How much HP can you get from a V-twin Motor??

[NoDak]

I was at a local motorcycle show this weekend and I saw a HD with the following specs:

2005 HD Ultra Glide
124 CI
S & S B2 Heads
Cam -640 Lift
D & D exhaust
170+ HP

I think a stock HD is 70 HP and a Victory is hovering at 100 HP.  This motor was built by a local speed shop that just opened.

So is this possible?  Can you get 170 HP out of a air cooled V-twin?  Or is this BS?

[Bender]

Think pro stock screaming eagle drag bikes......answer....easy.

[NoDak]

Think pro stock screaming eagle drag bikes......answer....easy.

On pump gas??

[cbsnbiker]

I was at a local motorcycle show this weekend and I saw a HD with the following specs:

2005 HD Ultra Glide
124 CI
S & S B2 Heads
Cam -640 Lift
D & D exhaust
170+ HP

I think a stock HD is 70 HP and a Victory is hovering at 100 HP.  This motor was built by a local speed shop that just opened.

So is this possible?  Can you get 170 HP out of a air cooled V-twin?  Or is this BS?

Probably.

The next question: for how long? Should the service life be measured in minutes?

[bandit1250]

Anything anybody says about their Harley motor is true.

[wibornz]

I am thinking 12,000 hp with naaawwss.

[ST for me!]

The question is, why would one want to? The hd chasis can barely handle the speeds it's factory engine puts out. fucking pirates...

[caddydaddy]

So is this possible?  Can you get 170 HP out of a air cooled V-twin?  Or is this BS?

So how much cash was put into this V-Twinkie, to get only 30 HP more than a Triumph Rocket III makes STOCK!!!??  

[atadaskew]

I was at a local motorcycle show this weekend and I saw a HD with the following specs:

2005 HD Ultra Glide
124 CI
S & S B2 Heads
Cam -640 Lift
D & D exhaust
170+ HP

I think a stock HD is 70 HP and a Victory is hovering at 100 HP.  This motor was built by a local speed shop that just opened.

So is this possible?  Can you get 170 HP out of a air cooled V-twin?  Or is this BS?

Why not?  A 124 cube motor is just over 2000cc.

It's not like it's a stock motor.

[Justin]

I am thinking 12,000 hp with naaawwss.

So a 100 HP Harley Engine with 11,900 HP shot of NOS?

[tomek]

Some of you guys are funny... in a "man, wouldn't it be cool if you had a clue, or a sense of adventure" kind of way.  

Actually, yes. STOCK a modern Big Twin puts out ~90lbs torque and revs to about 5500 RPM, peaking at about 4500 RPM ( do the math for HP ). The S&S heads do NOT float valves and with the right cam profiles (and those big flowing heads), the big twins will rev to about 8000 RPM, say it bangs out 135 - 145 ft lbs.... yeah, it's doable.

But as mentioned, I wouldn't want to count on it for any kind of long-term reliability.



That's not the question... the question isn't about making a "fast" bike, it's about making a certain kind or model of bike faster.

Didn't you guys build any hot rods in the 60s, 70s or 80s?

Well , 8000 rpm on 2000 cc pushrod V2 soon or later will end up like this  http://www.youtube.com/watch?v=g28ZlmZKk8c

Just saying ,,,,,,Buell tried to run that kind of rpm on XBR-R , much smaller powerplant (1340 cc) , and those things were blowing up all the time .

[veefer800canuck]

The pro-stock "Harley" engines really don't have any Milwaukee parts inside them, nor are their cylinders, cases, heads, etc, anything resembling anything that The Motor Company.

They are machined from solid blocks of aluminum and everything inside is beefy to the max for dragracing.

NOT something you could slide into your Ultra-Fat-Wide-Classic-Sporty-Tour-Hyrda-Glide.

http://www.starracing.com/G2/ProStockEnginePage.htm


OTOH, you can get a 145Ci monster motor that will slot into your average street-bound HD and make 170 HP, yes.

http://www.starracing.com/G2/145EngineSpecsDynoChart.htm

[DFH]

Why not?  A 124 cube motor is just over 2000cc.

It's not like it's a stock motor.

Some simple Maths...  

2000cc Boutiqe engine company using all the latest in technology (air-cooling, 2-valve heads, push-rod drivetrain, carbs, long stroke narrow angle V & extra shiny bits) claims 170hp at the crank/brochure.
Ducati 1198cc engine hindered by silly euro tech (water-cooling, 4-valve heads, belt drive dohc desmo valvetrain, fly by wire throttle bodies with fuel injection, 90 deg short stroke v twin, no chrome) claims 170bhp at the brochure... and a real 151 hp at the rear wheel.

Is an 800cc capacity hike enough to make up for 50 years of solid design & development?

 

[sammyseaman]

Some of you guys are funny... in a "man, wouldn't it be cool if you had a clue, or a sense of adventure" kind of way.  

Didn't you guys build any hot rods in the 60s, 70s or 80s?

You have to remember the demographic of this site. Prolly not too many cats here had street rods back in the day and the ones that did aren't automatically questioning the reason to triple the power of an "old" motor.

[bomber]

Much more to to make your own horsepower/performance than to simply hand over money and take it home with you.

It's tougher to improve on factory offerings these days, as the factories have gotten much better, and the legality of modding motors has gotten hazy -- but, hey, we're motorcyclists, free spirited, open minded, welcoming of ideas other than our own . . . . .  

Oh, wait . . . . . .


Those numbers are easily achievable with an HD big twin . . . .

[DFH]

Much more to to make your own horsepower/performance than to simply hand over money and take it home with you.

It's tougher to improve on factory offerings these days, as the factories have gotten much better, and the legality of modding motors has gotten hazy -- but, hey, we're motorcyclists, free spirited, open minded, welcoming of ideas other than our own . . . . .  

Oh, wait . . . . . .


Those numbers are easily achievable with an HD big twin . . . .

Sorry, which HD delivers 170hp?

[bomber]

excuse me, I forgot where I was -- not by a stock HD, that's for certain --

The one listed in the OP, on the other hand -- those numbers are not at all surprising.

[DogBoy]

Who needs 170hp when the bikes have more than enough power in stock form?

[steve.m]

well...here's the story there.

when you "old guys" were young you had the option of changing a needle and a seat in your carburator, pulling off a 2bbl and swapping on a 4bbl.  you could undo 10 bolts, remove your intake, shop around in a junk yard for a wrecked high spec car and pull parts, swap a cam fairly easily and so on and so forth.

then electronic ignitions and fuel injection came along.  in order to make THOSE motors perform, you NEED to spend money (unless you're a fecking computer genious and can make your own fuel map)  add in a turbocharger for good measure and you're talking some serious computation before you can even THINK about making a modification without completly ruining your engine.  it's not that the current generation CAN'T do mods to an engine (i just installed a holley 4bbl & performer intake on my pontiac), it's that modern engines don't permit these kinds of changes.

and yes, an HD motor can absolutely scream with proper tuning.  the S&S models will do their share of work to embarrass a gixxer in a straight line.  0-60 times are much faster when the front wheel stays on the ground.

[sammyseaman]

well...here's the story there.

you you "old guys" were young you had the option of changing a needle and a seat in your carburator, pulling off a 2bbl and swapping on a 4bbl.  you could undo 10 bolts, remove your intake, shop around in a junk yard for a wrecked high spec car and pull parts, swap a cam fairly easily and so on and so forth.

then electronic ignitions and fuel injection came along.  in order to make THOSE motors perform, you NEED to spend money (unless you're a fecking computer genious and can make your own fuel map)  add in a turbocharger for good measure and you're talking some serious computation before you can even THINK about making a modification without completly ruining your engine.  it's not that the current generation CAN'T do mods to an engine (i just installed a holley 4bbl & performer intake on my pontiac), it's that modern engines don't permit these kinds of changes.

and yes, an HD motor can absolutely scream with proper tuning.  the S&S models will do their share of work to embarrass a gixxer in a straight line.  0-60 times are much faster when the front wheel stays on the ground.

 
Mild, somewhat inexpensive h.p. upgrade for old bikes: Jetting, pipes, airbox de-restricting.
Mild, somewhat inexpensive h.p. upgrade for new bikes: Re-mapping fuel system (forums, torrents, etc...), pipes, emissions crap removal.
Big, expensive h.p. upgrade for old bikes: Head work, bigger pistons, pipes, bigger carbs, NOS, superchargers, etc...
Big, expensive h.p. upgrade for new bikes: Head work, bigger pistons, pipes, re-mapping of fuel system, NOS, superchargers, etc...

For the most part the kids don't tinker and get hands dirty as they used to.

[bomber]

 
Mild, somewhat inexpensive h.p. upgrade for old bikes: Jetting, pipes, airbox de-restricting.
Mild, somewhat inexpensive h.p. upgrade for new bikes: Re-mapping fuel system (forums, torrenst, etc...), pipes, emissions crap removal.
Big, expensive h.p. upgrade for old bikes: Head work, bigger pistons, pipes, bigger carbs, NOS, superchargers, etc...
Big, expensive h.p. upgrade for new bikes: Head work, bigger pistons, pipes, re-mapping of fuel system, NOS, superchargers, etc...

For the most part the kids don't tinker and get hands dirty as they used to.

I pains me to agree with the Simian, but he's right . . . .

I think a great deal of it has to do with the lack of a pressing NEED to hotrod much of anything. A Honda Civic so far outperforms a mid-60s Goat, there's not much point to do more to the poor dear.

[Rogue]

Buell had a near-production ready XB12R that was turbocharged and it put out a reported 130 bhp and that was from a 1203cc, aircooled, 2-valve motor running on pump gas.

[steve.m]

Plus, to do it *properly*, there was plenty of calculation involved. It's not like you just throw a dart at the catalog and picked a small-block chevy cam out of the Crane book by happenstance. There were plenty of shade-tree guys blowing motors left and right, or wondering why $1000 worth of parts netted them a 14-second big block, or why their quadrabog would make the engine stall when the secondaries were 1/2 way open.

The brainless "motorhead" stigma didn't apply to those of us who actually had a clue and made things faster, all for real, like.

 in order to make THOSE motors perform, you NEED to spend money (unless you're a fecking computer genious and can make your own fuel map)  add in a turbocharger for good measure and you're talking some serious computation before you can even THINK about making a modification without completly ruining your engine.  

i know plenty of intellgent folks who mod their cars today, one is a civic on pump gas getting 800+hp.  he did the mods himself.  the comment was made that people dont do work anymore, they just spend money to get the end result.  that's not true.  what is true is that the mods themselves are FAR more expensive than they used to be.  take the civic and gto comparison (since it's a line that's already been drawn) for example.  back in the day, you guys could get yourself a tempest with a crappy 4 cylinder or small 6 for short money, walk down to the junk yard, find a bonneville with a 389 under the hood, spend a day in the garage and have a beast for very little money.  add to that the availability of carter, holley and quadrajet carbs which would bolt easily onto a readily found intake and you've got a straight line performer for very little cash.  now take the civic...they don't perform admirably in any regard (personally i hate them) unless you start doing mods (same as the tempest).  but you can't walk down to your local scrap yard and get the parts needed to make a civic pump out real headturning horsepower, you have to go aftermarket.  at that point things get very expensive.  so the kids who would LIKE to tune their cars can't because it costs too much money.  when they finally do get the cash to sink into their cars, they will...and that is how you get a 32 year old with an 800 hp civic.

i always did whatever work i could to my own cars, but the cost of improving them was always outside my reach.

now i play with my 68 pontiac with a 400 under the hood.  and yes...it'll shame a civic  

[Blunder]

Who needs 170hp when the bikes have more than enough power in stock form?

The revenge of the shrubbery!  

HP=$$$$  How much money you got?

[sammyseaman]

i know plenty of intellgent folks who mod their cars today, one is a civic on pump gas getting 800+hp.  he did the mods himself.  the comment was made that people dont do work anymore, they just spend money to get the end result.  that's not true.  what is true is that the mods themselves are FAR more expensive than they used to be.  take the civic and gto comparison (since it's a line that's already been drawn) for example.  back in the day, you guys could get yourself a tempest with a crappy 4 cylinder or small 6 for short money, walk down to the junk yard, find a bonneville with a 389 under the hood, spend a day in the garage and have a beast for very little money.  add to that the availability of carter, holley and quadrajet carbs which would bolt easily onto a readily found intake and you've got a straight line performer for very little cash.  now take the civic...they don't perform admirably in any regard (personally i hate them) unless you start doing mods (same as the tempest).  but you can't walk down to your local scrap yard and get the parts needed to make a civic pump out real headturning horsepower, you have to go aftermarket.  at that point things get very expensive.  so the kids who would LIKE to tune their cars can't because it costs too much money.  when they finally do get the cash to sink into their cars, they will...and that is how you get a 32 year old with an 800 hp civic.

i always did whatever work i could to my own cars, but the cost of improving them was always outside my reach.

now i play with my 68 pontiac with a 400 under the hood.  and yes...it'll shame a civic  

I can't argue the cost of hoppin' up a newer car because I really don't care about Civics and their ilk but stuff really wasn't so cheap back in the day. Especially considering how much "kids" earned back then.
Also I have to   you and your choice in old sleds  

[bomber]

take the civic and gto comparison (since it's a line that's already been drawn) for example.  back in the day, you guys could get yourself a tempest with a crappy 4 cylinder or small 6 for short money, walk down to the junk yard, find a bonneville with a 389 under the hood, spend a day in the garage and have a beast for very little money.  add to that the availability of carter, holley and quadrajet carbs which would bolt easily onto a readily found intake and you've got a straight line performer for very little cash.  

And how much, compared to the standard income, do you think these mods and parts cost, Steve? Very little cash would buy you pretty much exactly what it does today.

now take the civic...they don't perform admirably in any regard (personally i hate them) unless you start doing mods (same as the tempest).  

I disagree -- you take a restored 65 Goat, and I'll take a new Civic -- if I can pick the road, I'll own your entire paycheck too sweet -- we romanticize the muscle cars, but, really, they were fun machines for a straight line, but they flat out sucked compared to today's cars . . .

[sammyseaman]

And how much, compared to the standard income, do you think these mods and parts cost, Steve? Very little cash would buy you pretty much exactly what it does today.



I disagree -- you take a restored 65 Goat, and I'll take a new Civic -- if I can pick the road, I'll own your entire paycheck too sweet -- we romanticize the muscle cars, but, really, they were fun machines for a straight line, but they flat out sucked compared to today's cars . . .

I'll still take a Goat over a Honda Civic any day. Just sayin'. Ya know, in case you have one just sittin' around  

[bomber]

Oh, me too, no doubt, but I wouldn't use it as a car, and I wouldn't try to turn corners or stop much  . . .

it's sort of, you know, a Harley with 4 wheels.

[Powder Addict]

A 170HP HD is like a 14 inch dick.

They sure look impressive, but aren't really good for anything.

[JSharp]

There are lots of Harley's in this area. Probably more of them than everything else put together. It seems like every one of them is 'making a hundred and blah blah HP'  

After riding a couple of them that friends own all I can say is - Show me the dyno sheet and some time slips or STFU.  The ones I've been on all seem to have one distinguishing engine characteristic. When you spin them up, right when you assume you should get that big 100+ HP hit, they're all done. It just ain't there.

170HP Harley's? Sure, they exist. I imagine even on the street. But there are probably about 1% as many making 100+HP as the there are owners that think they're making that much...

[Twistedpinion]

i know plenty of intellgent folks who mod their cars today, one is a civic on pump gas getting 800+hp.  he did the mods himself.  the comment was made that people dont do work anymore, they just spend money to get the end result.  that's not true.  what is true is that the mods themselves are FAR more expensive than they used to be.  take the civic and gto comparison (since it's a line that's already been drawn) for example.  back in the day, you guys could get yourself a tempest with a crappy 4 cylinder or small 6 for short money, walk down to the junk yard, find a bonneville with a 389 under the hood, spend a day in the garage and have a beast for very little money.  add to that the availability of carter, holley and quadrajet carbs which would bolt easily onto a readily found intake and you've got a straight line performer for very little cash.  now take the civic...they don't perform admirably in any regard (personally i hate them) unless you start doing mods (same as the tempest).  but you can't walk down to your local scrap yard and get the parts needed to make a civic pump out real headturning horsepower, you have to go aftermarket.  at that point things get very expensive.  so the kids who would LIKE to tune their cars can't because it costs too much money.  when they finally do get the cash to sink into their cars, they will...and that is how you get a 32 year old with an 800 hp civic.

i always did whatever work i could to my own cars, but the cost of improving them was always outside my reach.

now i play with my 68 pontiac with a 400 under the hood.  and yes...it'll shame a civic  

I think it has more to do with a lack of good junk yards these days.  Cars come in, get stripped, and the decent parts thrown on ebay within days.  So your choices are aftermarket, or hope to find it cheap on the web.  

And when it comes to aftermarket, it's all expensive.  Have your priced out a set of roller lifters and a cam for that 400 of yours lately?  

[JSharp]

That's a very fair statement. Stock, no, none are making these big numbers. None. The factory-limited RPM range is a huge part of that, plus the fact that -again, stock- their torque starts falling off at 4500, fully 1000 RPM below redline.

You're right about where the power falls off in my limited experience. There's no point in ringing them out since there's no power up there. They're all done long before they see redline.

Lots of mildly worked on bikes around here, a few S&S or other aftermarket motors etc. in custom bikes.  But I doubt any of them are making much over 100HP if that.

I think they feel fast to the owners because they are fast compared to their old bikes and with all the torque they make it seems like there's a ton of motor there.  And also, most of those guys have never been on anything that actually did make big HP numbers so they can only go by what they hear from their like minded friends...

[Rogue]

I personally know a kid, about 19 years old who works on his own Ford Focus.

He started out with a Ford Focus SVT then he modded it using aftermarket bolt on parts.  He began with nitrous for that big shot of power.  But he didn't like it so he went the old fashioned Hot Rod way and started putting a cold air intake, cat-back exhaust, headers (CA smog legal), then later he put a camshaft, finally a Supercharger.  All are CA smog legal and he did all the labor work.  The kid is good, meticulous, and has the right tools.  He does work for a dealership so that helps.  Now his Focus is beating all those Civic's his generation loves to drive.

This is just one example but there are plenty like him modding import cars.  Domestics, not so much because the big-three don't make affordable Hi-po cars.  Mustangs are common and I know of a kid who modded his GT and did all the work.  

There are kids out there doing exactly what their Dad's did in the musclecar days.  And there are plenty of people here who modded their bikes and did all the work right?  I've done that many times.  The only things I haven't done is swap motors.  I don't need to do that nowadays because today's motors are so well engineered and very easy to extract power from.  

[Giaka]

It all depends on the size of the V-Twin....  

The Gunbus 410 cubic inch V-Twin motorcycle is complete. The monster engine placed in a motorcycle frame of comparable size looked impossible and many who saw the photos were skeptical of the bike ever being finished but I guess, Clemens F. Leonhardt is one of those persistent guys who ignores the naysayers and keeps at his work.

The fuel injected, 45 degree 6728 cc / 410 cubic inch V-Twin runs through a 3 speed transmission with reverse and actually looks pretty good in its finished state compared to the initial photos, in fact, everything looks good. It puts out 523 foot pounds of torque.

[steve.m]

Oh, me too, no doubt, but I wouldn't use it as a car, and I wouldn't try to turn corners or stop much  . . .

it's sort of, you know, a Harley with 4 wheels.

poly body bushings and control arm bushings have made mine turn just fine, helluva lot of fun actually because you have the option of steering with your hands or your right foot.  

brakes on mine are upgraded to disks in front, so the stopping power, while not fantastic, is good enough for what i do, which is shame civics, in a straight line or otherwise.

sure the muscle cars stock aren't up to today standards, but with a few grand in upgrades, they'll outrun anyone for about the cost of a well equipped civic...which could not compete.  i know for a fact that i can get about 600 crank hp out of my car for about $6000 with a proper rebuild.  and that's normally aspirated with a carb.

my le goat with everything i've sunk into it has cost me a total of about 17k.  small cost of entry considering what that'll get you at a dealership nowadays...and i have a convertible muscle car that routinely moves porche's, lambo's and ferrari's away from cherry valet spots so that mine will grace the entryway.  it's a feel good thing.  and yes, i do drive it.

I think it has more to do with a lack of good junk yards these days.  Cars come in, get stripped, and the decent parts thrown on ebay within days.  So your choices are aftermarket, or hope to find it cheap on the web.  

And when it comes to aftermarket, it's all expensive.  Have your priced out a set of roller lifters and a cam for that 400 of yours lately?  

agreed with point one.

point two... a full cam swap kit including tappet lifters (dont want a roller cam), roller rockers, new valves and port/polish on the heads (top end rebuild) is right about $1500-2000 depending on the machine shop that does the work.  i think that's the cost to add bluetooth connectivity to a ford today.  

Like i said, i NOW have the cashflow to play with it, i didn't 5 years ago.  pay to play, but it's still easier/cheaper to work on a classic car than it is to chip a civic (which are crappy cars in my book, sorry bomber, but that's my opinion and i'm sticking to it).  case in point, i paid 250 bucks for my intake, carb and k&n filter/housing.  that's half the cost of a diablo chipset.

whether cars or bikes, old iron is simpler and cheaper to work on than modern imports...at least from any of the experiences i've had.

[JSharp]

My kid is 25 and has an 80's G-Body GM car that he's working on to run brackets.  It's really typical of the cars my friends had when I was a kid. A warmed over small block Chevy with a Holley on an aluminum manifold, moderate cam, headers, and the associated driveline.  But really, he and his friends are exceptions these days. Other than Mustangs any car that you can 'hot-rod' like the old days is a rarity. Not many left with RWD that aren't in the 60's collector category and totally unfordable to younger guys without wealthy families.

[cbsnbiker]

You're right about where the power falls off in my limited experience. There's no point in ringing them out since there's no power up there. They're all done long before they see redline.

Lots of mildly worked on bikes around here, a few S&S or other aftermarket motors etc. in custom bikes.  But I doubt any of them are making much over 100HP if that.

I think they feel fast to the owners because they are fast compared to their old bikes and with all the torque they make it seems like there's a ton of motor there.  And also, most of those guys have never been on anything that actually did make big HP numbers so they can only go by what they hear from their like minded friends...

And they're making so much noise, they *must* be fire-breathing powerful engines!  

[bomber]

poly body bushings and control arm bushings have made mine turn just fine, helluva lot of fun actually because you have the option of steering with your hands or your right foot.  

brakes on mine are upgraded to disks in front, so the stopping power, while not fantastic, is good enough for what i do, which is shame civics, in a straight line or otherwise.

You are absolutely correct, man -- at some point, though, you stop having a Goat and start having some sort of phantom car (something that never really existed)  . . . .

much like, "this is my grandfather's ax. I replaced the head twice, and the handle four times."

;-}

[Big D]

It takes money to go fast. It takes a shitload of money to make a Harley go fast.

[steve.m]

goes a little something like this...

you want to go fast?  how fast do you want to spend?  

[cbsnbiker]

Nah, it's still the same car. Certain incremental improvements have always been part of the aftermarket. Who HASN'T replaced their stock exhaust on their bike, or put better springs/valving in it, or changed out the carb jets (or put in a power commander)? Still the same bike, right?

Me, pretty much.

My apologies in advance if I already posted this anecdote to this thread, but here goes.

Often I hear about how unreliable Harleys are. Well, one of the first things I ask a Harley owner if I'm making small talk is to ask what modifications he or she has made to the bike.

There are exceptions, but the typical response is a list of stuff: new carb, new pistons, new exhaust (or even straight pipes), lowered shocks, etc., etc., etc.

Then sometimes they talk about how the bike doesn't run quite right (or I can see and hear the problems), or it breaks down, etc.

Those who haven't modded their Harleys (or at least not much) seem to do better.

So, the question becomes, is it that Harleys are unreliable, or that the modifications make them unreliable?

My belief: the latter.

[tomek]

It is more expensive to mod Civic then old American Iron .

Here are some prices for people who are ,,,,,,,ah older  .

Turbo kit , basically  ball bearing turbocharger , manifold , external wastegate  , downpipe - about 3-4 grand . I`m talking about quality parts , not some cheap made in china crap .

Standalone ECU (  piggyback won`t cut it ) - 1000 - 2000 $ .

Ungraded fuel system ( pump , adjustable fuel pressure regulator , higher flowing injectors , rail or two ) - at least 1000 $ .

Intercooler and associated piping , clamps ,etc - at least 1000 $.

Some sort of methanol/h2o injection - 400 bucks and up .

Compression needs to be lowered , set of forged pistons is not exactly cheap .

It is just way more involving and expensive compared to normally aspirated engines with one camshaft and pushrods .


BTW, I have never owned civic or any other front wheel drive Japanese car .

[bandit1250]

I have a buddy who has built a couple 150+hp Harleys (yes I've seen the dyno runs) which stayed together very well, but I know when the one that ended up at 156hp was 124 CI it was making around 135 hp. 170 is a bit of a stretch.

We always liked to see the poor Harley riders who would show up at the Honda dealer's open house to put their bike on the portable dyno. The local HD dealer would sell them "kits" that would supposedly get them over 100 hp.  Reality, none of them pulled more than about 85. Talk about some sad pirates...

[JSharp]

I have a buddy who has built a couple 150+hp Harleys (yes I've seen the dyno runs) which stayed together very well, but I know when the one that ended up at 156hp was 124 CI it was making around 135 hp. 170 is a bit of a stretch.

We always liked to see the poor Harley riders who would show up at the Honda dealer's open house to put their bike on the portable dyno. The local HD dealer would sell them "kits" that would supposedly get them over 100 hp.  Reality, none of them pulled more than about 85. Talk about some sad pirates...

Your second paragraph are the guys I'm familiar with. Lot's of kits that include LOUD exhausts, some intake work, maybe or maybe not different cams. All on a stock displacement motor. I've ridden a couple of those bikes and lets just say I wasn't afraid of controlling all the power. My stock C-10 Concours felt at least as strong...