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Old 06-08-2011, 08:26 PM
Sgt_Jim Sgt_Jim is offline
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Default fuel mileage with cams

I did a quick search but i have such issues with this site that I couldn't really find what i was looking for before I got annoyed..

Anyways, someone in the softail thread just put in some Woods TW-555 cams, and just from those got a 20.2 increase in HP and a great looking torque curve.. but I'm just wondering, how does changing cams effect fuel mileage? I mean i already dropped by like 10% doing a Stage I intake and exhaust (from 47mpg, to 41-43, average)..so what does this do to it?

Also, assuming I have a garage full of tools and gauges and all the bells and whistles.. how hard is it really to change chain driven cams?
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Old 06-08-2011, 08:50 PM
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A good torquey street cam can actually improve your mpg. This is true with cars as well as bikes. You're simply making more efficient use of your fuel and air. That translates to being able to cruise at a lower rpm without having to constantly shift gears to stay in a comfortable power band.

Regarding the installation, here's a link that shows you the whole process, with pictures:

http://www.fuelmotousa.com/cams.htm You gotta scroll down for the installation instructions. Unfortunately, it doesn't show the procedure for the inner cam bearings, which most people recommend replacing since you're in there anyway.

Probably a video or three on YouTube, also.
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Old 06-08-2011, 08:56 PM
Sgt_Jim Sgt_Jim is offline
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thanks man..yeah i saw that site earlier..they make it look so simple. my bike only has like 1500 miles on it so i'm sure the bearings are probably still good.. first i gotta find $400 for a set of cams, then the time to change them
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Old 06-08-2011, 09:09 PM
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I notice you didn't mention a calibration or tuner. You'll need that if you want the bike to run right. You could probably get your mpg back if you had the right fuel map and ignition timing.
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Old 06-08-2011, 09:18 PM
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well I have a PCV, and the map is good.. but i didnt' expect to keep my stock mileage with a higher intake/exhaust rate
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Old 06-09-2011, 10:04 AM
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You should expect to lose mileage on a stage i upgrade; the motor was running very lean from the factory. However, you should lose any more by installing cams provided that the tune is right. I get 42-44mpg from my 95" with ported heads, cams, 2:1 pipe making 104tq/94hp and I ride the snot out of it. The only in town riding I do is what it takes to get out of town and once out, rarely is the speedo under 70mph. The bike didn't stay stock long but the best I ever got when stock was 48mpg but that was a bike that made 80tq/70hp; trading a few mpgs for more tq/hp is a no brainer.

However mileage is a function of so many factors that it is really hard to compare your mileage with mine and understand why they are different.

Last edited by djl; 06-09-2011 at 01:33 PM..
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Old 06-09-2011, 10:18 AM
Sgt_Jim Sgt_Jim is offline
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sorry i'm talking about the same subject in 2 different threads.. didn't want to hijack the other so i made this one..

stock i was averaging 47mpg (96B engine), since the stage 1 (V&H BSS Black, Arlen Ness Big Sucker I, PCV) I average 43 or so.. but that's combination City/Hwy.. a lot of stop-n-go, so naturally that kills the average by itself. I don't really jump on her too hard unless I'm on a highway..

I just don't really know much about cams themselves, aside from the fact that apparently they make a really frickin fast boost in HP and Torque.. In my mind i'm thinking of it like adding a turbo charger or a supercharger to a car, where there is an immediate and noticable drop in MPG.. (for instance, my 2.3 Mazda 3 vs the 2.3 Turbo Charged MazdaSpeed 3.. i get 30+mpg, the Speed gets like 22-23 average)..

It doesn't seem like a really "hard" modification to do, except some in the other thread are saying I'd have to change out my pushrods and remove the heads, or use adjustable pushrods so i don't have to remove the heads... i'm sure it's more straight forward than it sounds, and me being a hands-on kind of guy, i really don't want to pay $65+/hr to have a mechanic do it for me. that and i'm not made of money.

but if your bike is making 94HP and still getting the same average fuel mileage that my stock (aside from what i've mentioned) 96".. then maybe it either won't affect it, or like cjlandry said, will help improve it..
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Old 06-09-2011, 10:58 AM
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As far as the install, make sure you get the "Quick Install" (or whatever they call them) pushrods, not just the adjustables. There is a difference. I'm gonna do a cam swap when I get home from Iraq, and have a few hours downtime (gonna spend some time riding first). I ordered some Crane quick install pushrods for this for about $90.
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Old 06-09-2011, 11:10 AM
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Recently did SE255 cams and stayed with stock push rods, and switched to Rev. Perf. wide band tuner from the SEPST. Bike runs much better and pulls real good. Got 44mpg when I checked it Tuesday.....riding two up, in the hills and fairly spirited cause I like to "hot rod" and I have new exhaust I was listening to....no interstates, no stop and go town riding.




Here is link for the cam change, plus the manual, should be all you need.

http://www.hdforums.com/forum/tourin...-write-up.html
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Old 06-09-2011, 11:33 AM
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Riding 2 up on country roads, up and down what we call mountains in Pa. getting 46mpg and thats hitting it every now and then . On a 98" with mucho work done.
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Old 06-09-2011, 11:33 AM
 
 
 
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