Problem with steering head bearings

[riffer]

Hi all,

as part of the fix for my fizzer, I'm completely replacing the steering head bearings before it goes back on the road.

I've taken out the old ones fine and have the new ones to put in.

It's my understanding that steering head races are an interference fit.

That's fine for the bottom one but at the top there's a good .5-1mm play all around that bearing race. That sure as hell ain't interferance fit!

What's my options? Can I take the race to a bearing outfit, say like Shrodoco, and as them if they have a race that's the same internal diameter but 1mm or more larger on outside diameter?

Or do I have to get the top of the head sleeved to take my race?

Help...

[DEATH_INC.]

Ummmm,why is there clearance?are they the wrong part?did the old one have clearance too?
If they're just a taper take some mesurements and go to your local bearing place (saeco,skf ect)they should be able to match something up.

[FROSTY:Me]

dude does it taper? and if so does it stick out a little bit proud ? like as not the bearings havent pulled down propperly. I'd check the numbers on both the old and the new bearings and see if theyre the same - Um the other possibility is you have the top bearing in the bottom

[riffer]

LOL there's a huge difference in size between the two bearing/race assemblies - the top one is the little one

One of my mates (Matt, a fireman, but a fitter/turner in his previous vocation) and I had a look over the bike this evening.

Without checking it with the vernier calipers which I will do later this week when I can borrow them off of Matt, we both believe that there is some slight ovalisation of the top steering head where the race goes in.

The previous bearings had this slight movement in them and I had gotten around it by tightening the steering head more than spec - it seemed to stop the 'clicking' when I braked. However I'd rather not do this again.

Three options I guess:

1. Completely strip the bike down to just the frame and send it to an engineering shop to have the top race holder milled out to take a larger bearing in an interference fit.

2. Liberal application of Lock-tite to the top bearing race, and tap around the top of the frame with a punch to tighten it up a touch.

3. Try and find a bearing race that is just a smidge wider than the existing race on the outside diameter.

I guess the Lock-tite is an okay option. I reckon there's bugger all play (maybe 0.25mm out of round) but I will reconsider after I've measured it exactly with the verniers.

This is obviously something that was existing when I got the bike, and probably happened in its first drop (previous owner), which is when the forks were replaced with the FZR1000 ones, which I now suspect were straightened previously, as they seemed to have folded pretty bloody easily in the off.

The bearing is a 3200SX taper roller jobbie.

The race is a 3300 SJ

*sigh* its never bloody easy is it. Still, a bloody good learning experience

[geoffm]

Ovalised steering stem holes are common problem with FZR400s, and so presuambly the same with bigger ones.
The best way is to bore and bush the frame - a major exercise. Alternatively, Locktite or shim stock.
Geoff

[pete376403]

Heavy landings after wheelstands? Although I'd expect that to stretch the frame at the bottom bearing first.
loctite bearing mount is good, but there is a limit to how much of a gap it will fill. See http://homershams.co.nz/a_loctite_641.htm.
This might be better: http://homershams.co.nz/a_loctite_660.htm

[riffer]

Heavy landings after wheelstands? Although I'd expect that to stretch the frame at the bottom bearing first.
loctite bearing mount is good, but there is a limit to how much of a gap it will fill. See http://homershams.co.nz/a_loctite_641.htm.
This might be better: http://homershams.co.nz/a_loctite_660.htm

I knew you'd know the answer Pete! That's why I came over to see you yesterday.

However your boy said you were out celebrating the wedding anniversary. Congratulations.

The loctite 660 sounds about perfect. There's about .5 total out of roundness in the race hole, so that should sort it.

D'ya reckon I should still use the centre punch to decrease the space at the top though? Probably don't need to if I'm using the loctite do I?

Where's the best place to get loctite in Welly?

[FROSTY:Me]

celtic i'd use a combination of shim stock and the loctite -shim stock is very thin sheets of metal in set thicknesses. It will in essence replace the steel missing in the steering head Id suggest trying your local engineering supply company.

[DEATH_INC.]

Yep,loctite660 is good stuff,I've used it before with good results.It should do the job just fine....

[riffer]

celtic i'd use a combination of shim stock and the loctite -shim stock is very thin sheets of metal in set thicknesses. It will in essence replace the steel missing in the steering head Id suggest trying your local engineering supply company.

This and the loctite sounds just perfect

Cheers guys

[pete376403]

Centre punching is a bit nasty (but it does work), I'd save that unless nothing else works. Try the loctite, then assemble the steering head into the bearings (don't grease them at this stage) so the top outer race gets pulled into alignement. Loctite also make a primer called locquic that will speed the setting (may not be recommended - ask when you buy the stuff) and the hole has to be immaculately clean. Isoproply Alcohol is good as it doesn't leave any residue when it evaporates. Does your work computer system use tape drives? Isoprop is used to clean tape heads.
Or again, ask what is recommended when you buy the Loctite.

Is the hole still round or has it ovalised? If oval, getting shim stock into the right place may be tricky.

Repco may have the common grades of Loctite, or try Schrodoco, upper Tory Street 385 8475

[riffer]

Cheers Pete.

I have sussed out the loctite, thanks to Tas who's clued up in this department

Probably won't need shims as it is not very much slop. And yeah, the socket is a touch ovalised. Just enough to make the race slot in, rather than jam in.

The isopropyl is no problem - got a bit of that (Gini used to be an IT manager), so I can clean out the socket easily.