YZF R6 front end in 400RR 3TJ

[enduro250]

Hi all,
I have a complete front end of an R6. I want to fit it in my 400RR race bike.
Based on the fact, that R6 yoke has app. 5 mm more width, I cannot only put in the fork legs and the wheel.
I think 1 have two options:

• Adapt the R6 yoke (change the center steering thorn, sorry German native speaker) and fit the complete front end.

• Keep the 400RR yoke, put the R6 fork legs in, change the distance of the axis spacers and the position of brake disc
and break caliper.

Has anyone done this job already?
Any help is welcome.

PS: I have fitted already a TRX850 front end to my other 400RR, there I have choosen option 1 (change the center steering thorn)

THX

[Evilchicken0]

Stem, not thorn

Really you want the forks from a FZR400RR SP - they're very similar the early R6 but shorter. The R6 Forks will go into the 400's yokes but the forks stick out the top a lot. You can't have the mirror brace on the bike (not much of a problem if you're racing). You'll need the R6 brake callipers and I think the 3TJ front wheel - not sure about the spindle or spacing it, you might just change the bearing internal diameter.

[enduro250]

THX for the Stem!

You are right, I would prefer the SP fork, but it’s nearly impossible to get them.
So I have adapted R6 (RJ03) forks, they are shorted and adapted for my and 3TJ race weight.
I have the R6 wheel and the calipers. I think the 3TJ wheel cannot adapted to the R6 axis,
ball bearing 3TJ 17 x 40 x 12
ball bearing RJ03 22 x 42 x 12
Outer diameter of 3TJ = 40 mm axis R6 diameter = 22 mm
ball bearing 22 x 40 x 12 I cannot find such a dimension.

[Evilchicken0]

Ok - you'll need a the R6 yokes with the 3TJ stem pressed into the bottom yoke and use the R6 wheel.

[maccas]

Unfortunately the 5EB yokes have a much greater offset than the 3TJ yokes. The 3tj yokes have about 25mm offset and the R6 is more like 40mm. So make sure to check your geometry!

(Measurements are from memory, probably a bit out!)

Dan

[enduro250]

Yes, that's correct, I think the offsets are
TRX 25mm -> already in a RR
3TJ 30mm
RJ03 40mm
the measurement was not so exact.
That is one of the disadvantages, and the reason why I have posted my question here.
It is less work to exchange the stem instead of adapting distances of axis spacers and brake caliper, and I can keep the standard for wheel and brake caliper, what results in easier exchange a.s.o.
I hope I will get some proposals, what will be the best way to do this.
The standard fork is a nogo for the track, and I expected, that someone else has already done a front end update for the standard RR.

[enduro250]

Hi again,
who of you have the front end exchanged?
What have you used and why?
How satisfied were you with the outcome?
I think there have been some changes. Please tell me your experiences.

[Evilchicken0]

I've used SP forks - they're hard to find though. They bolt in but the mudguard brackets were missing so I used a BDK one. It works very well but I got hit off the bike so I changed it all back before selling it.

[enduro250]

As you said, hard to get.
the only SP fork, that I found is in Australia!!!

hey guys, are there no further experiences in changing front end?

[mark28]

I have a set of sp forks and a billet ali bottom yoke and stem I may be willing to sell ?