Valve Clearances Should not be this Hard...

slusher454 · 04-17-2011, 07:34 PM

Ok, so I am having a bit of trouble getting the valves set right on my '71 CB350.

Following the Clymer Manual, I remove tappet covers, points cover, alternator cover; then proceed to turn the alternator bolt, watching the left intake valve.

I keep spinning until the valve opens fully, then just begins to shut, right around the LF mark. I crank the alternator on forward to the LT mark, then take the valve clearance, and adjust if necessary. All this goes on without a problem.

My problem happens when I try to take the clearance for the exhaust valve. The gap must be entirely closed, as not even my smallest feeler gauge will fit into the space. I try to loosen it more, but its ALREADY set to have the highest gap as possible. So naturally, I can't set the clearance here to .004"...it remains around .0000004" =/.

Am I supposed to take the exhaust clearance also with the left cylinder at TDC? The clymer manual did not say anything about rotating the alternator further for the exhaust valve..

Appreciate all help from anyone who has done this before, or who has some sort expertise to offer here. I am eager to get riding--as soon as I finish with this hangup (and complete my rack for my makeshift army surplus rucksack saddle bags

) I'm on the road out West!

HondaIlya · 04-18-2011, 10:41 AM

You have to have the rocker arm loose on one side and tight on the other(means that both the intake and exhaust valves are closed because the motor is @ TDC on the compression stroke) adjust both valves(intake and exhaust) then turn the motor till the other side is at compression TDC
I think the bigfest problem that you are having is that when you are adjusting your valves, one of them is not closed, and not giving you a right reading. Make sure the rocker arm that you are adjusting is able to tap back n fourt before you begin.

slusher454 · 04-19-2011, 02:59 AM

Mystery solved...

I had the rotor on LT, but the piston was not at TDC of the compression stroke. One rocker arm (intake) was loose enough to fit my gauge in, but the exhaust valve arm was not at all loose.

I spun the rotor around 360 degrees again and it was in the correct position.

Now on to ignition timing...

markk53 · 04-19-2011, 06:19 PM

I was gonna say it don't get much easier than Honda's two valve engine screw type adjusters.

04-17-2011, 07:34 PM	#1
slusher454 Verified Join Date: Aug 2010 Posts: 51	Valve Clearances Should not be this Hard... Ok, so I am having a bit of trouble getting the valves set right on my '71 CB350. Following the Clymer Manual, I remove tappet covers, points cover, alternator cover; then proceed to turn the alternator bolt, watching the left intake valve. I keep spinning until the valve opens fully, then just begins to shut, right around the LF mark. I crank the alternator on forward to the LT mark, then take the valve clearance, and adjust if necessary. All this goes on without a problem. My problem happens when I try to take the clearance for the exhaust valve. The gap must be entirely closed, as not even my smallest feeler gauge will fit into the space. I try to loosen it more, but its ALREADY set to have the highest gap as possible. So naturally, I can't set the clearance here to .004"...it remains around .0000004" =/. Am I supposed to take the exhaust clearance also with the left cylinder at TDC? The clymer manual did not say anything about rotating the alternator further for the exhaust valve.. Appreciate all help from anyone who has done this before, or who has some sort expertise to offer here. I am eager to get riding--as soon as I finish with this hangup (and complete my rack for my makeshift army surplus rucksack saddle bags ) I'm on the road out West!

04-18-2011, 10:41 AM	#2
HondaIlya Senior Member Join Date: Jun 2009 Location: Lake Placid, NY Posts: 419	You have to have the rocker arm loose on one side and tight on the other(means that both the intake and exhaust valves are closed because the motor is @ TDC on the compression stroke) adjust both valves(intake and exhaust) then turn the motor till the other side is at compression TDC I think the bigfest problem that you are having is that when you are adjusting your valves, one of them is not closed, and not giving you a right reading. Make sure the rocker arm that you are adjusting is able to tap back n fourt before you begin. __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

04-19-2011, 06:19 PM	#4
markk53 Senior Member Join Date: Dec 2009 Location: Delaware, Ohio Posts: 3,232	I was gonna say it don't get much easier than Honda's two valve engine screw type adjusters. __________________ KLX650C, Zephyr 550 SR500, Bultaco Sherpa T

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04-19-2011, 02:59 AM	#3
slusher454 Verified Join Date: Aug 2010 Posts: 51	Mystery solved... I had the rotor on LT, but the piston was not at TDC of the compression stroke. One rocker arm (intake) was loose enough to fit my gauge in, but the exhaust valve arm was not at all loose. I spun the rotor around 360 degrees again and it was in the correct position. Now on to ignition timing...