350x exhaust studs

[litebulblsc]

Hello,

Snapped my exhaust studs off, so I have a couple questions.

First, I need to know the thread size and length.

Second, it would be helpful to know the hole depth.

Plan is to mill out broken studs, helicoil, and install new studs.

Thanks,
Josh

[oscarmayer]

I would take it to a machine ship and let them remove it. way easier than trying to do it yourself.

[litebulblsc]

I am a machinist.

[oscarmayer]

Oh cool! Lucky you! Ok good luck with it.
I believe the studs are 6mX 1.25 the inner thread is the same as the outer.
Not sure the depth but holes are all the same depth or close to it.


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[wonderboy]

They are M8 studs. I can measure depth tonight when I get home if somebody isn't able to get in here sooner and post.

For reference, the parts catalog lists the studs as M8 x 40 mm.

[litebulblsc]

I still have to pull the head tonight and order the helicoil set. So if you can't get it till tonight thats alright

[oscarmayer]

8mm? weird, i thought they were the same as the 200cc stuff. ok my bad. i have not really fumbled a lot with my 350x in a while so after redoing 3 200cc engines in the last 4 weeks, i guess i got my head in the clouds. Sorry.

[litebulblsc]

Ya, I am pretty sure they are 8mm. Definitely bigger then the side cover bolts

[oscarmayer]

ok your probably right then. i can double check it tonight if ya want. I have my engine out of the trike and ez access to the head stud area.
i can then at least give you the size and thread pitch 100%.

[wonderboy]

The depth of the holes on my cylinder head varied from 0.810" to 1.15". Looking into the exhaust ports, the left side port studs were at 0.810". The right side was at 1.15". Mine were drilled out also, so the variation could be due to the rework, but you'll at least be safe to the depths I've noted.

Studs are M8 x 1.25 pitch, 40 mm length.

[Dirtcrasher]

I fixed a couple dozen of these on my Bridgeport. I mill them all off on a flat plane after I indicate it in.

Then drill them out, helicoil them and make SS studs out of 3' all thread.

Just start milling, you'll feel the end.....

[litebulblsc]

I run cnc so no feel.

They are already broke off below flush, so just going to circular interpolate them out.

Thanks for all the info guys. Just contimplating a top end rebuild now while I got it apart...

[oscarmayer]

8mm x 1.25