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Join Date: Jan 2011
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Where did you get the bearings?
Bearings can be common or special - I do not have a 400EX crank bearing in front of me and I cannot tell you if it is special or common, but most bearings have 'clock' sizes. Example; I am working on a Polaris 400L two stroke - the counter balance bearing is a 16006 C3 - the C3 is the clock number - standard bearings are C1 and not marked (a 6003RR bearing is a 6003 C1 with rubber seals on both sides and a 6003Z is a 6003 C1 with a metal shield on one side) - if the bearing you need is supposed to be a C2 and you got a C1, then the fit will not be as tight. If you got the bearings from a supplier other than Honda, it's possible they just sold you C1 bearings. It's also possible you might need to get a C3 bearing to take up a half thousandth of an inch of clearance. It's also possible the conditions under which you are working is affecting the fit. When the cases are heated to about 250 to 300 degrees, the bearings will fall out under their own weight.
If the bearings are OEM Honda (and Honda does not make bearings, they buy them from a bearing manufacturer), then it's possible the fit is just fractionally loose. It just depends on how loose they are. If you can cool the engine case in a refrigerator (about 45 degrees F) and tighten the fit to where you have to tap the outer race to get them in, then just use some Locktite cylindrical part retainer #609 - if the bearing will fall out under it's own weight at 70 degrees F, then Locktite 635 would be a better choice. If the bearing is loose enough you can see it moving in the case, then you need to replace the cases or as a last gasp, use Locktite 660, put it together and trade it off.