Swapping Front Ends – Example – ZX10 forks and wheels to an XS650 hard tail frame.
Here’s a question I get asked a LOT,I’ve had a few emails about the subject too. “D’ya know if an xyz’s forks fit a an abc bike?”. Short answer, in most cases, Dunno!.
Legends exist for example, that RGV250 forks fit the GS range etc but in practice it’s not always true.
So let’s assume that ye want to swap the front end on yer bike. Ye fancy a nice set of upside doonys on yer fizzy or CG125, hmmmm. Sit down, have a cold bath, throw a stick for the dog, just take a bit of time and think it out. All I can do here is pass on some experience and tips on the process.
In this example me mate Marty decided he hated his ZX-10 rat but loved his XS650 hardtail chop but had gone in the huff with it’s crap front end with single teflon disc and brake calipers which didn’t even have enough grunt to make ye smile if ye bunged yer knob between them.
As happens, Marty turns up at my door and grins, the grin ye recognise that is going to lead to one of those, “Ho Al, can ye make a ZX-10’s forks fit ma XS, grin, grin”, aye well…. c’mon in, ah’ll put the kettle on.
First Get yer precision measureometer out, rule, tape, metre stick, cat, tesco poppy seed baguette in order of accuracy of course.
A “very near” gauge or “vernier”, it’s posh sunday name, would be useful too.
I’ll tell ye what to measure in a moment but first.
First up, the yokes from the ZX-10,
measure the length of the spindle, which was 210mm,
measuring the headstock of the XS showed it to be 171mm.
The Top and bottom XS bearings were 25mm ID(inside diameter/ 48mm OD(Outside
The ZX10 spindle bearing surfaces were 25mm top and 28mm bottom.
The upshot of this was
1. The XS headstock was shorter than the ZX10 spindle therefore a bearing
cup extension had to be manufactured to take up the space.
2. The top bearing from the XS could be used in it’s existing bearing
A suitable headstock extension was turned down an the lathe. This
would fit in the bottom of the XS headstock and accomodate the 28mm
id/52mm od bearing.
The brown line indicated where the part fits into the
existing bearing cup of the XS headstock
The assembly is tested prior to final fitting
The bearing cup fitted
The ZX-10 front end is fitted and bob’s yer auntie.
Ther ye have it, a nice new front end which has brakes
that actually stop the bike, the return on investment being made through
cleaning costs of underpants caused by the previous single disc/piston
arrangement which would get you from 60-0mph in about the same time
as getting the cellophane off a packet of chewing gum when ye’ve bitten
all yer fingernails off.
In a nutshell, if ye still want to swap front ends then go to a breakers/mates/showroom
and get measuring, make it as easy as you can for yourself.