Great explanation. Thanks

 

I appreciate you guys

 

by the newest lowest mile bike you can afford

 

I bought one of the first M8 Road Kings made and never had the sumping problem. In about 2020 I got nervous after reading to much about sumping and put the new HD oil pump in. Touch wood but this Road King has been trouble free and I wouldn't hesitate to buy another.

 

My 2021 M8 Limited is at 51k miles, the 2014 TC FXDL at 65k, both are excellent motors and you are making a good choice with picking one with the 2014 + Rushmore platform as is said is quite a handling improvement.

 

I would be partial to a Rushmore 103. I love my '09 103, I've heard bad things about the water pump & then sumping issues with the M8s. But then again plenty have tens of thousands of miles w/o issue. So I suppose it's the luck of the draw. I have absolutely nothing against the M8s & actually really enjoyed the '17 UC that I rented. However I think the twin cam has more character & still like the twin cam 'shake'.

 

The M8 models that he's looking at are oil and air cooled, not water cooled.

 

That about sums it up.

If you end up with an M8, I doubt you'd be wishing you had a Twin Cam.
If you end up with a Twin Cam, you might wish you had an M8.

Regarding the previously mentioned oil pump situation in earlier M8's...
Chances are, that if the bike suffered from a sumping issue, it would have been dealt with by now.
Potential seller should be able to provide documentation.

I elected to switch to an S&S oil pump on my 2018 Road King (good enough excuse to swap cams etc. as well).

For what it's worth, I am very pleased with my M8 R.K.

Best of luck to you!

 

Another member has already explained sumping and mentioned the most common reason was the oil pump. There are two other reasons that some bikes sumped, but they are not talked about as much.
1 - The piston oilers were not seated correctly from the factory, and/or the piston oilers did not work correctly from the factory. Not an easy fix as the motor has to be taken apart, but it can be fixed.

2 - Where the case is bored and the sump plug is installed, the bore is not consistent. The length of the sump plug covers/interferes with oil flow. Easy fix, replace the sump plug with a Fueling short sump plug.

I’ve owned every year of the M8, except 2024. Most of them had performance work done to the motor. From a HD stage 2, to HD 131 to a FM 128. Thousands of miles out on each bike and none of them have had sumping issues. I’ve only replaced the oil pump on one bike. That was my ‘21 FLHTK with a HD 131 and aftermarket cam.

Good luck in your search for a Road King!

 

Thanks for your input!!