I'm sure this has been asked a million times, so I apologize. Trying to plan ahead, and my shop/tuner guy has been asking if I wanted a bigger engine in this like I did with my Sportster - which I'm thrilled with. If I go bigger than the 103, should I go 107, 110, or go even bigger? I don't NEED to hit 130 ft/lbs torque or HP, just looking for a little extra. Not sure how long he'll stay in business, he's about done with bikers, but I have a great resource and I figure I should use him while I can this winter.

 

The way to hp is cubic inches. The bigger cubes will pull in more air to fuel and return more power.

 

Actually, there are AT LEAST THREE ways to get more power:

- Spin the engine to a higher rpm, which our large displacement V-twins are not really eager to do without some issues

- Supercharge it or turbocharge it, which has the advantage of adding power everywhere in the rpm range

- Increase displacement, which makes the already large displacement V-twin engine even less happy about high rpm operation, and and which can affect the vibration level a notable amount

All 3mthods "pull in more air" per minute and "return more power".

All 3 methods stress that press-fit crank, but the first method stresses it the least, since it focuses on making the same or only marginally larger torque but doing it more times per minute. A welded crank is a good idea if using the 2nd and 3rd methods.

The second method makes more power than either the 1st or 3rd, but is a bit complex and usually leaves some ugly hardware exposed that sits where you want your leg to be.

If you want a racy sound and feel along with the power, the first method usually does that the best.

And, if what you REALLY want is simply snappier acceleration and throttle response, just regerar the Breakout from 32T front pulley and 66T rear pulley to 30T front and 70T rear. Guaranteed to make your bike a LOT livelier!! (see LA_Dog's sticky thread in this Softtail section of the forum). And, it will only cost you a few hundred dollars. Bargain of the decade as far as "going faster'.

Jim G

 

first thing to do is upgrade your drive belt pulleys to 30/68 or 30/70. it will make such a huge difference in felt acceleration you'll crap. This will take care of your acceleration potential and also give a better gearing foundation for motor upgrades.

For motor upgrade I'd do a set of cams first. that combined with the gearing will probably be all you need. We're talking $1500 area to do both pulleys and cams, and make quite a difference combined with good tuning. that's a lot of bang for the buck.

if you want to just go big- hell nothin' wrong with that- get one of the FM, hillside cycle, zippers 107 kits. it is extremely important to match all components when building up a motor. these places have already done the hard work for you and you just buy the kit. You'll have better than 110hp/115tq with the right kit and tune. Let's say $3k range with labor costs and tuning, and not including cost of the pulley upgrades ($900 range). very good upgrade but maybe not as big of bang for buck. really depends how much you want to spend and how much pow-pow you want under ya. On the upside, your 2016 BO already has 4.3 injectors and 50mm TB, so you can reuse that with the 107 kit and it will work fine. those of us with the smaller TB and 3.9 injectors would need to go bigger to support over 100hp.

 

Cams, Dan vance raised port heads or heads from hillside machine, bore your stock cylinders to 107. Set the compression right and be done with it.

 

Of course! I'm referring to p.n. 57040-08DH, which is the standard spoiler for non ABS equipped softail models but may be easily fitted to ABS equipped ones.
I think it has the correct dimension to fill a bit the gap between frame and front wheel without being bulky, it has the exact hole for the voltage regulator and complements well the overall look of the bike.
Here are some pics.

 

installed 50mm TB today with 4.9 injectors. now just need to build the tune file for it.

 

sweet!!!i like that prolly gonna take that idea...what is it made out of?..abs or steel

 

where did you source the tb and inj?will i need this for my 107 build?...i know tont told me about the tb but he didnt mention injectors..he may not of known about the change from 15 and prior from the 16

 

the TB is a stock 46mm from a 2007 TC - ebay special $50. had it bored out to 50.3mm but George at www.maxbore.com - $125, does a really nice job and cuts a new butterfly for it- I got it back in a sealed bag and it looked like brand new.

the injectors are the SE 4.9 injectors. surdyke.com usually has best price on the 2-injector kit. I'll look around for ya. about $130 for the pair. you definitely need, without a doubt, larger injectors and a 50mm TB. you'll have a **** poor time trying to tune it with the small 3.9 injectors and they do not support any more than 100hp tops. you can go larger like 54 / 58mm on the TB but you then need to design the motor accordingly. larger TB usually leads to lower intake velocity and reduced low end TQ. you do gain top end HP but on a street bike you have to pick the happy medium. I'd prefer more tq at low / mid than top hp.

BTW got bike fired up this evening - sounds like a beast now. that 50mm made a bit of good difference indeed. tomorrow is test ride and tuning.