Ideas Please, CBR250rr squirming

[Vapor]

Hey Everyone,

I have a bit of a difficult question...
My CBR250 used to be feel really stable at 100k and above, but just recently it has felt like it is almost squirming a little at those speeds, almost like im giving the handlebars a bit of a wriggle. Its a bit worrying to be honest.
I have checked what I thought was the obvious, The wheels/swingarm bolts etc seem to be done up ok, front forks etc seem ok.

Any ideas on what to check.

Cheers

[xwhatsit]

Hey Everyone,

I have a bit of a difficult question...
My CBR250 used to be feel really stable at 100k and above, but just recently it has felt like it is almost squirming a little at those speeds, almost like im giving the handlebars a bit of a wriggle. Its a bit worrying to be honest.
I have checked what I thought was the obvious, The wheels/swingarm bolts etc seem to be done up ok, front forks etc seem ok.

Any ideas on what to check.

Cheers

Well, in the Haynes manual for my bike (not that my bike is anything like your bike), it said if I get instability at speed, that you should check the swingarm bushings. Put the machine on the centre stand (can you do that?), so the swingarm is free in the air, then try and wobble it side to side. If there's any movement whatsoever, fit new swingarm bushings.

It also mentioned wheel balancing. I would've thought though that this would manifest itself through much more vibration.

It's not something silly like tyre pressures? When I first got my bike back out on the road after rebuilding it, the tyres were all pretty low, and I noticed some strange straight-line stuff like you mentioned.

[Vapor]

Thank Xer ;)

I haven't got a centre stand for it, but I did try wriggling the front and back wheel, and didnt seem to be any movement :) Also, I did just change the tyre pressures to 32 front 34 rear, does that sound ok? I weigh about 73 Kgs.
It just seems strange, I have only had the bike about 1 month and its only just started feeling a bit funny at speed.

I really appreciate any help

[beyond]

Ok, there's a list of things that can cause this.

1. Steering head bearing loose or worn. You need to get the bike off the ground so the front is free and then grab the front wheel and try and rock it backward and forward and see if there is any play and/or the front end turns from side to side easily without binding or grabbing.

2. Wheel balance as mentioned already

3. Front axle sufficiently tight and not loose or worn.

4. Bar ends missing on the one or both of your handlebars.

5. Tread evenly worn on both side or middle of your tyre or else you have an alignment problem. It's easy to misalign the rear from the front when doing a chain adjustment. Don't always go by the chain markers on the swingarm as they can be out from the factory. Always work on a the turns by counting the flats on the adjuster nut and keep it the same for each side.

6. You haven't hit a big bump lately and does the front judder at speed?

6. You'v eaten too many pies :)

7. Summary. Think about what you have done to the bike before the problem started. When was the last time you rode the bike and it was ok? What did you do between then and now to cause this problem to happen? Therein lies your answer.

[beyond]

(Standard pressures) For the CBR250
Front : 30-32 psi
Rear : 34-36 psi

[Vapor]

Thanks Beyond,

I can't recall anything out of the ordinary that may have caused the issues. I will however check all those things you have listed, thanks again.

Will let you know how I get on

[beyond]

Cheers mate. Be interested to find out what it was when you find out :)