120R engine
Most of the people suggesting the S&S 124" motor over the SE 120" motor are from people who repair & build engines everyday.
My point is that you asked for opinions on the SE 120" engine and didn't like what you heard so you decided to ask a different group of people the same question.
Are these engines reliable in terms of mileage? I know it's a performance based design but can one expect the engine to have some longevity with proper break in and maintenance adherence? Thanks.
One of the things that is completely shooting you in the foot right now in terms of performance is the too tall drive belt pulleys, and the stock "de-tuned" timing map in areas of off idle and roll on. makes your bike feel like a moped taking off from a stop or rolling it on in any gear. 6th gear is totally useless.
Again, JMO, you should call and talk to the following builders:
1. Dave Mackey (Ventura)
2. Hillside Cycle
3. Bennett's Performance (Signal Hill) - they are located next door to Branch Flowmetrics so they could do your heads, cylinders etc
4. Fuel Moto
5. AMS MotoMachine
I think you'll find the general and ongoing consensus is to not invest in the 120 motor, and for less $ you can build something very reliable and quite powerful. Regardless of what you end up going with for engine upgrades, be sure to get rid of the too tall belt pulleys for a 30/68 or 30/70 combo. uses the same stock belt. makes a massive difference.
but keep in mind that you have a stock HD transmission so the more crazy HP and TQ you throw at it, the more you risk issues later on. if you stick with a solid 107 kit then you'll have plenty of power but keep it all within reliability range of the drive train.
If you want to go for the ultimate, check out RB Racing here in So Cal. they know the 120 motors very well. Their Orca TC 126 will rip your nuts off with 150hp and be bomb proof. but of course you'd then need a Baker trans to handle it. either way they are a great source of info to speak with.
https://www.rbracing-rsr.com/113orca.htm
Are these engines reliable in terms of mileage? I know it's a performance based design but can one expect the engine to have some longevity with proper break in and maintenance adherence? Thanks.
If you are on a budget, get the Fuel Moto 107 kit. It beats the 120ST and comes close to the 120R without all the bad literature associated with the 120R.
It also depends on what you want for performance. Pretty hard to beat the Fuel Moto 107 with their heads etc... (for price) but if you'r looking to get over that 120hp/torque mark then I think S&S is the best way to go. Myself, I think that S&S T124LC is the best motor out there for me. Compression is slightly lower than their regular T124 so reliability and longevity should be great and the numbers look fantastic.
Bottom line..... I read a ton of positive reviews on the S&S T124 and a ton of bad reviews on the 120R and I'm not impressed with the low mileage repairs on the 120R or the lack of warranty when compared to the S&S.
Last edited by Berick; Apr 5, 2016 at 11:50 AM.
The Best of Harley-Davidson for Lifelong Riders
Nicely done -
what sort of cost difference are you seeing with a 107 vs the 124 you built? how does that stack up bang for buck wise?
Last edited by LA_Dog; Apr 5, 2016 at 01:04 PM.





