vibration??

[buttonhook]

When test riding the wifes 82 gs300L after the front brake change I noticed it had a constant vibration. Now when I asked her about she said it has always done it so I'm off the hook for messing something up, but I still need to fix it. I checked the front bearing when changing the brales and they seem to be new and have no play what so ever. anybody got a clue what is causing it??

I though it might be a tire out of balance (it still has the original 1982 suzuki wheel weights on them??) That's easy to fix when we put new tires on it. but could it be anything more costly or hard to fix that I can check?

[Steve]

What was the fequency of the vibration?
Was it related to engine speed or road speed?

If it is related to engine speed, check the engine for proper tune. Have you checked valve adjustment and carb sync?

If it was more related to road speed and it showed up at low speed, I would not ride the bike until it is fixed. If it was a wheel/tire balance problem, you should not notice it until you are over 50 mph or so, unless it's really out of balance.

If it is felt about once with every wheel revolution, I would look for a warped brake rotor.

If it is felt as small 'notches', several times in each wheel revolution, it might be wheel bearings.

Put the bike on the centerstand and jack up the front of the engine to raise the front wheel off the ground. From either side of the bike, grab the top and bottom of the tire, try to rock it sideways. If it moves noticeably, you need new wheel bearings. With the wheel still in the air, rotate the wheel to see if it drags, indicating a warped rotor.

.

[doctorgonzo]

Man, Steve, thorough and informative response. Bookmarked this one. Your turn signals went out today priority mail by the way.

[Steve]

Thanks, and thanks.

(It didn't waste any of your time, did it?)

[buttonhook]

What was the fequency of the vibration?
Was it related to engine speed or road speed?

If it is related to engine speed, check the engine for proper tune. Have you checked valve adjustment and carb sync?

If it was more related to road speed and it showed up at low speed, I would not ride the bike until it is fixed. If it was a wheel/tire balance problem, you should not notice it until you are over 50 mph or so, unless it's really out of balance.

If it is felt about once with every wheel revolution, I would look for a warped brake rotor.

If it is felt as small 'notches', several times in each wheel revolution, it might be wheel bearings.

Put the bike on the centerstand and jack up the front of the engine to raise the front wheel off the ground. From either side of the bike, grab the top and bottom of the tire, try to rock it sideways. If it moves noticeably, you need new wheel bearings. With the wheel still in the air, rotate the wheel to see if it drags, indicating a warped rotor.

.

Thanks for the reply

I Need to reride it and pay more attention I guess.
I know for sure it's not a warped brake rotor (because it doesn't have any rotors all drums).

I checked the wheel bearings when I did the brakes yesterday they didn't have any play in them at all, the wheel turns freely without noise, and They have plenty of "new" high temp grease.

It not related to engine speed as it matters not what RPM you are running. Plus I've just tuned it up rebuilt carbs, plugs, fliters, etc......everything manual calls for. It runs great now.

I guess the tires could be that out of balance at first I thought it was just the road, but it does it everywhere. Like I said they still had the original wheel weight on them from 1982!! but not the stock tires the PO could have done a home change and not rebalanced them. I didn't notice yesterday if it changed with speed. I need to check that.

Is there anything else it could be like the forks, rear springs, shocks, etc.....??
It is getting new tires before next season the tire have plenty of tread but I've notice some dry rotting starting. So time to change!!

BTW this bike only hasa little over 10,000 miles on it and we've put on almost 3,000 of that.

[tkent02]

Is there anything else it could be like the forks, rear springs, shocks, etc.....??

Chain would be likely, but it's usually pretty obvious that's what it is by the feel and sound of it.
Centerstand missing it's rubber bumper?
Footpegs or something like that loose?

[TheCafeKid]

They werent still putting spoked wheels on those lil things were they? And its not entirely inconceivable that you have a bent rim whether its spoked or not. It CAN happen, especially when loading a little bike down. I dunno either your wifes or your stature, and not calling you overweight or anything, but what is the load capacity on that bike? I know with *MY* fat butt on the lil KZ440, it sure didnt like it much. LOL

[buttonhook]

Chain would be likely, but it's usually pretty obvious that's what it is by the feel and sound of it.
Centerstand missing it's rubber bumper?
Footpegs or something like that loose?

All of those are good. I am going to change the chain when I do the new tires.
We just got back from a ride and It does change with speed. It starts at about 25-30mph it does speed up but it's never bad enough to shake your fillings lose or anything just kind of bouncy

[buttonhook]

They werent still putting spoked wheels on those lil things were they? And its not entirely inconceivable that you have a bent rim whether its spoked or not. It CAN happen, especially when loading a little bike down. I dunno either your wifes or your stature, and not calling you overweight or anything, but what is the load capacity on that bike? I know with *MY* fat butt on the lil KZ440, it sure didnt like it much. LOL

It's ok I am gravationally challenged. I'm around 250 or so but it doesn't seem to really fase it and my wife is much lighter than me.
This little bike does have the cast alum wheels on it instead of the spokes. Although some of them I believe did have the spokes. Although this bike is small the load rating on it is like 400lb or something close so I think I'm safe there.
It could still have a bent rim. I rode behind her tonight and I did look for that. I didn't see anything wobble/wiggle but that doesn't mean it's not slightly bent or out of round. I checked the front rim when I had it off the ground yesterday and it seemed to run true (I then polished it!!) but I'll double check it tommorrow.

[TheCafeKid]

Did you check your wheel alignment? Should be dead straight from front to back. Having it off, even slightly, will bring about the symptoms you describe. You mentioned you need a new chain, so id assume you've had to adjust it to tighten it up, or it had been before. Id double check the wheel alignement, then if that doesnt fix it, start looking at the chain/sprockets. If youve got a bent or twisted tooth, it will bind on the chain, and give you some shimmy as the bind passes...

[SqDancerLynn1]

If those tires are 25 years old GET rid of them NOW !!! then see if you still have the vibration

[buttonhook]

Did you check your wheel alignment? Should be dead straight from front to back. Having it off, even slightly, will bring about the symptoms you describe. You mentioned you need a new chain, so id assume you've had to adjust it to tighten it up, or it had been before. Id double check the wheel alignement, then if that doesnt fix it, start looking at the chain/sprockets. If youve got a bent or twisted tooth, it will bind on the chain, and give you some shimmy as the bind passes...

I havn't checked that!! But I will!

I just looking for anything else it could be besides the balance of the tires which is going to be fixed when I replace the tires.

[Steve]

As I mentioned in my first post, a balance problem should not show up until 50 mph or so, but if you still have the original tires on the bike, they could easily be the problem, just from degradation. If the bike sat for any length of time with the tires flat and the bike's weight on them, the wrinkles in the cords might have taken a permanent 'set', and that is your 'vibration'.

.

[buttonhook]

If those tires are 25 years old GET rid of them NOW !!! then see if you still have the vibration

The tire are not 25 years old (they are in metric measurements not inches) but I dont know for sure how old the tires are (not new thats for sure). I will nbe replacing them at the end of the summer I don't think they are dangerous (would n't ride it or let anyone else if I did) but they will need to be replaced soon just because of the unknown age.
The tires may not be the orginal but the wheel weights ARE for sure (they still say suzuki on them)and prob. are still in the original place. I think the PO did a home tire change and did not or didn't know how to balance them(thats my theory/hope anyway).

Since my wife loves this bike, and since it is becoming more rare, I am trying to restomod this little old bike for her to be as good or better than new (if possible). What I'm doing now is trying to rule out any other problems that it might have before the tire swap. That way I can try to find the parts,(which can be hard to do) get them here, and fix everything that is wrong at once while it is apart.
The main problem is I've not worked in depth on many bikes (lots and lots of cars) but not many bikes and it seems everytime I think I've fixed the simple and likely thing (according to my car experience) it turns out it's something completely different (which is very frustraiting!!). So this time I'm trying to check everything else first and if I can rule them out then I should have the correct cause for the problem. I can then correct/replace it and make this bike "perfect" (sorry it's the engineer in me )

I want everyone who has helped me on this and the many other questions to know I could not do this with out all your help. I have read all the manuals and books on this bike but sometimes it just takes help from someone with past experiences to really learn how to do something right.

Even though as a "teacher/engineer" myself I could be run out of my chosen professions for that last comment (books are all you need, sit down and read you'll learn it, blah, blah, blah!!)..it is true. I try to teach my student using hands on assignments as well as books. I want them (without help from me) to try new things and make mistakes then we can correct them (with my help) the right way.

"Every student CAN learn something from a teacher, but experience is always the best teacher!!"

Sorry....back on topic now!! The vibration.......

[buttonhook]

As I mentioned in my first post, a balance problem should not show up until 50 mph or so, but if you still have the original tires on the bike, they could easily be the problem, just from degradation. If the bike sat for any length of time with the tires flat and the bike's weight on them, the wrinkles in the cords might have taken a permanent 'set', and that is your 'vibration'.

.

You know....that COULD be the problem!!! I thought about that but thought it should have worked the flat spots out by now just from use. You know the tire warming up cooling down, flexing and reflexing, just general movement, softening them back up after sitting. I dont know if it really works that way but thats what I assumed.

With as few miles as this bike has on it (10,000 or so since 1982). I mean it only averaged about 300 mile per year before we bought it last year. It had to have set for a long time somewhere. Right??? with the bias-ply tires on it too. I'm sure it wasn't stored sitting on the center stand. At least it wasn't left outside.

Is there any easy way to check for that other than just changing the tires??