Thundercat forks on my 3EN2 wheel options

[Evilchicken0]

work on the marrage first
then work on the bike get the front sorted and ride it a bit ... then do the rear 3JT coversion.

[uniquefzrfreak]

Nightmare!!! - I fitted up the thundercat forks and front wheel tonight, and the disc bolts on the left side of the wheel, scrape against the inside of the forks.

I'm using the thundercat speedo on the right as a space and the original thundercat spacer/collar on the left.

I'm assuming that there is possible another spacer or washer on one side or the thundercat yokes are spaced slightly wider.

The confusing bit is, that there isn't really any room for another washer or spacer using the FZR yokes, so perhaps I need a combination of both the TCAT yokes and a missing spacer or washer?

I know it's unlikely that any one here will have much insight into the TCAT bits, but I'll keep this thread updated till I figure it for future reference.

I think I'll start by trying to get a TCAT bottom yoke and diagram to see if I'm missing anything.

[uniquefzrfreak]

Figured out why the disc was rubbing. - I had got the wheel fitted the wrong way around (now the speedo is on the left and the spacing collar is on the right) it fits fine.

The only problem is, the top yoke doesn't, so I guess that although the TCAT runs a wider front than the FZR, the forks are actually a couple of mm closer, width wise.

I must be pulling the forks in at the bottom causing them to move further apart at the top.

I'm going to keep looking out for a pair of TCAT yokes. - If anyone has a way of measuring some TCAT yokes for me centre to centre, I'd be grateful.

[uniquefzrfreak]

Just posting an update for future reference. - I've picked up a TCAT bottom yoke and the front wheel now fits perfectly.

For reference, the thundercat yoke stem is the same size as the FZR400 3EN2 and the roller bearings etc are all exactly the same. So at least that part was a nice easy slot in job.

Just need to get a top yoke to finish that part of and it's onto the next bit.

[Evilchicken0]

Glad it's getting sorted, I feel a bit responsable for leading you down this route thinking the forks could be interchangable when really you need the front end. At least you'll have adjustable suspension up front, and a 120 profile tyre

[uniquefzrfreak]

Hey, no worries. - I'm well happy with the outcome. As you say, fully adjustable and a 120 up front. No probs and your advice is always appreciated.

[Evilchicken0]

Ta Luv ....

[tsn73]

Greetings.

I see that uniquefzrfreak is getting it all sorted out by going with the full YZF front end. It did sound like a real pain to do anything else.

I have a 3en2 and have already purchased a set of 96 YZF cartridge forks (no front end just forks). I'm also on the fzrarchives and consensus over there is that the YZF (T-cat in UK) front wheel is an upgrade for a few different reasons so the way unique went was probably the easiest and best.

I dont' really want to buy any more YZF parts so I was hoping to swap the lower legs, i.e. put the YZF stanchions and internals into the fzr lowers so that I could keep the fzr front end. Since both bikes have 41mm forks I thought it might be possible but haven't had a look at the inside of the fork legs yet. Have any of you tried going this route before?

Any insight is appreciated

[Taggyd]

are the forks the same length? that could cause a problem if they aren't i think. Plus are the springs going to be too 'hard' if the t-cat is a heavier bike? Dunno if i is but could be worth considering! Wouldnt just putting progresive springs be an easier option?

[tsn73]

are the forks the same length? that could cause a problem if they aren't i think. Plus are the springs going to be too 'hard' if the t-cat is a heavier bike? Dunno if i is but could be worth considering! Wouldnt just putting progresive springs be an easier option?

Both forks are 30" from axle to top of fork cap.

The FZR's are ridiculously undersprung. From the racetech site the fork spring rate is like 0.46 kg/mm and recommended for someone weighing 75 kg is 0.83 kg/mm. The stock T-cat springs are 0.8 kg/mm so should be a welcome addition.

I have progressive springs in my forks now. Yeah that's an easy install, they helped a bit with brake dive (along with some heavier fork oil) but don't affect the damping performance. Cartridge forks are way more tunable than damper rods and actually have external adjustments.