Milled or unmilled

jug · Apr 9, 2015

Hi Guys, is there a measurement I can take to see if my 750's head has been milled. Ordered a cam kit from JS Motorsport and need to ensure the head aint been milled before I came into its possession.
A measurement of the squish band comes out at 3mm.
Thanks in advance.
jug

Nortiboy · Apr 9, 2015

jug said:
A measurement of the squish band comes out at 3mm.

jug

Hi Jug,

We ride dirt bikes from Kitchener pub to the Aberdare state forest so I am probably the only one on this site who knows where you are.

I just re-cut a squish band after shaving the head. Depth of squish band is not a good guide to determine if you have a std head. A pic and measurement of the gap between the fins will assist.

Cheers

jug · Apr 9, 2015

Cant get a good pic of the head tonight but the measurement between the gasket surface and the fin is 1mm (give or take).
Cheers Buddy
JUG

Chili · Apr 9, 2015

Sorry Nortiboy your not the only one by a bull's roar, that knows where he's at.
Peter

pete.v · Apr 9, 2015

Skimming .040" (approx. 1mm) from a stock head will bring it pretty close to the deck of the fin. You will see areas near the casting marks where is will blend as one.
I think yours has not been milled.

dynodave · Apr 9, 2015

1mm=.03937"
Most stock heads are .117 to .120" squish band not counting spigoted barrel heads.
Yours seems to be virgin 750
full auto 750 .125" yeilding 49.4cc
combat is .080" yeilding 48.1cc
I recently examined a radically (IMO butchered) cut RH10 850 head .056" yeilding 44.5cc
You guys in OZ must feel differently about head machining. How can you remachine a skimmed head to restore the squish band depth when the original is at the edge of the exhaust seat?

jug · Apr 9, 2015

Thanks guys for your input. I have passed both measurements on to Jim S.

There is no blending of the casting marks and gasket surface at all, still has a step so think I'm a virgin. LOL
BTW, often see you guys unloading your bikes across the road from the pub.
jug

Nortiboy · Apr 11, 2015

jug said:
BTW, often see you guys unloading your bikes across the road from the pub.
jug

Jug,

Yep, we do that under the big Gumtree opposite the pub. Great counter lunch there. I have a mate who told me a Norton run is on 19th May to the Old Road Warriors Café from 10 till 2. If its not raining I will go. Not far for you.

Cheers

jug · Apr 11, 2015

Next time I'm going into town and see the bikes there, just might stop and see if there are any Nortiboy's about. lol
jug

Milled or unmilled

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