[joeowens78]

I bought, actually stole, a 1991 Fatboy last October. I got a great deal, low miles good shape. I have been taking some day trips lately and have began carrying a passenger more often also. I have noticed the obvious difference in power. I was wanting to do some HP enhancing, ie. bore out or replace cylinders, new cam, new pistons, ignition, carb, valve job, porting and polishing, etc. It will be my daily driver, road trip, and street bike. So I would like more power with out losing reliability. I was wondering if anyone had any recommendations(brand names, part #s, etc.) as far as the parts or machining that I mentioned above. I have already replced the stock pipes with V&H 2-1 pro-pipe. Thanks for that info. Sounds great, runs great!

[hdotis69]

I like the pro pipe and the thunder header. If you have the money (4500-5000) you can buy a S&S 96" motor and keep your stock motor. It has plenty of horsepower and torque and is very reliable. If not, I like the screaming eagle heads, ross 10:5:1 pistons, crane hi-4 ignition, andrews ev-46 cam, adjustable pushrods, and beef up the clutch a little. Maybe even a mikuni 42mm carb and a few other things. This only my opinion.

[hotroadking]

The bike has an evo motor so JMHO

Sell the motor on ebay and buy an El Bruto 96 or 100 inch motor (or larger if you want) A 113 is about $4K or less and you can get maybe $1500 for your motor if it's low miles and in good shape. You can end up with 120 HP for $3K or less and a warranty on the new motor.

To go larger bore you'd have to do the cases and they are suspect on early evos for this stuff from what I've heard.

I think S&S has a kit where you can go to sportster pistons and get 89 cui out of it but I can't recall all the details. www.sscycle.com for s&S info, they can probably sell you the kit here at DP>

If you want to keep the same motor a cam, pipe change with new pistons raise the compression ratio and have the heads worked on, then get it tuned is your best money spent.

[CD]

The one major consideration of replacing the engine is your title and insurance. Most states will require it to be re-titled as a reconstruct and most insurance companies raise the insurance rate because they think it was in a wreck no matter what you tell them.
Don't re-title you say? Picture this, you are clipping along at 90 on I40 west bound just outside Flagstaff. Just going with the flow when the big DPS cruiser pulls you over. The officer has a hard on for bikers and he runs the numbers. When they do not match, you get arrested, your bike is impounded and you have a lot of explaining and a major hassle to go through. Happens all too often as it is one method used to help crack down on clubs riding stolen hardware.
Define how much more power you want. Torque is generally the answer as it does the work. Since we have a low RPM engine, we want all the torque we can get in the operating range. A set of heads, SE, Branch, Edelbrock etc, 10-10.5:1 CR, a good torque profile cam (will vary some depending on heads and CR). Mikuni HSR42, Crane HI4E ignition will get you into the range of 80ft lbs of torque with no increase in wear and tear. You can crack the cases and go 89" but I would only do it if I had to have all the power. If I actually did want the max I would go to a larger engine, re-title and live with the insurance.

[hotroadking]

Yeah that is an issue just make sure you carry the MSO on the motor if you buy a new motor, and the bike will have the stock vin on the frame, so who you tell is up to you (disclaimer no legal or insurance advice being given you're on your own)

Yeah heads, pistons, cams, pipes, ignition, tuning will make good power a lot more than you have now, but if you're a power junkie you'll have as much in that setup, especially if you do it over a couple of times as you would on a crate motor. Like cd said if you want the big numbers swap the motor.

[joeowens78]

Thanks for the info. Right now my shop is recommendig a top end job. If it is already opened up, I am thinking replace with SE Heads and new pistons. I am a school teacher so money is not at a premium. This will probably be an all summer project. I will keep yall updated as to my progress. Tahnks again!

[hotroadking]

A good port job on the stock heads may run you less money, shaving a bit off them or going to higher compression pistons, and a cam will help.

Save some bucks for tuning.