Yamaha TRX850 Enthusiasts Forum

Hello everyone, I have a problem with the thermostatic valve, I need to know the shape and exact measurements (external and internal diameters and thickness) O-ring seal that acts as the container valve. On this occasion, I wanted to know if there is a list of spare parts TRX 850 with their sizes and shapes, in fact I saw that the concessionaires have. Regards, Angelo from Italy.

Hi Angelo, use the forums search facility and you`ll find Yamaha TRX parts shown pictorially and with part no`s too.It`s also downloadable

Thanks for the reply, but the list of spare parts with the codes I already have, I mean if someone has the measurements of the pieces. Going to the Yamaha dealer when they open the program for finding parts for each piece shows the technical specification. The workshop manual, I saw, but does not give me the measures of the seal are looking for!

The thermostat housing O ring will be standard metric, why don`t you strip the housing and measure the O rings outside diameter and thickness?
You`ll need a vernier caliper to measure the thickness though.Are you hoping to save a little money getting a `non` Yamaha one?

I have already taken steps and I bought some O-rings, my question is why the form may be different from the usual O-ring. Original order, the cost is negligible (in fact I have ordered two!), The problem is that three weeks have not yet arrived and saw the nice weather, I use the bike soon.

Ah now I understand.
The O ring in the housing is of standard round form, I replaced mine last year.Unfortunately I`ve no idea of the diameter or thickness, my Yamaha dealer actually had one in their stores.
If you`re very lucky a member might have a spare thermostat that they can open to measure the O ring for you.

Many thanks for the clarification, it was what I wanted to hear. The O-ring should have a thickness of 2.36 mm and I have four. In fact since you've replaced it and told me that the form is standard, this week put it back together and prepare the bike. I hope to post pictures soon. Greetings from Italy. Angelo.