NC30 judder under braking

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TheRehabKid
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NC30 judder under braking

Post by TheRehabKid »

Hey guys, hoping someone can shed some light on a braking problem i'm having before i strip the front end down to investigate.
When braking, the bike shakes up and down a lot, the harder i'm braking the more sever it gets. It's not juddering from side to side, just up and down.
I thought maybe a disc was warped so put on some spares and it was still happening. However one of the disc bolts on the RHS of front wheel is not tightened properly as the threads in wheel are stripped.
Also thought maybe my brake pads were sticking so refurbed the calipers but still hasn't solved it!
The forks were refurbed by FoxRacing just before i put the bike on the road and setup for a 12stone rider (although i'm 13stone)

Could it be the steering head bearings needing replaced?

Any help appreciated guys
Cheers, Richie
Delboy
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Re: NC30 judder under braking

Post by Delboy »

Is the wheel balanced?
Is the tyre pressure correct?
:peace:
4 WHEELS MOVE THE BODY 2 WHEELS MOVE THE SOUL
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TheRehabKid
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Re: NC30 judder under braking

Post by TheRehabKid »

Good shout on the wheel being balanced!
Forgot that when i had the tyre put on they couldn't balance it as the discs weren't on, will have to get that done and see what it's like.
Although would the front end not always wobble if it was the wheel not being balanced? as opposed to just under braking?
The tyre pressure is correct btw.
mick.mh2racing
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Re: NC30 judder under braking

Post by mick.mh2racing »

My money would be either discs or fork bushes. If it was wheels out of balance then yes they'd wobble all the time.
I'd bet it was crap discs.
How hard can it be?
Dynamohum
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Re: NC30 judder under braking

Post by Dynamohum »

would check the head bearings by getting an asistant to pull the fork legs fore n aft whilst you put a finger on the headstock and feel for any play in the bearings .. if loose can give a judder also under braking.
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BillingCBR
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Re: NC30 judder under braking

Post by BillingCBR »

Got odds on the head bearings mate, happened to me with my VFR after they settled when I put new ones in, just nipped them up and haven't had any issues with juddering since :)
'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire
sil3nt
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Re: NC30 judder under braking

Post by sil3nt »

When i brake i can feel something moving up and down. I am fairly sure it is the steering head bearings. Just haven't had a chance to check it yet.
Dynamohum
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Re: NC30 judder under braking

Post by Dynamohum »

rehabkid i see you are in in washington i am in team valley gateshead every night if you wanted could assist with checking if needed just pm and could arrange a suitable time. davy.
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Sligeach
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Re: NC30 judder under braking

Post by Sligeach »

In order to do headrace bearings you will need to take the wheel off. Best the check wheel bearings as well. It can only be a finite number of things. I think you got all bases covered now.
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TheRehabKid
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Re: NC30 judder under braking

Post by TheRehabKid »

by the sounds of it i may need to check the headstock bearings then.
I didn't know these could be adjusted or anything?
I have had the whole bike stripped down to every single bit, and when putting front end back together i just put the yokes on with the bearings and tightened the top yoke nut up assuming this was all there was too it.

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