Thanks I have them sitting a bucket of carb cleaner, will give it a few days see how it’s working.The cylinder head is the odd duck of engine parts, when it comes to cleaning.
Hot tank soaking goes a long way toward loosening, if not removing, most of the dirt & carbon. A thorough soak followed by crushed walnut shell blasting may do what you want, quickly. It won't change the as-cast surfaces of the fins (sandcast texture) or the combustion chamber + valve heads (low gloss, if not oxidized).
It's when you're dealing with heavy carbon/rust in the combustion chamber or heavy oxidation/staining of the sandcast fin surfaces. The combustion chamber can be cleaned using glass bead...paired with low pressure, increased gun distance and working quickly. The ports can be heavily blasted with glass bead and normal gun pressure, working from the outsides of the ports. The valves must be left in place to protect the guides & valve seats (even if the need to be cut).
Aluminum prep, sold through automotive paint suppliers, Eastwood Tool, et al, or oven cleaner containing sodium hydroxide will usually do the job, without profiling the surfaces. A nylon bristle brush is used for the scrubbing, followed by immediate rinsing.
If that doesn't clean the staining from the outside surfaces, then the choices are living with the results...or media blasting. Unlike any other engine part, including the head covers & cases, wet blasting can deliver a result that is reasonably close to original. That sandcast texture is quite compatible with wet media blasting. Dry blasting with glass beads can deliver an okay result...if you work quickly (minimal blast time) and carefully (very low pressure) but it's not as nice, or as close to original, as wet blasting for this item.
Looks like an original seat pan, with the early stages of metal failure. See those puckered sections of the side rails? That's the Achilles Heel of these. You really should straighten, then bead blast, the metal...see what you're starting with. Finding one of these early pans without any cracking is uncommon. Any breaks, no matter how small, will doom your seat restoration to early failure. The metal is thin, structural strength comes from the shape of the pan and it must be intact. Otherwise, the pan will have the structural rigidity of rubber; the rear section will soon collapse onto the TL bracket. The good news is that it is possible to weld the breaks, add an angle brace to each side and prevent a repeat performance...while retaining all of the original stamping detail. Not much in the way of material resources are needed to do this and do it right.
FYI, Honda added angle reinforcements to the seat pans beginning with the K2 model. They also went to a synthetic foam, with a much longer lifespan. Unfortunately, the K0 & K1 seat foam each have a shape unique to their specific model. K0 reproduction molded foam is available from a few different vendors. Best to source the new foam & cover from the same vendor.
Ok thanks, the cabinet I use has sand or glass media, I guess I will just take a stiffer bristle brush to it.None are painted. To get it to look as new, vapor blasting/soda blasting is the way to go
Ok I have tried a few different things on it an just can’t seem to cut the oxidation between fins without damaging the surface. Why is the 16 tooth not good?Neverdull works great Chris, try it... It looks REAL GOOD, if there isn't built up grease which obviously yours does not have. 16T is not a good choice for 72ccs or even 88ccs.
Oh thanks, I figured one more tooth would give it a little more top end, guess I will have to get a 15 tooth.It will not rev out 3rd gear or hit normal top speed.