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Hitting a rev limiter at 5K on a TNT 125

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GoldenBunip

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Discussion starter · #1 ·
Hello all,
My Benelli TNT125 is hitting a rev limiter at 5K and I cant figure out why. Any help with this would be greatly appreciated.

The bike starts fine, high ideals and then settles to what sounds like a normal tick over at about 750rpm. Which I think means the choke isn't stuck on.
Bike rides and pulls fine to 5K RPM in any gear, but at 5K it hits and bounces off an electronic rev limiter.

I've serviced the bike, with spark, oil, filters. Just done the oil again again as getting it on the good red stuff (Motul 7100). So it's not oil level.

Only other thing I can think of is stand sensor, but would it still ride in all gears?
I'm new to bikes, but have been servicing and repairing mine and the wives cars for 20+ years, so happy with mechanics and electrics.
 
#2 ·
It does sound too low. Is it exactly the same revs every time? or does it vary. I’m assuming it’s got an ecu! If so it will need to be setup in diagnostics. But if it varies a little it may be a bad connection on the injection or ignition side and vibration might be triggering it.
 
Discussion starter · #3 ·
GBo said:
It does sound too low. Is it exactly the same revs every time? or does it vary. I’m assuming it’s got an ecu! If so it will need to be setup in diagnostics. But if it varies a little it may be a bad connection on the injection or ignition side and vibration might be triggering it.
Click to expand...
Yep same reves at all times. Standard rev limiter should be about 11k.
It has an ECU as its fuel injected.

Reading around it seems the 5k rev limiter is on when the bike thinks the stand is down. So next up is to work out how to check the stand sensor.
 
#4 ·
are we talking about a brand new bike or a used one. ?
i dont know these bikes but do they have a break in rev limit to be removed at a dealer after say 1500 miles ect .?

or could just be a bad ecu ive seen many tnt125 ecu`s for sale on ebay .....hmmm
 
Discussion starter · #7 ·
Its a 2019 bike, so not run in limited

Today I found the stand sensor was not installed correctly. So removed, cleaned and reinstalled correctly.
I also found the stand sensor was disconnected. Somebody has been playing with the electric on this bike!

Reconnected and now the bike doesn't start with the stand down, and cuts off the engine when put down. This I think is normal behaviour for a Euro 4 bike.
It does tell me that the stand sensor is now working.
Still limited to 5k RPM. The hunt continues.

Next up is to disconnect the battery and let it sit, then reconnect and see if it just needs resetting.

Any other areas anybody can think to to try?
 
#8 ·
I also have a used 2019 and it wont rev past 5k RPM's, the bike runs fine, starts fine, was asking this same question on a FB group:
So i just did the speedometer correction method: CC123 & F012.0 were used and I must have messed up....
my answer was: "you messed with the P1,P2,P3 settings, your at half rev's right now, you need to go back to P1"
I'm still looking into this, wonder if a ECU reset will fix this too....


GoldenBunip said:
Its a 2019 bike, so not run in limited

Today I found the stand sensor was not installed correctly. So removed, cleaned and reinstalled correctly.
I also found the stand sensor was disconnected. Somebody has been playing with the electric on this bike!

Reconnected and now the bike doesn't start with the stand down, and cuts off the engine when put down. This I think is normal behaviour for a Euro 4 bike.
It does tell me that the stand sensor is now working.
Still limited to 5k RPM. The hunt continues.

Next up is to disconnect the battery and let it sit, then reconnect and see if it just needs resetting.

Any other areas anybody can think to to try?
Click to expand...
 
Discussion starter · #9 ·
SORTED.... I think.

So in some distant reading I came across the speedometer correction method. In this you go into the settings and can adjust the speedometer correction factor, to make the speedo read correctly. In that post it mentioned not to change the Y value, as it can make the rev counter read half or double.... BINGO.
Changing this Y value corrected my issue.

Steps
Key in the ignition, but off.
Press both buttons on the speedo and turn the ignition on.
on the screen will be CC---
Tapping the top button moved the position on and the bottom button changes the value up one (they cycle round if you go past your target.) Holding the top button saves.

Using the buttons enter the code CC123 then hold the top button (only need to be held for about a second to move on)
This will then bring up the next menu screen. This has the Speedo correction at the bottom and a Y value at the top.
Cycle past the speedo correction number until the Y value at the top flashes.
Change the Y value, and press and hold the top button to save and reset.

My Y value was set to 1
Changing this to 2 gives me the correct max RPM.

I did try the others, the options are 1,2,4,6,8
4 was half again and 6 & 8 the bike doesn't start.

Now I am wondering if this also affects the speedometer reading, as when I was out practicing my gears on an old runway (My CBT is Tuesday) I thought I was going much faster than the speedo said, but put this down to not having ridden bikes for quite some time. Now I'm not so sure, as I'm used to knowing speeds from driving and cycling a lot over the years.
Best check my speedo is vaguely correct before my CBT.
 
#10 ·
CC123 then F012.0 then move up to the (lower case with the top missing menu) changed mine to p1 from p2, with p1 the bike rev's past 6k sitting, ill test drive tomorrow, pics are from the web
Image
Image
Image




GoldenBunip said:
SORTED.... I think.

So in some distant reading I came across the speedometer correction method. In this you go into the settings and can adjust the speedometer correction factor, to make the speedo read correctly. In that post it mentioned not to change the Y value, as it can make the rev counter read half or double.... BINGO.
Changing this Y value corrected my issue.

Steps
Key in the ignition, but off.
Press both buttons on the speedo and turn the ignition on.
on the screen will be CC---
Tapping the top button moved the position on and the bottom button changes the value up one (they cycle round if you go past your target.) Holding the top button saves.

Using the buttons enter the code CC123 then hold the top button (only need to be held for about a second to move on)
This will then bring up the next menu screen. This has the Speedo correction at the bottom and a Y value at the top.
Cycle past the speedo correction number until the Y value at the top flashes.
Change the Y value, and press and hold the top button to save and reset.

My Y value was set to 1
Changing this to 2 gives me the correct max RPM.

I did try the others, the options are 1,2,4,6,8
4 was half again and 6 & 8 the bike doesn't start.

Now I am wondering if this also affects the speedometer reading, as when I was out practicing my gears on an old runway (My CBT is Tuesday) I thought I was going much faster than the speedo said, but put this down to not having ridden bikes for quite some time. Now I'm not so sure, as I'm used to knowing speeds from driving and cycling a lot over the years.
Best check my speedo is vaguely correct before my CBT.
Click to expand...
 
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dduggan69
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