motogtp
CB750 Addict
I have '78 SS with 6,100 miles. After cussing at the carbs I found out it was burning oil (see pictures). Before I put it back together I would like to get input from the forum. There is some black smudge on the pistons but it is coming off pretty easily with carb cleaner and plastic putty knife (#21). Little bit at the top of the cylinders as well. Can I use emery cloth to remove any stubborn smudges at the top of the cylinder or do I need to hone the cylinders?
Rings are clean and seem to be in good shape (#26). I see no evidence of any blow by so I am not planning on replacing them. Cylinders are in good shape, you can still faintly see the honing cross hatch marks (#18). Valves appear to be in good shape and tightly closed. I don't have the valve springs off yet but I am betting that the seals are what was leaking. I am guessing this thing sat for a long time and they dried out and/or cracked. Does the darker discoloration on the valves tell me anything (#19)?
One last question. Do I replace the valve guides while I am at this point? Even if there is no excessive valve stem play? I don't want to spend a ton on this bike but I also don't want to rebuild it again in another 6,000 miles. Thanks.
Rings are clean and seem to be in good shape (#26). I see no evidence of any blow by so I am not planning on replacing them. Cylinders are in good shape, you can still faintly see the honing cross hatch marks (#18). Valves appear to be in good shape and tightly closed. I don't have the valve springs off yet but I am betting that the seals are what was leaking. I am guessing this thing sat for a long time and they dried out and/or cracked. Does the darker discoloration on the valves tell me anything (#19)?
One last question. Do I replace the valve guides while I am at this point? Even if there is no excessive valve stem play? I don't want to spend a ton on this bike but I also don't want to rebuild it again in another 6,000 miles. Thanks.