I know this a thread on the 120R but I have to mention I did a 103 Stage IV upgrade and I have all the power I need, at half the cost, and no problems whatsoever. This after about 17,000 miles on the build. The only reason I make this point is if the 120R is so bad why buy one? We all know the more power the better, but if your engine is sitting on a bench being rebuilt and I'm riding, who's better off.

 

Mine has 38,000 and another in this thread has 26,000 .
They both turned 3 years old last nov .
Remember the ones making claims that you have to do this and that to one , are the ones selling parts and labor .
I had one come in that the guy was told it needed cylinders Pistons , crank welded bla bla bla . The only noise it had was the throttle body resonating through a heavy breather . It got tuned and has been going 3 years now also . ( makes you wonder how many have been torn down for no reason ,other than greed)
The 120's are everywhere now . They are about as popular as a big bore kit used to be .
If your happy with your 103 stage IV that's great, it's a great kit .
But 17 extra ci is noticeable believe me , even if it were only good for 1 extra hp per ci . ( it's actually a little more )

 

Why buy one?
Because the dyno sheets in the catalog look enticing.
So does the description of the crate motor in the catalog.
Seems like a lot of bang for the buck.
For the record, I never took the bait.
Know a few guys around here who did.
All were disappointed in their numbers after it all panned out.
Not a whole bunch more power than a good 107 and less than a moderate 113.
So different cams was the usual fix. But now the bottom line changes considerably.
Still? For a crate motor? At the listed price? Not bad.
Assuming no problems.
Carry on.

 

So what are you seeing on a well tuned, all stock, 120R crate motor Jim?
For HP?
The guys around here that I was referring to were mid to upper 120s torque and low 120s HP.
With right sided curves.
At the time, they/we all expected more I guess.

 

That's about right .
A few have done a little better .

 

Didn't that one with 26,000 have loose valve guides, leaking head gasket, and different lifters? Who tuned and worked on that?

 

I don't get it. I have followed the discussion on the HD 120R engine from the start on this forum. Looked like a good deal for the price but shortly the complaints started to come in about build quality and problems with premature failures. Some of these were undoubtedly caused by HD dealers who didn't have the high performance tuning skills to tune them properly and others by owners that modified them before instillation. That being said there seems to be way to many guys with 120R motors having to come apart at low milage. What seemed to be a bargain price doesn't seem so good anymore, especially since S&S dropped they're 124 crate motor pricing sharply last year and you get a warranty to boot. I asked about a warranty on the 120R from my local HD dealer and he laughed. I don't see topics like this one concerning S&S 124 crate motor quality problems or premature failures which tells me which choice makes more sense. I went the S&S route last fall after watching this and other threads since the 120R was introduced. Just saying, seemed like too much smoke for there not to be a fire.

 

The difference as we see it is that S&S sends us a shipping crate, pays the freight both ways, does a complete rebuild,and pays us for the in/out labor.

 

That's a big difference and was the deal breaker for me. But there is more to it than that. There seems to be a real quality difference between the S&S crate motors and the HD 120R unless there are a bunch of S&S motor failures not being reported by owners on these forums and just being taken care of under the S&S warranty. I doubt that's the case since guys on these forums are quick to share information about quality problems on any product.

My question is do you see that many S&S motor failures that require sending the motors back under warranty and how does your experience with the reliability of the two crate motors (120R & S&S 124) compare.

These 120R installs seem to be divided into two rough categories. First are the guys that buy and install a 120R unmodified. The second is guys that buy a 120R with the intention of modifying the motor before installing it or are not satisfied after installing it and then start changing parts. Either way HD considers this a race motor and a taillight warranty applies.

 

gave up on harley

after getting brushed off by harley tech.I sent my crank to darkhorse and waiting on a set of jugs from axtell.I am still very disappointed in the reply and lack of caring at harley.live and learn.I should have gone with my gut and built my own motor in the 1st place.well the work I can not do my self if left to darkhorse/axtell !!thumbs.can not wait to get back on the road with a engine that is as it should have been from the get. sorry I posted this reply in the wrong place the 1st time:duh2:

 

Nope looks good other than the double dip down low.....a cam change would fix that in short order

 

right on

inspector12 is right on. ive installed and tuned 4 120 r's. all with the s.e. induction module and borezilla. 135 square on all of them. if you aint getting 130 hp square get a better tune and exhaust. and by the way, they are all runing after 3 years. sorry about the bad luck but hd sells this engine without a warranty. unfortunately they do have mechanical issues as of late. it just seems that the first run was the best i guess.

 

I had to rebuild mine at 10K after the outer front cam plate bearing blew up completely. Crank landed up being .016 run out on right side, worse on the left side .026 which was burning out compensators .. here is the thread, I got videos posted with the run out. If I would have to do it all over again, I would have torn the motor down to have the crank plugged, trued, welded and balanced with a left side tapered bearing line bored in the case right out of the create. I was thinking of doing it when I bought the motor, but I was too excited and just wanted to ride. Oh well, hind sight is 20/20

http://www.v-twinforum.com/forums/twin-cam-engine-mods/239706-scissored-crank-my-120r-10k-miles.html

 

20/20



If I have to hear I more condescending prick that has gotten lucky enuff to have gotten more miles out of the 120r (early run maybe?)say it has no warranty.I'd want to smack someone.
I am yet to meet anyone to be happy to have there engine fail.it just seems that a little more r&d would have gone into a race motor.so they would not keep selling a inferior design of a part that they know fails in a stock motor.
the argument that a race motor was not made to last is B.S.
In fact A race motor that is built right should be stronger and better built.and call it what you like.
a 10.5 to 1 comp motor is in no way the 15.+ comp. 700+lift race motor that was never intended to be street driven.
that everyone wants you to think this is and thats why it went bad well that it is not.....what is,is a hopped up stock motor.but it is hyped up an sold as a race motor.-2$en#e-

​

 

I agree with you 100%
Harley seems to get a C- or worse many times in the "integration, testing, and support" department.
Leaves a wide open door for independent shops to use parts they select and then go to the aftermarket for others and then the whole package has the potential to live and run well. The shop then in essence takes over where the MOCO fell short. Some of Harleys pieces are high quality and useful. Enter problem #2. Their Sales and Marketing gurus then decide not to sell any volume to independent shops. So if I want to buy 3 sets of valves from a certain head for example technically I would have to supply VIN numbers to get them.
When the 120r arrived on the scene I was pretty pumped, now that we have done the beta testing I am of the opinion a 124" is a better option. Yes it costs more but over time much less. When I used to work in a shop we installed many 124" S&S motors and they were rock solid. No issues. But that was 10+ years ago and their quality has wavered too at times on certain articles. But their crate motors carry a warranty. Big bonus, and essential in today's' world especially for the guys that don't so their own wrenching

 

@gree:I went back and forth with that same idea.got the 120r thinking I wanted to keep the bike 100% harley.20/20
ended up riding a buddys stock(lol) 06 roadking to daytona while my race engine was spread out in my garage:woohoo:

 

Not being a smart a$$, but why would one choose a 120R over a S&S 124?

 

money.....here is the edit: I just looked at the S&S web site and the T series engines are not that much more, but I do not think this was available 4 years ago when I went with the 120R..

 

My 120R is still running. I only have 7000 miles. Most of those miles are city streets and ran hard. Every stop sign is a drag race to me.

I expect it to blow. I've run it hard. If it blows I'll get it fixed. I only paid $4200 for it and will do it again if I have too.

 

Mine took a dump on me around 3500 miles, but it was due to clutch basket failure that took out the crank. When we took the motor down everything else looked pretty good. Sent the bottom end off to Darkhorse to have them put on some new JIMS flywheeels & Pro-Edge/Window. They said everything else looked good. As for the top end all was fine but decided to go with 4.07" +5.5 GMR pistons & do a little head work. Sucks because this chit isn't cheap but I can't blame the engine. I was only makeing around 110hp & 116tq though, bad tuner & horrible pipes.

 

Doing it right....
http://www.v-twinforum.com/forums/dyno-discussion/216914-my-120r-final-dyno-gmr.html

 

dr scott, I am sorry for your loss, in the $$ and your time, but mostly for feel bad about every man on this thread kicking a man while he is down, rubbing you nose in it,

the mo-co has issues, some choose to still drink the cool-aid, or there just pricks.....

I hope you get your issues sorted out,btw, I ran a thundermax for many years, at first there were issues, then after a software update, I had the best tune I had ever had on that bike, with a few manual ignition tweeks ...saying a thundermax can't tune is rubbush, unless you sell tunes....ya know.

and I dont need to hear from said pricks...thanks.

 

Does anyone realize this is a zombie thread? It's over a year old.

 

Thanks, I haven't been keeping up with pop culture for the last 35-40 years or so.