engine build question
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Road Warrior
Joined: Dec 2007
Posts: 1,498
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From: Atoka, TN
engine build question
Would bumping the compression up to 10:1 on a 96 inch motor be worth the hassle? I am seriously considering a 103 kit and some Andrews 54H cams, but am wondering about what the outcome would be if I just did the cams and went with a set of lighter pistons that bumped the compression up to 10:1 and stayed with the 96 bore? What's your thoughts?
Chris
Chris
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From:
Remember with 10 or 10.5 to 1 you will be running premium only . Not very often but a few times there was no 91 min available so I put in a couple gallons of 87 . The bike pinged like crazy . I carry some octane booster for rare times like this . But the horsepower sure is fun .
Paul
Paul
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Joined: Jul 2009
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From: Eastern NC
Would bumping the compression up to 10:1 on a 96 inch motor be worth the hassle? I am seriously considering a 103 kit and some Andrews 54H cams, but am wondering about what the outcome would be if I just did the cams and went with a set of lighter pistons that bumped the compression up to 10:1 and stayed with the 96 bore? What's your thoughts?
Chris
Chris
Last edited by ryanl; Sep 18, 2009 at 07:17 PM.
Tourer
Joined: Jul 2009
Posts: 384
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From: Eastern NC
Maybe look into running the 54's with an advance key for now. Then pull the heads and cylinders and do it right when the funds are available. By just swapping pistons, your CR will go up, but your not gonna know where it will be until you assemble it and do a compression test. Im not a big fan of guess work and assumptions on motorwork. My advice would be to consult a builder, and if a builder is telling you to just swap pistons and you will have a 10:1 CR with stock heads. Then I would look for a different builder. Just my 0.2c
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From: The Internet (& Dyer, Indiana)
In my opinion, if you are planning on staying with the 96", I wouldn't bother changing the pistons. I would shave the heads and use the Cometic head gaskets.
If you do decide to swap the pistons, you might as well go 103". Won't cost much more at all and you have to do the labor anyway.
10:1 is a safe choice with that cam. It is very well mannered. I run mine at 10.4:1 and it behaves well. The only ping I ever got was in the mountains near Sturgis when it was hot and running on the crappy fuel thay have there. ON decent fuel this thing behaves like a champ! (but I am pushing the limit). 10 - 10.2:1 would put you in a comfortable range for that cam. It is quiete and very well mannered. Lots of low end grunt and still some on the top to play with.
If you do decide to swap the pistons, you might as well go 103". Won't cost much more at all and you have to do the labor anyway.
10:1 is a safe choice with that cam. It is very well mannered. I run mine at 10.4:1 and it behaves well. The only ping I ever got was in the mountains near Sturgis when it was hot and running on the crappy fuel thay have there. ON decent fuel this thing behaves like a champ! (but I am pushing the limit). 10 - 10.2:1 would put you in a comfortable range for that cam. It is quiete and very well mannered. Lots of low end grunt and still some on the top to play with.
Banned
Joined: Sep 2009
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From: The Internet (& Dyer, Indiana)
Just read the budget thing.
If you really wanna skimp, just throw the 54's in for now. Perhaps pull the heads and reuse the stock pushrods, and throw some cometic .030's in there for a small compression boost. You will see a very noticable improvement, but won't see the full potential until you spend a lil more money. I knew guys who did just that (with the 54's) and were quite pleased.
Don't waste your time with the piston idea.
If you really wanna skimp, just throw the 54's in for now. Perhaps pull the heads and reuse the stock pushrods, and throw some cometic .030's in there for a small compression boost. You will see a very noticable improvement, but won't see the full potential until you spend a lil more money. I knew guys who did just that (with the 54's) and were quite pleased.
Don't waste your time with the piston idea.
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Ultimate HDF Member
Joined: Aug 2008
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From: eastern oklahoma
if you are going to do it, wait another month or two and save up for boring the cylinders and replacing the 96" pistons with 103" pistons. it's not a huge increase in cubic inches, but while you're in there, why not? if you've to the heads off anyway, swapping cams, you may regret not going with the 103". i'm waiting for winter to do mine.
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From: sayreville nj
103 upgrade question
Question when i had the stealer do the se 103 upgrade new heads flat top pistons se 255 cams se hi flo air filter se race tuner rine hart tru duals heavy duty clutch spring dyno tune on my 2007 road king my new numbers were 84 hp and 102 tq are these numbers in the acceptable range for this upgrade and how do i push the hp to the 100 range. thanx to anyone that can help. ps i think the cr is only 9.6 to 9.8
Tourer
Joined: Jul 2009
Posts: 384
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From: Eastern NC
Question when i had the stealer do the se 103 upgrade new heads flat top pistons se 255 cams se hi flo air filter se race tuner rine hart tru duals heavy duty clutch spring dyno tune on my 2007 road king my new numbers were 84 hp and 102 tq are these numbers in the acceptable range for this upgrade and how do i push the hp to the 100 range. thanx to anyone that can help. ps i think the cr is only 9.6 to 9.8
If your going to make any changes, I would consult a builder on what you have and what you expect. Someone like Hillside, Tman, HQ etc.... can get you where you want to be.