M8 Sumping - Warning signs to listen for?
#1
M8 Sumping - Warning signs to listen for?
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?
#2
I have been watching these threads on the M8 and what i see in common with sumping is that the folks that it is happening to like to ride way up on the RPM...4500+.
the only time I am at the above 4000rpm is when changing gears.....then i settle in between 2800/3500 rpm....
am I the only guy that is seeing this correlation?
the only time I am at the above 4000rpm is when changing gears.....then i settle in between 2800/3500 rpm....
am I the only guy that is seeing this correlation?
The following 2 users liked this post by giacomo56:
Don Michigan (04-14-2019),
Mark Moore (05-25-2018)
#3
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?
Last edited by tbob; 05-25-2018 at 03:52 PM.
The following users liked this post:
Mark Moore (05-25-2018)
#4
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.
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.
Last edited by Zerk; 05-25-2018 at 04:00 PM.
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#5
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.
Last edited by carpetride; 05-25-2018 at 04:56 PM.
#7
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.
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#8
The M8s aren't like the Tc motors,you just about can't lug one and no pinging what so ever. Most of my shifting is st 3000 and cruise 2500 to 2900 . Mine runs great and in 3000 miles I have used 8oz of
oil. Now if they could just get a right hand switch pack I would be happy it's no fun when your running the cruise and the front brake won't cancel it.
Do you know if your bike has the latest oil pump.Production after October.
oil. Now if they could just get a right hand switch pack I would be happy it's no fun when your running the cruise and the front brake won't cancel it.
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.
Last edited by ChickinOnaChain; 05-25-2018 at 11:47 PM.
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oldmanwayne (04-14-2019)
#9
#10
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.