2003 Honda TRX250ex swingarm questions.

[trx250exthebest]

G'day guys, just wanted to ask some questions regarding the swing arm. First of all I just wanted to say that I am very impressed by the trx250 I can't believe its19 years old it is my daily driver I live in a rural coast town and it gets driven off-road every day and on pavement for a few kilometers  I've had it for two and a half years. 500 km away and I drove it back home for in 2 days and I had nothing go wrong. All I've had to change on it is some bearings and carbons in the starter.

Last week I changed the bearings in my swing arm because the left side was broken, I changed both sides. The left side and the frame had a bigger gap then normal, I made some tests shaking around the quad and it didn't seem to move so I thought I would keep an eye on it. Yesturday it started moving around and when I opened it up I found the right side bearing was broken. I've put a new bearing in and this time the gap on the left side is smaller then last week but it's still not as small as the right side. Both installations I've torqued the bolts correctly. If anyone has any ideas it would be really helpful.

 

Edited November 4, 2022 by trx250exthebest

[Mech]

I take it you have the manual and did the bolts up in the right order.. The right bolt goes up solid first, and then the other side snugs up till the arm's positioned right is the theory. You have the solid bolt on the right hand side, and tightened that right up tight first ? And the bolt and locknut on the left. Did you hold the left bolt while you were tightening the lock nut ? If the left bolt tightened as you were tightening the locknut it would put too much pressure on the bearings and would wreck them. You did read the torque figures right.. didn't take LbFt for KgM or something ?

That, doing things too tight, would explain the bearings failing. That seems the most likely reason for the bearing failure and the miss-positioning.

If you did things in the right order and torque and  the positioning was wrong it could be because the new bearings, or one of them at least, was a different width. Bearings do come in different widths. Different widths though shouldn't cause a bearing failure.. Over tightening the bolts onto the bearings is almost certainly the cause of bearing failure.

 

[trx250exthebest]

Good afternoon, thanks for the reply. Yes I have the manual and followed all the instructions as well as torqueing correctly and doing the right side first. I'm thinking the gap could of been created from a bent frame or the engine is a little to the right. Also the bearing first broke 4.5 months ago after a hurricane hit my house and it had a few weeks of very off road driving. Honda took 4.5montha to get me a new bearing (I live in a 3rd world country). Since it's my only way to get around I had no choice but to drive around with a broken bearing for 4 months. It's possible that had affect it somehow but it was the right side that broke after repairing them so it might of just been bad luck. So the fact that the gap on the left side is a little big isn't a problem?

[Mech]

Even if the frame was a little bent and the bearings misaligned, it shouldn't damage a bearing doing that work in a hurry.  Side thrust will destroy a bearing real fast. Even if you were installing it by driving it on the inner race, which would normally be bad for a high speed bearing, it shouldn't harm it in this situation. The bikes are made for off road use, and the swing arm bearings normally last for years and years, till the seals wear and the bearings rust. Those bearings don't usually break, only rust. Was the original bearing really actually broken without rust, or rusted and hammering till it broke ? The answer to that might confirm it's alignment, or not

If it is a bent frame causing the misalignment, then the misalignment should always be on the same side when you assemble it.. I think.. Just mussing here.. I might be wrong about that. The position of the engine will not effect the bearings or the position of the swingarm. The swingarm and/or engine can be a little out of place, as long as the drive shaft isn't rubbing inside the arm. Having a little gap on one side should not be a problem.

The bearing failure I'm sorry to say is almost certainly something wrong with the assembly work...

The bearings are I think, from memory, perfectly common ball bearing races.. They  will have a number on them. 6204 or something like that. If you take the number to an engineering supply place, or a bearing specialist, they will be able to supply one easily, off the shelf, and if you take them the dimensions of the seal, or an old seal, they will supply one of those too.

At least they are easy to fit. I'd sling a new one in and take extra care about the order and torque of tightening.

[trx250exthebest]

Ok thanks for your insight, well left bearing broke 4 months and I waited to get an original one because it was so messed up I wouldn't of been able to get a size for it from a local engineering shop. 2 days ago when it broke again I was able to get one from a local shop this time so no waiting :). Todays the second and so far so good. I don't use the quad for racing just as a daily driver around my town. To get to my property my road is like a off road race track, very bad dirt road. Ive used to to charge lots of material to my property to build my cabin last year. Thanks for putting my mind to rest about the gap I'll just keep en eye on it and hope it doesn't break again.

 

Another unrelated question, my head light is gone and Honda doesn't have it in stock. I noticed that the newer generation have a different code for the headlight. Do you know if a new model bulb had the same special fitting? They are both 35w

[Mech]

Can't help you with that one. If you look up a new bulb though in an online parts place, you could manually compare the new and old models to see if they are the same, or, some parts sites have a feature where when you look up a part, and there will be some way where they tell you all the other models that part fits. Sometimes there is a link in the part index, sometimes just clicking on the part like you are going to buy it takes you to a page that tells you. There are only a few designs of fittings, but there are different power ratings for bulbs. A little different power rating will be ok.