A forum for owners of Yamaha TTR250 trail and enduro bikes!

jasparach · Senior Member

TTR unsteady at 50/55 mph

JOHNYBOY · Super Guru

you will have to spin the wheels see if they are true check spokes wheel bearings head stock bearings swing arm bearings linkages etc tyres for bubbles swelling etc you must be able to see something if you look close enough john

TTRfan · Super Guru

As John says, but most likely cause is loose or worn headstock bearings.

Get the TTR on a stand with the front wheel off the ground and grab the forks and see if you if have any back and forth movement.

If you do have play, I should be obvious if this is headstock bearings or worn bushes in the fork legs.

Before you jack it up though, check the front wheel bearings for play.

If all of that checks out then its down to doing the checks that John suggest at the rear.

Brian

mossproof · Super Guru

I read somewhere that poorly set compression and rebound can have some nasty effects - have you checked your suspension settings?
Simon.

jasparach · Senior Member

Thanks for the replies chaps. I must check the head stock bearings as everything else seems to be in good order. There is only 6k miles on it and very little of that offroad and it has had very little use really so there is nothing worn that badly on it. I suppose a fork oil change wouldn't be any harm either. Thanks for the input.

John

ttr steve · Super Guru

I had a go of my mate bozz's TTR and he had some tyres called Mitas Co2's ? Scared the life out of us on the road and he has changed them.

What tyre have you up front?

TTRfan · Super Guru

ttr steve wrote:
I had a go of my mate bozz's TTR and he had some tyres called Mitas Co2's ? Scared the life out of us on the road and he has changed them.

CO2s are brilliant on and off the road biggrin biggrin biggrin

Boz probably put the tyre on upside down

MITAS CO2 - 26 August 2009 002.jpg

jasparach · Senior Member

Hi Steve, runs an ordinary MX tyre on the front.

TTRfan · Super Guru

If the steering head bearings etc check out OK, why not swap the front wheels over with your older TTR just to see if that makes a difference?

Don't forget to use the axle and spacer from the whitey and tie back the loose speedo cable end out of harm's way if you try this.

Brian

ttr steve · Super Guru

TTRfan wrote:
ttr steve wrote:
I had a go of my mate bozz's TTR and he had some tyres called Mitas Co2's ? Scared the life out of us on the road and he has changed them.
CO2s are brilliant on and off the road
Boz probably put the tyre on upside down

The rear is great, it was the front I was talking about.

leigh · Senior Member

I have the same symptoms on my bike. Not as bad as it was (after I ditched the ac10 front) but it's twitchy at 80klm plus on the road. The things mentioned above are all ok on my bike. Wheels are balanced as well.

I just live with it.

I've tried different suspension settings and fork heights, nothing has made a massive difference. I started a thread on this a couple of years ago. Can't remember what other things people suggested.

Fronts are Pirelli xc mid hard and my other rim has a d605 on it - they both give the same symptoms on the front.

SAG set at 93mm rear and the forks slid up 15mm - clickers all set standard except the front rebound at 7 clicks out. Lowering link in place.

Leigh.

jasparach · Senior Member

leigh wrote:
I have the same symptoms on my bike. Not as bad as it was (after I ditched the ac10 front) but it's twitchy at 80klm plus on the road. The things mentioned above are all ok on my bike. Wheels are balanced as well.

I just live with it.

I've tried different suspension settings and fork heights, nothing has made a massive difference. I started a thread on this a couple of years ago. Can't remember what other things people suggested.

Fronts are Pirelli xc mid hard and my other rim has a d605 on it - they both give the same symptoms on the front.

SAG set at 93mm rear and the forks slid up 15mm - clickers all set standard except the front rebound at 7 clicks out. Lowering link in place.

Leigh.

I know what you mean Leigh, there is nothing jumping out at me that is the cause of it. Nothing is worn or loose, everything seems fine and in order from what i can tell. Tis a strange one.

John.

-- Edited by jasparach on Thursday 20th of April 2017 08:56:27 PM

-- Edited by jasparach on Thursday 20th of April 2017 09:00:26 PM

ttboof · Super Guru

jasparach wrote:
leigh wrote:
I have the same symptoms on my bike. Not as bad as it was (after I ditched the ac10 front) but it's twitchy at 80klm plus on the road. The things mentioned above are all ok on my bike. Wheels are balanced as well.

I just live with it.

I've tried different suspension settings and fork heights, nothing has made a massive difference. I started a thread on this a couple of years ago. Can't remember what other things people suggested.

Fronts are Pirelli xc mid hard and my other rim has a d605 on it - they both give the same symptoms on the front.

SAG set at 93mm rear and the forks slid up 15mm - clickers all set standard except the front rebound at 7 clicks out. Lowering link in place.

Leigh.
I know what you mean Leigh, there is nothing jumping out at me that is the cause of it. Nothing is worn or loose, everything seems fine and in order from what i can tell. Tis a strange one.

John.

-- Edited by jasparach on Thursday 20th of April 2017 08:56:27 PM

-- Edited by jasparach on Thursday 20th of April 2017 09:00:26 PM

Agree the TTR is interesting to say the least once above 80kmph , nothing quite like passing a road train with the wind under the front guard and the visor on my helmet trying to remove my head .Kepps me entertained
the bike is light and not real stable at higher speeds , having said that tire choice and balance can make it worse .

TTRfan · Super Guru

I run a knobbly (Michelin Comp IV) on the front and a Pirelli MT43 or MITAS CO2 on the rear and the TTR is rock solid at speeds up to and over 70mph.

Just to recap checks:

Check:

Wheel bearings are good with no play and that the wheel runs true between the forks with no more than 2mm run out on the rim.
Steering head bearings are good with no notchiness or play.
Fork leg seals and bushing are good with no leaks and no play in the bushings.
The tyre is perfectly seated on the rim and that it is reasonably balanced with the tyre clamp opposite the valve.

If the TTR passes all the checks then you may have to consider the possibility of a defect in the tyre.

leigh · Senior Member

Hey Brian, definitely yes to all those, mine doesn't move on the road but feels twitchy in the front if you move the bars much, doesn't bother me, in fact i don't notice it anymore, but my DRZ has a very different feel in the front on the road.