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Discussion Starter · #1 ·
Hi guys, I was wondering if anyone has adjusted the valve clearance on a CB450 (K6 in this case) with the cylinder head off the rest of the engine? If so, is it different than how you do it when the engine is assembled?

The reason I ask is that I had the seats cut last fall and the guy who did it said he had ground the valve stems the same amount but when I put it all together I couldn't get any clearance at all. After trying it a ton of times I took the head off with the plan to get him to re-check the valve measurements. I got side-tracked with another project that's now done so I'm back on this and wanted to check the valve clearance again with the head off before I take it to a machinist.

Cheers
 

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Unless the head is fully torqued down you won't be able to set the Valve Clearances.

The head gasket compresses and will change the measurements/Gaps.
 

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Unless the head is fully torqued down you won't be able to set the Valve Clearances.

The head gasket compresses and will change the measurements/Gaps.
Say what ??!!
 

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Sensei
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Valve clearance is primarily determined by position of the cam lobes, then by the tappet's positioning via the excentric adjuster's settings....
This WILL NOT change whether the head is installed or not (assuming the same cam and excentic positioning and same tappet)
The fully released (shut) position of the valve stem is the same within the head, regardless of head off or on the rest of the engine
 

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In theory Vendor is right, the head will deform when torqued down, and change the distance between the two axis (cam versus excentric adjusters), but I I never saw any measurable difference in practice, as I also adjust the tappet clearance before assemble the head on the engine.
 

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Discussion Starter · #6 ·
Thanks Bill, Sprint, Yendor, and Jensen. That's very good to know. I'd like to play around with trying to get enough valve clearance before taking it to a machine shop. With the engine not assembled, how do you ensure that everything is lined up correctly (i.e. check the left hand cylinder tappet clearances in the exhaust and inlet valves when it's top dead centre of the compression stroke)? Thanks again.
 

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Sensei
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Easiest way is to rotate one cam at a time and set the "pad" of the cam follower (tappet) you intend to adjust on the base circle of the cam lobe....There is about 180 degrees of base circle, so even if you are "off" the exact spot by 10 degrees either direction, you should be fine....But, TRY for the center.....Presumably, you WILL verify when engine is assembled..........
 

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Discussion Starter · #8 ·
Hi, thanks very much for that. Using that method I was able to get both the left intake and exhaust sides to allow a .0015 inch feeler gauge through, just barely. No where in the adjustment range can I get a .002 through.

I can't get it to work on the right side however. No where on the right side can I get a .0015 in throughout the adjustment range (even tried 360º around with adjuster just to experiment). I tried playing with where the cam lobe is meeting the follower a bit but it didn't make a difference.

When adjusting the valve clearance are people normally able to get a wide range of feeler gauges between the cam lobe and the follower (even if not the correct size)?
 
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