Centering new swingarm bearings - no shoulder or counterbore

queen of spodes
Edited Date/Time 8/18/2020 6:13am
I have a super handy swingarm bearing tool but getting the bearings lined up exactly dead center in the swingarm is kind of a pita. The swingarm is off an older 1987 KX250 and does not have a shoulder or counterbore to line up against.

How important that it be exactly, down to the thousandth, centered? The tool I have obscures the bearing edge so there's been a lot of tweaking it back this way and then the other way.

Is there a better way of installing and centering swingarm bearings?
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queen of spodes 8/18/2020 6:06am
8/18/2020 6:06am
Every how to or video I've seen just breezes past the centering aspect. Would love to hear how pro wrenches do this.
FGR01
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FGR01 8/18/2020 9:12am
8/18/2020 9:12am
Usually you can tell if it is centered sufficiently enough if all seals, spacers, collars will go in correctly and sit "flush" as they are supposed to. Beyond that, I doubt it matters a few mm either way. We're likely talking a few mm here, not 10-20 mm of potential difference?
queen of spodes 8/18/2020 9:30am
8/18/2020 9:30am
I feel like I'm going to have to just fight this thing until absolutely perfect. The 87 KX swingarms did not have lips/bevels/counterbores to press to. If the bearing is off by 1mm, it would make fitting the swingarm between frame/motor slightly difficult.
kpersonius264
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kpersonius264 8/18/2020 2:11pm
8/18/2020 2:11pm
I would use a vernier caliper and measure the depth to ensure they're centered.

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sandman768
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sandman768 8/18/2020 3:36pm
8/18/2020 3:36pm
I have a factory Kx service manual from 1988, makes no mention of swingarm bearing depth... I would put them at a depth that looks correct with all your spacers, sleeves & seals & then test fit in frame with engine mounted. I know it can be critical as my 88 Suzuki RM 250 bearings have to be just right or the swingarm will rub the shock spring.
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queen of spodes 8/21/2020 11:04am
8/21/2020 11:04am
Got them installed and centered. Found that once they were close I could take a small plastic mallet and nudge them either way with a punch.

Old bearings looked original and rusty af.

Now I gotta find stiffer fork springs for '88 KX models.
mxracer666
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mxracer666 8/24/2020 2:57pm
8/24/2020 2:57pm
Measure where the old ones were...before you take them out...;-)

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