Find Your Optimum Shift Points

[hulkss]

To accelerate the quickest, you want to have your rear wheel torque at the highest level possible.

Here is a chart showing when to shift the stock 103 HO engine based on dynamometer data published at Motorcycle.com.

As you can see, when the rear wheel torque curves cross, it's then time to shift to the next gear.

You can post your dyno curves here and I'll plot some of them for your bike and post them here.

 

[Klmack]

Hey hulkss- always providing the good stuff. That's an interesting chart. The chart displays ultimate/maximum torque value- as it affects engine performance. In other words, the best the engine can do. It got me thinking: since this curve indicates peak performance, how does that relate to engine wear? Then got me thinking even deeper: It is the norm for me to be in the 3,800 - 4,000 rpm range to shift. Is that the range where most rider's shift? Does it mean we are not working our machines to the pinnacle of performance on a regular basis? Or does it mean I should get another hobby during these rain- soaked stretches? Just ordered a powder-coated engine guard. Damn rain! Costs me money!

 

[hulkss]

The chart shows the highest rpm to shift at. No need to go to redline (6200) if you use a tuner. The shift points may be at redline depending on your engine's torque curve.

The earliest I would shift when out cruising (assuming you are accelerating normally) would be to change each gear when you will be at 2500 rpm in the next higher gear. This way you won't lug the engine. This would be 28, 38, 47, 55, and 65 MPH assuming your speedometer is correct. So shifting at 30, 40, 50, 60, 70 works just fine for the typical H-D speedometer that reads high. Then shift up appropriately at your cruise speed.

For me, 4th gear is a great passing gear. Both quick and fast.

 

[GlideLife]

That's some GOOD STUFF there HULKSS.
I used to have a little sleeper Wide Glide CVO that most thought was "ALL SHOW & NO GO". It was always fun to do some Stop Light Drag racing up against an opponent that had a bigger motor, but I'd notice that when we were playin' around, he'd run it to Red Line in every gear. I would sucker them into a cash race by talkin' about how fast their bike was. We'd meet at our secret OUTLAW DRAG RACE rural road on a Saturday night. I had a shift light on my little hot rod (NO TACH), set to optimum Torque rev spot (just like you describe). More often than not, I could take their money.

 

[Slimboybinz]

I tend to ride in the lower rev ranges.
Normally change up around 2500RPM.
Will this cause any engine damage?

 

[hulkss]

I tend to ride in the lower rev ranges.
Normally change up around 2500RPM.
Will this cause any engine damage?

No problem if you are easy on the throttle. Putting around is fun too.

 

[hulkss]

Here are plots for a stock dyno tuned 120ST motor with SE air intake and D&D exhaust.

 

[GlideLife]

Is that YOUR dyno chart HULKSS? Those are some outstanding #'s. The charts I've seen around here for the 120ST in a '15 RGS are not even close to that. A neighbor of mine has 117.95 HP & 124.68 TQ on his. Just had it dyno'd before Daytona bike week. He has a SERT, SE ELITE, FM header, & H-D SE CVO Slip-ons with 2.5"baff's. I actually thought HIS was pretty good, but your's is pure evil. NICE.

 

[hulkss]

The Dyno curve was posted by J&B Performance on facebook. It's not mine. Here's another from them. I will likely never have mine on a dyno...so I can believe whatever I want .....

I rode the 120ST for the first time yesterday. All I can say is WOW...WOW...WOW!!!

 

[GlideLife]

Sorry bout that. I'm out by the pool wearing polarized prescription sunglasses using my wifes tablet. I didn't check the chart close enough. Great numbers. I called my friend, Ron and he's going to look into setting up an appointment with MY dyno guy. He let dealer dyno it. That would scare me. NOT IN A THOUSAND YEARS would I let a dealer tech dyno my bike unless I knew "DOC" trained him.

 

[GlideLife]

The Dyno curve was posted by J&B Performance on facebook. It's not mine. Here's another from them. I will likely never have mine on a dyno...so I can believe whatever I want .....

I rode the 120ST for the first time yesterday. All I can say is WOW...WOW...WOW!!!

I hear ya. I rode my friend Ronnie's RG (with 120ST) on the way up to Daytona BW. "Wow" was my same thought. When I got back on mine, it felt like my lawn tractor. It was almost like I couldn't twist the throttle all the way... Something was holding it back. Hmmm.
I decided, at Bike Week (after consulting with many many builders to have my C Heads done and drop a set of "highly recommended" cams in her, then let Doc re-tune it. Low $$$ improvement. I think I'll be happy if Doc gets what he say's he can absolutely get from it. He has the exact same set-up (used same cams & porting service) in his personal SG. We'll see.
Enjoy your bad self with that 120!
Be safe.

 

[ALittleton]

So 45, 65, 85, 105, and 125 mph?

I rarely reach 5k rpms. Usually cruise between 2-2500 and shift at about 3k. I never liked cruising in the 3-4 range because of the engine noise. Didn't seem normal? After doing a 3-hole change to Amsoil I'm finding myself cruising in the 3-4 range a lot more. Shifts are much better and hardly any engine noise.

 

[ALittleton]

I hear ya. I rode my friend Ronnie's RG (with 120ST) on the way up to Daytona BW. "Wow" was my same thought. When I got back on mine, it felt like my lawn tractor. It was almost like I couldn't twist the throttle all the way... Something was holding it back. Hmmm.
I decided, at Bike Week (after consulting with many many builders to have my C Heads done and drop a set of "highly recommended" cams in her, then let Doc re-tune it. Low $$$ improvement. I think I'll be happy if Doc gets what he say's he can absolutely get from it. He has the exact same set-up (used same cams & porting service) in his personal SG. We'll see.
Enjoy your bad self with that 120!
Be safe.

What cams are you thinking about going with? I think that's my next step.

 

[hulkss]

So 45, 65, 85, 105, and 125 mph?

I rarely reach 5k rpms. Usually cruise between 2-2500 and shift at about 3k. I never liked cruising in the 3-4 range because of the engine noise. Didn't seem normal? After doing a 3-hole change to Amsoil I'm finding myself cruising in the 3-4 range a lot more. Shifts are much better and hardly any engine noise.

When your just out havin' fun, shift whenever it feels good.

 

[GlideLife]

Cams? Steve Cole's design...
Steve owns TTS.

TTS 100 cams (manufactured for TTS by Andrews).
I'll use my OEM pushrods (might buy new ones, but sticking with what I know works). I'll be using S&S premium "MADE IN USA" lifters. Lifters made south of the border scare me...
Are you listening H-D?? SAVE $ SOMEWHERE ELSE FOR CRYING OUT LOUD! Sorry, but THAT annoys me.
I digress...
But the key to the whole thing is the custom ported & polished heads (my OEM'S). They will bring the whole set-up together. No "off the shelf"
heads for me this time around. Bullet Proof 10:1 compression reliability and a ton of torque. My heads are already on their way to the porting service. They're gonna' have flow characteristics custom ported & polished specifically for the TTS cams. Bigger valves, & way better "perfect strength" springs. I'm expecting 24 - 26 more CFM. Bench testing has been ongoing for a little while now and has wrapped up. May be mass produced (CNC) at some point in the "not too distant" future. Will be a potent combination for us 103" guys with the aforementioned cams. They will play just fine with my SE stage one a/c and the stock cover. That's exactly what I wanted.

 

[hulkss]

Here's some 103" dyno data (with TTS 100 cam) from Steve Cole at TTS and the shift points for the blue curve.
This high torque cam has earlier shift points.

It all about horsepower and what's happening at the the rear wheel. A higher rpm cam (with higher power) will keep you in the lower gears longer (to a higher road speed) and will deliver more torque to the wheel due to the gear ratio in the transmission.

A high torque cam let's you shift sooner and may have better street manners as far as drive-ability and mileage go.

 

[chaderick]

That's some great info Hulkss

Sent from my SAMSUNG-SM-N910A using Tapatalk

 

[RuknRole]

...You can post your dyno curves here and I'll plot some of them for your bike and post them here.QUOTE]

Thanks a bunch Hulkss! Dyno posted.

 

[hulkss]

Here ya go. Short shift that torque monster!

Shift speed mph: 45, 62, 81, 96, 114
Shift rpm: 5760, 5490, 5350, 5120, 5200





View attachment Ruknrole.pdf

 

[RuknRole]

Here ya go. Short shift that torque monster!

Shift speed mph: 45, 62, 81, 96, 114
Shift rpm: 5760, 5490, 5350, 5120, 5200

Thanks a lot Hulkss!