76 CB360, Cherry Bomb at Barber's

Re: 76 CB360, before & after

correct me if i am wrong here, but it should be added all the time, its like a lead additive right? helps soften the wear on the valves?
 
Re: 76 CB360, before & after

Use it all the time, it's a high pressure additive that works well on cam and rockers plus transmission gears.

I only add 2oz to a gallon of oil as Rotella already has ZDDP in it
You don't want too high a level, 1800ppm seems to be optimum/maximum, 1200ppm is lower 'limit'.
Somewhere in the middle is better than low level but I don't know what level would be present using 4oz bottle /gal (it wouldn't matter in car engine, don't have a wet clutch to worry about)
 
Re: 76 CB360, before & after

Pistons cleaned up pretty nice. Any more tips for installing rings? I broke the bottom ones trying to peel them off both pistons. (I wasnt trying to be super careful, but they broke pretty easily) Enough so, I am a little concerned about installing new. Also, I am going to shove a tooth pick in those holes to clean em out.
cleanpistons.jpg


The cheap valve compressor didnt fit springs exactly as it was intended. But it worked very well.
compressortool.jpg


crap is really baked on there!
dirtyvalve2.jpg


dirtyvalve1.jpg


I used the extra fine wire wheel on bench grinder to gently scrub away debris.

OK now for a lesson in lapping. after a minute or two. I can still see like 5 tiny shiny spots, should I continue working until all these are gone, and the valve is evenly colored all the way around?
OR is this as close as I need to be?

the spot is almost centered in pic.
lapping.jpg


Good head.

goodhead2.jpg
 
Re: 76 CB360, before & after

The right valve came out perfectly...I made another pass on left. and still have those little spots. they are really small spots.
 
Re: 76 CB360, before & after

Hold valve in place and spray some WD40 inside port.
If it seals, it's good to go
 
Re: 76 CB360, before & after

Did I miss it somewhere? You are using lapping compound right? and by hand right? It shouldn't take long to be perfect.

and yes, synthetic is a transmission/clutch killer.
 
Re: 76 CB360, before & after

OK, Im pitching that head. Ive got another, a 1974. Its still fully assembled. I sprayed plenty of WD in there and its got no leaking to start with. Its freaking filthy. got a couple mud dobber nests in it. But w a closer inspection It looks as if the cam bearing surfaces may be better than the other head. So, here I go again.
Give me some time.

AND because it has no leaking of WD40 to start w it should be good to go.....right?
 
Re: 76 CB360, before & after

Seats probably need cutting
If you want, send it down with the valves I'll fix it
 
Re: 76 CB360, before & after

Yeah don't toss it, most are rebuildable.

Whats the chances the point gallery is flat backed?
 
Re: 76 CB360, before & after

re-installed all valves in 1st replacement head w springs and sprayed.
The LEFT valve (leaker) held tight. no leak. The right leaks. ( I only made one pass on that one). But even still it pissed me off a bit. So I set it aside.

Got 2nd replacement head. Still dirty, still fully assembled. Sprayed WD again. All valves held tight. And the cam bearing surfaces DO look better. So, I am using it.

Also, I got curious about the rubber valve seals. I pulled original Junk head out. Pulled the suspect cracked valve. It indeed is cracked in 4 spots. And the seating angle is all messed up. rounded scoopy like.

badvalve2.jpg


badvalve1.jpg


So, getting started cleaning the 2nd replacement head.
 
Re: 76 CB360, before & after

That valve has been lapped before, and it was overdone.
It should show a 45 degree angle, that looks like it's sunk into the 60 degree throat angle
The face hardening has probably worn away, if any of the other valves look the same they are also scrap
 
Re: 76 CB360, before & after

Hey PJ...are my 76 754A's the exact same carb as the earlier 745b's, just jetting differences?
 
Re: 76 CB360, before & after

Carb bodies are the same, probably different jets though.
Could also be screw in or press in air jets?
 
Re: 76 CB360, before & after

Finally got the 2nd head clean "enough".
Ill get stared lapping valves in morning. In theory shouldnt need much. They didnt leak WD40 to start with. But, I am learning theres always room for unpleasant surprises.

2ndheadclean1.jpg


2ndheadclean2.jpg
 
Re: 76 CB360, before & after

crazypj said:
Carb bodies are the same, probably different jets though.
Could also be screw in or press in air jets?
Ill open them up. and check em out. This is another pair I just recently got from my buddy, nick. They came off a running bike. Same bike as this second head.
 
Re: 76 CB360, before & after

I wouldn't mess with those valve seats, now it's clean, put it back together and re-check for leaks.
I would also fit new valve guide seals
I would remove the step where seat insert is fitted into head, just blend it into the radius of port
 
Re: 76 CB360, before & after

crazypj said:
I wouldn't mess with those valve seats, now it's clean, put it back together and re-check for leaks.
I would also fit new valve guide seals
I would remove the step where seat insert is fitted into head, just blend it into the radius of port

The first head had this rough casting imperfections.
intakeportrough.jpg


2nd head much nicer...
2ndheadbettercasting.jpg


checked the mating edges of each seat. really nice. They are smooth enough I cant catch a finger nail on any of the edges.
valveseatmatesmooth.jpg


new blue seals just popped on. This whole job shouldve went as easy as these!

valveseals.jpg


Springs installed in the correct orientation...and, SUCCESS NO LEAKS!!! HUZZAH!

2ndheadnoleaks.jpg
 
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