Head resurfacing question

1fasgsxr

Over 1,000 Posts
Can mostly car oriented machine shops resurface a motorcycle cylinder head? I know some of you out there are machinists...I have a few local machine shops but not sure if I trust them
 
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yes, providing they are not morons.

you might want it done on a wet stone machine but those are few and far between these days.

this will also retard your cam timing slightly but you can buy an adjustable cam gear if necessary.
 
Gonna have to line bore if cam journals are a factoid also... Squish will need some optical fornication as well :eek:
 
We surface heads in the shop all the time. Granted not MC heads, but the process is the same. Barnett468 is right, wet stone grinders are the bees knees, but a quality machine shop with a bridgeport mill can do a slight head resurface in probably an hour or less, and unless it's really warped, it shouldn't affect your timing enough to worry about. Our usual take-off on heads is between .005" and .010".
 
I dont know that it really needs it..had some knicks and scuffs on it..didnt want to take the chance in it not sealing up right
 
1fasgsxr said:
I dont know that it really needs it..had some knicks and scuffs on it..didnt want to take the chance in it not sealing up right

if the sealing surface just has light scratches, just put some 320 sand paper on a granite counter top and spray water or wd40 on it, clean the head then color it with black felt pen then rub the head around on it for maybe 10 seconds at a time until it looks happy.
 
barnett468 said:
if the sealing surface just has light scratches, just put some 320 sand paper on a granite counter top and spray water or wd40 on it, clean the head then color it with black felt pen then rub the head around on it for maybe 10 seconds at a time until it looks happy.

I really like that idea
 
Finnigan said:
I really like that idea

yeah, it works great, unfortunately, I have to go to a nice restaurant and use the counter in the bathroom because I don't have granite counters, and i got kicked out of Macys department store the last time I tried to do it on their polished marble floor.
 
barnett468 said:
yeah, it works great, unfortunately, i have to go to a nice restaurant and use the counter in the bathroom because i don;t have granite counters and i got kicked out of macys department store the last time i tried to do it on their polished marble floor.

BAHAHAHA!
 
Finnigan said:
BAHAHAHA!

I used to just tie the heads to the rear bumper of my pick up truck then simply drag them around the parking lot of Food Mart for a while but quit doing that after someone ran one over and crusjhd it.
 
The main reason to cut cylinder head on bike is to raise compression not correct warp.
A 0.020" 'skim' on gasket face will retard cam timing around 7 degree's, you don't need to slot cam sprocket but it may be a good idea ;)
You will need to check edge of combustion chamber to piston clearance
 
Some lapping compound and some plate glass make for a great DIY approach when used in conjunction with some Prussian Blue.
 
Sonreir said:
Some lapping compound and some plate glass make for a great DIY approach when used in conjunction with some Prussian Blue.
Yep, granite not needed. I use the glass plate and sand paper method. Now I am no "expert", but I was told to go in only two directions. Back and forth and left to right. A circular motion will tend to not get it flat but instead "domed" to a degree. (I know these pics are cylinders and not heads, but the process is the same). We have done this with multiple snowmobile jugs and heads with good luck.

If you look close, there is a plate of glass under the sand paper
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glass plate can flex.

going in a circle will not create a dome if you are careful, but if you simply go forward and back a few times, then rotate the cylinder 180 degrees and go forward and back again etc, it will also get flat.

if you color the surface with felt pen, then simply rotate it in a circle two times on 600 sand paper after you are finished, it will show if it is flat or not.
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The only truly flat glass is float glass, which is not tempered. But float glass is pretty flexible (your house windows are float glass), so it flexes to match the surface it's laying on. Might as well be doing it straight on the table. Tempered glass, either by heat or chemical is not truly flat since it comes into contact with rollers above transition or quartz inversion. It actually has waves. In other words, glass ain't no good when you need a perfectly flat surface.
 
What about a large piece of metal ...I have seen that done before...Just wrap the sand paper around the large piece of metal ( large tubing say 4x4 box tubing). I would be worried about anything not being truly flat.
 
barnett468 said:
lapping compound will not surface a warped head.

It's not meant to. If you have a warped head, I don't think dealing with it at home is the best fix anyway.

Lapping compound will definitely take out any imperfections and clean up the sealing surface, however.
 
My head surface is not warped..Just a few nicks here and there. Maybe just a few passes with some 320 and a new gasket. It wasn't leaking before. Guess I am OCD
 
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