Author Topic: Front and rear alignment  (Read 1685 times)

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Offline serafin

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Front and rear alignment
« on: April 18, 2009, 05:07:51 PM »
Hi everyone
I was doing some routine maintenance on the bike tonight and had the rear sub frame off so I could remove the rear shock (going to get the shock serviced) and get to the the suspension linkage as it hasn't been greased in a while.  With the sub frame off and the rear wheel still on and looking down on the rear wheel it appears that my rear wheel isn't centered in the swing arm.  So the question is should the rear wheel be centered or is it off set a bit?  It looks like it's off by about a 1/4 of an inch. I know that the bike has always rubbed the silencer a bit when the suspension is compressed and am wondering if maybe the silencer needs to be shimmed out a bit. 
This whole thing got me thinking about front and rear alignment and how one would go about aligning the front and the rear.  On a side note but on the same topic of alignment how does one align their front forks in the triple clamps?  Do you do it by sight or is there a measurement, way, or technique one can use.  Motion Pro makes a fork alignment tool that I'm considering purchasing to do this. Does anyone have experience with this tool?  All comments welcome.

Serafin

Offline KXcam22

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Re: Front and rear alignment
« Reply #1 on: April 18, 2009, 05:19:50 PM »
I can't say that I have aligned my dirtbike.  It is quite common thing to check on a performace streetbike.  Sometimes if a wheel has been relaced with new rim or spokes it can happen that the rim get trued a bit out of center.  Generally though they should be pretty close. Cam.

Offline Polar-Bus

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Re: Front and rear alignment
« Reply #2 on: April 19, 2009, 12:51:00 AM »
Hi everyone
I was doing some routine maintenance on the bike tonight and had the rear sub frame off so I could remove the rear shock (going to get the shock serviced) and get to the the suspension linkage as it hasn't been greased in a while.  With the sub frame off and the rear wheel still on and looking down on the rear wheel it appears that my rear wheel isn't centered in the swing arm.  So the question is should the rear wheel be centered or is it off set a bit?  It looks like it's off by about a 1/4 of an inch. I know that the bike has always rubbed the silencer a bit when the suspension is compressed and am wondering if maybe the silencer needs to be shimmed out a bit. 
This whole thing got me thinking about front and rear alignment and how one would go about aligning the front and the rear.  On a side note but on the same topic of alignment how does one align their front forks in the triple clamps?  Do you do it by sight or is there a measurement, way, or technique one can use.  Motion Pro makes a fork alignment tool that I'm considering purchasing to do this. Does anyone have experience with this tool?  All comments welcome.

Serafin

My personal opinion is your kinda splitting hairs as far as checking "alignment" on an off road bike that sees relatively slow speeds, and traveling on loose varied terrain. Now contrary on a high speed street driven motorcycle that's a different animal...

All's i've ever done for the past 25 years is line up the rear swingarm index marks and lock the axle!  Besides even if you did do an intense chassis alignment on an MX bike, it would be all in vain the first time you slam your front wheel off a tree and "slip" the front end within the triple tree. (and all that needs is a swift, agressive boot to the front wheel to correct)   :)
01' KX500
'84 GPz1100
'87 GSX-R  750
'06 HD Fatboy
'73 Kawi H1
'03 CRG KX500 Shifter kart

Offline kxpegger

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Re: Front and rear alignment
« Reply #3 on: April 19, 2009, 01:52:00 AM »
OEM manuals show the proper offsets when lacing wheels. I leave most of the front bolts loose except the top set of triple clamp bolts and the axle pinch bolts just slightly snugged up. I bounce the front end up and down a few times without the front brake on then torque all the triple clamps. I then bounce the front forks up and down again with the front brake on, torque the right side axle pinch bolts, then axle, then left side axle pinch bolts. I inspect the brake rotor to make sure it's not dragging and give the front end a close visual to make sure my eyes think it's straight too!

As far as your quarter inch goes I've seen tires where the tread pattern (Maxxis) is offset on the tire carcass by that much so it may not be wheel offset, bearing or a spacer problem just a cheap tire. I'd try checking the wheel spacing from the rim not the tire and see where you are at.

As far as how much all this matters and how much it effects handling I really don't know.
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"05" RMZ450, "08" KX500AF "11" KTM 450SX-F "12" KTM 250SX "15" KTM450SX-F