CB350 engine issue, post rebuild

[uncletwisty]

So, I've rebuilt my 73 350 engine for the second time. I've removed the starters but other than that, just a rebuild.

I'm trying to set the valves, when I turn the stator to get to the LT mark, normally the engine spins wildly and it's a pain in the ass.. but mines not doing that anymore, not sure of the issue.. any help would be great..

thanks!

uncle twisty.

 

[Sonreir]

By "spinning wildly" I'm going to assume you mean that it doesn't want to stay at that location and will attempt to move past that mark on it's own regard.

The crank will want to move past that mark due to the pressures being transferred from your valve springs, to the cam, though the timing chain, back to the crank.

If this doesn't happen you have some potentially serious issues.

First order of business is to remove the rocker cover and ensure all the rockers are properly installed. Then verify that all valves are present in the head along with their associated retainers. Pushing on the tops of the valves should not cause them to move unless you exert A LOT of pressure. Next check to make sure the timing marks on the cam sprocket are parallel with the top of the head when the left piston is at TDC (LT mark on the rotor at the end of the crank). After that, double-check the tensioner adjustment and ensure the timing chain is tight. Finally, readjust valve clearances.

If you need specifics for any of those items, please let us know.

 

[uncletwisty]

Thanks, I'll give all that a shot and let you know if I need any further assistance!


uncle twisty.

 

[uncletwisty]

Re: CB350 engine issue, post rebuild.. PHOTOS

So I've got the rocker cover off, and am looking inside.. I know the cam marking is supposed to be parallel with the top of the engine, but should the lobes be facing up or down? My concern is that perhaps I aligned it with the wrong stroke of the LT mark.. here are some photos of what I have..

Instead of throwing through the stroke it's just clicking.. as if the valves are open instead of closed.. please help!

thanks,

twisty.

 

[Sonreir]

Open the valve covers and take a look at what's happening when you rotate the crank. You should see the tappet end of each rocker arm depress the valve and then the valve should come back up as you continue to rotate.

As for the lobes up, lobes down question: It doesn't matter so long as the cap sprocket is level with the top of the head. The cam turns half as fast at the crank and so sometimes it will be lobes up, other times it will be lobes down. Half of the time, when the left piston is a TDC then the valves are closed because it's the end of the compression stroke / start of the power stroke. The other half, the valves will be open because it's the end of the exhaust stroke / beginning of the intake stroke.

 

[uncletwisty]

The tappet goes down and starts coming back down after F and then when it reaches the LT mark, the sprocket parallel mark is no longer visible (180 degrees opposite) Should I tear it down and flip everything?

 

[Sonreir]

Turn the crank another 360° and you should see the cam sprocket mark. This is normal.

As for the tappets, I'm not sure I fully understand. What should occur is that as you turn the crank past the LT mark (when the lobes are up), you should see the tappet press down against the valve stem and then (as you continue to turn past the LT mark) come back up again. The valve stem should be visible both before and after the tappet depresses it.

Did I explain that well enough?

 

[uncletwisty]

Ok, I'm not sure what's going on, I've reset the valve clearance, made sure everything is right and I've still got not pressure.. any other suggestions..