Front end "chirp"

[CleoBen]

'99 1100 RT, 19000 Miles, new (third or fourth) owner.

 

When hitting a bump, I hear a "chirp" from somewhere in the front end. Heard at slow and fast speeds. Not heard when on center stand and leaning forward, compressing front forks. Seems to be more impact-related, occuring during speed bump crossings, road variations, potholes, etc.

 

Any suggestions appreciated on where and what to start looking at.

 

Thanks!

 

CB

 

 

[rlc]

I have a 99 1100rt also, 136,000 miles. Got it 3 months ago, it has the same chirp you are talking about. I,m thinking maybe worn buttons on the brake rotors,not sure though. I hope someone with more knowledge of these bikes can answer the question.

[Rob L]

Is there evidence that the fender is hitting the bottom of the fairing? Many of these bikes will show a T shaped scuff mark on top of the fender because of the contact. I have repainted the fender 2 X and it still occurs even with Ohlins shocks.

[Clive Liddell]

Also on the same model RT I get a small rubbery squawk only once per ride as the bike traverses a change of angle between my drive and the sidewalk - 1st start of the day only.

 

I think it could be the lower front "shock" mount in my case - if I ever remember I will squirt a little water over it before riding off to check for a reduction in sound...

[realshelby]

I am betting on the lower front shock mount. Even though the bolt is tight there can be a little rotation on the bushing. If it is rubbing the metal bracket holding the shock it will give the noise you describe. I shoot a little 3M spray grease on mine occasionally.

[Chip]

To rule out the bobbins on the rotors, grab hold of the front brake rotors and try to wiggle them up and down from one side of the rim to the other.

 

If you can move them forcefully such that they make a sound as you go from one extreme to the other, then the "chirp" over bumps is probably caused by the worn out bobbins.

 

You can get the bobbins from Motobins in the UK. They ship fast and reasonably priced.

[CleoBen]

Is there evidence that the fender is hitting the bottom of the fairing? Many of these bikes will show a T shaped scuff mark on top of the fender because of the contact. I have repainted the fender 2 X and it still occurs even with Ohlins shocks.

 

Can you post a picture of the scuff mark? I am not 100% sure where to be looking.

Thanks,

 

[upflying]

My vote is the brake bobbins too but 19,000 mi is a bit low for them to be worn.

[philbytx]

Remove bottom bolt on front shock, lube it and replace and tighten it

[CleoBen]

No rub or scuff marks on the fender parts. The front rotors seem to have some free play on the bobbins. Mostly side-to-side movement, and I can see the bobbins moving, but not sure they're loose enough to be rattling.

 

I'm assuming the side-play is normal?

 

CB

[Mark K]

Side-play is normal.

[GordonB]

Grabbing the rotors and turning left & right (like a car's steering wheel) will result in some play but not much. My LD says to do this test after a ride 'cause the tightness of the bobbins increases as the rotors warm up, so if they a really loose while warm then you may have a problem.

In and out play off axis is normal.

[Chip]

Another way to rule out the bobbins is to ride over a bumpy road that you know causes the chirp.

 

Then, ride over it again, squeezing your front brake lever (slight amount of front brake). If the chirp goes away, it's most likely your bobbins.

 

So...if you can wiggle the rotors and the chirp is gone after the above test, get some bobbins.