Thought I post this up...
I replaced the SE266 cams that are stock on the 120R with TMANS 660SM cams. I wanted to change the RPM position where the motor was happy. According to the research the happy spot for a motor is dependent (among other things of course) on the cam.

Stolen from the web The SE 266 cams have a ABDC of 58 degrees so the stock 120R isn't realy happy until its wound up. Don't know about others riding sytle, but I typically shift before then. Oh sometimes with a lot of runway I crank it e.g. on-ramps etc. So I decided on changing the cam to lower the RPM curve. Course this will affect the HP since this style of cam is made for that...
The MAX 660SM ABDC is 46. This effectly (per TR) lowers the RPM happy spot 800RPM, or around 3.5-3.8K which for me is about right. I shift 4.5K typically. I thought of going to the 660-2's, but the are over 50 at 51. However, that would about 400-500RPM lower than the 266's. The 660-1 is interesting because its 45 so even lower.

After talking to TR, he suggested the 660SM his best selling cam for the 120R so far (followed by the 660-1 and the 660-2).

After installation my original dyno results really dropped (first dyno chart is the 266 verses the 660sm) - only changes were cams, roller rockers and jetting changed from feedback on the dyno. Talked to TR and he suggested trying a couple of things. First make sure the oil pump seal was OK, next ignition timing etc. I talked to the shop and they only tuned the fuel mixture.

OK second tune with ignition timing. This made a significant difference in the TQ value and curve. Big change and higher that the 266 (just a bit though). The HP upped some, but only a little The second dyno is STD verses the more accepted SAE values (I notice dealerships default to STD feel better values ). The first dyno shows the same original 660SM numbers is SAE (RED) and the 2nd shows it in STD (BLUE). They only vary a couple units, less that 2%... pardon the coffee stains on the 2nd...

So I learned something. Make sure you have the ignition tuned also. Not sure this affects EFI as a separate step. Mine is carb'ed for its a additional step which seems to be skipped - maybe lack of experience on the tech's part...

Finally, while not the strongest power numbers for the 120R's I have seen out there, but I'm happy. The power curve is much more street-able for me.

 

Interesting

 

Different Dyno's and/or different days will also affect the numbers. Sometimes drastically. In your case, I'd be mostly interested in the "butt" dyno. IE: are YOU happy with the performance results while riding?

 

Nice torque curve and well done - 120 throughout most of the rev range is quite something!

 

Yes my butt is happy. Not trying to get bragging rights, just have some fun

Concerning dyno differences - I thought the SAE/STD compensation calibrated out the environment differences - temp, air pressure etc...

 

I thought about swapping out the 266s forthe TMans prior to my Procharger install, but after reading some posts on another HD forum by some "hard core" builders I opted not to. They insist that the the 266s are ideal for the stock 120R.

 

Yes, I read those also. They have a valid point since the 266's are great for power and have an excellent power curve for the track. After all its a "race" motor.

For street it really depends on your riding style. If you want max power and typically ride high in the RPM range (consistently over 3000) then the 266 is ideal. For me the 120R with the 266 was awesome on the freeway in 5th; rolling on at 65+ was an experience for sure.

Guess my riding style isn't that aggressive, so I made the trade-off. A lower RPM power curve and better mid-range performance at the cost of maximum power. If I only used it for high-performance riding I would have kept the 266's though, but I ride it everywhere...

The interesting thing that TR told me they consistently sale over 7 TM660SM cams per week to just 120R owners. Probably people wanting the samething I wanted.

 

"The interesting thing that TR told me they consistently sale over 7 TM660SM cams per week to just 120R owners. Probably people wanting the samething I wanted"

I think there a lot of people using the Tmans w/120R that follow the same thought process as you. They prefer the rideablity rather then the performance. There's a local guy here that has a 120R in a newer Ultra that has swapped out the 266's for the TMans.

 

Nice post! Are you drag racing and always shifting at high rpm's, or do you have a heavy bike and want your power band for getting on the freeway, passing slower vehicles, getting out of trouble and pulling steep grades?

 

Am I reading the dyno chart wrong? It looks like the 266 cam makes more horsepower/torque across the board.