Squish Question

[oldbikedude]

Just remember, the deeper the valve head the higher the stem. This changes the rocker angle.

[DJM]

Perhaps not if you're fitting the valves that were meant to be in there in the first place?

[Dr. Frankenstein]

Here's some pics, in any case:

This is a comparison of the valve faces - the Late on the left, the Early on the right:

CA77 Valve Difference by Dr. Frankenstein1, on Flickr

Again, notice how big the Late is compared to the Early -
Intake Valves by Dr. Frankenstein1, on Flickr
Valve Differences by Dr. Frankenstein1, on Flickr

Here's the divot I spoke about - my machinist says it's okay to use...
Spare Head by Dr. Frankenstein1, on Flickr

The Early head, post grind...note the top/Intake ports ground at 45 and 30...kind of big there, huh...
The 'Spare' Head by Dr. Frankenstein1, on Flickr


...and the Late head, post grind:
The 'Original' Head by Dr. Frankenstein1, on Flickr



so whattya think...?

[Dr. Frankenstein]

Umm - I think I know WHY one of my two heads has bigger valves...

As you know, I had the seats on these two heads re-ground and noticed one had bigger valves...they were both 305's (or so I thought) and so had them ground at 45 and 30...I got them home, lapped the valves and took them back in to have the vacuum checked - and that's when me and my mechanic Both noticed the Spare head had TWO carburetor ports on it! I CANNOT believe I /we did not even notice this detail before!

The Spare head in the pics is the one with the divotlike-thing taken out of the rocker arm channel, pictured directly above...look at the similarities…plus you can SEE the two ports in the very first picture! DOH!

I believe the Spare head is from a Superhawk, but are there any other 1960's Hondas that have dual carbs that this head might fit?


OR, could I mount this dual-carb setup to the regular 305 tranny...? THAT might be interesting, but I'd need a two-carb throttle linkage...

[Geoff Hastings]

I'm sure we've all done it, been looking too deeply to see the obvious.
It does make me wonder though, how some of the damage we find in these strip downs occur. That chunk missing off your head for instance, I can't think of a reason that would ever have needed a wack hard enough to break that piece of casting.

[Dr. Frankenstein]

I'm sure I don't know - my mechanic says it should be OK, though, because the arm isn't really affecting the integrity of that area when it's in; I just would like to know how that happened too!

What could have caused it...?? I don't know...

[pemdoc65]

Someone may have tried to drive a rocker shaft out with the head still on the engine and the cylinder stud in the way. And they missed with the punch.