honda305 Home honda305 Auctions honda305 Gallery honda305 Forum


honda305.com Forum

Login
□ Search
□ FAQ 
□ 
Vintage Honda Owners,
Restorers, Riders and
Admirers

Worn Cylinder Sleeves? Piston Rings? Valve Lapping

Post Reply
Spargett
honda305.com Member
Posts: 592
Joined: Wed Jun 18, 2008 10:19 pm
Location: Los Angeles, CA

Worn Cylinder Sleeves? Piston Rings? Valve Lapping

Post by Spargett » Thu Mar 05, 2009 1:00 am

Cylinder Sleeves: So I pulled the cylinder head on my 1962 CB77. As you can see they were rather dirty. I'm going to pull the piston heads off and give them a nice soak in parts cleaner. I'm curious if you can tell the condition of the cylinder sleeves for me? I would say its time for a nice honing session on these ones. I was really wondering what would cause scratches/gouges like this?

Valve Lapping: I'd assume that the valves could use a good lapping at this point since the engine is apart. I was looking at kits for lapping, but I can't find any information on compressing the valve springs (which I assume needs to be done to properly clean). If anyone can give me some points on this, or recommend a decent tool set for this procedure, I'd be very grateful.

Piston Rings: Can anyone tell the condition of my piston rings. As far as I can tell, they seem to be in good condition, though I'm concerned there may be some relation between them and the scratches in the cylinder wall.

Image

Apparent scratches in the cylinder sleeve. Are these deep enough to warrant honing?

Image

Cylinder wall discoloration. Does this look like "blow-by" to you?

Image

Image

Close up of the left piston and piston rings. How do the rings look to you? Its hard for me to tell what's good or not.

Image

Image

Right cylinder valves and spark plug. As you can see the bike was running very rich, or possibly burning oil. Hard for me to tell at this point.

Image

Image

User avatar
davomoto
honda305.com Member
Posts: 2508
Joined: Sat Nov 18, 2006 7:36 pm
Location: Marin County CA

Post by davomoto » Thu Mar 05, 2009 2:52 pm

You'll need a valve spring compessor to remove springs. Slide the rings one at a time into cylinder, push the down about an inch with the piston, and measure the gap. The manual will give you serviceable limits for the gap. If end gap is excessive, and you want to do it on the cheap, get the next size larger rings, ie; .25 if standard bore, and file ends until correct gap is achieved. Use only fine lapping coumpound on valves. I attach a piece of rubber hose to valve stem to spin valve with lapping compound .

davomoto

Post Reply




 

CB-77 | CYP-77 | Road Test | Riding Log | Literature | Zen | Marketplace | VJ Survey | Links | Home