Topic: I have no idea what’s wrong with my 350f

[Coredozer19]

1973 Honda CB350. Smokes at idle. Cleans up when riding but has several bog spots. Sometimes the bike runs like a top. I don’t understand and I’m about to give up.

Fresh rebuild. Could I have put the rings in backwards? Would a compression test show that?

Also like a dark liquid looking circle coating on top of piston. Is that oil? Or built up gas

Recently set float hight and changed points but it hasn’t got any better

[Coredozer19]

No. I now realize the silver compression ring goes on top. Then the black compression ring. Then the oil ring. Is there any other orientation of rings (top and bottom) I should know about hurry please. Currently ripping the head down.

[Bodi]

The top compression ring is dead flat on the edge, if it is stepped the stepped in side goes down. The second ring has an angled edge, this must be oriented to scrape oil down. If there are letters or numbers on the rings these as a rule face up. Oil rings... three part ones go ring-corrugated spacer-ring, one piece go either way but look for markings and put a marked side up. Stagger gaps and avoid gaps on the pin axis or perpendicular to it.

[Coredozer19]

Is it possible the second ring is completely flat edge. I didn’t notice any taper and it’s already put back together now

[dave500]

if you don't have the chrome ring on the top your gonna have to take it apart,if its not been ridden much yet youll hopefully be ok?theres thread after thread of smokey 350 rebuilds for some reason?

[Little_Phil]

Seems to be thread after thread on CB350 problems here.
And an equal number about confusion on top two rings.
On one of my 500s I am about to do rings. I have some NOS genuine Honda rings and from information picked up:
R markings on ring side face up to the mechanic looking down at the piston top.
The first ring has chrome edge and has a slight bevel both sides (showing as a witness of silver in the black ring.)
The second ring has a black edge from new and is square at the edge.
Would the 350 be any different?

[dave500]

any markings or stamps go up,chrome rings are always the first or top ring,never use chrome rings in a chromed bore,not likely in our cases?



EDIT.. this goes for any engine assembly.

[Coredozer19]

Looks correct doesn’t it?

[dave500]

ive never liked those one piece oil rings though,they were used all through the early years on small bores without troubles,the bigger bores went to three piece,we never had trouble with one piece oil rings on 75cc motors etc though.

[dusterdude]

ive never liked those one piece oil rings though,they were used all through the early years on small bores without troubles,the bigger bores went to three piece,we never had trouble with one piece oil rings on 75cc motors etc though.

Agreed

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