Don't know if LT250 is the same, but Zilla's use wrist pin washers and not a crank thrust washer.
The washers keep the rod centered for even load distribution.

The motor runs ok without washers installed but will NOT last as long as a motor with the washers in place (as long as the OEM washer doesn’t fracture). These OEM washers are known to fracture.
Without the wrist pin thrust washers installed the bearing bore on the small end of the rod will wallow out.

Some tuners have had special high quality washers machined out of high strength material to successfully combat this problem.
Some tuners run em some don't.
No washer= no washer failure= early rod replacement.
Washers installed = long rod live.... unless a washer fails.
You decide

This is information learned from DR Q, the LT expert and I believe it to be accurate.

 

hey i know this is a very old post, but im about ready to put my top-end together, and was wondering what i should do with the thrust washers?? should i try and get some made? should i call duncan and get the bearing? not run them?? Someone WITH experience on these please help. (needaR what did you end up doing?)

 

If i am not mistaken, he didnt put them in and its still going strong.

 

mahanster is right.i put my top end togeather without them.the bike is currently totally striped down for chassis bearings and paint and powdercoat but the motor still runs good.no problems yet.im not going to reccomend that you dont use them nor use them.its youre bike.get that thing back togeather and ride hard!!!

 

I HAD A THRUST WASHER DROP TO BUT , I WOULD DEFINATELY USE THEM. THEY ARE KNOWN TO EVEN COME FRACTURED WHERE U CANT SEE WITH HUMAN EYE. ITS RECOMMENDED U HAVE THEM XRAYED FIRST. GOOD LUCK

 

I just put my motor back together with a Wiseco crank. No washers on the crank from Wiseco but washers on the piston!!!

 

the guy posting earlier is right,you must use the thrust washers if you want long rod/bearing life. THERE IS A WAY AROUND USING THEM THOUGH. i forget wich year/model it is,but certain year yamaha yz 250 and suzuki rm250 pistons will work in the lt and eliminate the need for thrust washers.ill find out what pistons will