wooble with hard brakeing

[mike042]

had a scare when coming home from laconia nh bike rally last night, had a deer jump out in from of me doing 65mph 2up. was fine no hit was 100 in morning so plenty of room to maneuver but when I hit brakes hard bike wobbled a bit, nothing uncontrollable but noticeable. my passenger felt it was front end I thought it felt more rear wobble. its my 83 venture. brakes are good original configuraton (still linked) tires are ok will need replacing after this season by my standards (state inspector says I could get couple years out of them so I'm changing them) so what do you all think it could be?

[Donvito]

If you haven't done it recently, you may need to adjust your steering head. It's in the manual in the Inspection and Adjustment section. Good idea to check the bearings while you're at it. The adjustment requires a special tool and a torque wrench. I think a member sells the tool in the classifieds if you need it. Let me know if you need the instructions.

[Great White]

Check steering head bearings.

 

Ratcheting, notchiness or hanging is reason for replacement.

 

Loose just requires adjustment.

 

Only other spot is swingarm pivot, but I've not heard anyone complain on the ventures.

 

One last thing to check is slide under the bike and have a look at the frame cross tube where the swingarm linkage attaches. 83's had a fault where the frame cracks on the tube. Not saying that's whats happeing and it shouldn't create a wobble, but worth a look...

[zagger]

Not sure if this is the issue, however you should know that hard front braking compresses the front fork and has the effect of reducing the front wheel "trail" measurement which also reduces your normal front wheel stability. Of course, a heavily loaded bike will compress the front fork even more when the front brake is applied hard. Even if the front end never reaches a truly unstable "negative trail" condition, the reduction in the trail will make the handling much more sensitive and more likely to produce a wobble. Of course, this is assuming that you don't have problems with your front disks, etc. which might also produce an odd handling sensation.

zag

[djh3]

Did you feel it in the pedal or your braking hand. Sometimes a warped rotor will give you some "feedback" thru them.

[cowpuc]

and tire pressures...

[DblTrbl]

I had a wobble come and go last week. bike was checked and I needed a new bearing......

[mike042]

thanks for the replys I checked everything and all normal but tires were down a cple of pounds so was probably just that like I said it was a barely noticeable, but enough to check out so thanks all!

[brummers]

I just confirmed I had a warped left front rotor on my newly purchased 1997 RS. I would describe the feeling as pulsing, not wobbling.

 

First I inspected both rotors. The left side had a few marks and obvious shiny and dull spots. The right side looked uniform.

I took off the left caliper and slid a speed square inbetween the pads. Zip tied it all inplace with a terry cloth towel for padding and hung it from my left passing light.

Tested down the street and the pulsing was completely gone. So now to find a good used rotor. I think V-stars rotors will fit, too.

 

My remaining issue is that I can bear down on the front brake (with just the right caliper) and just glide to a stop. I know the stopping power is half with just the right side, but I'm not even compressing the forks. The brake hand lever moves less than half way. It feels super firm and I really cant squeeze it any harder.

 

So I'm thinking I should rebuild the calipers and maybe the master cylinder as well.

Any thoughts?

ErikB

[brummers]

Replaced the left rotor and bled the front brakes and working quite well. Have new kevlar pads on the way.

 

I found two different brands of pads on the right and left sides. The rotor had marring from a screwdriver. I figure this was a brake job gone bad and a screwdriver or similar tool was used in an attempt to push in the caliper cylinders.

 

VStar front rotors are the same as the RS. I borrowed one off my 2001 650 Vstar Custom, but also checked a friends 1100 Vstar and a roadstar. All these front rotors are exactly the same. Roadstars also have the hub covers. Good to know for ebay hunters.

 

Not sure about the rear rotors.

Edited July 8, 2015 by brummers
updated cause of problem

[skydoc_17]

There are two things I would like to bring to your attention about the issue you just described. The first is with the "linked" braking system, when applying the front brake, you are only activating the right front rotor, in a panic stop situation the second item I wanted to mention crops up. If the upper set of fork tube bushings in the LOWER fork tubes are worn out, (these bushings are located in the TOP of the Aluminum lower fork tubes) the front wheel will move side to side because the right front caliper and the left front caliper have different piston sizes. Even with PERFECT brake lever/foot pedal application, the difference in braking action between the two calipers amplifies the worn out upper bushing effect. A tale-tale sign of the bushings being worn would be a thin, black oily ring on the shiny metal upper fork tube about 5" above the fork seals. When the upper fork tubes shift during the panic stop due to the worn bushings, the upper fork tube forces the lip of the fork seal to one side, which allows a very small amount of fork oil out of the lower fork tube which ends up on the upper fork tube as a small ring. These worn bushings are very hard to detect until they get really "sloppy". You may have just received your first "warning".

Earl

[dna9656]

I think every one here has made great suggestions; more than I could add that's for sure! However I would like to relate my experience with "Mr. Wobble".

I had a really weird feeling in my '83.5, It was more of an unsteady feeling that a wobble but I was inexperienced. At first I thought it might have been road imperfections but it happened again on the same ride. The next day it got worse so now I knew it wasn't road conditions. My tires had good tread but were old, no cracking in the side walls but still, they were old. I had been in the front wheel's bearings an had them replaced a couple months before by the $tealer (who had a good rep for mechanical work) so I was confidant with the front end, the fork didn't have any issues I could detect but I learn more about this bike every time I log on. So I got the bike up on my Harbor Freight M/C lift (best $300.00 I ever spent on myself) and got the back wheel off. Cleaned the black moly grease off the drive components and inspected all that, fine and good. I got the wheel on the tire changing thing and got down to the bearings, the outer ones looked old but ok. I was looking at the service manual and found there were more bearings "inside" (roller, needle, and a Yamaha proprietary spacer) behind the BIG seal. I found 4 balls missing from the roller bearing! It was dry, rusty, and pretty FUBAR. So knowing what the $stealer charges for parts I went on Ebay and found a set for the same generation but different year. I contacted the seller and he (of course was of no help) had no idea of how to look at his catalog and see if one set of bearings was used in multiple year applications. So I looked up the Yamaha P/Ns on the year he was selling and the P/Ns on my bike. Gee they were the same. So I ordered it.

Started removing the needle bearing. The outer race had become one with the wheel. I had no experience with aluminum wheels and heat. I have successfully removed many wheel/axel bearings from cars and trucks in the past however. I ground the outer race as thin as I dared used a sharp chisel to cut the remains but no joy. Now I have several spare parts for my 83.5 so I grabbed another wheel and took it to the local Triumph/Husky Dealer. He charged me $20.00 to lube and change all the bearings in the wheel. I also had him mount a new tire (I bought on Amazon) for another $20.00. Not just a cool deal but as my brother would say "FREEZIN' MAN!" I was so satisfied that I bought a front tire from him at a good (but not great price) and had him mount it to the front wheel. The Dealership is struggling to stay afloat and he treated me well so I do what I can for him up to a point. If I'm not saving $$$ and getting something done I can't do it's not a good deal. If I can save $$$, get it done, and help him out, what's wrong with that? Oh yeah; he also installed the right angle tire valves for me at the same time. My tire changing ability is still beak breaker, it's kind of a low priority right now because both the bikes that run (the Road Star and Venture) have new tires so I have other things to spend my meager $ on.

Considering the age of your bike and the (probably) unknown maintenance record I sure would be looking at those bearings.

[Prairiehammer]

the front wheel will move side to side because the right front caliper and the left front caliper have different piston sizes.

Earl

 

That is not correct Earl. On the 1983-1985 Venture, the pistons are identically sized on the front.

[skydoc_17]

Hey Kevin,

You are absolutely correct! I had MKII on the brain! Thanks for straightening me out.

Earl

[dna9656]

Personally I think it's old age catching up to all of us.....

[GeorgeS]

How many miles are on this bike ??

Do you know What , if any, maintenance has been done to the Steering head, fork seals, and have the fork springs ever been replaced ???

 

Have you, done a TEST, for front end wobble???

ie: On straight, level road, at about 40 mph, 50 mph, and 60 mph. carefully remove hands from both handle bars,

 

BUT, be ready to grab them !!!

 

Does the bike keep going straight?? Or does the steering head start to Wobble back and forth ?????

 

If it does, you deffinatly need to work on the steering head bearings, and possible fork springs, and seals.

 

ALSO, Check settings of the TORQUE, nuts on the swing arm bearings, ( and of course greese those bearings )

 

You have an OLD, BIKE, how much do you know about the Maintenance History of this bike ??? How many miles on it ???

 

Without this information, all of us here are just guessing, as to what may or may not need to be done to it !!

 

HEAD WOBBLE, was a very common problem with the 1st Gen Ventures !!!!!