The TRX900 Project kicks off

[dandywarhol]

That pic looks like the swing arm is pretty much directly in line with where the sprocket would be - making the chain (theoretically) at it's tightest point - it's like my ol' granny's knicker elastic - be even worse when not under power

[coxylaad]

and yet I cant say I felt a great deal of drive line shunt when riding it.

I would argue that the chain would seem more slack at the bottom when under power as it will be stretching the top side of it.

[coxylaad]

Sneak peek at the new paint. It's taken me long enough!





Still a lot of polishing to and some local touch up but given that it's a track bike I may be being a bit OCD about it.

[coxylaad]

Paintwork finished. Not perfect but a blind man on a galloping hoss wouldnt notice







Took it out for its first ride of the year yesterday, what a bike! My new riser plates lift the pegs just the right amount to enable me to move around the bike freely. The ergonomics are now perfect for me. Time to have some fun!

[dandywarhol]

Great job - I've enjoyed the thread - now get that yard cleaned out!

[Tarwetijger]

Awesome!
Is it a track or road bike?
(license plate but no headlight & mirrors - I'm confused. )

[dandywarhol]

That'll be the road testing plate

Although you can get a daytime MOT in the UK which doesn't require lights - often used with trials bikes

[Stu99]

Looks great, enjoy it.

[coxylaad]

That's it, its road legal so I can take it out if I want to. I have the facility to fit rear indicators but as of yet no front ones.
I have a little bar end mirror which to be fair works just as good as the originals
and at some point I will fit some led daytime running lights so I can be seen by the blind people, but first and foremost it was built for the track.

Al, I know the back yard looks like a dump, but there is at least 3 other ongoing projects in those pictures

[coxylaad]

Couple of snaps of the bike in action at Croft circuit last Wednesday:











Great fun. I am now looking into bike setup as I had the rear end spinning up out of slow corners, might have been me and the way I am riding, the tyre looked like it was wearing well and not showing any untoward symptoms, but it did spin up on a couple of occasions and the track temperatures were warm. Tyre pressures were good as far as I could tell. can anyone point me in the direction of some good setup advice? I know its not a million miles away.

[dandywarhol]

Definitely tyre spinning and not clutch slip?

[coxylaad]

Definitely Al, unless clutch slip makes the back end step out to the side!

[davamb]

G'day Coxy,

nice job! Did you do anything to shorten the sidestand? Mine's a bit on the vertical after the front end swap.

BTW, dunno if it's the pic angle or not, but your chain looks a bit tight. Dunno what that'll do to your setup.

[Tarwetijger]

G'day Coxy,
BTW, dunno if it's the pic angle or not, but your chain looks a bit tight. Dunno what that'll do to your setup.

I was thinking the same.
I could be wrong but the swingarm looks horizontal / flat.
I think it should be a little inclined, if you get what I mean. Is your rear suspension working properly?

[cobbadiggabuddyblooo]

With the rear axle alignment with the swing arm pivot, you will probably find the rear end squatting under power out of the corner and causing the problem.
Something I found the R6 shock suffered by the end of each trackday session.
Great for the first 10minutes or so but by the time I was getting to end of each session at 15 minutes I could feel the rear end beginning to break away and back end getting spongier.
With the rear axle below the swing arm pivot point you will find yourself into more of an anti squat position .
Chain angle has a part to play in this too so with a larger rear sprocket this allows the forces upon the back wheel to give more force to pull the swing arm up too.
If the swing arm is longer you will again find more leverage factor placed on things so this all has to play with your linkage and valving on your rising rate suspension.
So even if you change your gearing, moving your axle point forward and back, the 30 odd mm of adjustment available in your swing arm all have a part to play on your leverage and adjustments too and need to be compensated by slight changes to comp/rebound adjustment.

swing arm length from pivot point to rear axle
TRX850 505-530mm
FZR1000 520-560mm
YZF1000R 500-550mm

there is more than likely different relay arms and dog bone lengths on each of these bikes too so all these factor have a part to making your suspension work as designed.