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Bike sway's


saddlebum

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Any time I get over 120 KPH (75 MPH) the bike starts this slow leaning back and forth from left to right and the faster you go the quicker the tempo. @ about 145 to 150 KPH (90 - 93 MPH) this left to right leaning, develops into a front end high speed wobble.

 

Wheel bearings and steering head are in good shape. tires are new E3's and the swing arm has no play.

Any suggestions.

Edited by saddlebum
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Any time I get over 120 KPH (75 MPH) the bike starts this slow leaning back and forth from left to right and the faster you go the quicker the tempo. @ about 145 to 150 KPH (90 - 93 MPH) this left to right leaning, develops into a front end high speed wobble.

 

Wheel bearings and steering head are in good shape. tires are new E3's and the swing arm has no play.

Any suggestions.

 

How new are the tires? My last bike (Kawasaki Concours) developed a wobble 3,000 miles into the tire life. Had them rebalanced and it went away.

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Checked Air Pressure in Tires?

 

Same Pressure in Front Forks?

Tire pressures I have varied from 34 psi to 40 psi with no change.

The forks are controlled by the class system Though now that I think about it I have not checked the oil in a long while.

 

How new are the tires? My last bike (Kawasaki Concours) developed a wobble 3,000 miles into the tire life. Had them rebalanced and it went away.
The tires are just broke in about 100 to 150 miles.

 

What makes you think the steering head bearings are OK?

-Pete, in Tacoma WA USA

Moving the steering head left to right with front wheel off the ground they feel smooth with no grabbing even if I slightly over tighten them. Currently they are adjusted so that they bounce once off the stop if I gently flip them right or left. Any tighter than that then my bike wants to straighten up on the ramps. As they are now the bike handles turns nicely. I do admit I have not physically removed and inspected the bearings. I guess it's possible they may have very little grease in them and grease does tend to have a dampening effect in bearings.

 

One thing I also have not tried is running it with empty saddlebags to see if weight distribution is an issue. I tend to travel with loaded bags because I never know were or how far I may go on the spur of the moment. And I like to have a good selection of tools at all times.

Edited by saddlebum
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Moving the steering head left to right with front wheel off the ground they feel smooth with no grabbing even if I slightly over tighten them. Currently they are adjusted so that they bounce once off the stop if I gently flip them right or left. Any tighter than that and my bike wants to straighten up on the ramps. As they are now the bike handles turns nicely. I do admit I have not physically removed and inspected the bearings. I guess it's possible they may have very little grease in them and grease does tend to have a dampening effect in bearings.

 

 

You said: "I have not physically removed and inspected the bearings". Well there you are!

It is likely the bearing race has small defects that won't show up in your preliminary testing. If your bike has over 40K miles, then worn bearings are highly likely. Until you correct the situation, stay under 65mph.

-Pete, in Tacoma WA USA

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when you get the front end off the ground again rather then pull the front end left to right push/pull it fore and aft using the front wheel. If you detect any movement then it is time to redo the steering head bearings. Also your bike is 25 years old and Yamaha is not known for putting an abundance of grease in the steering head. You can reach in thru the headlight opening with a long drill and drill a small hole for a zerk and grease the bearings that way. Yes it will take a lot of grease to fill the cavity at first but not so much after that. It does create rather a mess when you go to change them, but you will never have to worry about the grease again. I got this idea from the old Bench Wrench section of the VTS magazine.

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when you get the front end off the ground again rather then pull the front end left to right push/pull it fore and aft using the front wheel. If you detect any movement then it is time to redo the steering head bearings. Also your bike is 25 years old and Yamaha is not known for putting an abundance of grease in the steering head. You can reach in thru the headlight opening with a long drill and drill a small hole for a zerk and grease the bearings that way. Yes it will take a lot of grease to fill the cavity at first but not so much after that. It does create rather a mess when you go to change them, but you will never have to worry about the grease again. I got this idea from the old Bench Wrench section of the VTS magazine.

 

It also keeps the water out when you ride in a down pour. :cool10:

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My 93 was doing that, i replaced the engine mounts with the solid mount, problem gone.

 

Thats a new one on me 93,, never heard that before,, THANKS!!

 

Saddlebum, I had a Honda 1100F one time that I was experiencing exactly what your describing,, found out I had the neck bearings just a little to tight,,thing drove me crazy with its weaving..

 

Hey you guys,, wasnt there a cracked frame issue on our 1st Gens somewhere along the line?? Seems like I remember reading about that somewhere... Might be worth a look see Saddlebum,, unless I was having another senior moment with that thought...

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The cracked frame, as it were, issue was with the shock mount on the '83 only...

 

Me an my big mouth,,, my poor ol beater bike is an 83,,, where do I look Bongo,,, oh well,, its why I named it "Tweeks",, tweek here, tweek there,,,

Hey,, I just dropped in a set of Progressives,,, do ya think 1 inch of preload on em is sufficient?

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when you get the front end off the ground again rather then pull the front end left to right push/pull it fore and aft using the front wheel. If you detect any movement then it is time to redo the steering head bearings. Also your bike is 25 years old and Yamaha is not known for putting an abundance of grease in the steering head. You can reach in thru the headlight opening with a long drill and drill a small hole for a zerk and grease the bearings that way. Yes it will take a lot of grease to fill the cavity at first but not so much after that. It does create rather a mess when you go to change them, but you will never have to worry about the grease again. I got this idea from the old Bench Wrench section of the VTS magazine.

I have checked the play by pulling the handlebars for and aft a few times over the years and have never found any play other than the first time some years back prior to adjusting them. However I like the idea about the grease.

 

I guess too I have to swallow the bullet and pull the head apart and visually check the bearings may as well change the fork oil and add that grease fitting while I am at it.

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Hey Ben,

You didn't mention how many miles you have on your bike, but at around the 50,000 mile mark you can expect to see the "weaving" issue you are describing as a result of the upper bushings in the lower fork tubes being worn out. The upper metal fork tube and steering head are stable, but the lower aluminum fork tubes are swaying back and forth due to the bushings having excessive clearance. The sway develops into a harmonic to the point that the front wheel will "squirm" from side to side until you slow down, and break the harmonic. New upper bushings for the lower fork tubes, a new set of fork seals, and one of Condor's fork braces will tighten up the lower front end of your bike nicely if you plan to continue to drive at the speeds you mentioned. :thumbsup2:

Earl

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Hey Ben,

You didn't mention how many miles you have on your bike, but at around the 50,000 mile mark you can expect to see the "weaving" issue you are describing as a result of the upper bushings in the lower fork tubes being worn out. The upper metal fork tube and steering head are stable, but the lower aluminum fork tubes are swaying back and forth due to the bushings having excessive clearance. The sway develops into a harmonic to the point that the front wheel will "squirm" from side to side until you slow down, and break the harmonic. New upper bushings for the lower fork tubes, a new set of fork seals, and one of Condor's fork braces will tighten up the lower front end of your bike nicely if you plan to continue to drive at the speeds you mentioned. :thumbsup2:

Earl

The fork seals were done at around 89,000 KM (55,000 miles) but I do now have about 129,00 KM (80,000 miles) on it. I do not know if the bushing s were done at that time and I did install one of Condors fork braces about 3 years ago.

I don't drive those speeds often just on the odd occasion when passing.

But thanks for all the pointers from everyone so far I will look closer at a lot of the items mentioned. Rather than just a casual inspection.

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Check out this thread,,,, and it isn't closed yet,, still have the issue.

http://www.venturerider.org/forum/showthread.php?t=21372

As you may remember Carl I had that so called rear end high speed waddle too when I had the Avons on it but as soon as I pulled them off and the dealer swapped them for a set of EII's it went away. What I have now is not front or back its the whole dang bike alternately leaning from one side to the other back and forth. It starts as a very slow lazy lean to one side and then straightening up and leaning to other side. the rhythm increasing with speed until eventually it will develop into a front high speed shimmy once I get going fast enough

Edited by saddlebum
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You say it has new tires, did it start doing this after the tire install? Might be rear bushings/spacers in placed in wrong place/axle(s) not cinched correctly......

Nope the bushing are in the right place . put them in wrong once and the rotor rubbed right up against the caliper body.

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  • 1 month later...

Solved the problem! I had carb issues and (no I know carbs don't effect steering). As I was saying I had carb issues and ended up rebuilding them. While the bike was down I rechecked the steering head and found the bearing preload was far too tight I backed off the nuts about 1/4 turn. Yesterday after I put the carbs back on I took it for a road burn and had it up to 160km (about 100 mph) and no sway at all, it just sat there rock steady. Going around the curves improved too, it was like it was on rails, were before the bike would try to straighten up while going around a bend.

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Thanks for the update Ben. Now that you see how much this affects the handling of your bike, I suggest you put it on your to do list to at least take the nut off and drop the triple tree down and clean, inspect, and regrease the bearings. With the old grease, you may have to have the bearings a little more loose than is optimum to not have sticky spots that caused your problem. With the bearings cleaned and regreased, you will be able to eliminate the sway and still improve the precision in the steering.

RandyA

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