OZZY
Needs a job
need guberment cheese
Posts: 3172
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posted June 15, 2003 05:02 AM
Hmmm, looks like there are 2 schools of thought here.
One school is lining the sprockets up to allow the chain to track on or near the centerline of the sprockets.
The other school is aligning the front and rear wheel to track on the same centerline.
Neither way is wrong, just that each bike is different and what is in alignment on one bike is incorrect on another due to those nasty manufacturing tolerances.
I have aligned many mechanical things in my 30 years as a millwright, some of it very big (200 tons), some not so big (2-3 oz). What I personally believe is that when an object is in motion the axis's (is that the plural of axis?)of travel must be on the same centerline.
In the case of a motorcycle, both the front and rear wheels AND the front and rear sprocket are of importance in this regard.
The question to me is which is more important because the alignment adjustment will only allow one of these two conditions to be adjusted.
The alignment of the wheels is foremost in my mind. Not only could hi-speed stability be affected, but also the turn in rate (effort also) of the steering. With offset in the wheel alignment the bike will tend "drop in" to a turn going one direction and have to be "forced" to go in the other turn direction.
The anal way to do the alignment that I use is to dismount both tires, then reinstall the wheels onto the bike, letting the front rim rest on the floor, and the rear of the bike supported on a race stand.
The reason for this is that I have used a dial indicator on wheels with tires mounted to them and have found that most tire sidewalls do not run true, and can be as far off as 3/32 of an inch, which gives a false reading of alignment.
Next is to use the string method, which is very similar to Vince's "ladder" method and find the true centerline alignment of the 2 wheels. Now I mark the swing arm with correct lines if needed.
At this point I take a measurement from the centerline of the swing arm pivot bolt to the centerline of the rear axle and record this number. Then compare this number with any offset that the string method mark adjustment caused. IF these 2 numbers agree you have a good frame/ arm assembly. IF not, well there isn't much you can do about it cuz the swing arm pivot location is not perpendicular to the centerline of the wheels. (You could fix this with lots of $$)
Once you know the swing arm pivot dimension offset if any, you can easily check the alignment with a tool such as DaveinDaytona posted.
The only way to get the chain to run true and centered on the sprockets is to move the sprockets into their own centerline without moving the rear wheel. This requires machining of the countershaft sprocket spacer (if the front sprocket needs to go right) and or the machining of the rear sprocket carrier (if the rear sprocket needs to go to the right). The front sprocket can be shimmed to the left to center the alignment is you don't or won't or can't afford to machine the rear assy.
Its hell to be anal.
  
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TurboBlew
Moderator
BUSY DOING THE SCHIAVO
Posts: 4590
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posted June 15, 2003 08:08 AM
Factory race and privateer teams spend thousands of $$ on suspension and wheel setup. Power is nothing with control.
quote:
I use the stock marks, they work fine. No need to over engineer this guys LOL the stock marks work fine at 204 mph...
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