YZF750 Fork Mod

[higbonzo]

Anyone do this mod, or something similar to it?

Link to mod -    http://www.fjmods.btinternet.co.uk/MarcRittner2.htm

I purchase the complete front end assembly minus the wheel, axle, spacers, speedo gear and fender.  It was to good of a deal to pass up.  I have already found the other parts to complete the set up, except the 1000 triple tree.  I know the hydraulics for the brake and clutch can be used without doing the fork mod, and it has been suggested I switch over to them already, but I will probably do the complete modification all at once.

Anyways, any input would be appreciated as I will probably get start on this after the new year.

Later.....

[Marsh White]

Yep - Marc Rittner did it!      He is on this forum.  Name: derbybrit1

At one time he was making those complete and selling them.  Gary Mastro has the one in those pics now I'm pretty sure.

My YZF600 front end came from  Marc as well.  So did my hollow rear axle...

[higbonzo]

Marsh,

Thanks.  This is great news.  But, I can't find anything posted by that user name, nor can I find it as a member.     Is he still a part of this group?  Or could he have possibly changed his user name?

Thanks again.

Later, Phil

[Marsh White]

He just joined up...only posted one message so far.  You can PM him - just start typing derb into the "To" field via PM and it will fill in the rest.  Get on his ass!  He has been missing in action for a couple of years - something about work and pouring money in Aprilia Supercharged bikes...and dieting.       I encourage everyone to nag his ass....    

He is the skinny one with the white T-shirt:

"180.784 bhp on a factory Pro Dyno...this would easily be a 220djhp run on a DynoJet or Fuchs, or Superflow"

Super Charged RSVR AF1 Racing Tuning Session 2

[derbybrit1]

I've put over 25000 miles on my YZF750 forks.  Adding them to the FJ was one of the best mods I have done.  I no longer recommend 1.0kg (very stiff) or 1.05kg fork springs (too stiff), as I am using 0.95kg springs and they are just fine.

The stock damping piston has virtually no adjustability...just fixed damping orifices and some primitive popoffs.  Changing to a heavier fork oil will just make them too stiff, and they will be mostly unadjustable.

I went through 2 upgrades on the cartridge damping.  First was a set of R-1 pistons and custom shim stacks.  They were setup to race specs, and were too harsh on the street.  The second time around I sent them to Dave at GP Suspension (Oregon?) and he made them work like magic.  Not only did he replace the pistons and shim stacks, he replaced the compression valve needle adjuster with one made by his company.  Turning the screw actually changes the damping now.

The best thing about the YZF750 forks is how solid it makes the front and how much feedback you get from the front tire.  It is a precision carving machine as opposed to a flexi-flyer.

YZF wheel bearings are not the best.  I have had 2 sets fail, but I ride it really hard.  Just something to watch out for.

My machinist buddy charged $150 to weld and machine the FJ stem to fit.  Not cheap, but he is the best.  If you need assistance on that, please contact me.

Regarding the YZF1000 top clamp, you may be better off keeping the YZF750 top clamp and figuring out how to put on some risers.  Gary Mastro had to do something similar on his Aprilia Falco and it only cost about $75.  Maybe the same guy can do the steering stem for you.

[Gazza]

Hello Gents,

I would post a pic of the aprilia Falco top clamp modded to accept some custom adapters and stock Tuono risers but I can't see how to attach pics without a url.  (Marsh?)  Your best bet would probably be to take your clamp, risers and handlebar to a machinist and let them know what you have in mind.

Rittner's getting so darn skinny he'll be using .85 springs pretty soon.   :wacko2:

[higbonzo]

Marc,

Thanks for chiming in.  I was thinking to myself "self, why didn't Marc just use the YZF upper clamp, he must have had a good reason for using the 1000 clamp....Hmmmm... I had better figure out why, and find me a 1000 top clamp. But it sure would be alot easier and save a few dollars if I could use the YZF clamp I already have."

Anyways, I will try not to pick your brain to much, but I am one of those people that has to have everything lined up before I even start a project.  I don't like to say "go" and then have to stop as fast I got started.  Plus, I have found having a full understanding of what you are doing makes it easier to solve any issue that may arise while you are doing a modification.  And, I must admit, my skill are more on the mechanical tear down and installation of parts.  I don't do so well with the technical design aspect.  Too much math!!! It makes my head hurt 

Later, Phil   

[derbybrit1]

I used the YZF1000 top clamp because it was flat and facilitated easy installation of the bar riser blocks, as opposed to the YZF750 top clamp, which is a dropped gull-wing style.  The YZF1000 top clamp did require boring the holes for the fork tubes.  The YZF750 does not, but has other challenges to mount the bar riser blocks.  I'm only suggesting that there are at least 2 ways to get a top clamp that will work. 

What I am using now is a billet top clamp for a YZF750 that I found on the YZF750 list.  Holes did not need to be bored. It was already flat.  I bored holes to mount the bar riser blocks, and mounted an Attack Racing ignition switch bracket to it to finish it off, just like with the YZF1000 tree.

Good luck.

[craigo]

Gazza,

I remember that FJ of yours.  You offered it to me for like $4400.  I was the poor sap who lost his house to my bike burning it down.  Anyone remember that story?

Craig
90FJ1200