5-Speed Cruising RPM

[glimmerman]

my 01 flhpi cruises in 5th at 3000 rpm for 60 mph. i noticed that i run out of gear when accelerating from a stop w/ other bikes. i seem to top out quicker. seems there should be another gear there somewhere. i thought the rear sprocket was larger. dont think the trans is different. i have both police and civilian manuals and there isn't anything there.

 

[Caper]

Just rode the 03 FLHPI home, 2500@60MPH... 3000@70 and 3500@80 give or take 100RPM's, 90MPH@3800

 

[Redfish-Joe]

If I'm not mistaken, I believe the police bikes have a different primary gearing for more bottom end.

I think something like this
3.73 in the primary for the police bike and 3.18 in the standard touring.

You are right with my 2000.

 

[dolt]

I’m curious if the Police bikes have the same final gearing as the civilian bikes. My 2001 Police Road King cruises 55MPH @ 2500RPM and 75MPH @ 3500RPM. This seems a bit high.

What RPM does yours cruise?

3.37 (24T comp sprocket/37T ring gear) gearing was once the factory setup for the first Twin Cam baggers. Back in 1999, 2000, and 2001 HD introduced the Twin Cam engine on touring bikes with either a carb set up or an EFI option. The carb Touring Bikes were given 3.15 (25T comp sprocket/36T ring gear) gearing and the MM EFI Touring Bikes were given 3.37(24T comp sprocket/37T ring gear) gearing.

In 2002 HD introduced the Delphi EFI throttle body and went back to the 3.15 gearing for EFI bikes and the carb bikes continued to run 3.15 gearing as well.

3.15 gearing = 2500rpm@60mph and 3500rpm@84mph
3.37 gearing = 2500rpm@56mph and 3500rpm@78mph

Of course, tire size and speedo calibration can cause variances but your numbers would indicate that you have a 3.37 final drive ratio. As Glider pointed out, the police models may have left the factory with 3.37 final drive whether EFI or carbed for the increased torque. If you have never done a back to back ride comparison, you will be surprised at the difference. A Stage I TC88 in a good state of tune with 3.37 gearing will surprise you at how quick it can be and it is a very economical performance upgrade.

 

[Delmar]

Thanks Dolt, this is exactly the information I was looking for. I’ll watch eBay for a cheap 3:15 sprocket set.

Or…if anyone here is looking to increase acceleration performance maybe we can perform a trade?!?

You also confirmed another suspicion about the fuel injection. I did not notice any oxygen sensors in the exhaust so wondered if it is an older setup (speed density?). Fortunately it operates great and delivers 39mpg.

 

[Caper]

Other than my eyeball accuracy at 60MPH, I could very well have been at 2700RPM @60MPH and variances like dolt mentioned it looks to me without counting teeth my 03 Delphi Police RK has 3.37 gearing, 3500@ 80(78) makes me think it. An 03 civilian bike would have the 3.15 gearing, so this would be an indication that the cop bikes are geared different than civilian models.

 

[dolt]

Thanks Dolt, this is exactly the information I was looking for. I’ll watch eBay for a cheap 3:15 sprocket set.

Or…if anyone here is looking to increase acceleration performance maybe we can perform a trade?!?

You also confirmed another suspicion about the fuel injection. I did not notice any oxygen sensors in the exhaust so wondered if it is an older setup (speed density?). Fortunately it operates great and delivers 39mpg.

It is the early MM EFI system, the predecessor to the Delphi system that was introduced in 2002. The MM EFI system is Alpha N; load sensing by throttle position. The later and much improved Delphi system is a speed density system; load sensed by intake manifold vacuum.