All depends on the build, and how good you are with maintenance. Reaper's engine started life as a stock 88ci, and was built into a 98ci, 10.5:1 compression, head work, cams, etc... pushing ~100hp/~120 ft-lbs at the rear wheel. She has 294,000 kms (almost 183,000 miles) and 15 years on her, and has been rock solid reliable, from bopping around town, to multi-week/multi-thousand mile road trips.

I just rebuilt her top end after almost 100K miles on the last rebuild, and am looking forward to the next 100K+ miles before another top end (top end rebuilds are not a sign of a problem with the engine. Just a thing that needs to be done on high mileage air-cooled engines).

Cheers!

 

... and so did I! Oops!

Cheers!

 

https://suburbanharley.com/Performance-Kits-Twin-Cam