1987 KX500 Information

[Cochran]

Hey guys, I am new here. I am purchasing a Tecate second gen trike and putting a 500 in it. There's no major mods needed other than motor mounts and a notch for the sparkplug. So the project that I am buying already has an 87 500 in it. From what I have been told it has a newer topend. This is he second conversion I have owned. I am familiar with the 500 engine. I understand that this is a one-year only design. Would I be better off buying a newer 500 to use? Are parts difficult to find for the 87? Any of the newer gen 500s interchange parts with the 87? Also who does the decomp in the head mod? Thanks guys!

[umberto]

The 1986 and 1987 motors are pretty similar, and the 1988 cylinder is pretty similar to the 86-87 (although the cylinder heads are different on the 88).  They all used just the two power valves, without the center flap.  The 88 lower end parts are very different from the 86-87 and will not work in those cases but will work in the newer cases with a few extra parts.  The 500 motor made most of its final changes in 1989, and did not change substantially from then until the production ceased in 2004.  If you can find an 89 and up motor, it would make finding parts a little easier.  The prices on motors have skyrocketed, so it may be that it's a ton cheaper to use the 87.  Parts are still available on eBay, and some stuff is still available new. 

[Cochran]

The 1986 and 1987 motors are pretty similar, and the 1988 cylinder is pretty similar to the 86-87 (although the cylinder heads are different on the 88).  They all used just the two power valves, without the center flap.  The 88 lower end parts are very different from the 86-87 and will not work in those cases but will work in the newer cases with a few extra parts.  The 500 motor made most of its final changes in 1989, and did not change substantially from then until the production ceased in 2004.  If you can find an 89 and up motor, it would make finding parts a little easier.  The prices on motors have skyrocketed, so it may be that it's a ton cheaper to use the 87.  Parts are still available on eBay, and some stuff is still available new. 

I have noticed a substantial increase in 500 prices since I sold and bought a few 5 years ago. I assume I will send out the bottom end to be gone through. I can do the topend myself. Is there a member that would go through my bottom end? Also is there someone that installs a decomp valve in the head?

[umberto]

Larry Wiechman offers the decomp for very reasonable prices, and he does fantastic work.  His section on the site is here:

http://www.kxriders.com/forums/index.php/board,30.0.html

As for the bottom end, I would check with Sandblaster.  He works with a guy named Jason Tanner who does engine work, and his prices are pretty reasonable.

[Cochran]

I am going to buy a newer 500. I found a 2000 k5 for 1600. The entire bike needs alot but that doesn't matter. It runs and shifts through the gears. The suspension is shot and it needs wheel bearings replaced. I will have a 2000 roller for sale in a few weeks.

[umberto]

Are you going to sell the 87 motor?

[Cochran]

I decided today to leave the 87 500 motor out of the package deal. The seller would get rid of the 87 500 for a decent price. I can give you his contact information.