Yamaha TRX850 Enthusiasts Forum

Righto my lovelies

I am having a mare fitting the new steering head bearings in my trx and wondered if you could help me out please. It used to have the open type bearings but it seems that they only do (KOSO) the new tapered types. On installation the outer race/cups will only go into the tube as far as the first machined steps will allow inside the tube, this then leaves the upper outer race about 5mm proud of the tube and the lower outer race about 2mm proud of the tube. I thought that the races should sit dead flush with the tube at the very least??

This then has a knock on effect when I put the bottom yoke and stem into the tube, as it only leaves me with enough thread for the fitment of 1 of the 2 tabbed washers.

I am totally fecked on this so any thoughts would be very welcome, I just wanna get my beauty back together again in time for the TT 2013.

Cheers.

what size or number are the bearings?

How did you put the bearings in? I generally get a small hammer and a punch then tap the bearing in very gently, trying to make sure it goes in as even as possible, another way is to use a bearing press.. essentially a bit of threaded rod with some hefty discs (large socket ) at each end to pull the bearing into place, i find the tap with a hammer and punch method best as it makes a different sound when the bearing is fully home

It looks as if you've had the frame powder coated? if so have you removed the paint from inside the headstock. A dremel tool will do this. And you did remove the old inner bearings?

That's not right at all Bill, we've fitted new taper roller bearings to the TRX we're doing now and the cups sit flush with the headstock tube. Something's amiss there Are you sure the old bearing races aren't still in there? They're quite skinny and unobtrusive (about the thickness of a locking nut).

Kayla wrote:That's not right at all Bill, we've fitted new taper roller bearings to the TRX we're doing now and the cups sit flush with the headstock tube. Something's amiss there Are you sure the old bearing races aren't still in there? They're quite skinny and unobtrusive (about the thickness of a locking nut).

Yep my money is on the old cups still sitting where mister Yamaha put them!

What a total f'ing holiest of holy I am, how did I not see the inner cups sitting there laughing at me!!!!!!!!!!!!!!!!

I dont know what I would do without you lot eh?

Thank you so very much for you help and guidance on this, I have got the bottom one out easy enough now but I cant get anything on the top one without slipping off...tight as a ducks butthole. I shall stick with it and come up with summat. Thanks again.

billy budge wrote:What a total f'ing holiest of holy I am, how did I not see the inner cups sitting there laughing at me!!!!!!!!!!!!!!!!

I dont know what I would do without you lot eh?

Thank you so very much for you help and guidance on this, I have got the bottom one out easy enough now but I cant get anything on the top one without slipping off...tight as a ducks butthole. I shall stick with it and come up with summat. Thanks again.

If you have access to a MIG welder, you can run a bead around the inside of the race (avoiding the frame!) and once it's stopped glowing red, give it a squirt with WD40 or something like that. It'll cause the weld bead to contract, pulling the race with it and it should drop out with a few light taps. There's not much that can stand up to physics and the bead of weld gives you something to drift against as well

Evening all

Well I finally have a little bit of spare time to work on the project but after sorting out the problems above, this frigging front end is still laughing at me and causing me heartache!! I really need to get the front end done asap so I can get the engine back in, I am moving house in the next 4 weeks and I need to get the project round my mates garage.

The new tapered head bearings now fit in lovely but I am having problems when it comes to torquing the tabbed lock nut/washer up, no matter what I try it is causing the front end to be very tight and wont rotate freely from side to side, as it should. I have done it as per the service manual which is an initial torque of 42N, back it off 1 full turn and then a final torque of 16N. What I would like to know is, is there meant to be anything like a spacer inserted before the end cap is fitted to the top of the tube?? I think that as the end cap is so flimsy it is crushing down when the tabbed nut/washer is torqued up and fouling on the inner race of the top bearing. Hope this makes sense, its the only thing I can think of but dont know how to get over it. I have looked at all of the relevant exploded diagrams for the trx front end and cant find anything that shows anything fitted as I mentioned above.

Any help would be very much appreciated as ever. I have attached some pics of how the upper bearing looks within the tube, with the end cap on and with the stem and tabbed nut/washer fitted.

The whole unit is the same as a trailer bearing, tighten it up so there is no play..maybe a bit tighter to be sure all the seats and surfaces are correct,..then back the nut off to ensure free play ,..and then tighten the TWO locking nuts against each other.
Just make it turn freely .
You might like to check the bearing tension after you have the bike on the ground and the bearing is under load.
Youre on the right track Billy.

alextrx850 wrote:The whole unit is the same as a trailer bearing, tighten it up so there is no play..maybe a bit tighter to be sure all the seats and surfaces are correct,..then back the nut off to ensure free play ,..and then tighten the TWO locking nuts against each other.
Just make it turn freely .
You might like to check the bearing tension after you have the bike on the ground and the bearing is under load.
Youre on the right track Billy.

What he said +1

Thanks chums, I will give that a go instead then.

I always struggle with what most would call simple stuff, I am OK with the complicated stuff!! Most frustrating.

Many thanks.

Billy mate, bearing are boxed with preservative oil/grease and this is not a lubricant, it is a PH neutral grease/oil designed to stop corrosion during storage. Before fitting any bearing you should clean out the preservative and then pack the bearing with the correct grease.
Cleaning the bearing is done using Kerosine and then left to air dry, you can use compressed air to blow out the excess, but don't spin the bearing using compressed air! as this will over-speed the needles/balls causing them to scrape/scratch the mating surface. Although this is great fun using a old bearing, as when the bearing reaches its over-speed it vibrates/screams

For head stem bearings a water repellant grease is the best, the bearings that you fitted will start to corrode as soon as the preservative grease is forced out, this is a real issue in the part of the world you live in if a bearing that has not been correctly greased, is left to sit for an extended length of time (ie, weeks, your winter) the contacting surfaces will corrode, resulting in a notchy/ruff feel when riding.

There are a couple of good Youtube clips that show how to correctly pack a bearing, just do a Google "how to pack a bearing".

Ahhh....thats embarrassing then!!!

Had better ping them out and do them properly as you say. There was me thinking that the grease it came drowned in, was there to stay!!

Thanks bud.

billy budge wrote:Ahhh....thats embarrassing then!!!

Had better ping them out and do them properly as you say. There was me thinking that the grease it came drowned in, was there to stay!!

Thanks bud.

i was trying not to sound condescending, which is sometimes hard to do when giving facts. I used to get the apprentices to pack the bearing by hand and after they had grease all over them and everything within a 50M radius, show them the bearing grease auto packer