The 10+ year KX500 rebuild thread

[Taipan]

Yay, pull start time!

[derek badger]

Err...brakes might be required before that sort of shenanigans happens.

[Nobby]

Iridium plugs ??!!
I'd. be swapping that. 2 strokes hate them.

[KungFooBob]

Iridium plugs ??!!
I'd. be swapping that. 2 strokes hate them.

My FAHRON tuned RD250 racebike hated expensive plugs. I had a big box of the cheapest council spec NGK's and at the first sign of any refusal to start new ones went in and the old ones straight in the bin. You can not 'save' sparkplugs by cleaning them in petrol, letting them dry out or wirebrushing.

[Taipan]

Think iridiums are okay in Fi ,water cooled engines, but not in anything else, at least in my experience anyway.

[MingtheMerciless]

When I took my 950 SM for a tune, the tuner binned the expensive iridium plugs as they were fouled and put bog standard NGK's in and said that they worked best in his experience and I was just wasting money on posh plugs.

[Nobby]

I've carbie water cooled and their fine in them.

[Taipan]

On my air cooled Harley, after I fitted iridiums, it'd splutter a bit when I started it up and misfire a bit in slow moving traffic. I was told to ditch the iridiums and put standard plugs in to cure it, which it did.

[demographic]

I know this point is well past but I spotted a couple of posts on KX riders about adding a cush drive to a KX500.

"Slight change, with the cush plate installed the KLR650 bearing to bearing is 159mm.
The KX500 swing arm inside to inside is 194.5mm.
So, I will be doing some more digging on this issue..
« Last Edit: January 20, 2014, 06:52:55 PM by sandblaster »"

A later post by Sandblaster...
"The spoke count looks good...
So it may be possible to use a KLR650 rear hub with cush on a kx500.
More info on the way.."

And another with disc to sprocket info from another member.

"FYI klx 650 wheel is exact disc to sprocket! A very little machine work to the spacers and I should be good!"

[derek badger]

Front caliper bracket in progress...

[demographic]

A bloke on one of the supermoto forums said he'd used ducati Brembo caliper (or an Aprilia one which is basically the left side of the same) four pot caliper and made that work.
From memory there were dificulties with spoke clearances and he just filed a bit off the side of his brake caliper to clear the spokes.
I'm not totally onboard with that idea and thought it might be possible to either do the relocation bracket differently, alter spacer sizes a couple of mm, or maybe tweak spokes if you absolutely have to.

I do have both front four pot calipers off a Ducati though I can't remember which one now and I never got to having a proper go at it to find out if it would work right.
It's kind of on my massive list to have a go at though.
I think I might even have sharpied the part number on em cos well, I can't remember it now can I.
I could send it to you to try and see if that type of caliper is any good to you, as long as you send it back so it can live in a drawer for a few years til I get my shit together and do something with it.

[derek badger]

Cheers dude. I've got a GSXR 4 pot and it does indeed foul the spokes. The 2 pot opposed piston Brembo fits, but the bracket would be more complicated then I can do here and would involve a machine shop. The 2 pot sliding caliper I got fits on a flat bracket and I can remove both sliders to fit the one I'm fabricating. The Brembo will go on the rear with a hanger welded to the RHS axle spacer with a boss for the torque arm. That's the plan anyway, fucking about with brakes always gives me the heebie jeebies so it's measure three times, cut once and lots of cardboard templates.

[derek badger]

Rear brake was originally a drum so I need to fabricate three mild steel tabs to weld to the frame to mount the m/c and reservoir. Most modern MX rear brake pedals arch over the footpeg, but won't work here so I've got a complete assembly off a 650 Ninja ECF and just need a brass bush to sleeve the spindle hole down.





Rear torque arm will need to be cut down or replaced as it's too long for the position of the caliper.





Cheb kindly turned me up two of these axle spacers so if I fuck up welding the hanger on I have a spare.



Front brake master cylinder is off a CBR125 and should suit the caliper.



This is the critical bit, getting the second pin hole spot fucking on.



The plate will then need a couple of stand-offs from round bar stock welding on to set the position from the fork leg correctly before drilling through both and threading them for the mounting bolts.





Chain rollers arrived, but the top and bottom sliders for the swing arm are no longer available in the UK so I'll have to make something up out of a pieces of thick polyurethane and countersink the mounting bolts.





Once these are done and the front brake is functioning I'll be happy to use the roller starter I'm going to fabricate. The majority of time spent on a project like this is making jigs, measuring, adapting and tooling up to make jobs easier. It's actually half the fun to be honest. The electric bike lift for instance is a prime example, it's making little jobs an absolute breeze.

[cheb]

What dimensions does the brass spacer need? I've got some bar somewhere.

[derek badger]

What dimensions does the brass spacer need? I've got some bar somewhere.

Very kind, as ever mate. I've not even measured it yet to be honest, just checked it cleared the footpeg and lobbed it in the box of 'good' parts.

[derek badger]

Stop. Bracket time.

Drilled the hole for the 2nd slider pin, greased them both up and they fit, slide and don't bind. Phew.







I connected up the m/c and bled the system with a mitivac, positioned the caliper where the pads fit the disc best and then cable tied the lever to the bar grip so I could mark the fork mounting holes. I put a blob of white paint on the end of a bolt to mark the bracket.







With the slider pins 95% home I need a 5mm stand-off welding to the bracket to meet the fork lugs. Once these are on I can mark the position more accurately and then drill and tap them for an M8 bolt.

[cheb]

Looks good. I'll confess that why I try to use opposed piston calipers, they are more forgiving when making brackets.

[derek badger]

16mm steel bar ordered for the stand-offs.

M8 and M10 rose joints ordered for the rear torque arm.

2 metres of 50x25mm box section ordered for the roller starter frame.

2 strips of nylon bar ordered to make the upper and lower chain sliders.

Next week booked off work, need to replace 11 fence panels it should be able to get some time in the workshop.

[derek badger]

Stop. Hammer time.

Front caliper bracket done. Need to service the caliper, maybe new piston seals and bleed it but it fit and I'm happy with the setup.







Back brake pedal has been modified to clear the footpeg mount a bit more. Cheb (again) kindly turned up a brass bushing to make it fit and a slice of MTB inner tube will do as a return spring. Next is the m/c mount.





Chain slider is nearly impossible to source in the UK, NOS does pop up now and then for stupid money in the states so I'm making something suitable with counter sunk bolts for the top and bottom. It's not going to be clearing table tops and double whoops on the MX tracks so Chain slap shouldn't be as much of an issue on the road.

[derek badger]

Chain sliders done.