My brother has a '00 CBR F4 that's acting fairly odd.

It was working fine and as of a couple days ago, but now it feels like it's got a flat tire.

The tire pressures are correct and there are still balance weights on both the front and rear tire. He hasn't done any burnouts or stunting.

Basically, when driving straight, it mostly feels fine (though around 50 mph you can feel it "hiccuping". However, if you're turning the wheel or leaning for gradual turns, it starts bouncing/hiccuping closer to 25 to 30 mph.

From what he's described it got really "heavy and hard to manuever" while he was riding in Provo Canyon. He thought it was a flat, and said it felt like it was getting "low" (described as the front tire losing pressure). When he stopped it was fine, but he did add some air to be on the safe side. But it's still happening.

The chain does need some tightening, but other than that, I don't really know what would cause such strange symptoms...


Does that make any sense?
Does anyone have suggestions on what the problem could be?
Or
Does anyone know some GOOD shops in the Provo/Orem Utah area?
(Monarch Honda and Escape Motorsports haven't been good experiences for us so far...)

Thanks!

(Edit: I thought it was a '99, but he says it's a '00)

 

Deffinitly tighten the chain and lube it, check the headset bearings.