decompression arm adjustment clearance... the manual states to put a feeler gauge Right exhaust @ .010-.012 and leave in place while measuring the decompressor screw and Rt. Side rocker arm gap which needs to be at .009-.011 according to manual. I’m putting in a new decompressor arm system due to a ticking noise and I believe this is where the ticking noise is coming from or at least I hope this is where it’s coming from. Everything ran perfect for a while Iand I all of a sudden I encountered a ticking noise top right side of engine after a 2 he run, I checked the gap on the old decompression arm and it was .020-.022... obviously I can’t be that much at least I don’t think and it was a little loose in the sleeve so I replaced it with a brand new one. After looking at many threads and videos on how to do this, seems like everyone has different measurements where it needs to be. I am sort of a perfectionist so I would really like some help anyone knows anything about this and where exactly the gaps should be also I’m not sure if I have an aftermarket cam or not, does that even matter? Does that change the gapping?If so I’m looking at my cam and I don’t see any writing or lettering on it, I’m not sure if it is aftermarket or not, Any help on this matter would be greatly appreciated. I’m attaching a picture of my cam. image.jpg
 

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Discussion Starter · #6 ·
exhaust valve clearance for 07 0.28 ±0.03 (0.011 ±0.001)
Ok thx much , got that, so total clearance should be .011 rt. Exhaust and .010 decompression arm for total of .021 . If I’m understanding correctly. I also just bought a compression tester, should be at about 58-60 psi. That should tell me if I’m correct on clearances correct?
 

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2004 TRX450R
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Yes and yes. Make sure you open the throttle all the way up when you crank it over for comp test. I'm not positive for the ER's, but I don't think it can hold compression too much longer than you crank for, as there is a slight valve over-lap at TDC.
 

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Seeing if your clearances are correct, requires the engine to be at TDC, w/CAM gear, & crank gear in alignment, then feeler gauge between the shim and valve and checking to see if your in spec and replacing shims to get back with in spec. Compression test should help locate where the unwanted air is coming in or escaping from when the motor is running or head gasket, or piston rings etc. w/out tearing the motor down to diagnose the cause of the power loss.
 

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Discussion Starter · #9 ·
Seeing if your clearances are correct, requires the engine to be at TDC, w/CAM gear, & crank gear in alignment, then feeler gauge between the shim and valve and checking to see if your in spec and replacing shims to get back with in spec. Compression test should help locate where the unwanted air is coming in or escaping from when the motor is running or head gasket, or piston rings etc. w/out tearing the motor down to diagnose the cause of the power loss.
Got it thx, appreciate the info and ur time
 
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