New guy with a brake question on 1986 KDx200

Not sure if newer KDX systems will easily swap.

I'll bet you have a very large bubble in your line that is not coming out with normal bleeding. I had that problem on a '90 I bought used. Very spongy and weak brakes. Bubble would not bleed out until I took the braking system off the bike and hung it straight on a wall, tapping the hose with a screwadriver handle.

That and a fluid change made a huge difference.

Personally, if it were my bike, I'd rebuild the caliper, get the bubbles out and put in good fluid. Spend the money you save on a brake system upgrade on other things, like catridge fork emulators, new tires and whatever bearings and bushings are worn out.

Oh, and if the bike is stone stock, you will want to lean out the jetting and put in stiffer fork springs, just like every other KDX 200 ever made, lol.

Good job on getting the bike!

Rebuild the stock one, as the other ones that fit won't be much better. 1993+ won't fit, anyway.

For mine, I hung it caliper up for a few days, then took it off the wall, elevated the caliper on some blocks of wood, then bled it off the bike with the caliper at the highest point. Big bubble came out. This was after I had tried bleeding the bubble out on the bike about 10 times.

I've also heard you can hang it with the reservoir/master cylinder up, and the bubble may spontaneously bleed itself out of the master cylinder, but I never tried that.

You may want to look into one of the vacuum systems. Everyone seems to love those.