wheel alignment an easy way?

[stevo as b4]

Popping the rear wheel back into my KMX with the new tyre on, I realised there are no alignment marks on the swing arm (probably been power coated over).

Anyway, I measured the distance between the axle spindle and the end of the swing arm both sides, and it seemed to be about the same. But the swing arm is not perfectly symmetrical on both sides, and the new wider rear tyre, is closer to the RHS than the left. I have a feeling I might be a fraction out with the alignment, but can't really tell by eye.

I know about the two pieces of string method and using a long straight edge to mark the ground in line with the rear wheel, and measure the distance to either side of the front wheel etc.

But I atm have a bad back, am feeling sorry for myself, and I can't do the alignment check with the bike on a stand, as it doesn't sit perfectly level on the frame rails under the motor.

Tl:dr, Until I can get a mate to come round and hold the bike upright and level while I mess around with straight edges and tape measures, am I stuck, or is there a trick I can use?

Have thought about bolting a bit of 3x2 to the garage wall and then strapping the bike to it using a spirit level, but I'm over thinking things I think, and I also thought that wheel alignment via making the adjusters exactly the same length, still does not take into account if the frame, swingarm, or forks where all 100% straight and in line with each other?

[gavcarter]

measure from swingarm pivot bolt to rear axle, the swingarm pivots will be perfectly 90 degrees to the frame ( provided the frame is not bent so it is a good reliable point to use). This will remove any confusion from un-symmetrical swingarm sides

Measure Centre to Centre, dont put the tape up against either side of the nut or bolt as chances are the other side will be different size

[G]

You don't really need the bike to be level, just the front wheel to be pointing straight forward.

What about propping something under the sidestand so it stands pretty much upright, if that's an issue? Do it next to a wall on the other side so it can't fall far.

[Beehive Bedlam]

My usual method is fraught with possible inaccuracies but I line it up best I can with my unmitigated hands then put it into first gear whilst on the centre stand and determine whether it is aligned by watching the wheel go around.

I also measure the adjusters with a steel ruler on both sides and count the threads to double check.

One final method is doing as gavcarter suggests; I use a welding rod with a rubber o ring on the end to measure each side making sure they're parallel.

No matter which method you choose trying to achieve perfect wheel alignment is something of a headache.

[Wull]

I use to just go by the marks on the swingarm and if they were close enough then I was happy,but now I use a ruler and measure like you do from the edge of the adjuster block to the very end of the swingarm and I'm happy enough with that.
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"Scooters are for men who want to ride motorcycles but prefer to feel the wind on their vaginas"

[jjdugen]

No-ones mentioned this, but.....
If you have a stand (or a winch) and can get the back tyre off the ground, you can use this method.
Get the chain slack right then spin the wheel, observing the sprocket teeth on the links. Aim for a consistant teeth in middle of link adjustment, allowing for any slight warp in the sprocket. I would far rather have a correct chain run than bother about a mill or two of wheel miss alignment. I've seen side-links squeezed off by a sprocket out of line.
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The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?

[Pete.]

[Nobby the Bastard]

Get two long pieces (the length of your bike) of wood/metal that you have confirmed are straight.

Push they against the rear tyre when the bike is upright. you'll be able to see if the rear wheel is aligned properly because they will exaggerate miss-alignment up by the front wheel.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[G]

[jjdugen]

You are spinning the wheel to move the chain over the front sprocket. The front sprocket is in line with the axis of the motorcycle. The rear sprocket should also be in line with the axis of the motorcycle. If it is not, then the wheel is out of line... or the swinging arm / frame is bent. (Spoken in that tone of sadness at peoples utter lack of mechanical cognisance).
____________________
The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?