Triumphrat

delrazor · 04-19-2009, 01:45 AM

Hi, since owning my t120 (71) I have taken a few steps to try and get the bike to track straight.
1) new seals on forks (more because of the oil leaking)
2) Followed the instructions on aligning the front forks
3) new (old) front wheel
4) matching the distance from rear axle centre to swingarm spindle centre.

Today I lined up string lines all over the place and it seems ok, but when riding I have to lean right about 10 inches (at the shoulder) to get it to track without holding the handlebars.

I have been told this wouldn't effect my tracking, but one thing I dont get is the front wheel sits in the forks unevenly. Probably 5mm to the left of centre (10mm difference in the gap between the tyre and the forks). I have ordered a new spindle and spacers but have also been told it is the right spindle (and have seen it spinning in a lathe perfectly).

I guess I may have to try and staighten the swingarm if it is deemed bent.

my questions for the oracle...

1) can anyone list the genaral causes of tracking issues such as mine.

2) is htere a resource for how to straighten a swingarm?

3) what are my chances of it being in the frame itself...... and how do I check this?

Phew!

derek

TBS · 04-19-2009, 06:30 AM

Your front wheel should be sitting in the middle of the forks, so I would imagine the wheel has been built with the wrong offset as if there is 10mm difference between the tyre and the forks, that is enormous.

pookybear · 04-19-2009, 11:40 AM

delrazor,

Wow, is all I can say ten inches of lean for going strait eh.
Something is way wrong.

First, you should be able to align the bike and get it to track
straight, out of align bike do funny things in corners. Like taking
a right corner well, but with effort and some shaking in lefts.
With the lean you are discribing it seems like your bike is already
trying to go around a corner.

Loosen all of the front end bolts again and retighten back in
the correct order, covered in the manual, realign the bike
and see if that helps.

If no good, the manual covers the measurements for checking
both the swing arm and the frame to see if it is bent out
of shape. Also check the yokes to make sure they are not
bent as well. This will show up as the fork legs will not be
parallel with each other.

Pookybear

delrazor · 04-19-2009, 10:28 PM

thanks mate,
I'll wait for the new spindle, rebuild the front wheel hub and work from there.
Next hope would be swingarm.

derek

delrazor · 04-20-2009, 08:14 AM

update
Today I measured a lot of stuff.
I made a measuring tool, put the bike on the centrestand, got it so the swingarm pivot was equidistant from the ground then started measuring.
Everything turned out ok at the back end.
I also measured the amount of offset in the front wheel and I may have been a little dramatic yesterday. It is 5mm different, meaning I need to space it 2.5mm more to get it central.
Also the amount I must lean to let go of the handlebars is about 3 inches at the shoulders.

I dont know enough about bike geometry to know if an offset (yet straight ) front wheel can caust balance issues.

cheers
derek

TBS · 04-20-2009, 12:05 PM

As I said before you need the front wheel in the centre of the forks, but if the wheel offset is correct, (give it to your wheel shop to check) you can adjust it by removing the bearing from the brake side and shimming it out with a spacer to move it one way or reduce the thickness of the existing spacer to move it the other way.

DerryUK · 04-20-2009, 01:30 PM

I like these articles by Rob Tuluie, sadly I can't find parts one and two on the same site.
http://www.motorcycle.com/how-to/cha...sics-3444.html

http://www.rg500delta.com/RG500_chas...nt%20part2.pdf