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Discussion Starter · #1 ·
I few quickies I need help with before I purchase a few more parts for the build.

First my build (so far): '01 Road King, 95", HSR 42, Thunderheader, Crane ign, HTCC non-ported heads & pistons (+.010), rollers, adj pushrods, and forged rocker plates. (Already have these parts)

1. Can the TW-5G take more then 10.5:1 compression. I was going to use the Cometic .040" head gasket (friend has extra set) and it may increase it by a little. I have no problems getting 93 octane or better

2. If I don't change the gearing to the 3:37 should I get the +2 degree advance key?

Thanks,
DEVILDOG {salute(
 

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About 9.8 to 10:1 should be right on the edge before ping dependant on the fuel you get, you might get 10.25/35 with 93 octane.

.040" is ok but .030" is better, but you dont say if your heads are shaved already or what the chamber volume is?

I dont think you need 2 degree advance for that cam in any bike......I dont think going to 3.37 is needed either but some guys on here are getting excellent results by doing just that.

All the best, Ozzie
 

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Discussion Starter · #3 ·
Heads aren't shaved and the chamber volume is whatever the stock HTCC non-ported chamber is. With factory head gaskets, HD advertises it at 10.5:1compression so any thinner of a gasket is going to bump it up a bit.

Oh how I miss the Al-Anbar area!!!! If you're near Nasser Wa Salaam or Khan Dari tell everyone I said hello.

DEVILDOG
 

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The HTCC (non ported) heads have a listed chamber volume of 84cc. Not an expert but those in the know say quench is critical with the unique dome shape of the HTCC pistons, so when using a thinner gasket careful tuning is required to avoid detonation. I run the ported version of these heads and with the recommended gaskets need a good tune to avoid detonation.
 

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I can say for sure you won't need the advance key for the TW5G. Woods designed it with a built in 2 degree advance. The forged rocker assy's might be a little overkill with that cam. Now if you were up to a TW6G then yes.

The 3.37 gearing will add to the smile factor for sure. Not really stunning, but noticable.
 

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Going with the .040 will have you slightly over the 10.5 mark. IMHO, going to a thinner gasket will gain you next to nothing in power and get you into hard starting, especially after a hot soak with the TW5. Most builds we have done with the TW5 has been with the +2 key with positive results to the torque band and most have been built with around 10.3 comp. Keep in mind that the movement in the powerband is only around 200 - 250 RPM, but with a big bike that is carbed, that is a nice little bit of help. As long as you have good fuel to feed this Torque Monster, 10.3 to 10.5 is OK, but no more.
 

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Good to see you back on here GRock.

All the best, Ozzie
 
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