Steering Head Bearings

[mattpope]

Hi guys.

I'm looking for a bit of technical help as I attempt to get my AT ready for an MOT following some time on south America's roads.

I rearranged the front end of my AT in southern Chile earlier this year causing damage to the frame at the bottom of the stock where the lower bearing is housed. The old bearing was shattered and some of the fragments were encrusted into the frame. All very alarming. The fix at the time was to reshape the stock and fill the new holes with some weld. The original bearing would not seat in the housing as Honda had intended so a conical needle roller bearing was fitted. Finding a suitable one was a mission and I had to resort to one with the correct outer diameter and machine the inner to fit the stem. This fix got me another 15000 miles but now the steering is not what the MOT tester would approve of.

After this long winded description, the question is where can I get another bearing to do this job? What size do I need? I don't really want to take the bike apart without the new bits nearby gagging to go on.

Hope someone can help. Great to join the site at last.

Cheers,

Matt

[iswoolley]

Great to join the site at last.

Took your time! Glad you made it!

http://www.xrv.org.uk/phpBB2/viewtopic.php?t=668

[mattpope]

Thanks Iain. Got anything more helpful re. bearings?

matt

[DaveS]

I can't really add anything other to say welcome!
If the MOT Tester wants it put back to what it was it sounds like your stuffed aren't you?
You need some of the clever engineeringy types that frequent here to come up with something really.
Any pics to help show the problem?
Not easy to take though I guess!

[Dilbert]

Matt
Not really sure what to recommend here, are you saying that you have ended up with a smaller or oval diameter headstock?
Why won't the original style bearings fit and what type were they.
Do you know what you ended up with regards stock ID and stem OD?
Conical needle roller bearings should work fine, but all bearings need to be clamped up properly.
Guess you're saying that there is too much play in the headstock, is this a sliding up and down (bearings not clamped up) or a rocking back and forth movement (bearings not fitted properly on diameter or also not clamped up on length properly).
Loctite do "Bearing Fit" which will help if the diameters are a bit loose or the seats a bit uneven.
let me know if you need help sizing bearings or look in the yellow pages for bearing stockists (usually also electric motor or gearbox stockists).
The MOT tester won't know what bearings you have in the headstock he will just be concerned with the amount of play and so should you, this can cause pitch and roll and easily flick you off down the road the moment you hit any dodgy road surface, my guess is you know this already though!

Big respect for even contemplating never mind actually achieving a tour of South America!

[mattpope]

Thanks Dilbert,

I will post a picture at a later date showing the stock - its a bit blurred but should get a few sharp intakes of breath and a bit of head shaking. In the UK the crash would have been a write-off but in South America in mid-trip it provided a mission that the good iswoolley ably assisted by FedEx was able to sort out. More pictures to follow.

I should explain what was done after the crash. There is no reason why I shouldn't do exactly the same again - it did me well for 15000 miles on some rough roads. Basically I need a conical needle roller bearing of the same od and id as the standard Africa Twin bearings. If you know where I can track down such a beast then that would be fantastic.

The head stock has lost its perfect round shape but it has been knocked back into shape and holds a bearing of the same od as the original. We went with the conical bearing because we thought it would sit better than the original ball-bearing type. I'm sure it will work again - just need to source the part! I was told that Honda bearings tend to be unusual sizes.

The bike doesn't handle too well at low speed but I am sure the bearings are just worn and need replacing.

Thanks in advance for any help.

Matt

[Dilbert]

Matt
check out these charts from SKF, they are the biggest manufacturer in the world bar none, the designations they use for their sizes is standardised across the whole of the industry, if they don't list it, it ain't made!

http://www.skf.com/portal/skf/home/p...link=1&lang=en

I don't know anywhere down south I'm afraid, best bet is to look in yellow pages or internet for bearing stockists, it doesn't necessarily follow that because it's made you can get hold of one, if you find a decent stockist they should be able to advise (or at least refer the application the manufacturers).

Your lumps bumps and ovality should be taken care of by the Loctite bearing fit which again you should get from a bearing stockists, just don't get any in the bearing races

[mattpope]

Hi,

Thanks for the helpful information Dilbert. Just one more piece of information needed - what is the depth and the inner + outer diameter values of the standard bearing? I will try and track something down this week.

cheers!

Matt

[Dilbert]

Sorry Matt, can't help you there 'cos a) I don't know what model you've got, b) I only have the parts list for the RD03 & c) I don't have any knocking about that I could measure

If you're going to try and get back to the standard size then you can get standard replacements from Wemoto for £26.50 a set (depending on exact model, though probably very similar across the range?)

http://shop.wemoto.com/index.dyn?oid=25392)

Or you could be cheeky and ask them what size they are (I would )

(tapered roller bearings appear to be standard? was a bit surprised when you said you had ball bearings fitted, I thought that these went out in the mid 70's? ball bearings aren't designed to take much thrust i.e. like when your front wheel goes down a pothole!)

p.s. maybe the able Mr Woolley can shine some light?

[mattpope]

Fantastic news. Just seen the Wemoto pictures and this is exactly what I am looking for.

For some bizarre reason my RD07's steering was fitted with ball bearings whereas earlier models had tapered needle rollers. Like you say these are never as tough as the conical species, so as long as they are going to fit my bike they will be a big improvement.

I will place the order tomorrow and look forward to riding in a straight line without the wobbly handlebars.

Just need to replace all the plastic at the front end now.....

Cheers Dilbert!

Matt