CB400 SUPER 4 VTEC 1 screeching

[hotwasabi]

Hi, can anyone help me?

 

I've just bought a VTEC1. It runs fine but when cruising at low revs(3000-4000) there is SOMETIMES a screeching/grinding sound from the front of the bike. It happens when going straight and without applying and brakes. When riding at 6000revs+ it seems to stop.

I have no idea as it is on and off. Any ideas would be greatly appreciated.

Wheel-bearings?Brake pads?

[Ah Pek]

Have you check your brake pad?..not necessary that when you brake you get the sound...check mounting of your caliper assembly too.

 

Likely the wheel bearing.

[bigboystoys]

When the grinding happens, does the bike slow down? To check, when the sound came on, clutch-in and coast (don't apply brakes). You may want to try this when your brakes are cool (first thing in the morning?) This is isolate that jammed brakes (if there's one) from the system.

 

So what happens if you tried all above and your bike is slowing down more than what it normally feels? Most probably you have a seized wheel bearing. You can still ride it around; it just consumes more fuel and wears the bearing even more although it doesnt really matter anymore since the bearings are gone anyway.

 

I just had a front wheel bearing seized couple of weeks back. It was so bad that when I removed the front wheel, the outer and inner race were separated already. The steel balls were completely dislodged from the bearing and they were rolling around inside the rim!!! Haha.

 

Anyway, what I felt before the bearing replacement was the grinding sound and severe vibration that can be felt from the handlebar. After the bearing has collapsed internally, I can't even push the bike around!!

 

You have 2 choices for pricing. Go to bike shop (donno how much they'll charge you, my guess is $50-$60??). Or you can DIY like I did and it cost only $30 for 2 bearings and 2 seals.

 

Hope the above helps.

 

[hotwasabi]

Thanks for the help guys.

 

The bearings seen ok as its just passed the roadworthy test and there doesn't seem to be any play in the wheel. Also pushing it is not stiffer than normal.

 

After jacking up the bike and spinning the wheel, the sound seems to be coming from the brakes. The pads are only half worn and the guy in the shop tells me that the and the callipers and pad's are both Honda's original product, so it can't be helped.... apparently!

 

Any ideas how to stop it???

[bigboystoys]

It's funny if both the calipers and pads are Honda Original product and they still make sound. Are you very sure that the brakes are the problem? Did you remove the brake pads and spin the wheel?

 

If you can spin the wheel freely (brakes not applied) and yet it still makes noise, it still can be due to wheel bearing problem.

 

If you're sure it's the brakes, cheapest option is to change pads.

Let us know if you solve the problem.

 

[Ah Pek]

Any ideas how to stop it???

 

Sprayed WD40 or 3M three in 1. Spin the wheel. Splashed or hose off with water. Dried with a cloth or with compressed air if you have access to one. Ride slowly and apply brake as you go to burn out the slipperyness.

 

The idea is to get the brake pad dust taht has accumulated from over a period of time. Thye harden and are very stubborn and trapped very tightly in the assembly tight space. When it get moist..it does 'generate' those irritating nose.

 

Worst come of it...disassemble it and clean away all stubborn residue you find in between moving parts. Good luck.