Rebuild Cylinder head

[DevonCbx]

Well I finally came down to business regarding my bike smoking etc. I had it proffesionally leak tested and and over all checked. I found out the rings are good, but I need to rebuild the cylinder head. Now what is involved here. I'm hoping to rebuild this myself due to labour costs. What is involved of rebuilding and can this get rather costly?

Thanks

[EMS]

This is difficult to answer, because there are several stages a head rebuild can occur on and prices for the material varies widely. I am going through one right now:

1. you can clean the head up and replace the valve stem seals. Cost for this is valve stem seals only. Special tools you need is a suitable valve compressor and I would recommend -although you don't absolutely need it - a valve seal removal and installation tool. What you also should do is relap (seat) the valves, if you want and are able to re-use all of them.
2. replace the valves. Cost for valves varies quite a bit. I have purchased inlet valves for $12/pc and outlet valves for $16/pc. But they can go up to 25/pc and higher. Reworking the seats is almost a must. Unless you have a shop and are a pro with the right tools, recutting valve seats is not something you can do yourself
3. Do all of the above and plane the head and flow it. Job for a specialist.

[DevonCbx]

Now this is getting scary. I guess the bottom line is want to save on labour. Also I like to try to tackle things myself. I did build the CBX out of three bikes, but have not had any experiance with the internal parts of the engine.

Thanks for the information.

Duane

[EMS]

Don't be scared, Duane. You may get away with just valve seal replacement. And that is a job you can do. But it all depends how bad the valves and valve seals are.
I also forgot to mention that the valve guides can be replaced and may have to be, depending how bad they are

[daves79x]

Duane:
If you would need a complete head rebuild, that would include new valve guides and that is expensive. A shop with the tools and know-how has to do that and there is a lot of labor involved. A head needing all new guides, valves, seals and labor can easily run $1000. You need to have the guides measured carefully to see if they are partly causing your problem because just leaky valve seats will not cause oil consumption. Worn guides and seals will. The cheapest valve guide replacement I know of runs around $300-$400. Maybe others have different experiences.

Dave

[alimey4u2]

Duane, First thing I would ask is ..Have you done a overhead cam cylinder head before ? If not, it's a daunting task but not one impossible with some basic engineering skills. First thing to do is make your mind up if your going to do a total head overhaul or repair the problem areas ? This decision would be based on how much money do you want/need to spend & how much time you have. It is important ( some may disagree) to place each re-used component in exactly the same hole/spot it came from. That means lots of ziplock bags & a good magic marker pen.

Isolate problem areas by doing a compression test prior. You then have 4 valves to check in that area. Valve leak rates can be individually checked by pouring kerosene in the inlet/exhaust tracts & comparing leak rates with the head off .

It is false economy not to replace ALL valve guide seals. One/two three are bad ? It is likely they are all near their service life.... Union shop, one out, all out... :)

Get a professional to do a 3 angle valve job. This requires special tools & skills & best left to the experts....

Check for head flatness prior to assembly & off to a reputable shop for light skimming if necessary...Maybe a good idea to check first before all your hard work.

We are here to help, good luck & don't forget to catalog ALL items diligently....

[DevonCbx]

Thanks so much for all the information


Duane

[alimey4u2]

Duane, If you do decide to do it yourself. If you are in a position of doubt, stop & ask questions first...