Big Bore Kit Questions
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Tourer
Joined: Jul 2011
Posts: 354
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From: Indianapolis, IN
Big Bore Kit Questions
Hi all. Been awhile since I've posted, but been doing a lot of reading. Starting to gather information about possibly doing a big bore kit. I'm one of those that asks tons of questions, and I'm learning as I go so please forgive me if they are "silly". My bike is a 96 FLHTC EFI. About 47K. I believe it is pretty much stock. I am getting more comfortable working on it. I've taken the tranny out and replaced the clutch plates, ran a new throttle cable, and of course regular fluid changes and brakes. This winters project was replacing the fuel lines and re-torquing the rocker boxes, hopefully to take care of a little seepage I was seeing. I had a top end job done almost two years ago. I think that covers the history of the bike and my limited mechanical experience.
Now on to my questions, probably for a next winter project but you never know:
I've been told I can do a big bore kit without having to change anything else, not sure if this is true?
What will doing this upgrade give me?
Is there a better bang for the buck investment?
I'm happy with my bike, no real issues, but starting to get the bug to maybe get a little more out of her.
Thanks for any comments
Now on to my questions, probably for a next winter project but you never know:
I've been told I can do a big bore kit without having to change anything else, not sure if this is true?
What will doing this upgrade give me?
Is there a better bang for the buck investment?
I'm happy with my bike, no real issues, but starting to get the bug to maybe get a little more out of her.
Thanks for any comments
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Back when I was looking at doing the same thing I was told that the cases had to be ground out to allow the bigger pistons to work.
If your just looking for a little more throw a cam in her and ride.
If your just looking for a little more throw a cam in her and ride.
Seasoned HDF Member
Joined: Nov 2010
Posts: 17,548
Likes: 7,175
From: Oxford, Nc
Yeah, Evo's aren't as amenable to big bore kits as are Twin Cams.
Most Evo guys boost compression, cams and fuel and get very close to 1 HP per cubic inch.
(Some install stoker kits if more power is needed too.)
Most Evo guys boost compression, cams and fuel and get very close to 1 HP per cubic inch.
(Some install stoker kits if more power is needed too.)
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
There are a number of things you can do to boost performance. The good tuning shops like HDF sponsor Hillsidecycle can boost CR, port your heads and use modern cams to give decent improvements, without boring, but also stroke out to 89". For best results use a tuning shop, so everything works together. You can remove parts, get them modified, then refit yourself, to save labour costs.
An alternative is to replace your engine with one of the many aftermarket ones. I have an S&S 107", which gives a very smooth wide torque curve and is great as a touring engine. You can fit as big as a 131", if you are in desperate need of GO! there are several 124/127 options out there, but also smaller ones around 111/113.
An alternative is to replace your engine with one of the many aftermarket ones. I have an S&S 107", which gives a very smooth wide torque curve and is great as a touring engine. You can fit as big as a 131", if you are in desperate need of GO! there are several 124/127 options out there, but also smaller ones around 111/113.
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,080
Likes: 2,153
From: Ohio
97" kits or any big bore kit will still need the cases split and crank removed for spigot boring which would make a 4 5/8's rotating assembly a better gig for a heavy bike, can't beat stroke for lower end power.
Simple Evo power is mentioned by Stiggy and several piston replacement builds have just been done. Compression, head clean up and cam is a recipe for a good running Evo
Simple Evo power is mentioned by Stiggy and several piston replacement builds have just been done. Compression, head clean up and cam is a recipe for a good running Evo
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
There are a number of things you can do to boost performance. The good tuning shops like HDF sponsor Hillsidecycle can boost CR, port your heads and use modern cams to give decent improvements, without boring, but also stroke out to 89". For best results use a tuning shop, so everything works together. You can remove parts, get them modified, then refit yourself, to save labour costs.
An alternative is to replace your engine with one of the many aftermarket ones. I have an S&S 107", which gives a very smooth wide torque curve and is great as a touring engine. You can fit as big as a 131", if you are in desperate need of GO! there are several 124/127 options out there, but also smaller ones around 111/113.
An alternative is to replace your engine with one of the many aftermarket ones. I have an S&S 107", which gives a very smooth wide torque curve and is great as a touring engine. You can fit as big as a 131", if you are in desperate need of GO! there are several 124/127 options out there, but also smaller ones around 111/113.
I found out that next month S&S is going to have a big sale (was told that engines will be 2k off retail) so I'm gonna get the 111 but would like to keep the old style rocker boxes.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I really have no idea! I have the basic finish on my 107, but the rocker boxes are chromed, the only part of my motor that is. The cheapest 124 is only a few bucks more than the 111......
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Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
The main reason I like the 111 is that its bore and stroke are the same.
That should mean less vibration which translates to fewer parts vibrating off.
Sorry for the hijack..