A forum for owners of Yamaha TTR250 trail and enduro bikes!

yamahalife · Member

Front Wheel Bearings Replacement

mossproof · Super Guru

This thread might be helpful, although it's not an "Official Brian how-to thread"

ttr250.activeboard.com/t49130795/wheel-bearing-removal/

yamahalife · Member

I saw that one earlier and i am assuming the front bearing is going to be similar to the rear. I am thinking I am mechanically inclined enough that I should be able to figure out everything out. I was just hoping to have a "how to guide" just in case I do run into a snag. But I really need the torque specs more than anything. I am guessing that they are pretty critical on the pinch bolts and axle nut.

mossproof · Super Guru

Front wheel spindle torque 58Nm/42ftlbs
Spindle clamp nuts 10Nm/7.2ftlbs
If the clamp has an arrow on it, this should point upwards. Nip the top nuts up first, then the bottom ones, then torque them up, tops first.

The layout of the bearings is the same front and back: Seal-bearing-spacer-bearing-seal, although the back wheel has 2 bearings on the sprocket side. Getting them out is a bit of a mission. I like the expanding bolt/rawl bolt idea. It may work better if you expand it in the spacer rather than the bearing as getting it to grip the hardened bearing surface is difficult. then knock it out from the other side. Don't over tighten the rawlbolt in the spacer - it might stretch it. You just want the grippers to be a slightly larger diameter than the inner diameter of the bearing.

The bearing has to come out from the side it's fitted in - that is you can't knock them all through from one side. Getting a punch to grip the edge of the bearing race can be hard, and risks damaging the spacer so be careful.

That all sounds more garbled than it should, but I'm not going outside tonight and dismantling my bike to take pictures

Good luck!

TTRfan · Super Guru

Oh dear! I only ever did a guide on replacing the rear wheel bearings - see here

However the thread Simon links to seems to provide all the info needed but, if not, ask away wink

Brian

yamahalife · Member

okay so i tore the front wheel apart and the bearings fell apart. I do mean fell apart, even the gear unit assembly (yamaha part number 4PX-25190-00-00) and I tried to put everything back together and the spacer that came off of the bike does not look like the pictures Ive seen on yamaha websites. Now I think ive got to buy the gear unit assembly and a new spacer unless you guys know if you can get away without gear unit assembly bearings. If anyone does the front wheel bearings and can snap a few pictures I would be greatly appreciated. Cause I am at a lost. I Knew this was going to be a slow process after the bike had been sitting for 2 years but i was not expecting what i found when i tore all of this apart.

-- Edited by yamahalife on Monday 18th of November 2024 11:13:20 PM

TTRfan · Super Guru

This thread might be useful regarding the speedo drive.

"Now I think ive got to buy the gear unit assembly and a new spacer unless you guys know if you can get away without gear unit assembly bearings." There aren't any bearings in the speedo drive. What bearings do you mean?

Brian

yamahalife · Member

I will get a pictures of them tomorrow and post them. I've got a too much to do to get down to the shop today. But I will post them tomorrow around this time. But it looked similar to the picture in the thread you linked in your comment Brian. The one with the gears on them, but mine looked like a bearing sitting right behind it. I do not have the OEM speedo on my TTR so that why I was wondering if I could get away with out all of the internals of the speedo drive. Thanks again, Ill get all of the pictures tomorrow and get them posted.

yamahalife · Member

Sorry about taking an extra day, something happened to the internet yesterday. But here are the pictures of the speedo drive gears. I meant to get some pictures of the spacer but I completely forgot. I was in a rush. If you need pictures of anything else let me know. Thanks again for all of the help.

TTRfan · Super Guru

I really can't see what's going on there but it looks as though the spacer part of the outer drive casing has become detached and is stuck on the drive gear cry

This is what to parts should look like (photo included in my thread here )

mossproof · Super Guru

I think the worm gear is stuck to the spacer part of the speedo drive casing, which in turn appears to have detached itself from the casing. Do you have the rest of the casing, as in Brian's pictures? It looks to me like you have the inner part of the speedo drive, with the worm gear stuck to it, and a dust seal added for fun!

If you are not wanting to run a cable driven speedo, the best thing to do is use the spacer part that you have, but knock off the worm drive and old seal. It should be the correct width to keep the hub to fork leg distance right (but is less important than the one on the left side), and fit a new seal (20/35/5 double lip radial seal). This should replicate a pre 2000 model setup:

Mine below, with somewhat grubby spacer!

yamahalife · Member

OK, I did not know it was a spacer and came all of the way apart like that. But yes I do have the rest of the casing. I would like to get rid of the casing because it doesn't have the factory speedo anyways and I like the cleaner look with out the cable running up the forks. Man I greatly appreciate all of the help. My local AutoZone has the seal in stock for $5 dollars. I may be able to get it back together Sunday afternoon after I get off of work. Yall are awesome! I really cant thank y'all enough for all of the help. I will try and get more pictures of the casing, spacer, and all that stuff when I get home from work tomorrow as well and get them posted.

yamahalife · Member

I got the spacer pulled apart from the worm gear and got everything back together. And it works like a charm. Thank y'all so much for all of the help.

mossproof · Super Guru

Good news!
Glad to help.