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I have a new 2020 Lowrider S all standard. The Lowrider S is a Milwaukee-Eight 114 ci and with a 102 mm bore and a 114 mm stroke a thick 1868 cc. The compression is 10.5 to 1 and with 4 valves there is plenty of potential! Harley says in the specifications “More than enough torque to drive in any situation” First of all, give this bike a run on the couch, what does it do without mods?

In the graph of truth ( J ) the power is shown in red, and the pink is the torque of the standard Lowrider S. No less than 180 Nm at the wheel at 2760 rpm and a maximum power of 97.5 hp ! So that's not wrong at all! The clutch line is actually exactly what you feel when you drive the engine through the revs. The only thing I miss about the sporty look of the bike is a bit more top power, so not just power at the bottom, but power up to the red line!

To let the engine breathe, we will mount another exhaust, another air filter, a camshaft and of course we give it a good adjustment on the test bench.  The exhaust is a Vance & Hines 2 in 1 with a nice aggressive racing look and sound. Fits well and set up is a breeze. The air filter the mini teardrop from S&S and this is also child's play. Of course, the customer chose the exhaust and air filter based on emotion, but now that it's the turn of the camshaft, I can choose J As the camshaft, I take the 30-30 camshaft from Star Racing this time instead of S&S.


This camshaft is a cam with .485 lift and is made for the standard heads. I also always replace the camshaft bearing with a type without a cage. The caged bearings remain dangerous and fail regularly. The force per roll is simply higher than a bearing with only rolls.

To ensure that the engine is not slowed down by the oil in the crankcase at higher speeds, I mount an S&S cam support plate with an S&S oil pump. This combination is unrivaled for me to prevent the crankcase from filling up with oil. This is a problem with the M8 and Twin Cam problems and causes oil from the crankcase breather, and the braking of the crankshaft thus loss of power.

  Why S&S? S&S has fitted all parts of the cam support plate in which the camshafts and crankshaft rotate with brass bushes. If damage occurs later, they can easily be replaced. S&S is the only one to have a cam support plate where you can manually adjust the oil pressure. The S&S oil pump is the only one to have a double return pump, with a coarse filter in the pump and a magnet to collect large metal parts if things really go wrong, and therefore there is a chance that you can use the pump again after heavy damage. use big. Finally, the S&S pump has milled a ring on the back for the original seal, which closes the crankshaft bearing, which ensures less chance of "sumping". All these extra benefits have e.g. Fueling of  other brands do not.

When the exhaust is off and you cut the pushrods, mounting the pump, plate, camshaft and the new adjustable pushrods is done relatively quickly and a few hours later we can start the engine. I tune the motor with diag4bike and mapping it to the couch is about an hour's work.

The result is really great. In any case, a camshaft is a huge improvement on all 4 valve models because the cams have a negative overlap which means that the exhaust valve only opens when the inlet is really closed. In the graph, the green line is now the power curve and the black line is the torque.


More than 130 horsepower at the wheel and from 2700 rpm to 3750 rpm a kick in the butt with 205 Nm of maximum torque. The engine also runs with great pleasure up to the pa-pa-pa-pa rev limiter. Very striking was that the bike still drove wonderfully quietly, but if you want it goes beastly. Mission accomplished and on to the next one.


Parts used :

Starracing camshaft: 400 euros

S&S camshaft bearing and gasket set (ZPN 782494): 42 euros

S&S pushrods quickies ( ZPN 752906)  : 280 euros

S&S cam support plate and pump ( ZPN 760605)  : 765 euros

Vance & Hines exhaust (MCS 569761): 965 euros

S&S mini teardrop stealth air cleaner kit (MCS 563069): 385 euros

Diag4bike tune with adjustment on the couch: 800 euros

With assembly around 4000 euros in costs with a huge gain in torque, power, sound and driving pleasure  


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