Hi group, [img]i/expressions/beer.gif[/img]

My first postiing here an was wondering if anyone knows the exceptable compression range on the 2006 350 Rancher. The honda manual said "97#", but thats not a range like most repair manuals give you. Anyone taken a measurement of theirs? I have about 1000 miles on my unit. Any know what it should be for a 350... thanks in advance

 

Yes, my friend, that is the cranking compression. If you want to find your true compression you will need to loosen the exhaust valve rocker adjuster. The cam has a decompressor on it so cranking compression will read low when tested with the starter turning the unit over, hence the low compression spec.
The built in decompressor on the camchaft slightly holds the exhaust cam follower at low engine rpm (below idle) and once the engine starts, it moves away from the cam follower and the engine compression rises as a result.
The decompressor system is incorperated for ease of starting and less strain on the starter sustem and battery.

----- Gimpster -----

 

Well good news! I was only measuring 83# on the 06 Rancher 350, and I read another tester was measuring only 60#. Both of us had our chokes open, and throddle wide too.

I dont have a manual for this bike yet, how big of a project is it to check the compression as you describe?

I just bought a 08 Rancher 420, 4x4 es this weekend,and will need to aquire a maintance manual for it too. My g/f would like to buy my Rancher 350 es since she sold her Recon, (without es), but we would like to verfiy the Rancher's condition first. I hadnt had it long at all, so its only a guess for both of us

 

To get at the valve adjusters you will need to remove the seat, the big black plastic side covers on the quad,fuel cap, the black plastic cover on top of the fuel tank, the fuel tank, and heat shield under the tank to access the tappet cover. Remove the tappet cover and find TDC on the compression stroke. Loosen the adjuster lock nut and back off the exhaust valve adjuster screw. After doing compression check, readjust valve clearance to .006 in. while on TDC.
You do not have to have the choke pulled to do compression test.
Hope this helps

----- Gimpster -----

 

Far as I know/have heard & Read, if you dont have your choke fully open, the NON-choke mode, (and throttle fully open for that matter), you will cause the compression value to be lower. This is how we checked ours each time. Sounds like alot of work to check it without the decompression valve disable. Perhaps we won't bother as the ATV runs like a top, and there is no reason to think that it has a compression issue going on. Thanks