My R80 seems - well.... slow.

[RonKMiller]

This is my first airhead, and I'm not complaining. I guess what I'm trying to figure out is if this is just the way they are!

At 21K miles it starts great hot or cold, idles great (hot only). Carbs are balanced, valves adjusted, carbs rebuilt, timed including advance check (bean can) and points set. Thunderchild installed and seems to be working just fine. Nothing really to whine about...

It just seems kind of "sluggish" and very slow. There is no power band to speak of, and above about 4500rpm nothing much happens. I kinda feel like I'm riding a 500, and pretty sure my 77 Yamaha 650 could easily spank it in a drag race.

It pulls fairly well, but only when I roll on the throttle hard. I'm also getting a fairly strong vibration during low rpm roll ons, yet it cruises nicely and is very smooth at 55 or so. I have not had a chance to take it up to speed yet since I live quite a distance from a freeway.

It feels kinda like my old AMF Sportster, but with no pieces falling off every couple of miles. :lol

So, is this the "Airhead experience" or should I start thinking about dual plugs, hotted up ignition, etc. ?

[lostboy]

Many flywheels in that era were marked incorrectly, leading to retarded ignition timing. Consider checking the marks with a degree wheel-or-just push the timing ahead until it pings.

[RonKMiller]

Many flywheels in that era were marked incorrectly, leading to retarded ignition timing. Consider checking the marks with a degree wheel-or-just push the timing ahead until it pings.

Thanks, that makes a lot of sense and brings up an interesting question:

The Clymer manual I got with my purchase is a mess - it shows in the appendix for 79 models that I should have an "S" mark with a dot on the right side, and a "Z" mark with a dot on the right side.

My flywheel is marked "OT" for top dead center - and has a white line under it. I lined up the white line with the notch mark on the left, and it is stable with the timing light at idle.

Another issue that I had when I first got the bike was a high idle when warmed up, which is apparently caused by a sticking advance mechanism. I took the bean can apart, cleaned, and sprayed with a little light oil. The advance seems to work well and when I hold it at 3000 rpm, I see only a dot lined up with the notch. A also put a tiny dab of regular synthetic grease on the cam/rubbing block. I still hear a bit of a "chirp" from the can and wonder if I should apply a different type of grease?

[jforgo]

If you are timing it at the OT for idle, the timing there is retarded.

[Bombayduck]

Something might be wrong with the clutch, like slipping or warpage. There shouldn't be any strong vibration, just smooth power with those thumpin' jugs.

"It pulls fairly well, but only when I roll on the throttle hard. I'm also getting a fairly strong vibration during low rpm roll ons, yet it cruises nicely and is very smooth at 55 or so. I have not had a chance to take it up to speed yet since I live quite a distance from a freeway."

[20774]

I wonder if part of the problem with response might be the flat-top carbs you have. I noticed that in the other set of videos regarding valve noise. I've heard the flat-tops were hard to get synched correctly, etc. I remember Snowbum talking about them before.

[lostboy]

In 1979, there was still an "F" at full advance. The "Z" was used from 1981.

[boxermaf]

Yes - what the other guys have said -
Idle speed should be with an "S" (possibly a small line above the "S") lined up on the mark. If your idle is with the top dead center mark (OT) in the center, then it is retarded by at least a couple degrees to begin with. Full advance ("F" mark) should occur at 3000 - 3500 RPM.

The flat top Bing carbs are a bit trickier, as I understand, but none of my airheads have had flat tops, so I can't be much help there - sorry!

[RonKMiller]

Well, reset the timing to "S" and it seems better. I think I just need to come to grips that it is just a lazy, lopey engine with two valves. I've been able to get the flat tops synched well.

It sure ain't no Ninja, but I'm kinda gettin' to like it's attitude. Very relaxing - it forces you to slow down and smell the roses. That's cool with me.

All in all it runs great. :thumb

I bought 24 rubber grommets at Ace to see if I can quiet down the metallic sound - kinda ghetto but worth a try for a few bucks.

[20774]

I bought 24 rubber grommets at Ace to see if I can quiet down the metallic sound - kinda ghetto but worth a try for a few bucks.

I believe BMW even sold a kit to do the very same thing. Snowbum might even have a write up on this as well.

[yankeeone]

Ron, I to felt the way you do,I went from a 87 k75c , to 86 k100 then picked up 86 r80, I hadn't ridden a bike in thirty years, took the course , and the k75 felt like a rocket , then my wife and I took it to Nova Scotia and half way around Cape breton she said " you need a bigger bike" it was not due to lack of power, but the lack of wind protection . When we got back there she was, k100rt on craigs list 25 miles away That baby goes. Then I found the r80 that had been sitting and had a great time, with the help of this forum bringing it back, and when I first rode it I thought the same thing, feels slow, you can watch the tach go up to the red line , I don't do that to much on the k bikes. But I love the sound at idle and it really does roll-along nicely, I do enjoy it,

Good luck with your bike,

[RonKMiller]

I believe BMW even sold a kit to do the very same thing. Snowbum might even have a write up on this as well.

Yep, indeed he did - and recommended different placement than BMW. I think I've got something else going on, but my bet is just a little tweeking will take care of it. It's not enough to cause any issues with how it runs, I just always like to listen carefully to engines, and there's plenty going on in there.

What's the saying? If you hear hoof beats don't go looking for Zebras.

Time to get out the stethoscope! :brow

[RonKMiller]

WOW. Those 24 grommets I installed made a BIG difference. Much quieter with no metallic ring. $9.36 well spent.

[rpeckham136133]

Being of the "show me" state of mind.... can you elaborate on the rubbers and how/where they were installed.... pics...please....:)

[RonKMiller]

Being of the "show me" state of mind.... can you elaborate on the rubbers and how/where they were installed.... pics...please....:)

I should have taken note of the size grommets I used - but I just eyeballed them at the hardware store and jammed 'em in with a metal knife I have with a rounded, blunt tip. A thin putty spatula would help, just watch your fingers. Nuttin' to it.

I stole Snowbum's blurb on it, and located them the way he recommended.

I'll measure the grommets in a minute since I bought one extra... and it is 20mm od, 9mm thick with an 8mm id. (of course that doesn't matter..) I don't think there is a chance they'll fall out, so I omitted the adhesive he used.

http://bmwmotorcycletech.info/quietingpads.htm

[crazydrummerdude]

it cruises nicely and is very smooth at 55 or so. I have not had a chance to take it up to speed yet since I live quite a distance from a freeway.

For what it's worth, my airheads live for 75-85mph (indicated).

[boxermaf]

One can ride an airhead fairly briskly - the key is SMOOTHNESS and maintaining decent speed and line through the curves. These engines - especially the pre-81 engines with much heavier flywheels/clutch assemblies- don't make revs quickly. They DO make fairly flat, usable torque and will literally run all day long at 5000 RPM and 80 MPH without blinking. As you're beginning to notice, take your time, practice smoothness and you'll really enjoy the machine. Trying to ride it like a Japanese inline 4 sport bike will result in frustration - the engine and brakes aren't up to that.

The shorter-stroke R65 engines are definitely more quick to rev than the R80/R100 engines (all use the same clutch & transmission though) and the R65 motors do need more revs to make power, but they are still slow-responding in comparison to many of the Japanese 650s. But, with basic maintenance the airheads can easily eat up mileage over years that will often destroy all but the best touring Japanese bikes.

[RonKMiller]

One can ride an airhead fairly briskly - the key is SMOOTHNESS and maintaining decent speed and line through the curves. These engines - especially the pre-81 engines with much heavier flywheels/clutch assemblies- don't make revs quickly. They DO make fairly flat, usable torque and will literally run all day long at 5000 RPM and 80 MPH without blinking. As you're beginning to notice, take your time, practice smoothness and you'll really enjoy the machine. Trying to ride it like a Japanese inline 4 sport bike will result in frustration - the engine and brakes aren't up to that.

The shorter-stroke R65 engines are definitely more quick to rev than the R80/R100 engines (all use the same clutch & transmission though) and the R65 motors do need more revs to make power, but they are still slow-responding in comparison to many of the Japanese 650s. But, with basic maintenance the airheads can easily eat up mileage over years that will often destroy all but the best touring Japanese bikes.

Thanks for the input!

It definitely has a different mantra... that smoothness is soooo needed. I guess I was just surprised that it takes so long to build revs. Kind of the exact opposite of my 72 HIB triple that I foolishly sold a few years back.

I'm thoroughly enjoying it's "personality" - it's a "Sunday go to meeting" kind of scooter. It wouldn't mind going 500 miles to that meeting. Except for the seat - which will be taken care of in short order.

[DennisDarrow]

These MACHINES have definate quirks and tendencies. No one has mentioned that you don't lug them. Yes, they take a bit to get up to their power curve; but once there they do produce HP, torque, and revs in a hurry.............One doesnt ride in the 2 to 3K RPM range.......Instead, wind out to maybe 5.5K and then when you shift it will drop into the 3.5-4K range where the power curve actually begins........If riding in curves keep that power band in the 4.5 to 5K range or up a bit and you will be pleasantly surprised at how when you twist your wrist it will dig in and go.........NO you aren't gonna do 3rd gear wheelies but you are gonna produce power that will pull you around and through the apex of a curve.....Good luck.......Dennis

[mchaven]

Yours too? :laugh

[osbornk]

Ron, I to felt the way you do,I went from a 87 k75c , to 86 k100 then picked up 86 r80, I hadn't ridden a bike in thirty years, took the course , and the k75 felt like a rocket , then my wife and I took it to Nova Scotia and half way around Cape breton she said " you need a bigger bike" it was not due to lack of power, but the lack of wind protection . When we got back there she was, k100rt on craigs list 25 miles away That baby goes. Then I found the r80 that had been sitting and had a great time, with the help of this forum bringing it back, and when I first rode it I thought the same thing, feels slow, you can watch the tach go up to the red line , I don't do that to much on the k bikes. But I love the sound at idle and it really does roll-along nicely, I do enjoy it,

Good luck with your bike,

I had both a K100 and a K75 before I got my R80. The K bikes were much faster and did everything better than the old R80. But there is just something about the old airhead. I still have the R80 and the K bikes are long gone. The R80 is slightly quicker than my R1200CLC but it doesn't bother me.

[yankeeone]

Dennis , that's good to know about the rpms, when the weather breaks I am going to give your recommended driving style a try, for some reason I thought I could lug it , I also had the fairing on with the wind shield at the worst height , the wind noise was incredible even with ear plugs my ears were ringing, after 10 miles, now it is a naked bike. I do like it though.

[rocketman]

Dennis , that's good to know about the rpms, when the weather breaks I am going to give your recommended driving style a try, for some reason I thought I could lug it , I also had the fairing on with the wind shield at the worst height , the wind noise was incredible even with ear plugs my ears were ringing, after 10 miles, now it is a naked bike. I do like it though.


EEK! No! Like he said it should Never be below 3K unless first starting off. It takes a bit of getting used to, having it run in the 4-5.5 or 6K range, but they do get smoother and pull the best in that range.

Just be carefull of downshifts, esp. in turns as with the dry clutch they re-engage real fast and can break the rear loose for a moment when you decel. Plus its probably not all the good for the drive train.

Have fun!

RM

[scjack]

Other than just starting off of idle or coming to a stop, I never run a BMW twin at less than 3500 rpm's. As a general statement, I'm usually in the 4k-6500 rpm range because that's where the engine is happiest and most responsive. Lugging a BMW twin will eventually cause a myriad of problems. Many people who have never ridden a BMW twin do not understand this and cause themselves a lot of headaches and $$$$ in repairs.

[Rapid_Roy]

Dennis , that's good to know about the rpms, when the weather breaks I am going to give your recommended driving style a try, for some reason I thought I could lug it , I also had the fairing on with the wind shield at the worst height , the wind noise was incredible even with ear plugs my ears were ringing, after 10 miles, now it is a naked bike. I do like it though.

No fairing and keeping the revs up, you will find it has a different feel.
You still may want a 1000 airhead, just in case.(They do vibrate a little more, I am told)
:laugh

[RonKMiller]

It all makes perfect sense: :german

I'm pushin 440 lbs. plus my 220 and another 60 of fluids with 32.4 horse power! :dance (at sea level on a good day)

[bikerfish1100]

Other than just starting off of idle or coming to a stop, I never run a BMW twin at less than 3500 rpm's. As a general statement, I'm usually in the 4k-6500 rpm range because that's where the engine is happiest and most responsive. Lugging a BMW twin will eventually cause a myriad of problems. Many people who have never ridden a BMW twin do not understand this and cause themselves a lot of headaches and $$$$ in repairs.

i would not limit that statement to only those who have not ridden a beemer twin. quite a few who own airheads think that they should be low-revved like a H-D. bad move.
up shift @ 5K or above, run at 4K up. the owner's manual of my '78 RS listed "continuous max RPM" as a mere 500 rpm below max redline. that made for some quick rides thru the Deserts of the Moon region of Idaho, lemme tell ya :p

[154048]

My R100 is very happy as well between 3500 and 5500...just seems to hum right along. and seconds to the idea that these elgant ladies are meant to be seranaded, and not flogged (too much). And do head the warning about the 'bitey' clutch snap when downshifting.:nono

After I bought my K11, as I watched and listened to the new owner of my R100RS putter away, with that distinctive Boxer sound, I resolved at that moment to get back in that world....Well, the K is gone (beautiful, excellent bike), but I am totally happy with my 100RT.
Strange fellers we Boxers are (as my Honda ST1300 riding buddy is fond of telling me)...

[Anyname]

So why would an airhead with a plain bearing engine have issues with running at less than 4,000 RPM? The rider may not like the vibration of the engine lugging, but the machine should be unaffected.

BTW I have been vaguely surprised by the performance of my 86 R80. I expected it to be kind of leisurely, but it's not half bad. I do recall that BMW lightened the flywheels in 81, so maybe the newer ones rev better.

[crazydrummerdude]

BTW I have been vaguely surprised by the performance of my 86 R80. I expected it to be kind of leisurely, but it's not half bad. I do recall that BMW lightened the flywheels in 81, so maybe the newer ones rev better.

Abandon hope, all ye who have a pre 81!

:p

[scjack]

So why would an airhead with a plain bearing engine have issues with running at less than 4,000 RPM? The rider may not like the vibration of the engine lugging, but the machine should be unaffected.

BTW I have been vaguely surprised by the performance of my 86 R80. I expected it to be kind of leisurely, but it's not half bad. I do recall that BMW lightened the flywheels in 81, so maybe the newer ones rev better.

A quote from Paul Glaves:
Shock loads on the connecting rod big end bearings and wrist pin bearings are higher at lugging RPM. Because it is over engineered in many respects the engine won't come apart immediately, but the increased wear will take its toll eventually. When you can feel and hear the engine complaining you need more RPMs.
[B]From a site talking about bearing wear:
Lugging the engine when pulling heavy loads can also contribute to bearing fatigue. http://www.thirskauto.net/BearingPics.html

A quote from this thread: http://www.bmwmoa.org/forum/showthread.php?t=18933&highlight=revs
Running a high performance machine (any brand) at low rpm's will cause carbon build up in the heads which in turn will have negative effects on performance as well as fouling spark plugs. BMW's are engineered to run continuously at their maximum torque range. You can run your oil head boxer twin at 5,000 rpm's all day long without concern. On the other hand lugging, the engine at low rpm is not the best thing you can do for your machine.

**Personally, I've been riding BMW twins since 1976 and every BMW twin mechanic and long-term owner that I have ever spoken with about this subject has recommended that the BMW twins be ridden over 3500 rpm's for the reasons that I pointed to above.

[bikerfish1100]

additionally, you don't have full electrical output from the alternator until something north of 3K rpm, which means that running in lower revs can lead to incomplete re-charging of the battery. over time, that will decrease battery life. add in that shifting becomes much more tractor like at lower prms, and i would think that anyone is hard pressed to make a valid, fact-based case for low rpm running.

[rinty]

Ron:

I had a 1982 R100RS, with a highly modified engine, for many years. While the power was what I would describe as adequate, it was not in the same league as many modern bikes. You have to accept these bikes for what they are. Their technology dates back to the sixties, just like your old Sporty.

Having said that, I think your carbs may be out of balance, because you mention a lower rpm vibration. I would suggest you have an airhead specialist check your bike over, to make sure everything is properly dialed in. I would not let a general mechanic work on any BMW boxer. These bikes are very sensitive to carburetor/throttle body balance.

Enjoy your new machine.

P.S. What do you fly?

[jforgo]

Many seem to want to lug their Airheads, as if they were some sort of farm machinery. When I tune a bike, I expect it to run with no issues throughout the RPM range - yet I horrified many when I mentioned running a loop at 6500-6800 continuous to sort out a high RPM issue. They get only a fraction of the pleasure and utility of their Airhead, it would seem, by using 5K as redline.

Amusingly, there are also those who feel higher RPM is "worse" with the 1000's. Yet the stroke, and therefore piston speed, is the same with the 1000's as with all the other Airheads, except the R65.

The powerband is there to be used. For example, when merging on to a crowded freeway, I keep it in the 5-6K range, so I have power on tap for rapid shifts in speed. A definite safety issue would emerge if I used a 5k redline.

Since I mostly ride 1000's with 2.91 rear ends, I can cruise all day at speeds well into the "go directly to jail" range. Interestingly, though, the tall gearing also makes for later shifts, and at times higher RPM's, in an urban setting. The bikes seem to like the wide RPM range I use - I will often cruise 3.5-4.5K, yet readily use the higher ranges as conditions dictate. This is what they were made for - Airheads are eminently practical machines.

[yankeeone]

" farm machinery" like a two cylinder gravely ?

[Anyname]

Abandon hope, all ye who have a pre 81!

:p

Nah! Just hitch up a side car and learn to live for that low end.

[Rapid_Roy]

Slow is relative.


My first ride this year was on my R50, and it was the best I had.

There is nothing finer, IMO, than barreling around merrily at speeds up to 65 mph, on motorcycle older than myself.

Of course, it is the only ride I have gone on this year so far.

:ha

[RonKMiller]

Ron:

I had a 1982 R100RS, with a highly modified engine, for many years. While the power was what I would describe as adequate, it was not in the same league as many modern bikes. You have to accept these bikes for what they are. Their technology dates back to the sixties, just like your old Sporty.

Having said that, I think your carbs may be out of balance, because you mention a lower rpm vibration. I would suggest you have an airhead specialist check your bike over, to make sure everything is properly dialed in. I would not let a general mechanic work on any BMW boxer. These bikes are very sensitive to carburetor/throttle body balance.

Enjoy your new machine.

P.S. What do you fly?

I'm fortunate to have a BMW tech at our dealership 6 miles away that has owned 5 airheads. He is intimate with the R80 and I'm sure will be able to sort out my issue easily. I just love trying to figure it out by myself, but am coming to the end of my knowledge base. I think an hour of diagnostic time will be money well spent with a pro. I can ALWAYS easily fix what he tells me is wrong...

I've been a commercial LTA pilot for 28 years and currently fly 12 and 5 passenger balloons as well as airships. I've got a few hours in fixed wing, weight shift high performance LSA and helicopters as well.

My life long business has been www.balloonridesusa.com, but started Kontour Seat as a business five years ago. Both are doing well in this rotten economy - much to my surprise. :thumb

[rinty]

I just love trying to figure it out myself...

You'll enjoy this bike; they're fairly easy to work on, and there are lots of good airhead sites on the internet.

They pump about twice as much oil as a conventional bike motor, so you can run them at very high rpm's all day.