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Technical Forums => Twin Cam => Topic started by: jake2351 on April 14, 2018, 07:04:26 AM

Title: heritage questions
Post by: jake2351 on April 14, 2018, 07:04:26 AM
im now thinking for doing  a displacement increase on my bike. i really at this point dont want to touch the bottom end. from what im rerading here
it loos like 95 or 96 CID is about it without touching the bottom end. my bike has 17 k well maintained miles on it. pipes carb and air cleaner have been upgraded and it made a nice difference in how she runs. bowing to the other owners here experience what would be a good combo to spunk the old bike up a bit more? ill do my own work as far as disassembly and reassembly goes after 50 plus years of working on bikes i think ive got this one. but my lack of experience with HD products tells me learn from others who have already been down this road and  dont go into to this blindly making changes and hoping for positive results. im just looking for a nice rideable bike with a little more hp and torque then who knows what ill do once this is completed more is almost always better although i have  created some monsters in the past that were only fun to ride wide open and im done with that kind of thing. how much difference would a cam change make ? whats the optimal bore size for good ridability etc. im here to learn.   
Title: Re: heritage questions
Post by: Hossamania on April 14, 2018, 07:29:44 AM
What year is your bike? Efi or carb? If it is an 88" motor, going to 95" and a cam upgrade, many choices, gives a nice bump on power with not a lot of money put out. Include a good tune in your pricing.
Title: Re: heritage questions
Post by: papaduke on April 14, 2018, 08:14:56 AM
What year? You said carb so assuming its an early twin cam...

A really standard build:

Screaming eagle flat top 95 pistons
Bore your cylinders
I would find a good set of 96 heads and get them ccd and decked.
Gear drive cam conversion.... I like the Andrews 37 but youll get 100 different opinions here. The Andrews 21 and 26 are also really popular.
I did a feuling oil pump and cam plate since mine was showing wear
And an ignition module....

I just finished my build up. Did a valve job, a light port and polish, and rebuilt the heads. Had them decked to 80ccs which gave me 190 ccp.

One thing I found really helpful was to use the bigboyz compression calculator to help with cam, piston and head cc numbers.
Title: Re: heritage questions
Post by: smoserx1 on April 15, 2018, 05:52:48 AM
I have kind of done my FLHT in stages, with a 203 cam first, then a 21 cam and finally a 95 inch kit with the SE flattops.  Realize the 95 inch route affords many options for compression ratios.  Even with the SE pistons there are several of them I believe all with various compression ratios.  Those cast flattops will raise the compression ratio a little over stock but not much.  That is what I have. The 203 cams to me made a noticeable seat of the pants improvement in around town performance with the 88.  Later I went with the 21 cam because I wanted a conversion cam (that option was not available when I did the 203).  I really couldn't tell any difference between the 203 and the 21.  Finally I went with the 95 inch because I had developed  an oil leak at the base of the cylinder, plus I had high mileage.  As far as I can tell, no difference around town between the 95 and the 88.  I did notice a little better roll on at 60+ mph in top gear.  You really need to ask yourself where you want your power and torque to be.  FWIW, when I took the 203s out I gave them to a buddy who put them in a Dyna.  Later he traded it for a Fatboy and just recently installed an Andrews 26 set in it.  He told me the 26 cams are noticeably softer on the bottom than the 203s were, and that is just the opposite of what I would want.  I want a stump puller and could care less about what happens above 4000 RPM.
Title: Re: heritage questions
Post by: rigidthumper on April 15, 2018, 07:00:54 AM
Displacement?  XX= 95" or 96", or 98"  bore of your stock cylinders, or 100" kit from S&S is available, your choice.

Take some time and evaluate where you shift ( RPM wise) 90% of the time. If you shift around 3500 RPM 90% of the time, then the build list might include port cleanup (deburring and valve job) work, valve springs to match an early close cam, XX" @ ~9.5-9.8:1 compression, improved clutch spring, current carb, pipes, etc (mild-ish build).
If you shift closer to 4500 on a regular basis, then +1 valves with velocity port work, better valve springs to match a mid range cam,  XX @10-10.5 CR,  off the shelf exhaust, 45mm carb.

There are conversion cams, which allow use of the 07-present hydraulic cam chain tensioners/cam support plate/oil pump in an 06 and older twincam. Better product IMO.
Title: Re: heritage questions
Post by: jake2351 on April 16, 2018, 04:50:23 PM
its a carbuerated 2006 bike.
Title: Re: heritage questions
Post by: jake2351 on April 16, 2018, 05:00:36 PM
thanks for all the info this will be a street bike so i want a nice rideable machine with good bottom end its not going to be a race bike but a good strong midrange also wouldnt hurt but i have no intention of screaming it on the top end im trying to mellow out in my old age. i got really tired of screaming the four cylinders to the redline.
Title: Re: heritage questions
Post by: gregfxs on April 17, 2018, 06:06:54 AM
02 FLSTC carbed CV, 95", 37g cams dtt ign. runs good, good mid range,  :chop:
Title: Re: heritage questions
Post by: bigfoot5x on April 17, 2018, 05:50:37 PM
It's all about the money, really. I had an 88" and had it bored to 95". I used the SE forged 95" pistons. They had a 9.8 reported compression ratio. I used a cometic .030 gasket which gave a little more compression bump in theory and SE 204 cams. The 204's like a little more compression than stock but were a good choice for mid range torque. After tuning, it had 85 hp and 100 ft/lbs of torque. It had more pep across most all of the rpm range. Enjoyed it until I had 72,000 miles on it. If you have the extra money, you can get head work done with valve springs that allow more lift. That would allow more cams to choose from for even more hp. I did all the work myself with the help of the service manual. It is excellent.
Title: Re: heritage questions
Post by: koko3052 on April 17, 2018, 06:58:22 PM
Same build as bigfoot., only had some headwork done. Was a fun machine but with the 204s it ran  out of breath by 4800. For a cruising engine it was great!  :up:
Title: Re: heritage questions
Post by: N-gin on April 18, 2018, 09:42:25 PM
With only 17k, why not just check pinion runout and go from there.
A set of gear drive 509 cams will really wake things up. then you can see what it was suppose to run like out of the factory.
Title: Re: heritage questions
Post by: jake2351 on May 08, 2018, 09:54:42 AM
who makes these 509 cams? im going to look into this.
Title: Re: heritage questions
Post by: Hossamania on May 08, 2018, 09:58:47 AM
S&S. Call California Phil.
Title: Re: heritage questions
Post by: jake2351 on May 16, 2018, 06:44:33 PM
Thanks very much. Im going to check into those cams I havent changed cams in a HD this should be fun. 
Title: Re: heritage questions
Post by: Hossamania on May 16, 2018, 06:52:04 PM
Phil set me up with everything I needed. Great price.
Title: Re: heritage questions
Post by: Lone Ranger on May 23, 2018, 01:56:18 PM

Did you have change tappets and pushrods?
Title: Re: heritage questions
Post by: PoorUB on May 23, 2018, 04:50:28 PM
I would change the lifters without question. I don't know the base circle on the 509 so not sure if the stock push rods will work, but I would use them over adjustables if they will work. The last cam change I did I cut apart a stock push rod and made an "adjustable" push rod to measure the length I needed and ordered custom length push rods from Smith, about $60.