Topic: RE: Almost went down today hard!

[Old Scrambler]

Glad you were SAVED.............no reason to put temptation on the front line...........the head shake could be many things...........but check the swingarm bushes........My K3 felt like a bucket of worms at 50 but smoothed out when going faster..........it was the bushes.

[chewbacca5000]

Glad you were SAVED.............no reason to put temptation on the front line...........the head shake could be many things...........but check the swingarm bushes........My K3 felt like a bucket of worms at 50 but smoothed out when going faster..........it was the bushes.

Thanks for the tip.  I will recheck the bushes.  Is there anyway to verify the headbearings are good or bad?

[evanphi]

Glad you were SAVED.............no reason to put temptation on the front line...........the head shake could be many things...........but check the swingarm bushes........My K3 felt like a bucket of worms at 50 but smoothed out when going faster..........it was the bushes.

Thanks for the tip.  I will recheck the bushes.  Is there anyway to verify the headbearings are good or bad?

Lift the front end, and the steering shouldn't feel "notchy"... where balls have worn a spot into the races.

I'm also doing all new bearings after this season... wheels, steering head, and swingarm. yayyyyyy

HackaweekTV/Dino here on the forums has AWESOME videos for doing bearings on these bikes.

[Imago]

My Dad used to have the best advice that covered almost any conceivable situation you can think of, even if it was an accident.

For example, you get a poor mark on an exam, you get a speeding ticket, you stub your toe, etc. etc...

















Smarten up!

[chewbacca5000]

I used the ceiling hoist and got the rear off the ground, but could not tell from that if rear bushes are bad.  Will need to find centerstand and put it up on that.

A few days ago I had the front end apart and the trees just seemed to "flop" over to the side with no resistance.  Did not feel notchiness, but was not checking for it either.  I am thinking the bearings are a bit worn.

Shouldn't they provide a little resistance?

[chewbacca5000]

the front end should smoothly flop to one side and the other when unweighted. Grab your fork legs and give them stem a sound "jerk" in all directions. If its not apparent, I'd investigate your wheels/tires.

Thanks Cal!  I will do as you say.  I am thinking old hard front tire, and rim trueness are suspect.  I have a perfectly trued front rim, with new bearings, but before installing I want to rule out head bearings.

What impact will high / low tire pressure have on a hop?

[SOHC4 Cafe Racer Fan]

Lucky once, but don't push your luck a second time.  That wobble can be downright scary if/when it comes on at higher speed with greater oscillation.

[chewbacca5000]

Lucky once, but don't push your luck a second time.  That wobble can be downright scary if/when it comes on at higher speed with greater oscillation.

It is not a wobble, it is a hop at 40 to 50 MPH.  Solid at other speeds. So far on my list to check is swing arm bushings, chain, chain alignment, tire, tire pressure, and head bearings.

If there is no notchiness in the balls on the headstock that would indicate they are good and I can repack with grease or replace the balls?  I have extra NOS balls for headstock.

[chewbacca5000]

Here is another thought.  While adjusting my chain I noticed that there are some "tight spots"  I keep at it, but still is not perfect.  Could it be that my chain is wore out and binding just a bit causing the hop?

If I pull in the clutch it should go away if it is the chain correct?

[chewbacca5000]

I got it up on the center stand and the swing bushes are pretty badly worn.  Guess new bushes are in my future.

Trying to move from side to side move the chain up and down.  What do you guys think is this the source of the issue, or just one piece?

Front tire PSI 41 Rear 32 psi.

[Stev-o]

sounds like you have multiple issue: swing arm bushings, chain and possibly front tire.

41/32 psi....where did you come up with those numbers??!! Rear is typically higher and 41 in the front is too high.

[chewbacca5000]

sounds like you have multiple issue: swing arm bushings, chain and possibly front tire.

41/32 psi....where did you come up with those numbers??!! Rear is typically higher and 41 in the front is too high.

that is what the tires  were inflated to.  i am running splitfires.  What psi should I inflate to?

[evanphi]

I run 38 up front and 40 in rear, also Spitfires. I weigh about 165lbs, FWIW.

[ekpent]

Kyle -  just get out and run the bike this summer and enjoy. If you know the little wiggle I am sure you can adjust. I finally put some rollers  in my stem this winter after a couple years of some stem problems on a 74 everyday rider but it was not like I was running on  a race track everyday. A little wiggle will not kill you and its all part of riding  bike that is 30-40 years old. Good riders adjust to the machine they are driving and unless you do a major oil bath I think we will be talikin' in the future

.

[chewbacca5000]

Kyle -  just get out and run the bike this summer and enjoy. If you know the little wiggle I am sure you can adjust. I finally put some rollers  in my stem this winter after a couple years of some stem problems on a 74 everyday rider but it was not like I was running on  a race track everyday. A little wiggle will not kill you and its all part of riding  bike that is 30-40 years old. Good riders adjust to the machine they are driving and unless you do a major oil bath I think we will be talikin' in the future

.

I hear you, but want to be safe too.  I took the swing arm off and it was a rusty mess on the inside.  I wish someone would make an affordable kit collar and bush together.  What good is new bushing with a tired wore out collar?

If you add up the parts it makes sense to send it to Hondaman.  Pretty sure he makes the bush match the collar.

O well.

[seanbarney41]

Chewie, I think every sohc4 I have ever had (enough that I have lost count) had the 40-50mph bounce/shimmy, at least when I first get them.  I find it very strange the way the exact symptom is caused by so many different things...possibilities in no particular order-bad front tire, bad rear tire, too loose head bearing adjustment, worn out head bearings, out of round/true front or rear wheel, poor chain maintenance, worn out chain/sprockets.  You just have to keep scratchin' em off the list until it's fixed.
     I have never had the front end problem caused by bad swingarm bushings, but that doesn't mean it can't happen.  In my experience, bad swingarm bushings will cause a weave in a curve or sideways movement during acceleration and/or deceleration.

[ekpent]

Kyle -  just get out and run the bike this summer and enjoy. If you know the little wiggle I am sure you can adjust. I finally put some rollers  in my stem this winter after a couple years of some stem problems on a 74 everyday rider but it was not like I was running on  a race track everyday. A little wiggle will not kill you and its all part of riding  bike that is 30-40 years old. Good riders adjust to the machine they are driving and unless you do a major oil bath I think we will be talikin' in the future

.

I hear you, but want to be safe too.  I took the swing arm off and it was a rusty mess on the inside.  I wish someone would make an affordable kit collar and bush together.  What good is new bushing with a tired wore out collar?

If you add up the parts it makes sense to send it to Hondaman.  Pretty sure he makes the bush match the collar.

O well.

Lube her up and ride and do not take anything off until winter time. Unless you feel totally unsafe then take her of the road.

[chewbacca5000]

 I got a low mileage swing 3,400 that seems to have decent bush and collar.  Lacks grease groves since it is a 76.  Gonna try to cut some grease groves in.  Worse case it lube up and ride on.  Maybe it will last the summer until I can get a rebuild done.

Pretty funny there Sean guess anything can cause that 40 to 50 MPH hop.  It's gettin' kind humid today there she goes boucing up and down again.

Crossing off front rim, front bearings, and front tire along with chain and swing tomorrow.  If that does not cure it I am just going to ride on.  Not way I am I taking that front end apart to to tapered bearings.  Not now anyway.  It does not shake it's head at all so it should be "fixed" tomorrow.

[scottly]

Pretty funny there Sean guess anything can cause that 40 to 50 MPH hop.  It's gettin' kind humid today there she goes boucing up and down again.

A member had a front end hop a few years ago that was due to loose spokes; the rim was true while on a stand, but was way off with 300 pounds of bike and rider pushing against the spokes. With the front wheel off the ground, tap the spokes with a wrench and listen to the pitch; a tight spoke will ring, while a loose spoke will make a dull thud.

[Powderman]

Last night I threaded a 3mm o-ring in the oilier hole trimmed the excess off and reassembled.  It seems to have worked as there was no oil on the tire or rim and this is after 10 to 15 miles highway speeds.

Lubed up the chain and I should be good to go with no more oil slick worries.




It does have a bit of a head shake / hop at 40 to 50 MPH, but smooths out after that.  Not sure I want to do head bearings if it can be put off until later.

No, put that off till it throws you off, then fix it. Head bearings are so cheap and easy to replace, do it.

[chewbacca5000]

Thanks for your concern Powderman.  Just taking things one step at a time vs doing it all at once.  I would like learn why it is doing that.

Now with all the play in the swing arm it might be possible that the chain was out of alignment or binding a bit at those speeds causing the hop.  At highway speeds the chain is fully loaded so no hop.  Just guessing right now.

Gonna install low miles swing and take it for a short ride and see if the hop persist.

[chewbacca5000]

So I did Hondaman's suggested modification on the latter low mileage 3,400 mile swing by adding grease grooves to the collar and installing US zerks on an early bolt, and what difference!  This thing is solid and takes grease like you would not believe. 

Hopefully this mod will extend the life beyond the 10,000 miles which is the wear out point for these latter style swings.

Other interesting bit the front sprocket is a 16 tooth and the rear is 48!  Good thing I am switching chains as the other one was very tired and might have broke with that 16 up front?

[chewbacca5000]

Rear end rock solid.  Still has the 40 to 50 MPH thing going on.  Just loosing my grip and I can really feel the shake.  Think I am just going to order the all balls kit and be done with it.  I don't think a different tire, bearings, and rim are the cure here.  If it was a tire issue wouldn't it do it at all speeds?

[Retro Rocket]

R I don't think a different tire, bearings, and rim are the cure here.  If it was a tire issue wouldn't it do it at all speeds?

No, it depends on what issue the tire has. With rotating parts its usually at certain revolutions that the resonant frequency hits the point where it all goes shaky or out of balance, there are many reasons this can happen with a tire, out of balance, age, wear and poor fitment for example...

[Stev-o]

R I don't think a different tire, bearings, and rim are the cure here.  If it was a tire issue wouldn't it do it at all speeds?

No, it depends on what issue the tire has.

I agree with Mick here. And my money is on the tire. 

Have a good spare front wheel/tire?