deanogasgas Posted February 23, 2016 Report Share Posted February 23, 2016 Hi all, After refreshing my bike over the winter I replaced my head bearing, Had the bike out for a quick spanner and check over after a couple of trials and found the steering to be very notchie lock to lock, There is no play at all while holding the bottom of the forks and rocking back and forward. There is also free play lock to lock ? Thanks Deano. Quote Link to comment Share on other sites More sharing options...
heffergm Posted February 23, 2016 Report Share Posted February 23, 2016 What does very notchy mean? Sticking? Overtightened the lock nut perhaps. You really don't need to tighten it down at all. Snug it up then another quarter turn. 1 Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted February 24, 2016 Report Share Posted February 24, 2016 What does very notchy mean? Sticking? Overtightened the lock nut perhaps. You really don't need to tighten it down at all. Snug it up then another quarter turn. Quote Link to comment Share on other sites More sharing options...
richt Posted February 24, 2016 Report Share Posted February 24, 2016 Sounds like over tightening and the new bearings have become indented ('Brinnelling') and need replacing. Never set the free play then tighten the locknut down. Always set the free play then run the locknut down only finger tight, then turn the bearing nut backwards (undoing) against the locknut with a firm nip. After this you may only need to carry out a very fine adjustment. by turning both nuts together 1/8th turn until they feel right. When right the bearings should be just tight enough to have minimal to no detectable play. Hope this helps. Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 24, 2016 Report Share Posted February 24, 2016 The symptoms you describe are almost certainly indented bearings. There is a chance you could have got a piece of dirt or metal shaving under the bearing seat causing it to tilt. Indented bearings can be caused by over tightening, Indents can also be caused by having the bearings too slack. slackness results in uneven distribution of load on the rollers. I have seen this happen on MX bikes. New bearings have been fitted or old bearings re greased. The mechanic assembles the bike in the workshop until there is no play in the bearing. However the reason there is no play is because of the thick grease especially in cold weather. A few laps and the grease pumps out, play develops and the bearing becomes indented. Steering head bearings should generally be bedded by applying a constant torque of about 15 ftlbs whilst repeatedly moving the handlebars from lock to lock. Once the nut no longer moves then back it off a shade until the bars fall from side to side with minimum input, say 1 ftlb or less. Quote Link to comment Share on other sites More sharing options...
deanogasgas Posted February 24, 2016 Author Report Share Posted February 24, 2016 Well Guys, I think in this case a double problem, Over greasing and over tightening ... , With the bearings only being a couple of trials old, could they be re-used. or is it NEW. Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 24, 2016 Report Share Posted February 24, 2016 Check them with a magnifying glass - any dints they are scrap Thoroughly clean them then lube with WD 40, put rollers and inner bearing in and rotate wth your fingers, any notchiness / roughness they are scrap Quote Link to comment Share on other sites More sharing options...
deanogasgas Posted February 24, 2016 Author Report Share Posted February 24, 2016 Nice one Thank you... Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted February 24, 2016 Report Share Posted February 24, 2016 If you do need new ones, buy them from a bearing supplier. They are a fraction of the price than from bike dealers Quote Link to comment Share on other sites More sharing options...
cbutler Posted February 25, 2016 Report Share Posted February 25, 2016 Over greasing is that even possible? Quote Link to comment Share on other sites More sharing options...
heffergm Posted February 25, 2016 Report Share Posted February 25, 2016 I wouldn't really think one could over grease anything, unless you were forcing grease under pressure into a sealed housing. The head bearings definitely aren't that. Slather them with as much grease as you like... the problem is the over tightening, not the grease. Quote Link to comment Share on other sites More sharing options...
deanogasgas Posted February 25, 2016 Author Report Share Posted February 25, 2016 Stripping it down at the weekend. Genuine GasGas bearing number Please... . Quote Link to comment Share on other sites More sharing options...
crazybond700 Posted February 26, 2016 Report Share Posted February 26, 2016 BT280210008 Quote Link to comment Share on other sites More sharing options...
deanogasgas Posted February 26, 2016 Author Report Share Posted February 26, 2016 Good stuff, Thank you, . Quote Link to comment Share on other sites More sharing options...
dadof2 Posted February 26, 2016 Report Share Posted February 26, 2016 Original question answered but I thought I would post again because of a couple of posts using the term "overgreasing" which I did not. see http://www.machinerylubrication.com/Read/28664/dangers-of-overgreasing-for a full explanation of what overgreasing is. The issue I was referring to is that when you initially pack a bearing there is a much thicker film of grease on the bearing surfaces than there is after a few rotations of the bearing. If you do not rotate the steering head bearings several times with the correct torque to load the bearings you will not set the bearing at its correct operating fit. After a bit of use when the grease film settles at its correct thickness the bearing will be slack. A slack taper roller bearing concentrates the load on a few rollers and causes them to dent the races and put flats on the rollers. 1 Quote Link to comment Share on other sites More sharing options...
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