Journeyman

"And this one is just right" ~ Goldilocks
Joined
Aug 13, 2017
Messages
2,101
Location
Old Fort, NC 28762 USA
Ride
2020 3R
At 3,000 rpm, which is 80 mph in 5th I'm getting a gentle thump in my left foot peg. Feels almost like the kickstand bouncing a little, but it's not. Same in 4th at 3k. I haven't noticed it in lower gears or other rpms. I don't hear anything, just feel it.

The tuner asked me where I tend to cruise- well, I don't do a lot of cruising, but I said about 80. Wondering if he leaned it out there and that's what I'm feeling. Also, where I got the bike tuned is at 600 ft. elevation. Where I live is 2400 feet.

It was several months after the tune that I noticed this, so not sure if it is tune related and I just didn't notice it for a while, or developed later. Of course now I'm focused on it and always aware of it.

I just got a PC5 that I will install soon and an auto tune is coming. Hoping this is a fueling issue. I can't imagine what else would be so specific at a certain RPM. I can definitely creep right up on 3k and produce the result.
 
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Is it there/any differences when going uphill, downhill and on the flat, all while holding 3000rpm?

Does it make any difference if you pull the clutch lever slightly (enough to take up the slack but not enough to disengage trans from engine)?
 
Also, where I got the bike tuned is at 600 ft. elevation. Where I live is 2400 feet.
Approx 6% Atmospheric Pressure difference. I need Mr @Speedy but I would expect the stock ECU to be able to deal with that.

Get a POD-300. Yes they're expensive, and you will get headaches from all the data. But second guessing is a futile experiment.
 
Is it there/any differences when going uphill, downhill and on the flat, all while holding 3000rpm?

Does it make any difference if you pull the clutch lever slightly (enough to take up the slack but not enough to disengage trans from engine)?
I don't think so. I tend to end up cruising in 4th at 3k going uphill on my route home, but I don't think it's the grade causing the thump, just where I end up in 4th in that situation. As you know, I just replaced the final drive. Just in case someone throws that out there, but the specific RPM is what is the head scratcher.

Add- I'll try pulling the clutch slightly to see. Good idea.
 
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I don't think so. I tend to end up cruising in 4th at 3k going uphill on my route home, but I don't think it's the grade causing the thump, just where I end up in 4th in that situation. As you know, I just replaced the final drive. Just in case someone throws that out there, but the specific RPM is what is the head scratcher.

What I mean is the engine is under high, medium and low load when going uphill, on the flat and downhill, while holding an RPM.
Increased load is increased risk of knock.

Re the clutch I've noticed with the cable clutches the lifter piece can rattle about at a specific rpm, can be felt in pegs and handlebars. If you pull the lever a little it takes up the slack and stops the knocking. Worth a test
 
What I mean is the engine is under high, medium and low load when going uphill, on the flat and downhill, while holding an RPM.
Increased load is increased risk of knock.

Re the clutch I've noticed with the cable clutches the lifter piece can rattle about at a specific rpm, can be felt in pegs and handlebars. If you pull the lever a little it takes up the slack and stops the knocking. Worth a test

I can produce it on the flat and uphill. I think on downhill it's the same, but I'll check that to be sure, as well as the clutch.
 
I can produce it on the flat and uphill. I think on downhill it's the same, but I'll check that to be sure, as well as the clutch.
Are you going to up the octane to see if it makes any difference? I too am curious about whether you can reproduce going up hill, flat, and down hill. I'm wondering how your torsional damper bearings are . Next oil change you might want to droo the sump pan for a visual inspection.
 
I just moved (divorce) and have some octane boost somewhere in storage. I'm going to see if I can get to it. Neville also recommended I try that, just haven't had a chance yet.
 
I just moved (divorce) and have some octane boost somewhere in storage. I'm going to see if I can get to it. Neville also recommended I try that, just haven't had a chance yet.
Yes I'm sorry for the turmoil in your life during a pandemic. So I give you 50 points for putting your bike towards the top of the list. Some 108 octane boost from the petrol station or Walmart will serve its purpose. Make sure you get enough to do two tanks that what which ever way it goes you tested it more then once. Oh and enjoy the riding part !!!
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