Who has switched to the longer left cam chain tensioner here?

[JCtx]

Don't remember the details about the 'old' and 'new' left-side cam-chain tensioner, other than the hex head is larger than before (17 vs 19mm?), to differentiate them, I'd guess. And that BMW started installing it on new bikes at some point, but not sure if that's true or not... and if yes, starting which year. At any rate, yesterday rode without earplugs from the gas station (about 3 miles), and by lowering my helmet to each side of the bike at a traffic light, then inside my garage (both times cooling fan was on, so fully hot), I could tell the left side being noisier. It's not a big difference, but I could tell. I hadn't done this 'test' before, so not sure if that has gotten any worse, or it's been like that since day 1. I bought the bike 2 years ago with 0 miles (leftover 2020), and has 3,300 as of yesterday, with Castrol Power1 4T 5w40 oil just 600 miles old (2nd oil change).

 

When I found out about this new tensioner a while back, I was told to leave the bike alone, unless it became noticeably noisier on the left side. Now that I noticed the difference, want to revisit this topic, and see what the experts have to say, and what exactly 'noticeable' means. In other words, how much noisier requires a change. I don't want to change it if not needed, and possibly  cause extra wear on the chain guides, chain, etc. On the other hand, if BMW changed it on newer bikes, and nothing else changed (like the length of the chains, sprocket diameters, etc), meaning somebody screwed up the initial tensioner length (since chains are routed differently, and are of different lengths), then it might be a good idea to change it now, regardless of noise levels, no? Just curious about the expert opinions here, to decide what to do. Thank you very much.

[Cap]

I have installed the double-secret experimental left-side cam chain tensioner mod in my 2019 RT.  I haven’t noticed any difference in the noise, or the way the bike runs.  The good news is that I got it for free as a beta tester.  I was hoping for something like the sound of a sewing machine.  But it is more like shaking a coffee can filled with nuts and bolts.  Which is completely normal.

[JCtx]

Thank you very much for your reply. So you didn't notice any difference with the new tensioner??? That's strange. Do you remember when you installed it, and how many miles you had? And do you also remember if your left cylinder started getting louder over time/mileage, or was always the same? I'm trying to guess what was the reason for the change. I can only think that the shorter tensioner was basically maxed out when bikes were new, so any cam-drive wear due to normal use, cannot be compensated, and it starts making more noise. But maybe there are other reasons. I'm just trying to determine if I'm better off leaving the bike alone, or changing that thing. 

 

By the way, the right cylinder of my bike is actually pretty quiet for a boxer twin (my ex-R1200RT was louder for sure). The left side has a little bit of the 'nuts and bolts' noise you described, but mildly (nothing worrisome at all). It could also be inconsistencies in valve clearances, and that might be what's happening to your bike, no? At any rate, if the longer tensioner could make the left cylinder as quiet as the right one, it'd be awesome. Thing is I cannot adjust the timing and valves to Boxflyer specs until 10K miles (when engine is fully broken-in, per his recommendation), so the question is what do I do from now (3K miles), until then. I'm sure a lot of folks who changed the tensioner, did so at much more than 10K miles, so I don't mind leaving it alone if that's advisable. I don't run my bike hard; rarely floor it, and yesterday ran it several miles at 90+ following a fast driver, mainly to 'polish' the high cam lobes, since I don't get it above 5K rpm for more than a moment too often. Thanks again for your help.

[Cap]

9 hours ago, JCtx said:

..Thing is I cannot adjust the timing and valves to Boxflyer specs until 10K miles ...

 

That is not so.  You can adjust your cam timing and valve clearances whenever you want.  And yes, there may be some additional break-in after 3K miles, which is why there is a general recommendation to wait for 10K miles.  But if you are doing the work yourself, and you have the proper tools and skills, then there is no reason to avoid checking and setting the valve system.  And especially if you have noted a change in the sounds coming from your engine, then it is absolutely a good idea to investigate.

 

You have very low miles for a ~4 year old bike.  If your factory warranty hasn't already expired, then you must be close.  It might be a good idea to take it to the dealer and have them perform the 12k service just to have them document a thorough inspection of the bike.

 

I was being somewhat tongue in cheek with my response --  I have owned many R-bikes, and they all are noisy at idle.  And with all of them, if you take care to set the valves near the tight limit, and also set them all very close to the same clearance as each other, on both sides, then you get a really sweet and smooth-running engine at higher RPMS.  And it still rattles a bit at idle.

 

The Shiftcam has an additional source of non-sweetness, if you will.  I don't know how carefully the cams are synchronized at the factory, but I have never seen a shiftcam that was correctly aligned at the first service.  Usually the valve clearances are within spec at first service, but they might be all over the place within that limit.  And finally, the timing reluctor setting is often not well aligned at first service.  Getting all those adjustments nailed down with precision will result in a smooth engine... except at idle.

 

The left-side cam tensioner is a minor source of irritation.  I replaced mine at about 16k, and now have about 18k.  In my opinion, with 3k miles on your engine, there is near zero probability that changing the left-side tensioner will make any difference.

[JCtx]

Thanks again for your help. To clarify, I never put my ear over each cylinder until the other day, so I have no idea if it was the same before or not... but I bet it was. I've only owned another twin (2014 RT), but have heard many others before, and this engine sounds very healthy, so not worried about that at all. And I bought the bike exactly 2 years ago, so still have 1 year of warranty left. But no way I want the local dealer (only one 300 miles around) to touch my bike again. My battery was installed backwards (cables severely pulled), mirrors all crooked, the red positive terminal cap was missing, both cover rubber grommets were missing too, AND the tech couldn't reset the service warnings, so basically everything they touched, they f***ed it up. Ha ha. So I immediately bought a GS-911, because I'm pretty much on my own. Anyway, I'm mostly curious if the slight difference in noise from left to right is due to valve adjustment differences, or the left tensioner. Honestly, there's no reason to go in there now, so if anything, I'd only replace the tensioner, and see if the noise goes down a hair, and matches the right side. It'd be very easy to do. But I'd only do it if new bikes already come with it from the factory, meaning there wouldn't be any drawbacks to do it this early. But I'm perfectly fine leaving the bike alone too, if I don't hear from a '23 (and maybe even '22) owner, stating which tensioner those bikes have from the factory. And if they have the new one, I'd check part numbers for the cams, chains, etc., to make sure nothing else changed.

 

Finally, I've done all the maintenance on my vehicles for decades (and have the right tools, of course), so when the time comes, I'm going to tackle the job myself, and buy all the needed tools, including the timing one, and adjust the valves as perfectly as possible (with .02 shims), like you said. On the RT, I only checked clearances (all were fine), but this time, I'll adjust them all equally, and zero-in the timing as well, to leave it running like a swiss watch. Ha ha. But will probably wait until 10K miles (unless there's a real reason to go in there earlier), to only do it once. And that leaves me with when it's a good time to change that tensioner. No rush to do it now, so will continue watching for info on that subject. I might ask dealer if there's a TSB on that by any chance; it might give me the answers I need, like when to change it, etc. But even if there's a TSB that would cost me nothing if dealer does it, I'd just buy the tensioner out of pocket, and change it myself. Take care.

[Sean Michael]

I did on my '20 GS and, at least to my ears, it did quiet it noticeably.

[JCtx]

We have the same year engine, so may I ask you how many miles you had when you changed it? Did the engine become noisier over time (since new)? And finally, did you have to pay for the new tensioner out of pocket, or did BMW pay for it, meaning there's some kind of TSB about that potential issue? Thank you.

[Sean Michael]

On 10/21/2023 at 10:10 PM, JCtx said:

We have the same year engine, so may I ask you how many miles you had when you changed it? Did the engine become noisier over time (since new)? And finally, did you have to pay for the new tensioner out of pocket, or did BMW pay for it, meaning there's some kind of TSB about that potential issue? Thank you.

I installed it early this year at 5900 miles, and just turned 9000 this week.  I don't recall noticing it early on, but rather became increasingly aware (and annoyed) with it.

 

I just bought and replaced the tensioner myself.

[JCtx]

Thank you for your input Sean; greatly appreciated. Hey, may I assume your bike is now as quiet (or noisy. Ha ha) on both sides? Hope so. Anyway, I called Max BMW, and they knew nothing about that tensioner. So called Bob's BMW, and I'm waiting for a call back. My take so far is that BMW noticed the 'issue', and quietly made the change at some point (maybe 2021 or 2022). Max told me there's no TSB for my 2020 bike, which means it shouldn't be a problem leaving the original tensioner there... but that doesn't mean it wouldn't benefit from the new one, so I plan to also change it myself. By the way, can you please confirm the part number as 11 31 7 108 586? The strange part is Max BMW parts fiche doesn't show it at all, but Bob's does, although with zero description, and just a '!' symbol, meaning to call dealer about it. Finally, do you have the torque figure for that part? Thank you.

[Toter]

My 2021 GS Rallye does not have the new tensioner. Both 17mm. I set cam timing, reluctor, and brought all valves to Boxflyer recommended specs (.12 and .36) at 12k mi. Cam timing was off. Reluctor was ok. All valves in spec, but I uniformed all at tighter spec. Engine is pretty quiet and runs smoother.

[PODMAN]

Amusing topic I have to say. Sounds like some people are trying to build a better mouse trap.My suggestion to some is go ride an 1100cc boxer because the 1250 runs like a sewing machine compared to the 1100cc boxers. Honestly if it is not broke don't fix it. You will be amazed how much that engine will change once you put some serious miles on it. Have 18,000 miles on my 2 year old 1250 which is low for me. Usually I ride 12-14,000 miles a year. You will notice a change within the first 10,000 miles then again by the time you hit 20,000 miles. Talkn about a tractor the 1100's where like a tractor the 1250 is a revelation compared to them. The best advice I can give anyone is just go ride your bike and ride it hard in other words don't baby. I have run into more people that ride BMW motorcycles that try and "make them better" and end up only screwing something up. The boxer engine is not the Honda sewing machine V4 i.e ST1100 and 1300 and that's why people love them-----because they have character.

[Sean Michael]

On 10/27/2023 at 2:12 PM, JCtx said:

Thank you for your input Sean; greatly appreciated. Hey, may I assume your bike is now as quiet (or noisy. Ha ha) on both sides? Hope so. Anyway, I called Max BMW, and they knew nothing about that tensioner. So called Bob's BMW, and I'm waiting for a call back. My take so far is that BMW noticed the 'issue', and quietly made the change at some point (maybe 2021 or 2022). Max told me there's no TSB for my 2020 bike, which means it shouldn't be a problem leaving the original tensioner there... but that doesn't mean it wouldn't benefit from the new one, so I plan to also change it myself. By the way, can you please confirm the part number as 11 31 7 108 586? The strange part is Max BMW parts fiche doesn't show it at all, but Bob's does, although with zero description, and just a '!' symbol, meaning to call dealer about it. Finally, do you have the torque figure for that part? Thank you.

Yep, sounds about same on both sides...hardly quiet!

 

I ordered mine through Cross Country Cycle.  See attached image; same p/n you note above: 11317108586.

 

 

 

[Trash Hauler]

I have it fitted to my 2020 GSA. Free under warranty after persisting with the dealer.

[JCtx]

Nice. With my dealer, it's not even worth the waste of time. Ha ha. Plus they'd have to do the job, and don't want my bike touching that place. Heck, not even Bob's or Max BMW knew anything about that new tensioner, when I asked them recently. Weird, huh? Anyway, I'll just buy it out of pocket from Max BMW (no tax for me). I'm going to order it today, as a matter of fact. Hey, do you know when that updated tensioner was installed on new bikes? 2021? 2022? Just curious. Apparently it was a very quiet upgrade. Ha ha. Thank you.