Harley will be replacing my M8 117 motor on my new 2018 CVO Street Glide in a couple weeks and I'll need to go through the grueling 800 km break in period all over again. Arghhh! When my stock M8 117 motor sumped and catastrophically failed at 1200 kms there was no pre hand warning. I was travelling at highway speed in 4th gear at around 4500 rpm and I didn't hear any strange sounds prior to it cutting out, the motor just simply stopped and all I was left with was the 900W stereo system still blaring and 2 lanes of traffic now to cross without getting creamed. I safely rolled the bike to the side of the road and when the bike came to a stop I could instantly smell burnt oil. I didn't experience any kind of power loss at the time but I'm thinking maybe it was always a little sluggish right from the start? This was my first bagger and obviously it was also my first M8 117 so I had nothing else to compare the power with except to my 110 Dyna Low Rider S which there was no comparison, the Low Rider S was much quicker but also 300 pounds lighter so I kind of expected that. Thinking back the engine always ran super hot on the right side, maybe it was a dud right from the factory? I'm curious if I hadn't been listening to the stereo if I would have heard some kind of pre warning sign??? What does a motor sounds like when it's sumping?

 

 

Next time you get the motor back try not to labor the motor at 4500 just traveling down the highway. Never labor the motor more than it needs to produce your desired speed. These motors aren't made for high RPMs for long distance.It makes them build heat.A good RPM is around 2800 to 3000 . The performance stage kits claim to let you run a higher RPM.And we see that's not working to well either.

 

I don't consider 4500 laboring the motor. IMO.

If that is more that the bike can handle, something is wrong.

With my96 6 speed and tall gears I rode there alot until I put after market exhaust on. Then it was loud. Lots of Harley shift on noise.

If a bike is failing at 4500, it is going to fail at lower rpms pretty soon.

 

OP must not be too concerned with gas mileage. Not sure why one would want to run down the highway at 4500 rpm in 4th when you got 2 more gears. Maybe he likes to hear very loud music over loud pipes or he's just clueless. True, the motor should be able to handle it (for a while) but these are not rev happy motors and it's not necessary plus it just wears things out quicker.

 

I agree that the only time I am at 4,000 or more rpm I am shifting to a higher gear.

 

I didn't say that I cruise around at 4500 for long periods of time that's just what I happened to be doing when the bike failed. If I'm cruising on the highway I'm usually around 3000 -3500 but if I'm in the twisties and I'm having to make quick speed adjustments I definitely like to keep my revs up higher.

 

 

I'll check the dates and report when I get it back.

 

Can't imagine how someone would say, you are clueless for keeping the power up.

I have not rode this engine. But when I am in traffic, I don't want to down shift to get out of the way. I bought a bike cause I like the power of being on two wheels.

If we were worried about gas mileage we would be riding 80 evo or sporty.