Good good vibrations

[Gru]

Like the old Beach Boys hit, good vibrations. That’s what I have now on my r1150 RS. My recent purchase of this 20 year old bike with 19 k miles seemed a good deal. Than the vibrations ……… first I balanced the full injectors, then dug around in my million dollar boxes (don’t ever throw any thing away if it is still usable) I found som old throttlemeister bar ends. But the throttle side didn’t fit, I disassembled it, with intents to just use it for the weight. However it worked as a weight and a throttle lock, I got lucky. The vibrations are now very manageable up to 6 thousand rpm, but who rides up there. Here in Texas with most roads having  a 75 mph (120 kilometers)speed limit, it’s sweet at about 3800 rpm and 75 indicated. Gonna love it.

[Paddler]

My '98 R1100R came with bar end weights.  It's still a bit buzzy but not bad.  I tried the "Italian Tune Up" today to and from the gym.  Several full throttle accelerations up and through redline.  A ton of fun!  That 25-year-old bike (41K miles) still puts a smile on my face every time I get on it. 

[King Herald]

Check your oil level. If I overfill my 1100r by even 1/8" above the middle of the glass I get awful vibes above 3500rpm. First time I did it I was right at the top of the glass and on the first ride out I thought I'd ridden over some sort of rumble strip in the road. A few minutes in the UK BMW forum and all was revealed. I drained some oil out and it was smooth as normal again.

It doesn't seem logical, or even possible, that such a small amount of extra oil could cause it, but it does. I've repeated it once or twice since, by mistake, but realise it as soon as get the rpm up. 

[dirtrider]

On 8/23/2023 at 10:46 PM, Paddler said:

My '98 R1100R came with bar end weights.  It's still a bit buzzy but not bad.  I tried the "Italian Tune Up" today to and from the gym.  Several full throttle accelerations up and through redline.  A ton of fun!  That 25-year-old bike (41K miles) still puts a smile on my face every time I get on it. 

Morning   Paddler

 

All the BMW 1100 boxers have that mid to upper-mid RPM buzz, it is just the way a large piston 2 cylinder boxer is as the pistons are offset in relation to each other.  Those big pistons completely stop then change travel direction twice per revolution. With no balance shaft or shafts they do buzz. Some a little more some a little less but they ALL do buzz. 

 

The good part is that while they do buzz,  to most riders it isn't a harsh buzz so the buzz isn't that annoying. It is even less bothersome if the rider can get the handlebars to calm down a little using bar end weight tuning.  

 

The 1150 (larger pistons yet) were even worse, the writing was on the wall that anything larger displacement in the 2 cylinder  boxer was going to need an internal balance shaft.

 

So when the 1200 hexhead  was introduced BMW added an additional internal balance shaft. That helped but seeing as it was only a single balance shaft added to an inherently balanced 2 cylinder boxer it didn't (couldn't)  completely  remove the mid to high mid RPM buzz. 

 

[02R1150RT6M]

@dirtriderhave you ever heard of anyone doing a blueprint and balance on an R1150 RT or GS? I'd be interested if it reduced high RPM vibrations. I just bought an 02 R1150 RT and have been working on getting rid of the excess vibrations. I found that both TBs have damaged shaft bushings which I will remedy but there is a general vibration that starts around 4000 RPM and gets worse through redline. I still have to check the valve clearances but it's hard to know which vibrations are normal on this bike. If it helps, my other bike is a Honda CBR500R. 

[dirtrider]

7 hours ago, 02R1150RT6M said:

@dirtriderhave you ever heard of anyone doing a blueprint and balance on an R1150 RT or GS? I'd be interested if it reduced high RPM vibrations. I just bought an 02 R1150 RT and have been working on getting rid of the excess vibrations. I found that both TBs have damaged shaft bushings which I will remedy but there is a general vibration that starts around 4000 RPM and gets worse through redline. I still have to check the valve clearances but it's hard to know which vibrations are normal on this bike. If it helps, my other bike is a Honda CBR500R. 

Morning  02R1150RT6M

 

I'm sure someone has tried but I have serious doubts that it would help much if at all.  

 

The primary engine balance on the BMW boxers is pretty good from the factory as long as a new clutch wasn't installed with the balance marks incorrectly lined up. 

 

None of the things you mentioned will help that boxer BUZZ much as the valve adjustment effect & throttle body effect really doesn't have much if any influence on the higher RPM boxer buzz. That higher RPM (4K & up) boxer buzz is mainly mechanical, not firing induced.

 

I think the key thing to look for here is    "I just bought an 02 R1150 RT",   that 4K & up boxer buzz seems to bother newer BMW 1100/1150 owners. After riding them for a while most 1100/1150  riders get used to the buzz & some long term BMW boxer riders would even miss that inherent boxer buzz.  

 

My suggestion to you is to: wait 6 months or about 3000 miles then reevaluate if that inherent boxer buzz still bothers you, if it does then you might consider selling it & buying a later boxer (one with a balance shaft) or better yet a multi-cylinder engine motorcycle.  

 

If you want to try something then start by trying heavier handlebar end weights, and/or something like grip puppies. You aren't going to get rid of that inherent boxer buzz but you can work with things that effect how that buzz transfers into the rider or blurs the mirrors. 

 

 

[02R1150RT6M]

Thanks! That explains a lot. My cars have inline 6 turbos or N/A 4 cyclinder engines with double balance shafts so I'm used to smoith powerplants. Even my Honda CBR is quite smooth for a parallel twin but I did just correct a vibration with it that was caused by degradation of the fibreglass in the performance muffler. I'll sort the issues I know about on the RT then just ride the bike. I can be ok with vibrations if they are normal and won't impact reliability. When I initially test rode the bike, I asked the former owner and he didn't seem to think the high RPM vibrations were a problem, then again he also didn't notice the racket caused by both TB shafts being very noisy (especially the right one) so I wasn't sure what was normal. He said that he owned Harleys before he bought the RT.

 

One question mark is the condition of the clutch and transmission input spline. The bike has about 58k miles and I'm going to pull the starter today. I'm hoping to find good things but the fluid level in the clutch reservoir was pretty high so... I already ordered a new clutch with a longer hub from beemerboneyard, hopefully it won't be something that needs to go in right away.