Headstem bearings 07 CBR 600

[Ozboy]

I'm just about finished on my CBR trackbike build so I've rolled the bike down the driveway to feel the brakes/steering and when I applied the brakes, the front end felt like it was going to tuck under the bike.

Theres about 20mm of freeplay in the headstem, problem is, the headstem bolt is tight.

Could the bearings be buggered? Steering is light and easy, no grinding feel. Just a fair bit of movement when applying the brakes.

[darkfibre]

Almost sounds like the top bearing race has fallen out.

[Ozboy]

Where would it go? it may have collapsed. Looks like I'll be pulling the bike apart to find out.

[Stephan]

You can just pull the top triple clamp off and you'll see if the bearing is collapsed...but you probably knew that already...

[Sammi]

Let me know if you need a new bearing. I ended up with a spare when I changed mine

[Ozboy]

Let me know if you need a new bearing. I ended up with a spare when I changed mine

Cheers Sammi, I'll stop sulking and go have a look. ^_^

[Goldmember]

Bugger and you were so close to riding tomorrow Well theres always collie

I hope you get it fixed soon!

[g0zer]

'Theres about 20mm of freeplay in the headstem, problem is, the headstem bolt is tight.'

What do you mean the headstem bolt is tight?

You know its the two c spanner collars that set position/torque to the headstem bearings right?

The top bolt/nut just locks the triple tree down.

Edit: btw in case you havnt setup stem bearings before don't go torquing up those collars. Jack the front off the ground so steering is free and tighten till they start to bind and turn the bars back and forth a few times- if they are still binding great back off between quarter to half a turn (u don't want to set them so exactly they start binding from additional pressure from torquing the head stem bolt).

If they go loose again the races aren't seated properly- repeat the tighten till they bind wiggle the bars trick to re-seat the races.

[Ozboy]

'Theres about 20mm of freeplay in the headstem, problem is, the headstem bolt is tight.'

What do you mean the headstem bolt is tight?

You know its the two c spanner collars that set position/torque to the headstem bearings right?

The top bolt/nut just locks the triple tree down.

Edit: btw in case you havnt setup stem bearings before don't go torquing up those collars. Jack the front off the ground so steering is free and tighten till they start to bind and turn the bars back and forth a few times- if they are still binding great back off between quarter to half a turn (u don't want to set them so exactly they start binding from additional pressure from torquing the head stem bolt).

If they go loose again the races aren't seated properly- repeat the tighten till they bind wiggle the bars trick to re-seat the races.

Thanks g0zer and yes, I've not worked on the front end of a bike before, I'll be an expert on 07 CBR's after this though.

[g0zer]

steering stem bearings can be tricky to get right, too loose and the front end will clunk under brakes, too tight and they can bind.

binding will cause the bike to weave back and forth cos the steering cannot return to neutral. a lot of binding is obvious but you can also have an ever so gentle bind so all you will notice is the bike will be a little vague in finding and holding its line.

remember what i said about backing off from the bind about half a turn, the head stem main bolt/nut is usually torqued pretty hard and will squash the headstem bearings together a little more despite the locking collar. best to set it up with front jacked up.

also you might need to relax the forks in the triple clamps to reset fork height after a big adjustment.

[Ozboy]

Cheers G0z, it all seems obvious now, but if you haven't worked on the front end before, it certainly is daunting. Shame I didn't know about this earlier, I may have gotten the bike finished for the track today.

[g0zer]

its something you can do in the paddock, assuming the bike isnt street registered paddock and 1st session is probably the best place to set them up so you can go out and test the adjustment

[Dejavu]

Ozboy, if you need a hand, call me.

I know some tricks that can fix yo shit, and will p/up that chain breaker at the same time if your finished with it

[R160]

i have a honda steering head bearing locknut socket in the shed if you need one, its a 4 lug "crown" type socket thingo about 50mm diameter from memory