head and cylinder prep

[bustedplastic]

So i got the head off today, here are some pics.  Did we overtorque, not prep the surfaces enough?

I read a post on here about prepping the surfaces with 400-800 grit paper, should I do this with my next gasket or should i just pull the cylinder off and take it and the head to a machine shop to get them prepped?  If the cometics are so finicky, is there a better alternative for a 105 mm bore?

Thanks,

David

[preddy08]

I think first we should try to find out how you preped the cylinder and head before the first install, then go from there.

[bustedplastic]

I think first we should try to find out how you preped the cylinder and head before the first install, then go from there.

the cylinder was bored and decked, so the suface of the cylinder was perfect.  However we only cleaned the head, no sanding or anything...

[preddy08]

I think first we should try to find out how you preped the cylinder and head before the first install, then go from there.

the cylinder was bored and decked, so the suface of the cylinder was perfect.  However we only cleaned the head, no sanding or anything...

From this point I would clean up everything with brake clean and a clean cloth and take a stright edge (not a ruler) and see if there is any low spots on the head or cylinder by seeing if you can put a fealer guage inbetween the head and stright edge. I've never sanded a cylinder or head, nor do I think it is nessasary in this case. I had Bo put a good surface on my head and cylinder on my first build and I've had it apart three times since then and never touched the surface with anything other than a towel and brake clean. I'm running a 105 bore and 14:1 compression and have never had a problem.


Another possibility is that the gasket got twisted during install. Those rivits that hold the head gasket together should move freely. If any of them dont, then the gasket got "cock-eyed" during install.

[bustedplastic]

Awesome, thanks for the tips, i'll have my new gasket Monday, so hopefully i can get a good seal, no more bubbling in the overflow and crazy ass vaccuum in the radiator...

[Troy]

I sanded my cylinder and head starting with 400 and moving on to 600 the other day when I freshened up my rings.  This was the first time I've ever done it.  My bike has been strapped to the dyno all week with around 200 runs on it with no leaks.  I will tell you I copper coated the shit out of my cometic gasket, I give the copper coat as much credit as anything at this point, I've had good luck with it.  There are new gaskets coming out, Tonto is sending me one for testing and I think a few others, sounds like it should be a great alternative to what we have out there now.  I used a 12x12 inch granite tile and glued the sandpaper to it for the cylinder and head prep.

[Kenny]

So i got the head off today, here are some pics.  Did we overtorque, not prep the surfaces enough?

I read a post on here about prepping the surfaces with 400-800 grit paper, should I do this with my next gasket or should i just pull the cylinder off and take it and the head to a machine shop to get them prepped?  If the cometics are so finicky, is there a better alternative for a 105 mm bore?

Thanks,

David

I think there is....... Don't prep anything and I will ship you one of my new head gaskets to seal this dude up. PM your address