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Strange temporary loss of compression?

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So after my '06 DRZ S with about 29,000 miles on it sat for 4 days I was starting it to go to work yesterday morning.  I've been kickstarting it exclusively for a couple years now after putting on the kit.  Anyway my procedure is to use my right hand pushing on the lever until it just gets past TDC (removed the decompressor form my exhaust cam a few years ago, started rattling loudly and the pin was loose when I cut it all off) and then kick it thru.  It will have a lot of resistance and takes about 5 to 10 seconds for hand pressure with the weight of my upper body to ease it thru TDC.

 

So yesterday morning I eased it past TDC by hand, kicked it thru, didn't start.  So I used my hand again to get thru TDC but there was hardly any resistance, couldn't really tell where the hell TDC was, tried numerous times.  Then I just started kicking it and after about 3 or 4 kicks it started and sounded normal.  Rode it the 27 miles to work and it seemed maybe just a smidge down on power.  Got to work, parked, turned it off and tried the kick lever again with my hand and the normal TDC compression resistance was there.  That afternoon leaving work it was just like normal again, resistance by hand easing thru TDC and then kicking thru.  Rode home, felt fine, no smoke, again maybe just a tiny bit less power than normal.

 

Got home, checked the oil level, pulled the airbox cover.  Oil level normal, no blowby in the airbox.  Strange as hell, can't figure out what would cause a temporary loss of compression other than a sticky exhaust valve or a ring problem.  I was thinking that I had broke a ring or something but would think there would be a lot of blow by and oil usage.

 

Have a 3 day weekend coming up and thinking maybe I need to check valve clearances, could too small of valve clearance on a cold motor cause this?  I checked them at 18,000 and didn't have to touch them, all were nearly in middle to max loose clearance.

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Somewhat unique to a single because it only has 1 cylinder to start on.  A piece of carbon flakes off and gets under a valve, holds the valve slightly open.  Starting is difficult but if/when it starts it beats the carbon off the valve face and all is good again.

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Maybe a whole bunch of seafoam in the next tankful to try to clean it up some.  Probably will check the valves, maybe finally get the E cams in it that have sat for months waiting. 

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