ZX636 USD's onto a ZXR400L

[Mori Man]

I found a thread months back about some one who had done this conversion.

When doing the one on my own bike I had sussed that the H & L clamps were different and the ZX6 USD's would fit the L's.

I'm nearly ready to go ahead with the conversion and I can remember reading that they had new spacers made and reducers to fit the front spindle for the original wheel.

Well, I am going to use the 636 front wheel (lighter) as it has petal discs on it , I've gone digital on the speedo already so will buy the 636 spacers and have 12.5mm shaved of each (spacing difference between 636 and 400 ).

Thing is, I am stuck as what to do with the front muddy and can't remember what they said they used or done

Any insight greatly appreciated, Cheers

Drew

[zimm]

ballsout racing used the 636 mudgurad on his iirc..

thing with the yokes/headstocks is the H bottom yokes are a smaller diameter, tops are the same, H1 stuff has a smaller diameter "stem" than H2/L though, so im not sure they are a straight swap.. bearings at least are different, not sure if the yokes on your zrx are H1 or H2 (the forks are H1 i know) but it's something to bear in mind.

[Mori Man]

ballsout racing used the 636 mudgurad on his iirc..

thing with the yokes/headstocks is the H bottom yokes are a smaller diameter, tops are the same, H1 stuff has a smaller diameter "stem" than H2/L though, so im not sure they are a straight swap.. bearings at least are different, not sure if the yokes on your zrx are H1 or H2 (the forks are H1 i know) but it's something to bear in mind.

I'm running the H yokes on my ZRX just now (slightly smaller bearing) but i have L yokes for the 636's - I believe these bearings are a better fit for my ZRX but haven't tried yet.

I've got a 636 front muddy but no way is it fitting unless i cut it half removing 25mm from the central area - could be done but want a simpler solution.

[Gemini]

but want a simpler solution.

bend the forks out to the side a bit!

gem

[zimm]

yeh, H2 and L are the same afaik, its H1's had the smaller stem and bearings, other thing though, the stem on L's is shorter i think, worst case scenario you'll have to ream out an H1 bottom yoke to take the forks (its only like 1mm or something) or get a diff stem pressed into the L yoke.

sure you'll get it sorted though..

[Mori Man]

sure you'll get it sorted though..

yeah, my ankle grinder is a good tool

Good point about the stem length and i believe that's why my H yolk has a billet top bridge - taking up the extra length

I've seen my bike with the standard bridge fitted with ignition barrel and wondered why mine aint

Think my paddock stand and bike jack is going to be busy soon

oh, I already have a few alternative mods planned - if they pan out you'll all be the 1st to know

While we're on the subject, is there any external "markers" between a SP engine and a standard?

If i do a BEET 441cc conversion with cams I want to start on the best motor

[zimm]

internally the only differences between an SP and stock engine are the cams, and the close ratio gearbox..so if you are swapping the cam's anyway it's just down to wether or not you can live with the CR box on the road.

im sure you can trace engine numbers too .. but god knows on that, and nearly every engine ive pulled apart has turned out to be a bitsa in some respect or other anyway.

L9 conrods and crank are (apparently) heavier though so unless you plan to lighten/balance them i'd start with an earlier engine

from the pics i dont think your billet top yoke is much thicker than stock, but its nothing a cnc'd titanium spacer wouldnt sort

[Mori Man]

internally the only differences between an SP and stock engine are the cams, and the close ratio gearbox..so if you are swapping the cam's anyway it's just down to wether or not you can live with the CR box on the road.

im sure you can trace engine numbers too .. but god knows on that, and nearly every engine ive pulled apart has turned out to be a bitsa in some respect or other anyway.

L9 conrods and crank are (apparently) heavier though so unless you plan to lighten/balance them i'd start with an earlier engine

Quality info,



I feel the need for " A worm drive "

[Red Devil 777]

I've just done this (sort of) well zx636 into a KR1 using zxr400 bits and I was just coming on here to ask a question and saw this thread.
Here's a couple of pics




What I've used is 400h yokes (easier stem swap for the kr) opened out by 2mm on the bottom yoke.

Bushed the 400l spindle out to fit the 636 legs, used the 400l spacer and speedo drive reduced by 3mm.

280mm disc (kr1) on zxr400 wheel, could use 400h or l discs by making a spacer to fit between the caliper and leg (10mm and 15mm I think). Standard 636 b1 mudguard

Gixxer 600 calipers, cos I wanted black one, need to take it all apart now to get fork bottoms repainted matt black to match calipers.

Speedo drive angled down, cable will be fixed to bottom of caliper mount then curve up behind, might need a longer cable, if so will get a custom one from Venhill

So here's the question, can anyone tell me the length of a zxr400 speedo cable, save me having to get one, thanks very much in advance.

[zimm]

NICE !

H or L wheel ?

if L you might have got away with stock spacers if you'd used an H as putting L wheels into H forks you need to machine down the spacer 2-3mm.

quality though, if i hadnt already got a front end sorted for my project, i'd be doing this too.

[Ballsout Racing]

Well, I am going to use the 636 front wheel (lighter) as it has petal discs on it , I've gone digital on the speedo already so will buy the 636 spacers and have 12.5mm shaved of each (spacing difference between 636 and 400 ).

Thing is, I am stuck as what to do with the front muddy and can't remember what they said they used or done

Any insight greatly appreciated, Cheers

Drew

I don't understand why you'd need to shave 12.5mm off the spacers If you're using the ZX6r front wheel, spacers, forks then they should all just slip into the ZXR400L yokes, (can't speak for the H yokes but believe the forks are is 2mm narrower at the bottom yoke!) Use the ZX6r axle as well! and the mudguard, nothing needs to be modified

[chris675]

red devil, i have been watching this project on the PB forum looking very good! i was hoping to see how you got around fitting the zxr front wheel so i could copy!! but ended up getting off my backside and doing it myself.