Knocks in foot-peg, transmission ?

[Deleted account 251212001]

Clutching at straws a bit here but have any of you had any issues with foot-peg ‘knocks’ or feedback or perhaps where it feels like there may be too much slack somewhere in the transmission?

There are occasions when it feels like the rider foot-pegs esp the right hand side, are being light tapped with a hammer.

I noticed it a lot on a recent trip away, i was mostly sticking to speed limits, trundling, for large parts through towns and villages. It became annoying after a week of it.

This is not a hooning about problem, youve already built the speed up, its a nil throttle, high gear, so perhaps on a slight down hill gradient 50mph in 6th but it happens in 5th and 4th - and then a tiny bit of throttle on and off again just to maintain the speed is accompanied by this occasional knock sensation in the footpegs.

I mentioned it to the dealer and got fobbed off and at the time before they’d even looked at it (they all do that sir) and nothing was mentioned when i collected it, didn't have the time or energy to pursue further , something just doesn't feel quite right….i notice this on this bike but not on any other boxer ive had would i be right in thinking the gearbox was moved on these 1300s?

 

[Hann]

I saw this on Facebook, a quick check should eliminate this as a possible source of your knock?
The swingarm has side-to-side movement, seen a few posts about it unfortunately.

Facebook

www.facebook.com

 

[Deleted account 251212001]

Thanks Hann i will check that out at the weekend

 

[botus]

what revs ? sounds like transmission backlash snatching through the drive-line - its often an issue at low revs and low throttle settings where it can't work out how to run smoothly as we need. This is because emission regs don't allow as rich a mixture as the engine needs to run correctly

its not healthy for the transmission, or pleasant to feel. Its best to change down a gear or find a way to go faster

it would be interesting to know if its become more troublesome on 2025 model year bikes. They've had to play with most stuff all over again as Jan 2025 introduced another change in emission stds with Euro 5+ We now they have to prove the bike can reach 22k miles and still meet the original emission regs of Euro 5. So more tweaks and many getting large CATs

Just this week been debating on a K1600 forum re why does this guys bike run like a pig. So I pointed out when the K16 was first out Europe we didn't have ethanol infected fuels, and they only had to land Euro 3 emission control. Then for bikes first registered after Jan 2017 we got Euro 4 - and I thought the world moved to wideband CAT sensors so it can sniff the AFR (air fuel ratio), rather than just land Lambda 1 of old world O2 sensors, so we were ready for the Ethanol trash fuel.

But it turns out they never mandated wideband sensors even though we all need it. Then 2021 brought in Euro 5 and still they weren't mandated - yet Europe were about to get 10% Ethanol as std fuel - and that rubbish runs 4% lean and steals 6% power. So of course, without the best way to fix it, we will have difficulty running nicely.

Checking one of my BMWs this week, the AFR changes day to day with the weather. Some days it runs great, others like an utter pig. Yesterday was good. Today its a pig and AFR is stupidly wrong. If you read about the correct way to make an engine run we need a MAP sensor to detect engine load and inform the ECU how to cope. Honda and Ducati now run MAP sensors as do most cars and have for many, many years. But as far as I can tell BMW bikes do not have a MAP sensor and even 2025 model year bikes don't appear to have widbeand sensors - but my Mercedes car was running these in 2006 with a Bosch ECU !

I had read someone thinks bikes rev too high and something else about air mass is insufficient due to low capacity engines, meaning a MAP sensor won't perform correctly - but that must be old ideas and old MAP sensor tech - as a CBR600 revs way more and they use MAP sensors

 

[botus]

it produces the knocking sensation because that's effectively what's happening, the rough running means the engine unloads the drive line for a split second as if going into engine braking, then milliseconds later produces sufficient power taking up the backlash with a bang – like a small hammer blow metal on metal, which through all the casings becomes the dull tap you hear and feel

 

[Deleted account 251212001]

what revs ? sounds like transmission backlash snatching through the drive-line - its often an issue at low revs and low throttle settings where it can't work out how to run smoothly as we need. Because emission regs don't allow as rich a mixture as the engine wants to run a smoothly as it could

its not healthy for the transmission or pleasant to feel, best to change down a gear or find a way to go faster

would be interesting to know its become more troublesome on 2025 model year bikes. They've had to play with most stuff all over again as Jan 2025 introduced another change in emission stds with Euro 5+. We now they have to prove the bike can reach 22k miles and still meet the original emission regs of Euro 5. So more tweaks and many getting large CATs

Just this week been debating on a K1600 forum re why does this guys bike run like a pig. So I pointed out when the K16 was first out Europe we didn't have ethanol infected fuel, and they only had to land Euro 3 emission control. Then bikes first reg after Jan 2017 we got Euro 4 - and I thought the world moved to wideband CAT sensors so it can sniff the AFR (air fuel ratio), rather than just land Lambda 1 of old world O2 sensors, so we were ready for the Ethanol trash fuel.

But it turns out they never mandated wideband sensors even though we all need it. Then 2021 brought in Euro 5 and still they weren't mandated - yet Europe were about to get 10% Ethanol as std fuel - and that rubbish runs 4% lean and steals 6% power. So of course, without the best way to fix it, we will have difficulty running nicely.

Checking one of my BMWs and the AFR changes day to day with the weather. Some days it runs great others like an utter pig. Yesterday was good, today its a pig and AFR is stupidly wrong. If you read about the correct way to make an engine run we need a MAP sensor to detect engine load and inform the ECU how to cope. Honda and Ducati run MAP sensors as do most cars and have for many, many years. But as far as I can tell BMW bikes do not have a MAP sensor and even 2005 model year bike appear not to have widbeand sensors - but my Mercedes cas had them in 2006 !

I had read someone thinks bikes rev too high and something about air mass is insufficient due to low capacity engines mean a MAP sensor won't perform correctly - but that must be old tech and old MAP sensor tech - as a CBR600 revs way more and they use MAP sensors

not sure on rev's lowish guessing 2-3k. This is on a flat road or downhill I understand/accept a bit of backlash applying the power from a null throttle at lowish revs, it's the knocking through the rh footpeg which gets annoying something ive not noticed on any other GS ive owned. It is an October 2023 bike one of the first ones in the country.

 

[botus]

wot miles / servicing,

try the same roads where you've noticed it at higher revs / speed - and or change down when you spot it and see if it goes away...
maybe try software update in case they did something to help it run nicer down the bottom, - check with GS911 or Motoscan - both with show the i-level of the bike and will help determine if they updated it at any point, if its not at least late 2024 I'd get it updated - will be loads on the cluster to do so the rest is nothing whilst they sort those bugs...

try other bikes from same age / if its still there / different to others warranty query ?

 

[Deleted account 251212001]

wot miles / servicing,

try the same roads where you've noticed it at higher revs / speed - and or change down when you spot it and see if it goes away...
maybe try software update in case they did something to help it run nicer down the bottom, - check with GS911 or Motoscan - both with show the i-level of the bike and will help determine if they updated it at any point, if its not at least late 2024 I'd get it updated - will be loads on the cluster to do so the rest is nothing whilst they sort those bugs...

try other bikes from same age / if its still there / different to others warranty query ?

I could change down but it happens in an instant, it's a tiny amount of throttle on off from no throttle. It's intermittent , hard to pin down but seems associated to the example I gave. I was interested if anyone had noticed similar in their footpegs, I tried an adventure last time it was in I didn't notice it as pronounced but it was a 30 minute test ride each way and mostly motorway.

The mileage is 11400, 3 services and just serviced.

I will try the swingarm check this week, as I need to get the bike out take the bike back to the dealers again (new headlight under warranty this time).