Bike Shakes/Vibrates at low speed Braking...?

I Checked to see if there were any similar posts but didn't find anything.....
Ok so here's the situation. Was approaching a red light so I pulled in the clutch and started using the front brakes to slow down....was at around 10-20kmph and the front end of the bike started shaking and the vibration came right up the handlebars.

I figured that I must have hit a grated part of the road, and left it at that...and the next day it happened again. Same scenario stuck in traffic - can't get out of first gear without hitting a red light. Engage the clutch apply the front brakes and away she shakes right up the bars and vibrates the mirrors ... around 7-12 kmph/4-7 mph. I looked at the road the second time it happened, and it was fine. The shaking stops if I press the rear brakes.

(No wheelies ever and I don't ride the brakes hard...)

2009 VFR
6000 KM ->3700 ish miles

 

Warped rotors? Loose steering head bearings? Loose/worn wheel bearing? Axle nut loose? Caliper bolts loose?

 

Do you use a silicone cleaner or detailer on the front wheel?
If you get it on the disks it can cause the pads to grab intermittently possibly causing what you experience.

 

Im gonna go with either the wheels need to be rebalanced or its time for new tires. Shouldnt be the stem bearings since you have very lttle miles and you usually feel a thud when those need to be replaced.

 

Hmm, off the top of my head here are some things to check:

Warped rotors?
- check this by putting a rotor down on a known-flat surface like a piece of glass & running a feeler gauge around the edges. Not the most precise way but good enough for most things. Probably not warped rotors, or you'd feel the same shaking at any speed, but good to check them if you can't find anything else on this list.

Worn wheel bearings?
- check em same way you'd check an older car's wheel bearings.

Axle nut loose?
Caliper mount bolts loose?
Rotor bolts loose (unlikely)?
- check 'em with a torque wrench, based on book specs.

Front brake piston sticking?
Cleaner on the front rotors causing the pads to grip intermittently?
- Try using CFC-free brake cleaner to clean your pistons, rotors & pads. Be careful not to get the spray on any painted surfaces.

Crud in the master cylinder/lines/dirty fluid?
- Bleed the brakes to make sure they're not gummed up. Unlikely to cause the specific symptom you described but a good annual maintenance task and problems here could mask other problems. So I suggest at least checking that the brake fluid is OK when doing most brake maintenance. Be careful not to spill any on painted or plastic surfaces (use lots of big towels to cover the front of the bike).

Worn or broken or brake pads?
- Should be able to visually examine these.

Loose steering head bearings?
- Check torque and side-to-side play like the manual says.

Notched or damaged (rusted) head bearings?
- Unlikely but I'd check them if nothing else comes up wrong. Usually you can feel this just in normal riding.

 

Checked the following
Front Rotors -Straight
Handle Bars and Steering-Straight
Steering Head bearings-OK
Front Wheel bearings -ok
Brake Pads-fine

I'll try a good thorough cleaning of the pistons this weekend.

 

the fact that it stops if you apply the rear brake, suggests you need to look at the REAR of the bike, not the front for the cause of your issue. its entirely possible, and has happened before, where a rear end vibe transmits up the frame to the bars. look into it. chain slack, as well as condition, sprockets for unusual wear/damage, wheel bearings, just as the front end. possible trans problems as well.

look at EVERY component, dont just look at what you suspect is at fault, look at ALL of the parts. it may be something seemingly unrelated.

 

Show us a picture of your front tire, is it cupped in the center?

 

His bike is pretty new 09? Giving you this much protest are you under warranty? Is your bike an ABS model ?

 

Guys,
Thanks for all the input, I removed the chain and cleaned it and somehow the problem resolved itself....

 

shouldn't be a problem with dirty pistons
You say the rotors are straight, how did you check them? What you are really looking for is if they are perfectly flat, and don't have any low or high spots or any spots that are discolored which may mean they have a hot spot or some chemical spilled on them

have you checked the balance on the front wheel/tire? You might have hit a pot hole that bent it or even just lost a weight that was on there.