New guy in the Asylum

[limeymike]

Hi all, just joined the airhead community with a recently purchased R80RT ('86). I am in Sioux Falls SD and wondered if there are other 'airheads' close by. I do have a question; This is my first BMW and it vibrates throughout the rev range turning into a buzz in the pegs and grips at speed, is this normal for an R80. I have cleaned the carbs, replaced plugs and wires, changed all fluids and checked valves and timing which were OK.


Here's the bike;

 

[88bmwjeff]

Run while you still can....Ah it's probably too late anyway. Welcome to the Asylum.


If it's really buzzy, then I'd say no that's not normal. You said you cleaned the carbs, so I'm wondering what you used to sync the carbs. Also, did you warm the bike up with a 10-15 minute ride before adjusting and syncing the carbs? I had problem keeping my bike in tune when I got it. There were several issues, but a common one is the coils on these bikes are known for cracking. If you have the grey (I think it's grey) coil, it may need replacing. My coil was not providing a good spark. If that's the case, check back here as there is a good aftermarket replacement.

Others will chime in, but that's my suggestions on where to start.

Anyway, nice looking bike.

Edit: Sorry if some of my response seems basic, but you didn't indicate your expertise level in spinning wrenches.

 

[20774]

Check the engine motor mounts.

 

[Dave Backmarker]

buzz buzz...hmmm

Mike,
Good recommendations above.

After you check the coils...

After a riding up to speed for a bit, is one head hotter than the other? I'm thinking along the lines of synching the carbs or one side running a bit leaner. If you have ethanol in your gas and the gas has been sitting in the bike you may want to clean the carbs all the way down to a tear down.

It IS a lovely bike! Best of luck with it.

DaveM
1975 R90S, 2000 R1100RT

 

[ultracyclist]

Welcome!

Check the valves to see if they are in the correct specs.
Get a Clymers Manual for something similar because you will need it.
Check your handlebars for tightness.

Practice working in tight spaces that allow just enough room for the part but not your finger or a tool while smelling oil and other lubricants. Practice Yoga as you will bend and contort in ways you never knew. U-Boat experience really helps.

 

[PeoriaMac]

I have the same 1986 model R80RT. No buzz, nice and smooth ---after I got my carbs back from
the Bing folks. Idle circuit not synced yet...but you shouldn't have a buzz through the range.
Are you feeling it both the grips and pegs? You might want to make sure that all the hoses to the carbs are tight. Additional air into the system downstream of the carb can lead to lean running...

Mac

 

[limeymike]

Thanks for all the ideas guys. I'll start looking at it this weekend, the coil is black, not grey and I checked it for cracks and it looks OK. The engine mounts are tight. The previous owner drained all the fuel from the bike before storing it but it was in a non heated garage in Omaha for a couple of years so maybe the rubber seals/parts in the carbs might be iffy. After cleaning the carbs I made one of the $4 sync tools, went on a 20 minute ride and set them up. I found some tech info from 'Snowbum' on the net which I've been reading about carb balancing which should come with a prescription for Tylenol. I'm thinking I might need to order a carb rebuild kit just for peace of mind.


PeoriaMac; Yes both the pegs and bars. Did you have a vibration/buzz problem before your carbs were rebuilt?

Now where did I put that yoga mat?

 

[tvrla]

The R80 is known for it's smoothness, so something aint right if yours is buzzing.

I'm guessing the carbs aren't in synch. You'll be amazed what a difference it makes having them properly adjusted. Get the bike good and warm after a 20 mile ride. First step is to start with both butterflies open the same amount - I usually set them at a 1/2 turn open. Get the idle down below a thousand where you can hear each one firing, and it's a nice steady even thump thump thump...

Then adjust the throttle cables so they pull exactly the same.

If that doesn't do it, then it's possible one of the needles is in the wrong slot or a jet o-ring is compromised and not sealing well. Also, did you clean really well around the atomizer - up above the main jet? It tends to get pretty gunky up there and makes a big difference cleaning that up.

Stick with it, and she'll be as smooth as glass. BTW, beautiful bike! I'm not into RTs, but that's a pretty one!

 

[88bmwjeff]

The previous owner drained all the fuel from the bike before storing it but it was in a non heated garage in Omaha for a couple of years so maybe the rubber seals/parts in the carbs might be iffy. .... I'm thinking I might need to order a carb rebuild kit just for peace of mind.

If you didn't replace the O-rings as part of the rebuild, that would be my first place to start. Make sure you get new floats with the kit. If you soaked the carbs in carb cleaner, the O ring on the throttle shaft would need to be replaced. That entails removing the butterfly. The screws are peened, so grind/file the back end of the screws down before removal. Otherwise you will be buying new shafts. They're not expensive ($10/each), but it's an unnecessary expense if done properly. DAMHIK

BTW, I didn't see how many miles are on the bike. Also, how long was it stored for? Just curious.

 

[limeymike]

If you didn't replace the O-rings as part of the rebuild, that would be my first place to start. Make sure you get new floats with the kit. If you soaked the carbs in carb cleaner, the O ring on the throttle shaft would need to be replaced. That entails removing the butterfly. The screws are peened, so grind/file the back end of the screws down before removal. Otherwise you will be buying new shafts. They're not expensive ($10/each), but it's an unnecessary expense if done properly. DAMHIK

BTW, I didn't see how many miles are on the bike. Also, how long was it stored for? Just curious.

It has 61K and was stored for 2 years. I used the spray carb cleaner rather than a soak but I think you are right about replacing the o rings.

 

[limeymike]

The R80 is known for it's smoothness, so something aint right if yours is buzzing.

I'm guessing the carbs aren't in synch. You'll be amazed what a difference it makes having them properly adjusted. Get the bike good and warm after a 20 mile ride. First step is to start with both butterflies open the same amount - I usually set them at a 1/2 turn open. Get the idle down below a thousand where you can hear each one firing, and it's a nice steady even thump thump thump...

Then adjust the throttle cables so they pull exactly the same.

If that doesn't do it, then it's possible one of the needles is in the wrong slot or a jet o-ring is compromised and not sealing well. Also, did you clean really well around the atomizer - up above the main jet? It tends to get pretty gunky up there and makes a big difference cleaning that up.

Stick with it, and she'll be as smooth as glass. BTW, beautiful bike! I'm not into RTs, but that's a pretty one!

The atomizer was the dirtiest part I found in there but after cleaning I had the same results. I'm leaning towards putting new seals and diaphragms in the carbs and then get them properly adjusted. I like the RS model but this RT caught my eye. Thanks for the ideas.

 

[txedomoon]

Greetings from Fargo, Mike!

Great looking airhead! Good call on checking in here, plenty of good advice
to be gathered. As far as Clymers -- get one! (but also be aware that the valve
lash measurement they give is wrong.)

Nothing else aside from me aside to say Hi and Welcome. Good luck on the
trouble shooting!

todd

 

[88bmwjeff]

I'm going to throw something else at you. I noticed in the photos you still have the Pulse Air system. Most people remove it. Here's a good article on what it is and how to remove it.

http://bmwmotorcycletech.info/pulseair.htm

 

[tvrla]

I rarely have any trouble with the butterfly o-rings and think I've only replaced them maybe two times. I've had airhead beemers since 1990 and have had at least 30 of them and fixed quite a few for friends, so it's not like I'm talking about only one or two personal bikes. And it's the same for diaphrams - I don't run into bad ones that often - it does happen, but it really isn't very common. And your problem doesn't sound like a diaphram situation, but who knows, it may be the beginning. Diaphrams aren't cheap. One way to check them is to stretch them while holding between you and a light bulb. If you can see any pin holes, it's bad. And, if you get new ones, it won't hurt having spares should they check out ok.

But the jet o-rings can be a problem. I used to have constant problems with them, especially if I removed a jet - they always came out torn. Until - I realized the damage was coming from the sharp edges of the jet! Once chamfered and polished, they no longer slice the o-rings.