I have just finished putting together an NC29 to race this year. Bike was dynoed last week and the lads mentioned that the head bearings needed adjustment or replacement as the stem was moving slightly in the chock on the dyno. I had replaced the bearings and races and so thought it was just a matter of adjustment. Today I stripped the front end down just to check I hadn't done something stupid like putting something in upside down or leaving something out (a distinct possibility at my age!). All seems in order so put it back together and it felt fine. However, looking at various bits on youtube and on other sites, it seems to be a bit of a mission to get the bottom bearing off the stem whereas mine just came staight off. The bottom race was apain to get off but the bearing itself just lifted off. Is this normal or is something amiss?
Cheers

hiya Jo again!

Waaay past my tech knowhow! (Balance carbs about as far as I go)

Hope someone comes along to assist.

You can always try Graeme Francis, he always has time for advice, and can probably sell you stuff you need, especially for racing


Cheers
Martin

Hi Martin
I got a full set of bearings from Graham Silver and replaced everything that came off the old stem, including the top and bottom races in the headstock. I 'think' everything is ok but I suppose I just want some reassurance really, must be getting a bit insecure as the season draws closer!
Cheers

Could you be missing 1 or 2 dust seals, that might cause a small amount of movement. They are item 3 & 4 in the parts book.

Or, you can wait for DD to reply! 8)

He seems to be the main man in this section


Cheers
Martin

Hi mate the bottom race IS the hard part to get off, the bearing just lifts off.
Have you tried tightening everything down fairly tight then backing it off to the correct setting?
I assume the outer races are both fully seated and not loose in the frame.
When fitting the races you should hear tap tap tap then a clunk as they bottom out in the frame.
If one wasn't fully home it might have moved later on the dyno and left the stem a bit loose.

marty400 wrote:Or, you can wait for DD to reply! 8)

He seems to be the main man in this section


Cheers
Martin

Thanks Marty, trouble is I'm no expert and can just try my best. I did have a fuller reply but the internet decided not to post and stopped working!! so had to redo my reply, by then I was leaving work so just posted that small amount, as it happens dobbsic has posted more to my original thoughts and I would try that reasoning first. But make sure you have dust seals if the bearings need them anyway. I know my bottom bearings had a built in dust seal. Anything missing could cause a very small amount of wander.

BTW, the clocks on the forum are an hour forward, just noticed as my post last night was at 11:37pm not 12:37am

Hi DD,

Apologies, just being flippant first thing in the morning! 8)

It's always handy to have somebody who's had the bike for years,
he's Done loads of work on it, and can give Bike specific advice on oddities experienced by others on same bike 8)

Cheers
Martin

No problem Marty, honestly I wish I was a bike guru but like most people you just learn these things as you go along hopefully helping others out.

One thing for the original poster, although not your problem I don't think. It could be worth making sure your forks are centred as you have had everything off. Do this by loosening everything forward of the top bolts on the forks, that's the wheel, bottom yoke and axle clamp bolts, leaving the top bolts correctly torqued so your forks don't slide through, and just crack off the rest then push down on the top a couple times and hopefully every thing will snap in true. Now tighten everything up. That will be one more thing out of the equation.

Thanks for the tips fellas. I'll try backing everything off and do some boinging to see if it makes any difference.
Cheers