This may be a dumb question, but I have to ask...

[brs127s]

Last night, I was trying to clean up the head on my 850. I was using a wire brush on my Dremel tool to remove the carbon from the valve areas and the dome of the cylinder. I realize that my bike had alot of carbon, but is the head(top of the combustion chamber) coated with anything?

I removed everything down to bare aluminum, and hope I have not made a mistake. This is all pretty new to me, so I am sorry if this is a dumb question. I have rebuilt dirt bikes, but the carbon was blasted off with a sand blaster and it didn't have any little nooks and crannies for the sand to stay in. It was basically a cap that bolted to the cylinder. I am not glass beading the head on my 850 because it is painted. My machinist buddy said if we beaded it, we would have to run it through the high pressure washer at the shop to remove all the glass beads, and this would remove all the paint.

Thanks

[Billy Ricks]

You haven't hurt anything. Just don't do anymore to the valves than you have to to get them clean.

[Anonymous]

gs850 head

hi brandon. if this is your first multi cyl head there are a few more things to check out.take a straight edge and check for any warping use a feeler gauge under the straight edge to see how much warp there is, depending on how much there is you may have to replace the head. if the motor had extesive carbon you should check the valve guides,put thevalve in the guide and see how much movement you have. a new guide is not a loose fit. if you have loose guides have them replaced, new guide seals will only help for a short time. another thing to look at are the valve seats, are they pitted or worn, if they are have them re surfaced at a reputable shop if you do this you will have a valve adjustmint ahead of you. now look at the valves are the seating surfaces smooth if not replace.now flip the head over and check the cam and cam retainers for wear as well the bearing areas of the head if they are bad you may have to replace the head hope i have enlightened you about your head project thanks reg

[Anonymous]

Valve stem seals are always smart to replace. Another thought is that while you are using your dremel it would be an excellent time to lightly polish the combustion chamber to be sure that you didn't leave very tiny valleys while you were de carboning.

[brs127s]

When my machinist buddy removed the valves, we cleaned and measured everthing. The valves and guides were okay. I am going to replace the seals. We are going to grind the valves and seats. After everything is ground, we will measure the butts and but grind the valves if possible.

So far the only thing that needs replacing are the seals and the rings. I also plan to replace the cam chain. Another buddy who is a mechanic recommended that I do this. He replaces them by breaking and repressing a pin, so that is the route I am going to go.

[Anonymous]

When my machinist buddy removed the valves, we cleaned and measured everthing. The valves and guides were okay. I am going to replace the seals. We are going to grind the valves and seats. After everything is ground, we will measure the butts and but grind the valves if possible.

So far the only thing that needs replacing are the seals and the rings. I also plan to replace the cam chain. Another buddy who is a mechanic recommended that I do this. He replaces them by breaking and repressing a pin, so that is the route I am going to go.

Please let me know about your cam chain replacement. I have always believed that breaking an pressing in a new link was quite acceptable. Lots of mechanics don't recomend it. I will be doimg the same thing soon. Good luck with your rebuild job.

[brs127s]

Hey Scotty,

When I talked to my buddy about it, I had him order a cam chain for me. He always uses DID chains, so that's what I had him order. While we were talking about it, he mentioned that he had just got a new catalog with cam chains that were not endless, and you had to buy a master link separately. Guess what brand it was...K&L. Just like the info you sent to me a few monthes ago. He had not used them, and said he would probably continue using the DID, since that is what he has exclusively used, and never had a problem.

Let me tell you, most of the machines he works on are 4-wheelers that see lots of rough and tumble farm usage. If the repressed link was ever going to fail, I would think that he would have seen one by now. He just uses a chain break to push a pin out, pulls the chain through the engine using the old one, then represses the pin on the link he pushed apart.