grbrown , one last thing ,, i wish i had your motor . always wonted a big motor . if you could do it over again ,, would you do the same thing " 107" or larger ? pro's & cons . I have to say everyone on hd forums are very friendly , thanks guys .

 

I rebuilt my evo...a big motor will pull impressive #'s..but there's no reason a 80" motor can't be built to pull. My 80" evo makes 91 rwhp and 94 lb ft of torque at the rear wheel...it get's up.

 

90hp @ the wheel is impressive. I bet the bike is fun to ride. But I wonder how mileage the engine will last - 20-50- 100k miles? Or maybe there will be no (major) difference between stock and hot rod engines? I`m thinnking about buyng new engine for my FXR - stage 1 evo is a little to slow - accelerations could be better especially in higher gears.

 

my motor will last sometime..it's only 10 thou over..just enough to clean up the bores.

10 to 1's
S&S E
Twin Tek ignition
a crane 296 cam
and alotta headwork..flow bench..oversized valves

Build your motor..

 

1yrb4hd , what did you do to get 90 hp ?

 

id say thats great. i think they came with 55-60 hp stock.

 

Hi hogcruzen,

I live in the UK, so the changes I make to my bikes (I have owned Harleys since 1974) are driven by things that don't affect those of you who live in North America. I chose an S&S because they are well supported here (although my dealer is 200 miles away) and the prices are very good. Other brand engines, like Ultima, I would have to import myself, which shoots the costs up to similar levels to an S&S. It would also be very difficult to get any after-market support.

Given a free choice I would probably have bought a bigger Ultima and I envy you guys! My S&S dealer advised me against fitting a 124" because they don't run well in dressers, at low engine speeds. Their 107 is expressly tuned for just that use, which is why I chose it.

While my 107 gives plenty of power and torque I am not very pleased with it, because it vibrates a lot around 65-75mph. Mine has their IST ignition system and I know someone over here with the normal ignition, which does not vibrate like mine! Very frustrating. It does run happily down to 1500rpm in top gear without snatching and will pull away nicely on a light throttle and is really sweet up to that vibration band.

So to answer your question, would I do it again, then my answer is No! I may get this thing to run smooooothly, but don't like it as much as S&S advertising tells me I can expect to. Also 103 bhp does not feel as much as I expected, so I would also probably go much bigger.

The trouble is the torque of most engines, of any size, does not vary a great deal in the lower engine revs we all prefer to use, say up to 3,000rpm. I compared figures for all the S&S engines from 96" to 124" and a 124" costs a lot of money to get only a small increase in torque over a 96" for that rev range. If you spend a lot of time above 3,000rpm, the difference gets big very rapidly!

It seems to me an Ultima 127" runs really nice, from what I have read here on HDF, so that would be my choice if I were doing it again. I don't know anyone running an S&S 124" in a dresser and haven't seen anyone comment about them here on HDF. So if they are not good at low engine speeds, my next brand of choice would be Ultima.

After-market Harley engines over here are very rare. I came back to mine while it was parked to find a keen-eyed guy looking it over. He couldn't believe it was a whole S&S engine, not just new heads! The only other S&S engine I have seen is at my dealer.

Hope some of that helps!

 

hi grbrown , thanks for your help , i wont more power

 

It's a pleasure! Let us all know what you decide to do.