Clunk When Braking.

[Alastair]

I have a K3s. When braking anything other than moderately hard I get a clunk and a bit of movement from that from my days as a cycle mechanic feels to me like the head bearings being either lose or well passed their best.

Doing a search on head bearings however has revealed the standard SV clunk/knock when hitting potholes etc. This happens to me too and is the same sound/feeling as when braking. When stationary if I apply the front brake hard and rock the bike I get the same clunk, that's the head bearings right?

I don't have any workshop manuals but do have the manual that comes with the bike, haven't looked but I doubt the how-to is in there.

Can anyone tell me what I need to do to tighten it up a bit or point me to a link? Any special tools required?

[Spanner Man]

Good afternoon.

Sounds like the head bearings, or possibly the brake disc rotors moving on their mountings. You don't say what mileage your bike has done, but it's not unusual to see knack...ed head bearings at low mileages due to a lack of grease used on assembly......I personally think that the Jap bike industry budget for grease is one tin a year & they share it!:D

Adjusting head bearings is really a matter of 'feel'. Loosen the headstock nut & the bottom yoke pinch bolts, then rotate the notched adjuster ring located below the top yoke in a clockwise (viewed from above) direction...Assuming you haven't got a 'c' spanner, use a slim punch & a small hammer. Use caution for the adjuster ring is made from alloy, & easily damaged....Move it small amounts at a time, & certainly don't bash the thing until it goes tight!....I usually keep on rotating it until I feel a touch of resistance. Then tighten the headstock nut, followed by the bottom yoke pinch bolts.

Make sure your headrace bearings don't feel notchy when turning the handlebars from side to side, sometimes this is difficult to detect. Any hint of a notch & it's replacement time I'm afraid.

Cheers.

[Biker_Billy]

I have the clunk too - think its the LH brake disc which moves on the mounts a little - only forward to back, not side to side.. never noticed it whilst riding, only when manoevering the SV in the garage.

I really should get it looked at...

[Alastair]

Good morning Spanner Man, thanks for the detailed reply.

Looking at the bike this morning the brake discs do indeed move on their mountings when I rock the bike when stationary. Is that normal? Floating discs?

I think I'll have a go at tightening the head bearings anyway just to make sure. When you say pinch bolts on the bottom yoke you're referring o the two bolts on each side that hold the forks in place, correct? Also, there are what seems like two notched adjusters under the top yoke with a washer in between. Do I need to turn both clockwise at the same time, are they actually one adjuster that look like two or should I be loosening the top then tightening the bottom one and then the top one back up to hold it in place, like on on fashioned push bikes?

Thanks again for the advice.

PS - it has nearly 30k on the clock :oops:

[Baz M]

My K6 has similar symptoms when rocking it with the front brake on. Thought it was the forks or head bearings, or the discs mounts or even the pads in the calipers. My mountain bike does the same and the headset is spot on; just play in the forks / brakes so i'm not worried. SV has done it since brand new and never got any worse. Never had it checked out as I'm under the impression that most pointy's do it. Let me know if you source the problem, it's interesting. Good luck!

[2mths]

I had a small clunks I could feel more than hear. A friend diagnosed it as loose headstock bearings and tightened something along the lines of what spannerman said. It did fix the problem.

He said that it was an unusual fault to get on 2 y.o. bike and that normally if it was tehre the bearing are knackered. However mine was ok. I think though what happned with mine was a previous owner took the front end apart but when they put it back together they didnt' do it up tight enough.

My point was more that in my case I couldn't so much hear as feel the clunk.

[Spanner Man]

Evening all.
Good to hear that you're sorted 2mths....Alistair, I must have eaten too much beef in the 80's as I had forgotten that Pointies have the double adjusters that are locked together.:)

Sometimes you can rotate the adjusters without separating them, effectively rotating them as one. If not then they have to be separated & unless you're lucky you need the special tool for this & you have to take the top yoke off which is a bit of a pain.
The bottom ring obviously does the adjustment part, and one still does it by 'feel' The official torque figure for the top ring is believe it or not 80nm which is a touch excessive if you ask me....(On Hondas with a similar set up this figure is 25nm).....I think that as long as they're firmly locked together it's good enough, as I can't see them going anywhere once the steering stem nut is done up. Torque for the stem nut is 90nm. & yes the bottom pinch bolts are the ones in the bottom yoke that hold the forks in place.

As to your brake discs, a little bit of movement after that mileage is normal, providing the side to side movement is still minimal...I usually resort to my patented 'clunk test' which is, if I can make an audible clunk 9or clonk) when trying to rotate the disc rapidly in both directions with my hands it's time for new discs.

Cheers.