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zx12 A2 to zx14 A7F fork swap project

32K views 86 replies 19 participants last post by  Paul tankard 
#1 ·
Hi all my front end on the old 12 has not been feeling to grand as of late so i am treating her to a new front :lol:
I am waiting on the forks triples and calipers from an A7F zx14 to turn up this week, but in the mean time i have stripped the old setup from the 12.












I have noticed that the top bearing on the steering stem is smaller the the bottom bearing on the stem 25mm top internal diameter and the bottom is 35mm ID.
This means that i will have to machine the zx14 steering stem to accomodate the smaller top bearing. Newer generation 12s have the same size bearings top and bottom so its nearly a straight swap to my annoyance !:rant:







Will post some more progress in the week when the forks arrive.
 
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#43 ·
I still wouldn't chance it. I have one in the stock setup... Anytime you change the stock geometry, even slightly, it is (not) a good idea.
Don't tell that to certain AMA race team that sawed an R-1 frame in half and welded the back half of an R-7 frame to it in order to have an adjustable swingarm pivot.

Of course, that was about a decade ago, so they surely must have crashed and burned by now.... :runaway:


BTW, I don't think you've deterred him, he's still posting..... :lol:


I've been running a VFR800 with RC51 upside down forks/triples/brakes for the past 6 years and zero handling difficulties. A little more ride height in the rear solved the longer trail problem due to triple clamp offset just fine.

The numbers are so close I'm certain he'll be good.

I await the results of the first road test of the ZX12/14r :mfclap:
 
#39 ·
DRP nearly there more progress tonight got the triples all fitted but ran into a few clearance issues with the top triple had to use a 3mm washer to raise it up of the stem lock nuts as the zx12 ignition barrel does not fit correctly ! i have also had to modify the triple ignition mount and cut them down by 3mm also now all is well but no steering lock which i can live with at the mo.



From the top

 
#40 ·
Did run into another issue with the steering stop but just drilled and tapped the frame stop to m6 and fitted a bolt with a 4mm head and 4mm the other end which has given me good lock.

Got a 22mm 1mm pitch tap now to make my top lock nut to look factory, as you can see the zx12 top nut looks pants !
 
#42 ·
Zumina even though the stops are in the same place the handlebars point further back and the forks are also further back with the lower offset.
The b model zx12's have a 4mm less offset than the a1/a2 bringing my conversion in line pretty much with newer models.
 
#45 ·
My forks are extended at least 1/2 inch over stock by cutting the internal stops, but raised thru the triples 10mm, and I run the ass end up close to 3/4 inch.. no idea what the resulting rake/trail is.. guess I should have burst into flame by now..

Don't want to even discuss my widow maker TL1000 with the Busa forks, raised swingarm pivot and shim on the rear shock... :)
 
#46 ·
As you guys know... The point when you NEED a steering damper, and you don't have one, could possible be too late. The bike can handle perfectly, then that specific tire combination with altered steering geometry (even stock geometry) could result in tank slappers (once the tires are just worn that specific way).

I am honestly not trying to argue, I am more trying to plead.

I noticed that on my bike (stock) when I ride one handed (rest the other hand) I used to notice that the handle bars would giggle back and forth. Once I put the damper on, that went away. I am not saying that would ever lead to slappers, but I just didn't feel comfortable after I saw that.

Don't a lot of tracks require bikes to be fitted with dampers? I could be wrong, but I'm just assuming that when you start to push the bike, you increase the likelihood of having tank slappers.
 
#53 ·
NONE of mine, and I have 4 bikes with different set ups, have a front wheel wobble or hunt on a smooth road.

Something is off, even as simple as misalignment between your wheels, preload difference in the forks, road surface...
 
#54 · (Edited)
Honestly... ride with only one hand holding the steering. You will see it. It does not sit perfectly straight. Every one of your bikes will do it, it is very slight, but is there.

It is something, I never noticed until I was paying attention, but from that point, I see it on all bikes.
 
#56 ·
I've had my hands off the bars at around 90 before and she went straight and smooth as a babies ass. I do it at 50-70mph all the time goofin off. I even got pulled over for doing it once. I ride 1 handed all the time, highways, back roads, I even let go and go no handed coming to stops....never have I had a wabble in the front end of the 12R. Even hitting huge potholes (which we have plenty of here in good ol' Minnesota) on the interstate, she wabbles a sec and right back to good.

I had the problem on an old LTD750, but the suspension was shot on that thing and the tires were junk. Let go at 10mph and she slowly start to wabble, and steadily increase.

I will add, that after a couple of power wheelies this year, on touchdown, the front wabbled a bit, but I'm quite sure that was my own fault. I probably didn't have the wheel straight. They were nothing that would raise the blood pressure, but got my attn.
 
#57 ·
I've had my hands off the bars at around 90 before and she went straight and smooth as a babies ass. I do it at 50-70mph all the time goofin off. I even got pulled over for doing it once. I ride 1 handed all the time, highways, back roads, I even let go and go no handed coming to stops....never have I had a wabble in the front end of the 12R. Even hitting huge potholes (which we have plenty of here in good ol' Minnesota) on the interstate, she wabbles a sec and right back to good.
I wouldn't say it is a wobble. The steering just moves a little. I could have ride with no hands, or one hand any day. It just moved slightly.
 
#58 ·
Sometimes, when the front tire feathers, it may have a shake to it. These 12's love to chew on tires...:lol:
 
#60 ·
Oh..my wheelies weren't intentional. They were results of hard acceleration. As far as letting go over 100mph...no thanks. I have held it one handed to 115 120 quite a few times....sitting straight up...rolling on fuckin with my buddies...that's bout when it's time to tuck and hang on.

I don't do intentional wheelies. I've always thought tho, that when you're up, you kinda wanna keep that front wheel spinning....gyro and such. I've never been one to "ride wheelies", as a kid on a bike or on motorcycles. I used to jump dirt bikes and quads over everything that had a lip...never did the wheelie thing tho...escapes me. Looks cool tho. Sometimes I feel like I should be doing one at certain moments...:headscratch:...I just like twisting the gas and taking off like a raped ape...
 
#62 ·
Still waiting on my discs now thats holding me right back !
But as its been raining most of the week and now into the weekend its no biggie.
The top Triple bush worked well as did the pressed in steering stem but the first road test will tell if its all working as i want.
 
#64 ·
Loving the gold wheels look, just waiting on the discs before i can fit the tyres and get them balanced.



Nissins are the dogs !
Notice the white bracket this is only temp until i can make some better units these will tide me over for my road test.



 
#68 ·
All finished and the result is very pleasing.
Bike feels a little more nimble and the front is a little more prone to lifting but that also because of the 47t rear.
Have tried a couple of rebound and compression damping settings and I'm nearly there just got slight pogo effect on it, had to put it to sleep as it looked like it was going to rain.





 
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