Yamaha TRX850 Enthusiasts Forum

ok..

so, I´m riding my TRX and if I take my hands off the handlebars they wobble a bit... well a bit is enough to hold them straight away as I don´t feel safe..

The headsock was a bit loose and sometimes making a knocking sound when goin over potholes, so I have tighten that up and the knocking sound is gone....

unfortunately the wobbling of the handlebars isnt...

any ideas of what can be causing the handlebars to wobble?

you could have damaged the ball races by letting them clatter about you will notice a notchiness when you move the bars from left to right if this is the case ,(at a standstill of course )you may also have overtightened them , also how badly worn is your front tyre as this can also have an effect most bikes do this wobbly thing but if you have dropped the top yoke down the stantions this will also aggravate the wobble,,,,, hope this helps

Ok..

the tyre is in good nick and correct tyre pressure...
I can´t feel any notchiness moving at a standstill...

A bar wobble at around 30mph is a common complaint. Different people have different experiences, and different ideas for causes. Mine used to do it, but I've changed a lot since and it does no more as far as I am aware.

My bet goes on tyre type and wear being the most likely cause. But of course any slack or wear in headstock bearings or wheel bearings may have an influence. There may be other subtle influences such as rear ride height etc

Mine used to do it (years ago) with what appeared to be a "good nick" 120/60 Michelin. Since I've gone to 120/70 Pirellis, never had it happen again.

hmm... will check which tyre my TRX has...

Mine was fitted with well worn Bridgestone 020s when I had the problem.

I'm wondering if "anyone" that uses 120/70s still has this problem. Like I said with my old but still fairly fresh 120/60 it was the classic let go of the bars and about 50kph the thing wanted to shake itself apart. Now with the 70 series, the tire can run a 4hr Endurance race, a full day of trackday instructing and have gobs of rubber hanging off the side and still, none of the headshake.

Those 60 series tires just don't seem to like the TRX's geometry and they were put on because they supposedly looked cool in the '90s. Look at any racing tire today, all have much higher and softer sidewalls than those old "low profile" tires.

I have a picture on here somewhere of the 4hr race where you can see the front tire flattened out under braking entering a downhill right. I couldn't believe it when I saw the picture, looks like the air pressure is way too low but it's not, that's how the new generation tires give so much grip by giving you a huge contact patch through flexible, yet stable carcass structure and soft yet durable compounds. Simply amazing, and the biggest improvement to motorcycles over the last 20 years.

Of course, most Japanese still try to fit 19"~20" wheels on their cars. Pay a fortune for tires that ride like shite and bend those expensive hoops over manholes and railroad crossings...

Found the picture... If your monitor is dark (like my old CRT was) you may need to brighten it up. But look how that front tire is flattened out. I'm still on the brakes here and the front felt like it had plenty more to go (felt like that over 4 hours...). Almost like it was hardwired to my brain.



Mind you that Brembo pump helps too...

Yep I have a 120/70 in front and the problem remains.
Both front and rear are michelin pilot sports, kinda new.

I heard it can be caused by the suspension settings as well.
I just cant get rid of it.

PS. Very nice picture Max, nice style. Nice layout duck up as well.

Duck up?

Max wrote:Duck up?

Yup, im trying not to be rude.

Oh, and here I thought you were talking about me not having my head tucked down and glued to the side of the bike like all the latest generation GP dudes. I was going to blame it on lack of stretching, memories of bias ply tires and my OOOSDA belly...

Forum layout m8.

Dont get me wrong.

Ok guys..

I have checked my tyres..they are:

Front - Avon Azaro 120/60 17
Rear - Avon Azaro 160/60 17

Might be because of the tyre size then?
What do you advice to get when I need new ones? I'll probably go for Bridgestone BT020 as I have on my thundercat but what size?