RE: [Honda-C70] piston hiting on valve's

Mike : Correct me if I am wrong but could Jill determine if the piston is hitting a valve or the head by checking tappet clearance on both valves? The valves should be closed with the piston up & tappets would be open. That might indicate if the cam chain is on the wrong tooth of the crank shaft or if the piston [if it is not the original ] is too tall & hits the head. Baby Huey

To: Honda-C70@yahoogroups.com
From: mgladu@mindspring.com
Date: Mon, 6 Jun 2011 12:33:29 -0500
Subject: Re: [Honda-C70] piston hiting on valve's

At 5:16 PM +0000 6/6/11, Jill wrote:
>I got my timing all set up and stuff after swapping cylinders, but
>now the piston is hitting on the valve's. I can't even get close to
>being able to turn it all the way over. I swear i have all the
>gaskets and stuff. Any ideas on what to do next?

You must have either the crank or the cam in the wrong place when
setting the cam chain on the cam sprocket.

TDC happens twice, once is 'false' (180 degrees off), the other is
'true' (zero or 360 degrees).

I'm guessing you used the wrong mark on the flywheel ("T" mark is
correct) or indexed it to the wrong place on the case.

http://autos.groups.yahoo.com/group/Honda-C70/files/C70%2080-81%20Passport%20Shop%20Manual%20%28JPEG%29/185.jpg

It could also be that the wrong place on the head was used for the
cam sprocket (something other than 9 o'clock), but that's less likely.

http://autos.groups.yahoo.com/group/Honda-C70/files/C70%2080-81%20Passport%20Shop%20Manual%20%28JPEG%29/188.jpg

Only thing left would be if you used a 6 volt head or cylinder in the
rebuild. If so, the higher-domed 12 volt piston could be hitting the
HEAD - not the valves.

Mike G.
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[Non-text portions of this message have been removed]

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