HarleyTechTalk

Quote from: Adam76 on November 10, 2024, 05:02:10 PMThanks, that's easier than machining the base of the cylinders.
Cheers

Adding a shim adds to the base of the cylinder. Machining removes from the base. Not the same thing.

Stick with the o-ring seal and set the cylinders properly.

I agree.  I thought those cylinders and cases used the standard size .020 base gasket by the sound of the previous discussion.

My 4.060 barrels did but had +.003 deck height that I dialed in with the base gaskets.

Quote from: Ohio HD on November 10, 2024, 05:08:19 PM

Quote from: Adam76 on November 10, 2024, 05:02:10 PMThanks, that's easier than machining the base of the cylinders.
Cheers

Adding a shim adds to the base of the cylinder. Machining removes from the base. Not the same thing.

Stick with the o-ring seal and set the cylinders properly.

OK, thanks. Got it.

 

Quote from: Ohio HD on November 05, 2024, 06:26:22 PMFYI, the 3.937" cylinder bore (107 cu in) uses a 3.954" head gasket as I recall.

Hey Ohio, just out of curiosity - if I was using a piston with a bore size of 3.915 (oversize 103" piston) what HG would I use? Would the 3.954" be too big? Does Cometic even make a HG that would suit that bore size?
Thanks.

Quote from: Adam76 on November 15, 2024, 04:38:25 PMHey Ohio, just out of curiosity - if I was using a piston with a bore size of 3.915 (oversize 103" piston) what HG would I use? Would the 3.954" be too big? Does Cometic even make a HG that would suit that bore size?
Thanks.

Adam, it might be easier if you called Cometic, give them the gasket ID and thickness that you want, and see if they have them or will make them.

Quote from: Ohio HD on November 15, 2024, 06:00:52 PM

Quote from: Adam76 on November 15, 2024, 04:38:25 PMHey Ohio, just out of curiosity - if I was using a piston with a bore size of 3.915 (oversize 103" piston) what HG would I use? Would the 3.954" be too big? Does Cometic even make a HG that would suit that bore size?
Thanks.

Adam, it might be easier if you called Cometic, give them the gasket ID and thickness that you want, and see if they have them or will make them.

Thanks. That's the obvious answer  .
I'll probably just go down the 107" route as it seems easier to work things out and get parts for.
I've found the KB V-Twin KB714LCA.STD flat top pistons which look pretty good and reasonably priced. So I'll probably just use those.
Cheers

What cam are you using? 10.1, 10.3?
Have you CC'd the heads. If so, I missed it.
What's the concern here?

Quote from: 60Gunner on November 15, 2024, 07:10:11 PMWhat cam are you using? 10.1, 10.3?
Have you CC'd the heads. If so, I missed it.
What's the concern here?

Using stock heads, assuming they are around 85cc / 86cc, haven't got them cc'd yet. Aiming for 10.2 compression. Main concern was keeping compression at 10.2 with a 107" build...

I just finished a .040" 88" top end.3.915" bore. You need to use Twin Cam 100MM bore head gaskets.
Cometic # C9894 = .030"
Cometic #C9894-.036".
They are the same head gaskets as the gaskets used for 96" and 107"
John

Quote from: Adam76 on November 15, 2024, 09:38:03 PM

Quote from: 60Gunner on November 15, 2024, 07:10:11 PMWhat cam are you using? 10.1, 10.3?
Have you CC'd the heads. If so, I missed it.
What's the concern here?

Using stock heads, assuming they are around 85cc / 86cc, haven't got them cc'd yet. Aiming for 10.2 compression. Main concern was keeping compression at 10.2 with a 107" build...

10.2 is the target because???. 
Make the valve pockets a little deeper/bigger and you're back to 10.2 if you're worried about going over 200psi CCP. That's if it actually IS 10.4.

Quote from: jsachs1 on November 16, 2024, 01:09:08 PMI just finished a .040" 88" top end.3.915" bore. You need to use Twin Cam 100MM bore head gaskets.
Cometic # C9894 = .030"
Cometic #C9894-.036".
They are the same head gaskets as the gaskets used for 96" and 107"
John

Thanks John.

So if I'm reading you correctly,  it's the same C9894 gasket whether I have bore size of 3.915 or 3.937.... Thanks for clarifying.
Cheers

100 % correct. The same.
John