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ovanay elinquentday
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Discussion Starter #1
After checking the deck height, I went ahead and bolted on the cylinder heads and rockers. I'd kept all of my old gaskets, so I used those to put things together. (The new gaskets will wait for the final build.) Everything got torqued down to spec but I didn't loctite anything since it was all coming back apart.

Before I buttoned things up, I put a circle of kitchen baking clay in the valve reliefs for the pistons. After everything was assembled and the new Feuling adjustable pushrods adjusted, I rotated the engine through the two full turns of a complete combustion cycle.

The pic below shows the clay after I pulled the heads back off. In the middle of the top of the clay in each valve relief, you can see the dent from where the valve hit the clay.



With the 577 lift cam that I'm using, I had a relatively huge 0.181" clearance between the valve faces and piston top. Lots of room there for a possible bigger cam! The other thing I looked at was the "eyebrow" measurement, or space between the edge of the valve and face of the pocket. With these stock size valves, I had nominally 0.215" of clearance in both pockets. Lots of rooms for larger diameter valves, if I was ever so inclined.

It was nice to know that I'm not even close in terms of clearance issues.
 

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ovanay elinquentday
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2,021 Posts
Discussion Starter #3
SEDELUXE said:
dam nice job there clay just keep in mind the expansion of the metals once she gets hot. but you got plenty of clearence there. way to go boy.{salute(
Seems to me I remember hearing that .060 is good valve to piston clearance for the intake valve, and .090 for the exhaust. I've got that comfortably beat! Hmmh, maybe I should just change now to a higher lift cam.... :whistle:
 

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ovanay elinquentday
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2,021 Posts
Discussion Starter #4
pa-glazier said:
Were your lifters pumped up when you did this?
Lifters were nicely pumped, thanks! But also, I've got S&S limiters in the stock lifters. They can't collapse too much beyond where they will ultimately be running.
 

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Administrator
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GPO03FatBoy said:
Hmmh, maybe I should just change now to a higher lift cam.... :whistle:
Remember that is TDC lift you are checking. A cam with less overall lift can still have a higher TDC lift.

For example, Andrews 31 vs 37. They both have .510" lift but the 37 has about .040" more intake lift at TDC and about .030" more exhaust lift at TDC.

Although you are probably right that you have plenty of room for more.
 

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ovanay elinquentday
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2,021 Posts
Discussion Starter #7
springer- said:
Remember that is TDC lift you are checking. A cam with less overall lift can still have a higher TDC lift.

For example, Andrews 31 vs 37. They both have .510" lift but the 37 has about .040" more intake lift at TDC and about .030" more exhaust lift at TDC.

Although you are probably right that you have plenty of room for more.
Thanks for pointing out the fine points!

I think I've gone about as far with this bike as I plan (famous last words). If I were to change though, I have plenty of clay.... :)
 
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