Vibration still a question????

[grumpyone]

Morning friends; The l986 R80 still has the vibration. The question I think is the wrong wording in my post. Im not sure the vibration has anything to do with missing. Can a mounting bolt cause a severe vibration? Or a clutch maybe been replaced (dont know) and things put back together out of balance??
Can a carb out of sync cause a bad vibration?? And still run with very very close exhaust temp on both pipes??? or would you show up with a heat dif if the carbs were out of sync?? Im not up enough on carbs to know if there is a way they can cause a vibration from idol to top and a pretty good one ???
Thanks again ; We will find the problem. I suspect we have it narrowed a whole lot from where we were when we started ::)):bow
Thanks much
Jim and Esther

1986 R 80
2 spoiled corgi s

[20774]

Some of that was discussed on the previous thread...not sure why you've started a newer one.

Since you're experienced at looking at header temps, then it's probably a good indication that the carbs are working equally, although maybe not in synch. Valves are probably OK. No one else is there to get a sense of the vibration levels that you're concerned about. It may be minor for someone who's been around these bikes for a while. So, yes, out of synch carbs could be an issue.

So could bad spinning parts in the engine/clutch area. Yes on the motor mounts. You need to make sure they are tight.

[kbasa]

Start with the simple stuff: are the carbs completely and accurately balanced? Have you done a valve adjustment on it recently?

Is the vibration rpm or speed related? If it's rpm, it's somewhere in your engine, if it's speed related, it's somewhere in the driveline.

If it's speed related, start with the simple stuff, most likely to get mucked up, like tire balance.

[grumpyone]

Sorry for starting another thread : Im not real up on the protocal here about such and figured I had thought it was a miss problem and now believe it has nothing to do with missing so I figured I should start over with more accurate questions. My goof:stick
The vibration has nothing to do with speed. It is a vibration at idol and also stays as fast as you wind it up.
I understand that the clutch stuff could cause it but if it were in the clutch area would it not change or be effected if you pulled in the clutch and let it out??? at least some in my way of thinking. It has no effect on it. I had thought maybe the previous owner had replaced the clutch and got things out of balance when replacement was done? But again I would think that the clutch lever would effect this some.
Now the issue of the carb sync and some vibration is normal:::bottle I think it may be the problem ; I remember when I got it down the left plug was black and right not. Also all the things we have fixed have helped some here and there. We found one plug wire in the coil barely in both carbs very unlevel and so on so if the carb sync helps a tad too we may be in business.
Should the carbs be rebuilt before sync if the bike sat for several years even tho it seems to run rather good?? Just to keep from having to have it done twice??
O the amount of vibration I know is hard to describe but mirrows are the easiest way to get an idea for me and now we have a vibration but the mirrows are generally speaking always steady enough to tell whats behind you.
Thanks so much and if your replying form the Alamo country : try and stay warm I know these cold spells this time of year down there can really chill you. :D Raised down that direction ; two things you cant forget , the heat and the dust.
Thanks Much
Jim and Esther
gettin there :clap

[26667]

Synching your carbs is a fairly regular and simple procedure....(lots of posts re: carb synch in the Airheads forum) ...part of a regular tune-up. And the idle mix is something you might change say if you went to a different altitude. Or just a slight change in conjunction w vale adjust/carb synch. But if you can't get them to balance it's a pretty good sign they need to be rebuilt.

That said, you could almost bet that having sat for some time, anything rubber(including carb diaphragms) is dried out and will need to be replaced.

Given enough time, anything greased is now glued.

good luck

[20774]

I understand that the clutch stuff could cause it but if it were in the clutch area would it not change or be effected if you pulled in the clutch and let it out???

When you pull the lever in, the clutch parts are still spinning, just not connected to the flywheel. So, yes, if there's a serious imbalance problem due to the clutch, it's likely to still be there.

Should the carbs be rebuilt before sync if the bike sat for several years even tho it seems to run rather good??

If there's some doubt about the health of the carbs, it would be a very good idea to rebuild them so you can rule that part of it out.

Have you used a timing light to verify the timing, at idle and at full advance? I'm not as familiar with the electronic ignition modules, but you might have a double image of the S-mark at idle. This would mean that the left cylinder and right cylinder don't fire at the same point in their rotations and thus can give a rocking moment through the crankshaft. The BMW has a wasted spark firing sysem. When one cylinder is at the firing point on the compression stroke, the other cylinder is on the exhaust stroke. But the ignition system fires both plugs at the same time. The one on the exhaust stroke is "wasted". Using the timing light, you should get an idea of how the firings on both sides are related to each other. You want a single image of the S-mark in the timing window at idle.

Some say it's important to hook your 12v timing light up to some other source other than your bike's battery. Not sure I've ever seen any differences, but you might pull your car up close and use its battery for these initial tests.

...if your replying form the Alamo country : try and stay warm I know these cold spells this time of year down there can really chill you.

The chilling has begun...it's only going to be 90 today!!:thumb

[grumpyone]

Thanks Kurt we will get all that done and report back.
I was raised in a little hole down that way called Paducah before moving to Colorado so Im rather Up on how coooool it is down that way in the summer. :D
You suggest carb kits from a bmw dealer or Bing direct?? Im sure the bike has years of no miles.

Thanks again and Stay Cool.
Jim and Esther

[20774]

You suggest carb kits from a bmw dealer or Bing direct?? Im sure the bike has years of no miles.

My personal preference is Bing...but price might be different. But if there's any question as to application, Bing can answer it without hesitation.

I have a Bing o-ring/gasket kit in front of me. It identifies the o-rings by size and color. I seem to recall that the kits the dealer gets are labeled a bit different and could be confusing...hard to say as I've never experienced a dealer-supplied kit for the carbs yet.