Earles Fork frustrations

Ok... lol... which way do you turn the lever to tighten or loosen the shock? ( I've got to get a manual..)

Thanks, Dewayne

Just try turning the lever. If you're fighting the spring in one direction, that's putting more preload on the spring. It'll be pretty obvious when you give it a turn.

Got an update for us yet??

Update... I've got a little better 'feel' after puting on new tires, replacing the wheel bearings and loosining the steering head bearings a tad. Which of those made the most difference is anyones guess. I probably could have loosened the steering head a bit more, but after my experience with the 'tank slapper' I'm hesitant to go much more.I tried checking the play in the swing arm and as far as I can tell, there isn't any..
Kurt in Alaska sold me a good set of final drive gears since my splines were all but used up. Now I just need to get the gumption to tackle that project.
Thanks to all who responded to my call for info...

Dewayne

Just as a matter of information, I run my /2 with NO tension whatsoever in the steering. She is very stable at speed, and I prefer to be able to move the bars easily at slow speeds. I find the bike to be surprisingly "nimble" (not that the /2 is really nimble, just surprisingly nimble....

Be sure there is no wiggly luggage far back

Be sure if handlebar mounted windshield that none of it extends
rearward of a line extending the axis of the stearing head

Be sure that bearings races are tight in the frame - I once took
apart a used bike and lower race just fell out - I am sure the
prev owner had some tales to tell about wobbles

Be sure spokes are not loose enough for wheel rim to move
relative to hub - learned this the hard way after flying the chair
with alloy wheels and sidecar and then going for fast solo ride

I have had speed wobbles on a number of earles bikes in the past
at speeds 75 mph or greater on sweeping curves with dips or
bumps in them - I do not understand the cause but suspect it is
caused by the forces induced by the mass of the heavy rear knuckle
of the setup being acted upon by the bumps when leaned over.
I have bikes with roller bearing conversion in fork head and others
with the old ball bearings and notice no difference in performance
if greased and adjusted for free movement of fork with no obvious
shake when one grabs fork when wheel off ground

Often run bike solo with fork setup for sidecar use in the forward
position - BMW says don't do it but it doesn't seem to bother
me either way and speed wobble in overpowered conversion
will sometimes occur at speeds over 80mph with fork in either
position - also occurs with /5 type US fork at times.

Best recovery from speed wobble in my experience is to decrease
throttle gently and smoothly while fixing eyes on point well ahead
down the road - never look down in front of wheel - you go where
you look but still very unpleasant experience

I have no idea but I did save this link awhile back. Might consider contacting him... http://jeffdean2.home.att.net/earles-fork.htm

Sunday Nov 9,2008 motorcycle crash



After nice Sunday Ride up to Pink Floyd restarant filtered down through the horse country

to int 484/75 and got on I-75 for quick run down to Bushnell exit for burnt bird on the way

home.



Running in center lane at traffic pace I suspect was about 75mph I saw an opening to

move into the right lane where I would not be so crowded or quite so fast. When I made

my move into the right lane encountered wake turbulence or slight tar strip wiggle which

VERY rapidly in about 4-6 ocillations escalated into full unrecoverable lock to lock tank

slapper wobble which splattered me all over the pavement and then off the road onto

the paved shoulder and then the grass.


FHP report shows I tumbled 180 feet and the bike tumbled 219 feet from the point of

impact of the bike to the pavement. Report shows only 34 feet from first tire skid mark

to point of impact with pavement.


Sumter Co First responders next thing I remembered - they packaged me up for transport

to Shands Gainsville in helicopter.



Damage was 4 broken ribs, collapsed lung, bleeding spleen, broken right hand/wrist, some

spectacular road rash, and no glasses(I seemed to have eaten them-found glass in mouth).



Good news was no head, neck,spine,hip,knee,leg,ankel, or foot injuries other than road

rash. Yes - I was wearing helmet which looks scraped but not impacted. I wish I had

left the helmet home - I would never have gotten on the interstate without it.



Shands ICU stopped bleeding spleen without having to remove it by use of some tool

entered in big vein in groin area.



I was discharged noon Wed Nov 12 to go home and recover for followup at later

date relative to hand surgery not yet evaluated or scheduled.



Lynn and Mac Arimtage from Floral City area provided transportation for me and many

other helpfull services. Charles Root picked up the bike from impound and brought

its remains to my home.



The motorcycle is essentially destroyed - appears to have launched high in the air and

tumbled end over end. Had to be my favorite 1967 BMW I bought for a throw away

bike to ride to Alaska in 1989 and gave me in excess of 220k miles before trying to

kill me in an instant without warning or chance to recover - my mood at present

alternates between strip and rebuild or pack with dynamite and blow it to hell.



Beemerbob may be known for the immediate future as Slowmotion Bob.

I feel like a bag of disconnected parts tied together by strings of pain.

Pre Crash Bike

Adjusting the Earles fork can be tricky. Consult Duane Ausherman:

http://w6rec.com/duane/bmw/earles/index.htm
http://w6rec.com/duane/bmw/slash_2/index.htm
http://w6rec.com/duane/bmw/steeradj/index.htm

Here is what I have done with my slash-2s with Earles forks.

First, most important, I install nothing on the front end -- no windshield or handlebar-mounted fairing. The wind pressing on these sensitive forks is something I do not want because it can cause strange happenings. If I really wanted a fairing, I would get an Avon frame-mounted fairing. But I ride these bikes "naked." I find I like doing that.

Next, I have installed tapered steering head bearings on my Earles fork bikes. You can get them from Vech -- http://benchmarkworks.com/onlinestore/partno.htm



Next, adjusting the tightness on the bearings is critical. Too loose or too tight is not good. Again, consult Duane.

Next, I do not load up the rear of the bike. I keep the load pretty even. Ken Craven, for example, made it a point to keep his saddlebags small in order to prevent overloading. Too much weight behind the rear axle is asking for trouble, IMHO. I even suspect that the mere presence of saddlebags may even affect handling and fork adjustment.

44006 said:

Pre Crash Bike

Click to expand...

I would be concerned here about the handlebar-mounted windshield and the large saddlebags and large luggage rack behind the rear axle both of which invite overloading to the rear. These things can present serious problems.

I would agree with you on the fairing but have used same plexstar II on
many /2 /5 /6 /7 bikes for many years and over 200k miles at much
higher speeds with no problems - it is the suddenness of this crash wobble
that disturbs me - absolutely no chance to react.

Tires are not the issue - still up and in good cond.

The bags and rack are large HD and ATV and also have more than 20 yr
history of fast riding without incident - bags and rack very firmly mounted
to shock towers absolutely no shake and in this case both empty save
for rain suit. The load of both is applied far forward of most peoples
bags because this is strictly a solo bike.

What bothers me most is the lack of warning. I ride 35 - 40k mi per
year and about half that on /2 conversions - this bike pitching me so
suddenly is a mystery - 2 days before incident I had done thorough grease
and adjust check whl brgs swing arms front and rear. The fork head pivot
had no play I could detect and normal slight smooth resistance - the
steering dampner was not applied with any detectable effect.

Normally I tour this bike loaded with much more weight and can usually
run down a smooth Interstate at 85 without weave tendencies and
if it starts to get light it does so with easy warning and stops upon gradual
decelleration.

So far a complete mystery - I am not yet fit to dissassemble and inspect
closer.

You mention that you had worked on the rear swing arm; here's an anecdote of mine:

When I first got my R60/2 restored and put back together, I took it out on a "test ride". Everything seemed good and I was relaxing and having a good time, when -- as I was going through a 40mph sweeper with a couple bumps -- suddenly the bike wobbled horribly! I managed to save it, an tiptoed back home.

Of course, I had just finished touching just about everything on the bike, so where to begin? The steering head and Earles fork seemed ok, but when I checked the rear swingarm I found that I had never torqued the swingarm pivot jam nuts. I had only hand tightened them... must have gotten distracted at that point.

Nothing loose about swing arm - though I had a similar experience on an
R75/5 once - got that flat tire feeling and found pivot totally backed out of threads
and tipped down but not falling out - since then many years ago have been
religious about setting up the jam nuts.

attached pic of same bike in 1989 with very much more load on same luggage
rack and much bigger fork mounted fairing and windshield. On that trip to Alaska my Harley riding friend and I were running the relatively rough Canadian roads at speeds in mph = to what was posted in kph and the Cassiar Highway in a light rain in one day at 60mph when it was all slick mud/smooth gravel all the way.

Never a wiggle -- What pitched me off this time??

Tank Slap?

Pardon my ignorance...what is tank slap?.......
I just pulled the rear fender, swingarm, drive, wheel, transmission on an Earles Fork.... R60......today.....
I'd be REAL interested in finding out how to avoid "tank slap".........I mean...while I'm down there!.....
I've already survived "death wobble"...in the wife's Jeep......

DEDGCOMB141129 said:

Pardon my ignorance...what is tank slap?

[...]

I've already survived "death wobble"...in the wife's Jeep......

Click to expand...

It's kind of the same thing. A "divergent oscillation" that rapidly gets out of control, wagging the bars from stop to stop, just before it spits you off.

Just a Thought...

I mentioned Death Wobble....
The problem was solved NOT by replacing every part of the front end of a brand new Jeep Sahara (the dealers ineffective solution), but by a Jeep mechanic I met at the bar.....
It starts with tire pressure....gotta maintain correct pressure.....
And with us doityourselfers...that means firing up that little compressor and adding some air...quite often...
Well...you're not just adding air....
Unless you're fastidious about draining your tank, and your water seperator...you're adding water as well....and there is yer sign!...
Imagine the effect of a few extra ounces of water sloshing around inside the tire....at speed....
I'm not sayin' this is the cause for 44006' mishap....but it sure was the cause of the Jeep's "wobble".....

Thanks for mentioning tire pressure. It is very important.

I will never mount anything large on my handlebars (a little clock is o.k.), nor will I load up the rear end. It is asking for trouble I do not need, most especially mounting something on the handlebars that the wind, gusts, or wake turbulence can push around. I install tapered steering head bearings and adjust them regularly. I check the tire pressure regularly. I do those things. So far they have worked for me.

A lot of soul searching going on while I am mending and I have to admit that if I am honest with myself I may have made an almost fatal error. After more than 20 yr of Harleys, BSAs, Motoguzzis which all were unreliable runners I found BMW models 1955-1973 to be reliable and easily owner serviceable for that reason and they fit my frame better than all other competitors. True - they were sometimes slightly unstable and exhibited weave tendencies at higher speeds but I gained a confidence in the seemingly easy recovery from such behavior.

I am losing confidence in the Marque.

If I am honest with myself I have to admit that none of the many other motorcycles I have owned and toured for serious miles has ever without exception exhibited any instability whatsoever even in relatively serious stages of neglect and
hard and fast use at a time I was much younger and braver and less sober. Not once!!
1950 HD 74" HydraGlide
1957 BSA A7
1960 BSA A10
1965 Harley ElectraGlide
1965, 1967, 1972 HD Sprint
197? Honda 500/4
1975 Honda Gold Wing
1980, 1981 Guzzi V50
And even a few wild choppers mixed in between
More recently 2000 and 2002 GS500 Suzuki

I seemed to have totally missed the most important point.
Reliability, ease of owner service and character isn't worth
**** if it kills you!

Interesting thread. 44006, very glad you lived to tell us what happened.

I would love to one day own a 1962 airhead (to match my age), Earles forks and all but so far my brief experience is with a 1972 R60/5, 1983 R100T and a 1976 R90/6. But I think some principles and concerns apply to all years.

I posted the question: "What causes a tank slapper" a few weeks back. I'd just bought a '72 R60/5 SWB Toaster project and had heard horror stories, not unlike yours. It appears that the problem is not isolated to SWB models.

In short, I never definitively got the question answered. Some referred to load, steering head bearings, tire condition and type, suspension, etc. Owning a bike that can be serviced by the owner is great--so long as I am a competent wrench of sorts. I am 80% comfortable doing anything on my bikes, but I think suspension, above all else requires the most indepth understanding of the sum of all parts. I mean, carbs out of balance won't do nearly as much harm. Heck, even run on one cylinder. Maybe a turn signal isn't working right, true it could cause an accident but a tank slapper takes the cake in my estimation. Then again, I'm new at this and most of my friends think I'm nuts for riding a bike in the DC area. That' just makes me even more cautious and furthers my curiousity to understand.

Assuming all mechanical suspension areas have been addressed, like bearings, forks, shocks, etc. and set to specs, that leaves the variables to consider--namely tires. Tire choice, condition and pressure. I've often wondered about the use of nitrogen rather than air since it neither expands or contracts with temperature changes. Every air compressor has moisture in it (gas stations, a friends compressor, even a 12v compressor develops moisture) and that ends up in your tires. I drain my tank often and even still I get moisture. Interesting to think about the cummulative amounts built up in motorcycle tires over the course of a year and the temperature changes from riding and atmosphere changes.

I'd love to know the answer to what causes a tank slapper. Tires seem to be the more vunerable to changing conditions. Just my two cents.

Godspeed healing!