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Nervous handling after CBR fork swap. Stock geometry numbers/Advice?

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Nervous handling after CBR fork swap. Stock geometry numbers/Advice?

Old 06-20-2012, 01:55 PM
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Nervous handling after CBR fork swap. Stock geometry numbers/Advice?

I swapped in a 06 CBR1000RR complete front end last year but forgot to take reference measurements (doh). After flogging it around Deal's Gap a few times I found the steering a bit too quick and nervous. I also have a 40mph wobble and some chatter during trail braking. I had the suspension looked at by a tuning guy at Deals Gap and a local guy at Superbike Italia. They both thought the forks probably changed the geometry, leading to instability. (One of them described it as extremely dangerous and told me to hold off going to the track until I get it sorted).

Suggestions on what to adjust? Does anyone have the stock geometry setup for the superhawk so I can compare some numbers? I apologize if someone already wrote this up, but I've been searching for a while and I can't find any concrete numbers or people who ran into this issue.
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Old 06-20-2012, 02:03 PM
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How are the forks set in the triples?

What sag are you running?

Is the rear suspension stock? Ride height changed? Different rear shock?
What sag are you running in the rear?
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Old 06-20-2012, 02:05 PM
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I beleive the CBR forks are shorter than the stock forks so this alone will have affected a significant change in the bike`s geometry and weight distribution. This is one of the reasons many choose to go the RC51 route as they are almost identical in length.

Don`t despair, however, as others have fit USD CBR forks (from 1000, as well as 929, 954) and made them work.

FWIW, I think my 900RR forks are also shorter......
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Old 06-20-2012, 02:15 PM
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When talking to a suspension guy about doing the swap in the first place he said it could lead to a chattery bike due to stiffening up the front end and having a frame that's still flexy. That could be part of it. Though as stated many seem to have done the swap with good results.

The questions would be how high up in the tripples are the forks. And how has your ride height changed?
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Old 06-20-2012, 02:17 PM
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Forks are at the stock height for the CBR, sitting on the retaining clips. I can check sag numbers when I get home, but I had that setup then reexamined by two professionals.

Rear shock is stock.

Last edited by mahatmajonny; 06-20-2012 at 02:19 PM.
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Old 06-20-2012, 02:30 PM
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Are your clip-ons above or below the upper tripple?
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Old 06-20-2012, 02:31 PM
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Originally Posted by GTS View Post
Are your clip-ons above or below the upper tripple?
I have Convertibars that are attached right below the upper tripple.
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Old 06-20-2012, 02:50 PM
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How far do the forks protrude above the top of the tripples?
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Old 06-20-2012, 02:57 PM
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Originally Posted by GTS View Post
How far do the forks protrude above the top of the tripples?
The only part of the fork above the tree is the retaining clips and fork caps. The clips are probably 2-3MM and the caps are probably another 3-4MM on top of that.
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Old 06-20-2012, 02:59 PM
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Originally Posted by GTS View Post
How far do the forks protrude above the top of the tripples?
Anything more than 3-5 mm of fork leg above the triple is a bad idea... I have 3 mm showing...

On another note... If you have a speed wobble... How is the tire? Proper pressure, cupping? How many miles?

And the steering stem bearings? Rollers or bearings? New or re-used? Correct torque?

Last edited by Tweety; 06-20-2012 at 03:05 PM.
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Old 06-20-2012, 03:39 PM
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Originally Posted by Tweety View Post
On another note... If you have a speed wobble... How is the tire? Proper pressure, cupping? How many miles?

And the steering stem bearings? Rollers or bearings? New or re-used? Correct torque?
New tires at the start of the season. Michelin Pilot Road 3s all around. I ran 34 front 36 rear at Deal's Gap based on a recommendation from the suspension guy there. I put it back to stock pressures after that.

Stem bearings makes a lot of sense for the wobble. Reused the ones from the CBR. Checked torque all around. Maybe I'll switch to some new rollers?

So you took the retaining clip off your forks and pushed them down all the way? Do you still have the caps showing?

Last edited by mahatmajonny; 06-20-2012 at 03:44 PM.
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Old 06-20-2012, 03:46 PM
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Also, aren't most of the guys on here running CBR 1000 forks using the 929/954 triples with gull-winged upper. That's like another 20mm of lost fork length if mahatmajonny is using a flat 1000rr triple clamp.
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Old 06-20-2012, 03:58 PM
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I know tweety is using a set of CBR1000 front forks, so he might be a good person to talk to. He also has a LITTLE knowledge on the workings of the Superhawk.
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Old 06-20-2012, 04:02 PM
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Then again he is also using an after market rest shock, rc51 swingarm, and he has Ohlins internals I his forks.
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Old 06-20-2012, 04:50 PM
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Well I'm no help. Just remembered the older 1000rr forks are gulling. I should think before posting.
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Old 06-20-2012, 05:08 PM
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Well, I'll try removing the clips and pushing down the forks a bit. Also, new steering bearings. All-***** seems to be pretty popular...I guess I'll go that route unless anyone has any other suggestions.
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Old 06-20-2012, 06:33 PM
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Originally Posted by mahatmajonny View Post
New tires at the start of the season. Michelin Pilot Road 3s all around. I ran 34 front 36 rear at Deal's Gap based on a recommendation from the suspension guy there. I put it back to stock pressures after that.

Stem bearings makes a lot of sense for the wobble. Reused the ones from the CBR. Checked torque all around. Maybe I'll switch to some new rollers?

So you took the retaining clip off your forks and pushed them down all the way? Do you still have the caps showing?
Tapered All ***** is a good product, works really well, that will probably fix the problem with raising the triples on the forks, either way it is a good practice to replace the bearings anytime you do a swap, did you change the old SH external bearing ring? What I mean is, did you mix the CBR1000 bearings with the external rings from the old Superhawk bearings? If that's the case then that could be the whole problem!
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Old 06-20-2012, 06:50 PM
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Hawkrider did a 100rr transplant and had similar handling problems. He had me measure the distance from the shop floor to the head of the drain plug and that helped him sort it out. I think the number was 19mm but it would be best if you could find his notes in the KB. The bike needs to be on a stand or suspended from above to keep it level if this measurement is to be valuable.

What is said above about the neck bearings is also important. The folks at All-Ballz can be real helpful.
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Old 06-20-2012, 07:18 PM
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I bought a sh with the 1000rrtrade front (currently for sale) but the forks are even with the top of the triple it has no issue like you have described it has all ***** tapered bearings in the stem...
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Old 06-20-2012, 07:32 PM
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My vtr with the 1000rr forks handles amazingly well. Really feels like a cbr. BUT I also have a penske shock on a single sided swingarm so geometry is totally different. I think nothing is showing above the triples but I can check if you are still having issues.

I do find these are the most sensitive bikes for even slightly warn tires.
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Old 06-20-2012, 07:51 PM
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cbr fork swap

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Old 06-20-2012, 08:34 PM
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did you follow the fork/front wheel installation procedure or doesn't that apply for cbr forks?

my geometry is radical ***-end high.

I assume your bike doesn't go straight with hands off?

Make sure your tires are seated on the rims evenly(lines equal all the way around), check front/rear alignment(set rear wheel evenly with chain adjusters axle pushed against swingarm, tighten axle, affix long straight pipes or boards to back wheel on both sides.........your front wheel should be centered perfectly between the pipes/boards.

Last edited by nath981; 06-20-2012 at 08:51 PM.
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Old 06-21-2012, 10:26 AM
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Originally Posted by nath981 View Post
set rear wheel evenly with chain adjusters axle pushed against swingarm, tighten axle
When doing this don't trust the markings on the adjusters to get the wheel straight. You should always sight down the chain and you'll see if the sprocket lines up or is off to one side or the other. Use that as your guide.
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Old 06-21-2012, 12:46 PM
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Originally Posted by GTS View Post
When doing this don't trust the markings on the adjusters to get the wheel straight. You should always sight down the chain and you'll see if the sprocket lines up or is off to one side or the other. Use that as your guide.
agree. i always use the markings as a gross approximation and then measure for chain align/adjustmt. I was suggesting pushing the axle max forward preferably against the swingarm to get the back wheel straight but yes, always have to double check. I've measured from the swingarm pivots back too, but it can get tedious.


Last edited by nath981; 06-24-2012 at 04:42 AM.
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Old 06-23-2012, 01:12 AM
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Originally Posted by mahatmajonny View Post
New tires at the start of the season. Michelin Pilot Road 3s all around. I ran 34 front 36 rear at Deal's Gap based on a recommendation from the suspension guy there. I put it back to stock pressures after that.

Stem bearings makes a lot of sense for the wobble. Reused the ones from the CBR. Checked torque all around. Maybe I'll switch to some new rollers?

So you took the retaining clip off your forks and pushed them down all the way? Do you still have the caps showing?
Caps plus a 3mm sliver of fork visible... But that's with a lot of other mods... I'd recommend you set the forks with only the caps showing to start with...
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