75 CB360 - Jolene

[mydlyfkryzis]

A tight valve would affect compression that much. A slightly open valve = no compression.

 

[suthern]

Wow I didn't know it could make that much of a difference! I was going to adjust the valves, but I couldn't get the dang stator cover off. I sprayed some pb blaster on there and will try again tomorrow.

 

[frogman]

Go to harbor freights web site and put in Impact Screwdriver into the search box. Then go buy one, most of your problems will go away with those screws.

 

[suthern]

That impacter did the trick. Thanks for the tip. After adjusting the valves the left cylinder tested about 170 psi. The right cylinder was way too loose but after adjusting and testing compression again I was still only at 100 psi. I rechecked the valves and I must've fudged the adjustment the first time around because they were too tight then. I readjusted but still couldn't get the compression above 100.

 

[suthern]

Looks like I might be tearing this bad boy apart. It should be a learning experience to say the least. Does anybody have any suggestions/ideas before I go through with taking the motor apart?

Also, I read somewhere that you could tell if the ring/piston was the cause by pouring a bit of oil into the cylinder and see if that helps. Well the retest with the oil it went up to about 120. Thoughts?

 

[dualero]

That increase in compression after pouring oil, could mean worn or broken rings on that cylinder

DH900sl

 

[frogman]

Can do the top end of 360s in frame if you like. If it sat years before you got to it, I would buy some Seafoam DEEP CREEP spray and apply it to that side for a week or so every day. There's a chance you have a stuck piston ring and that stuff does a great job of loosening things up without taking things apart.

Other wise as I said, not much to pull the engine down to the block in frame if that is what has to happen. Shop manual has an outline for how to do so if you need to.

 

[Sonreir]

50/50 mix of acetone and ATF works wonders as well.

 

[suthern]

Well I'll try to see if it's a stuck ring before I tear it down. So about how much are we talking about pouring in to the cylinder? A few tablespoons or so?