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Rear axle alignment problems 500 exc

By Dansmith1965,
in 250-530 EXC-F/XCF-W/XCR-W

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Dansmith1965

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So am I the only one who struggles to evenly align the rear axle on the 500 exc? Every time push the spacers blocks FLAT against the 10 mm bolt heads and begin to tighten the axle nut, the spacer block on the nut side wants to twist a tiny bit and it ends up changing the alignment a small amount. I hate having everything lined up perfectly, the chain tension perfect, then go to tighten and the block moves. It seems like a simple 5 minute install turns in a 30 minute tighten and loosen contest. It doesn't matter if I push the tire from behind, because the block usually twists just before I reach the final torque of 59ft lbs.

The only thing I can think might help would be to apply some grease between the block and nut. But I'm not sure if that would change the torque value in any way.

Last, the lines / mark system for comparing the position of each side is kind of crummy. Couldn't Ktm come up with a little better system?

Edited by Deepseadan
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oldfuddy

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Try not to over think it. It's good to be as perfect as you can with your maint habits, but at the end of the day it' s a dirt bike with knobbies and a hair off won't be a safety issue IMO. 30-mins is several laps or two beers depending on what you're doing, either way its wasted time you can't get back.

I "kick" the back of the tire as I tighten the nut. I don't torque it though and yes I probably should, but 40+ years of habits are hard to kick... get it... kick? Oh well, I digress....

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biggziff

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Try not to over think it. It's good to be as perfect as you can with your maint habits, but at the end of the day it' s a dirt bike with knobbies and a hair off won't be a safety issue IMO. 30-mins is several laps or two beers depending on what you're doing, either way its wasted time you can't get back.

I "kick" the back of the tire as I tighten the nut. I don't torque it though and yes I probably should, but 40+ years of habits are hard to kick... get it... kick? Oh well, I digress....

There are things on a dirt bike that one should try to get perfect.  Chain tension and alignment isn't one of them.

 

?

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Mikek671

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Before you tighten the chain put a 6mm or small open end wrench under the chain and spin it on to the rear sprocket - it will pull the axle tight against the adjusters while you tighten the nut.  I do not go by the marks when adjusting anymore, use a dial caliper and measure from the back of the block to the back of the swingarm, seems to work better for me.

Edited by Mikek671
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BillDirt1

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So am I the only one who struggles to evenly align the rear axle on the 500 exc? Every time push the spacers blocks FLAT against the 10 mm bolt heads and begin to tighten the axle nut, the spacer block on the nut side wants to twist a tiny bit and it ends up changing the alignment a small amount. I hate having everything lined up perfectly, the chain tension perfect, then go to tighten and the block moves. It seems like a simple 5 minute install turns in a 30 minute tighten and loosen contest. It doesn't matter if I push the tire from behind, because the block usually twists just before I reach the final torque of 59ft lbs.

The only thing I can think might help would be to apply some grease between the block and nut. But I'm not sure if that would change the torque value in any way.

Last, the lines / mark system for comparing the position of each side is kind of crummy. Couldn't Ktm come up with a little better system?

 

A scale works good but I use calipers.  Tighten axle nut till spacers touch inside of swing arm, now give it a 1/4 turn.

This will create a little resistance when jacking the axle back.  Then I tighten axle nut, now I make sure jack bolt is snug against the block and tighten the jam nut.

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Spud786

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The final test I use is rear sprocket chain side to side play, you want a little play on both sides, keep spinning the wheel stop and retest.  always put a rag in the rear sprocket and rotate the wheel backwards this keep the wheel forward when you tighten the axle, and keep in mind a fully torqued axle , will read differently than one thats half torqued.  when testing your specs.

Edited by Spud786
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Burnrider

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+1 what the guys said about putting something btwn sprocket and chain, to pull wheel back to axle blocks.

 

To align or check chain alignment- you can use a 12" steel rule from a carpenter square and place it flush on the back sprocket. Look straight down and pick a mark or the rule, then look at the rule front and check for the same inch mark. The center slot alone will be good indication. Proper alignment eliminates the chain slap common to KTM's.

 

Here's another way to do it.

10778981466_bbc3f5051c_z.jpg

Edited by Burnrider
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Dansmith1965

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The final test I use is rear sprocket chain side to side play, you want a little play on both sides, keep spinning the wheel stop and retest. always put a rag in the rear sprocket and rotate the wheel backwards this keep the wheel forward when you tighten the axle, and keep in mind a fully torqued axle , will read differently than one thats half torqued. when testing your specs.

Good idea with the rag. I'm going to do that next time.

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exIT

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A scale works good but I use calipers.  Tighten axle nut till spacers touch inside of swing arm, now give it a 1/4 turn.

This will create a little resistance when jacking the axle back.  Then I tighten axle nut, now I make sure jack bolt is snug against the block and tighten the jam nut.

You are placing a great deal of confidence in the quality of the swingarm casting.

 

Unless the ends of the casting where you are measuring from was a machined surface (or a datum surface when placing the casting in the machining fixture) cut parallel to the pivot pin bore, you could be off a considerable amount.  The only way to insure accurate alignment is to use a tool that measures the distance from the swingarm pivot to the axle centerline.  Measure the distance on both sides of the bike and you will have a very good alignment.

 

All that said, I simply use the cast marks on the swingarm.  Close enough for dirt bikes.  This isn't rocket science.

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BillDirt1

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You are placing a great deal of confidence in the quality of the swingarm casting.

 

Unless the ends of the casting where you are measuring from was a machined surface (or a datum surface when placing the casting in the machining fixture) cut parallel to the pivot pin bore, you could be off a considerable amount.  The only way to insure accurate alignment is to use a tool that measures the distance from the swingarm pivot to the axle centerline.  Measure the distance on both sides of the bike and you will have a very good alignment.

 

All that said, I simply use the cast marks on the swingarm.  Close enough for dirt bikes.  This isn't rocket science.

1:  First of all, I wasn't quoting you.

2:  I'm aware of the swing arm to axle measurement.

3:  You just contradicted yourself.

4:  Suit yourself.

5:  :moon: ? ?

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