Just the rim/teeth. Mounting face and everything was fine. Was less than 5 minutes on the lathe.

 

Dropped my machined down 30 tooth sprocket at the dealership today. Even being smaller in diameter and machined down to the same width it was still noticeably heavier than the stock 32. The stock 32 has weight removed with the 6 holes. I would be afraid to drill holes in the 30 tooth though for fear of stress crack or imbalance. Thoughts? Also got to see my 70 tooth pulley while at the dealership. Still hoping to get this thing together and get my break in miles done in early December so I can get the dyno done yet this winter. Plan is to deliver an Airstream TT to southern Florida, Gulf coast or Tucson AZ take her off the bed of my truck and get my break in miles done. Fingers crossed for some good weather.







and for kicks.. and yes the locals said my legs were brighter than the sun that day.

 

I did notice that, quite a bit heavier. I think if you had holes drilled at equal distances around it wouldn't throw it out of balance. I am unsure about if it would weaken it at all.

I haven't put on my 70 Tooth rear pulley yet but with the 30/68 combo I'm very happy. Rode around on the weekend, highway riding, local streets, up the mountain and I'm stoked with the results.
I have been in contact with V&H about recalibrating my speedo with my FP3 Tuner. It isn't an option through the app anymore but they are going to help out and adjust the settings based on the gear ratio change.
The belt guard fits back on, very close fit but it's on. It's definitely not going to fit with a 70 Tooth rear, modifications will be necessary.

 

Yeah I know I have to mod the guard. Still working with Heal Tech on their SpeedoHealer for speedo / odo correction and top speed limiter removal. Reason being I still plan to tune with the Harley tuner so as to retain the warranty. I believe both Power Vision & TTS tuners have that option as well but void warranty in doing so.

 

Not sure about keeping the warranty with the gearing change. Exhaust emissions are measured in grams per mile. A gearing change may make the bike emissions non-compliant, if so, no warranty.

I would not try to lighten the pulley. Reducing the diameter has probably reduced the rotating inertia, even with the extra weight.

 

I asked my dealer if the gear & pulley change could affect my warranty. They thought possibly as MoCo may take any excuse if I made them aware of it but otherwise highly unlikely as MoCo has their radar on tune & exhaust. Would it pass an EPA emissions test perhaps not.

 

It's probably only an issue if you have a major engine or transmission failure and a Harley rep gets involved. Problem is, that's when you want the warranty the most. Very unlikely to happen though.
If you break the belt, that not a warranty item anyway.

 

Dealership is active in racing programs so they have a fair amount of more serious builds around. Said they have had 6 or 7 M8s strip belt teeth and that it seems to happen when they reach 130 foot pounds or more & get traction.

Not sure if changing the gear & pulley will affect this threshold. I’m mean the calculation with 30/70 is 13 percent more torque to the ground but the motor is still putting the same torque to the belt. Thoughts?

 

What matters is the tangential tooth load in the belt.

If the belt system is engine torque limited, the front pulley radius has been reduced, raising the tangential load by 30/32. Also, there is one less load carrying tooth in mesh on the front half of the pulley, raising the tangential load per tooth by another 15/16. So your belt engine torque capacity is now 88% of what it was.

If the belt system maximum load is traction limited, not engine torque limited, then the rear tire contact patch is what limits tension in the belt. Since your rear pulley is bigger by 70/66 you will have 6% less belt tension at the traction limit. That is offset by the 15/16 drop of belt teeth in mesh, so basically no change.

Answer: Stay off the drag strip where traction is high.

 

Lol what fun would that be. No dyno yet but pretty sure she will be well below 130 foot pounds. Thanks for the info. Always good to learn new stuff.