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Newbie in need of help

CB160, CB350, CB360, CB450
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jvmills
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Posts: 16
Joined: Mon Feb 20, 2012 8:45 am
Location: Wilmington, DE

Newbie in need of help

Post by jvmills » Wed Mar 28, 2012 2:13 pm

Recent purchase of a 65 cl72. claimed to be running. I haven't been able to get started. While trying to kickstart felt a sudden change. Became easier to kick. Original thought was something in kickstart or clutch (stuck disengaged because I was playing with the clutch lever about that time). Just did a compression check found to be 50 psi on left and just under 40 psi on right. I know these are low and won't run like this. Shop manual says to check valve tappet clearance. I don't think this is the problem. don't have the tools to do a leakdown test and not sure how to do. will check forum on that. Open to suggestions how to proceed from here.

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Snakeoil
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Joined: Wed Aug 04, 2010 6:45 pm
Location: Upstate NY

Post by Snakeoil » Wed Mar 28, 2012 4:13 pm

Felt a sudden change is probably not a good thing. Open up your valve cover caps and see if the rockers are moving when you turn the engine over (slowing) with the plugs out. I'm going to guess that your cam chain broke. No rocker movement means no cam rotation means broken chain.

For future reference, they all run or ran when last put away. But unless you actually hear it running yourself, the engine does not run and you are buying a non-running bike.

Don't keep kicking it. Although it is probably too late. You could bend valves. If you rotate the engine, do it slowly with the plugs out.

On a brighter note, maybe you just have a couple of stuck valves. That would give you low compression as well. Remove all 4 valve caps and see if you have excess play on one or more valves, which might indicate they are stuck open a bit. Could even be a piece of carbon broke loose or a nut from a critter and is holding the valves open. But with low comp in both jugs, I tend to believe they are linked and the common link is the cam rotation.

I was looking at a CL160 a guy had for sale. Said the engine was free and should fire up with some TLC (you never seem to find TLC mentioned in the service manual). I kicked it a few times, not hard, just running it thru the stroke and listening for noises. About the second or third rev it locked up hard. Told the owner what happened and passed on the bike.

jvmills
honda305.com Member
Posts: 16
Joined: Mon Feb 20, 2012 8:45 am
Location: Wilmington, DE

Post by jvmills » Wed Mar 28, 2012 7:16 pm

Rechecked compression, carbs and tappet caps off. Rockers moving 100psi on left 95 on right

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Snakeoil
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Joined: Wed Aug 04, 2010 6:45 pm
Location: Upstate NY

Post by Snakeoil » Sat Apr 07, 2012 10:18 am

Sounds better. So, were low reading your fault or did something change again?

And I have to ask why you are posting the questio in this section. Although the forum is a 305 forum, the 250 versions of these bikes are considered to be for the most part the same bike and you can post your question in the 305 section. I suspect you will get a lot more replies from folks that work on these regularly. I only have one and if it ain't broke, I'm not working on it.

regards,
Rob

jvmills
honda305.com Member
Posts: 16
Joined: Mon Feb 20, 2012 8:45 am
Location: Wilmington, DE

Post by jvmills » Mon Apr 09, 2012 4:39 pm

my mistake as far as the section. reposted in 305 section. The difference I think is because of my inexperiennce and tool used. Placing the adapter in the hole and possible leak between adapter and gauge. Hard to get tight due to lack of clearance.

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