Problem with Aluminum Cam End Plug, Won't Fit

I've got new aluminum cam end plugs and they won't fit the right side of my cylinder head ('78 KZ1000 A). I measured the casting thickness of the head at the cam plug area:
LH side = .0245"
RH side = .0275"
Aluminum cam end plugs are .0265" inside width (lip on both sides)
The cylinder head casting must be slightly off center. The original rubber plugs fit fine since there is a lip on only one side.
So now I'm wondering if any specific brand of aluminum plug ends would be wide enough for this head? Anybody had this problem before? It's a new one for me....
These are the plugs I bought and they are all exactly the same size:

Cant you just file a little off the casting on the right side?

I had the same problem on my 77 KZ1000 only i had just one that would not fit. It wouldn't seat as far as the other 3. They are Blue APE ones. I was hoping the one you got from Z! would be better, You may have just saved me some money.

peter1958 wrote: Cant you just file a little off the casting on the right side?

Right side of the head? I could but I'm not crazy about that idea. Doesn't look like enough material to file the plug. I'm hoping to find another brand of plug that's a couple thousandths wider.

kaw-a-holic wrote: I had the same problem on my 77 KZ1000 only i had just one that would not fit. It wouldn't seat as far as the other 3. They are Blue APE ones. I was hoping the one you got from Z! would be better, You may have just saved me some money.

I have the blue APE ones on my MKII...they fit that head no problem but I never measured anything. Do you have a loose APE plug that you could measure?

I will go measure one of the apes. 0.2695 inside lips of plugs

kaw-a-holic wrote: I will go measure one of the apes. 0.2695 inside lips of plugs

Cool, thanks a lot. Pretty much the same size as mine. There are a few others on the market but I'm not sure that any would be wide enough.

I'd like to file the head on the inside but no way to do it assembled. I'm afraid of what filing the outside would look like. I'll have to get a better look at the head and the plugs...hopefully can file a little somewhere.

peter1958 wrote: Cant you just file a little off the casting on the right side?

I didn't realize the area around the cam end plugs was raised so much. That made it very easy to neatly file down that area to the proper size. All fixed....thanks!

Prep before filing:



Filed:



Filed, sanded, touched up - Finished:

common problem .

Looks good!