Mike's CB550 Project

[Mike_Berkshire]

Thanks all so far with the help in my initial steps with this project: rebuilding the carbs to get the bike running pre-stripdown, removal of the stuck rocker cover, knocking out the shock mounts from the swinging arm, removal of the steering races and identification of mystery parts along the way. The bike is now stripped down apart from the bottom end which Im intending to leave intact and, so far the wheels are still 'bearings in'. The first outside job of repainting the frame, swinging arm and various other brackets etc should start tomorrow.

Whilst Im waiting for the frame painting I am getting on with the head. All valves etc are out, the head is decarboned and Im now decarboning the valves pre to lapping them in. Whilst working on the inlet valve for #2 cyclinder I can see there is damage/an imperfection in the valve face (see picture). Should this valve be replaced with a new one and if so is it OK to replace one valve only? I have checked piston #2 and there is no sign of any impact damage on the piston. Also there is a single valve collet hiding somehwere on the floor of the shed which Im hoping to find but is so far proving elusive. Thanks, Mike

[McCabe-Thiele (Ted)]

I had a similar damaged valve on my 400 exhaust valve - just the one like you.

I found a good used valve that (Steve at 400fourbits) I did not need to have refaced so it was an inexpensive fix.
I was able to do a normal had grind presumably as it was a standard factory cut valve.

[Bryanj]

PM me your address and i will send you a used one

[Mike_Berkshire]

PM me your address and i will send you a used one

Thank you so much Bryan. I have sent you a PM.

[Mike_Berkshire]

So de-carbonising the inlet valves was easy. The exhaust valves less so. The deposits on the valve face & stem are like concrete. I am assuming this is normal (?) Are there recommended ways of removing the deposits from the exhaust valves? As the crust is so hard Im worried about damaging the valves. I have been using a Dremel clone with softish Scotchbrite mini-mops.

[Bryanj]

Steel wire wheel on bench grinder or in drill and yes it does feel like concrete

[McCabe-Thiele (Ted)]

Call me a vandal - I put my valve in an electric drill using an old screwdriver holding it as a cutting tool. I kept away from the vet edges then finished the job with 400 grit Wet & Dry.

[Mike_Berkshire]

Call me a vandal - I put my valve in an electric drill using an old screwdriver holding it as a cutting tool. I kept away from the vet edges then finished the job with 400 grit Wet & Dry.

That’s quite reassuring Ted. I will continue Dremelling for now then. You don’t say if the bike ran or not after you did this though; I assume it did :-)

[McCabe-Thiele (Ted)]

Call me a vandal - I put my valve in an electric drill using an old screwdriver holding it as a cutting tool. I kept away from the very edges then finished the job with 400 grit Wet & Dry.

That’s quite reassuring Ted. I will continue Dremelling for now then. You don’t say if the bike ran or not after you did this though; I assume it did :-)

Yes it ran and still does - I've used this method for decades on mainly on car engines in the days of leaded petrol.