Vibration in rear (1985 250es)

[maxdallasfan]

When I'm really pushing the throttle, I notice a pretty good vibration coming from the rear. Doesn't happen at slow speeds.

Could it be the rear diff. or possibly bearings? I change the oil regularly in the diff. I know the 85's had a bad seal which gummed up the oil quite frequently. If it's the rear bearings, then I have no idea how to swap them out.

I'm still learning about repairs. Heck, I spent 2 weeks diagnosing my electric start when all it turned out to be was a dead battery. LOL.

[atc007]

You'll have to try and pinpoint where it's coming from. Get it up in the air and shake and check everything you can,wheel,hub and bearing wise. If that doesn't show you your problem,try and pinpoint where it's from while you're riding it. See if you can hear/feel,anything in reverse. That's usually a tell tale sign of the diff. But it sounds like you've been religous with that.. Otherwise,,tear into it,or let it get a little worse,,,still gonna have to find the problem though lol.

[barnett468]

I'm still learning about repairs. Heck, I spent 2 weeks diagnosing my electric start when all it turned out to be was a dead battery. LOL.

...Sorry, couldn't help myself.



In addition to atc007's comments, you can try the following if you want.

I would put it up on a box and try to wiggle the ends of the axle front to back and up and down to see if it moves. If it moves more than a hair, your axle bearings [items 19 and 20] are worn but may NOT be causing your vibration.

I would then remove the clamps from the rubber driveshaft boot [item 6] and move it enough to inspect the u joint [located at item 3 arrow] for wear. Try to wiggle it and see if there is play in the joint [not the splines on the engine end of the shaft]. If there is, it is worn. If it moves more than a few hairs or is dry, it can cause a vibration.

Rotate axle and listen for noises.

Put bike in neutral, have someone apply the rear brake then try to rotate the driveshaft in both directions at the u joint. If it rotates mote than around 1/8th of a turn, the diff is worn. If it rotates around 1/4 turn or more, it has too much play and might cause a vibration.

Pinion shaft bearing [item 9]may be worn which can cause a vibration.

Axle bearings 19 and 20. U joint boot item 6.

http://www.cmsnl.com/honda-atc250es-...5.html#results


Number 9 is pinion shaft bearing, 26 is diff bearings.

http://www.cmsnl.com/honda-atc250es-...0.html#results


Free factory service manuals online. Might take 6 minutes to download.

http://www.oscarmayer.net/atc/manuals/

[maxdallasfan]

Thanks guys. Good stuff! I'll try what you said barn. Yeah, the battery thing. It was only a few weeks old, but now I know that they should be charged constantly.

[barnett468]

Thanks guys. Good stuff! I'll try what you said barn. Yeah, the battery thing. It was only a few weeks old, but now I know that they should be charged constantly.

Hey, we've all been there. I've taken some black ignition rotors out of some old cars when I work on the points and set them on the black ac unit then install the dist cap forgetting the rotor and try to start it. I'm not sure what it means that I have done this more than once.

[dougspcs]

Also a possible seized or worn u-joint on in the driveshaft..only problem is you have to either pull the engine or the rear axle/diff to get it out and check it properly. Not very easy to get a good look by peeking past the boot.

I'd say it's time to pull the rear end apart, it'll give you a chance to look at all the other stuff Bill suggested..grab the manual online and follow the directions. I'd never done one before either when I got into mine a couple years back..pretty simple and the manual is pretty straight forward.

Have an electric impact handy is my best advice..you will completely waste yourself trying to break loose all those crusty bolts!!

It'll only take you about an hour with the proper tools..

But before you go balls deep maybe pull the rear drum off and make sure you don't have a half brake shoe tumbling around inside..I love it when it's the simple stuff The 85 shoes always fall apart because the brake design isn't very water tight and they corrode off the backing plate.

[DohcBikes]

With the symptoms described, my money's on a bad u-joint. Which means I got about 14 cents on it, so no big loss to gamble a guess I suppose.

[maxdallasfan]

Geesh....I wouldn't even know where to start on something like that.

[DohcBikes]

The service manual would be a good place to start !!

[oldtime3wheeler]

You will.figure it out. How's the big red been.coming along?

[MNhondaguy]

Your creepy ass grinny picture next to "vibe in rear" is easier to make fun of than the battery thing. Maybe because it took me a little bit to realize I needed the battery hooked up and charged for lights to work. Who know haha

[dougspcs]

Geesh....I wouldn't even know where to start on something like that.

You've been around long enough now to know how this works Max.

It's time to dig in then..the group has given you a lot of great information..

We can help you, but we can't make it paint by numbers for you.

Time to grab some tools and a manual and dig in..start with what you do know, like pulling the wheels and the rear brakes off to have a look. Then grab the book and keep going from there!! Pull up the manual on your computer..it's pretty step by step. Have you even looked in it before?

..or just keep riding until something bad happens!! Your call.

[maxdallasfan]

You will.figure it out. How's the big red been.coming along?

Other than that, it's been flawless. Guess i'll start turning some wrenches this weekend.

[barnett468]

..or just keep riding until something bad happens!! Your call.

I have found that this is the easiest, simplest way to pinpoint a problem.

[dougspcs]

Other than that, it's been flawless. Guess i'll start turning some wrenches this weekend.

Attaboy..it's not as difficult as you'd think. Slow and steady as she goes..ask questions if you get stuck and take your digital camera out with you. That often helps us 'see' where your are.

But like I said, track down an electric impact..it'll make the job a ton easier!!