Yamaha TRX850 Enthusiasts Forum

Hi
in the process of rebuilding the cylinder head as using oil and the inlet valves are tight and looking to replace a couple - the question I have is what is the difference between the inlet valves - when you look at Yamaha parts manual there are listed as two different types - center vales and the to outer ones

thanks

?Kex

The centre inlet valves are a different length to the 2 outers. Slightly longer if memory serves me.

Take time when examining the seats of the inlet valves. Some, but certainly not all wear very badly indeed. This has been discussed at some length on the forum with a great photograph of one of my original inlet valves to illustrate the wear that can occur. The only solution if any are found to be as bad as that is replacement. The seats in the head only seem to suffer normal expected deterioration.




Mark.

Thanks Mark

I noticed a couple of the inlet valves were worn so there is a ridge -the seats look ok

kev

Do you know the year( eg95-96) of the motor???
I've learnt Yamaha had a recall on these motors to replace the inlet valves due to a manufacturing fault hence the revised part number and no problems on the last couple of years of manufacture of the TRX. Contact Yamaha if it's a pre 97 model and argue the point. You may at least get the valves free. It's worth a try....

cobbadiggabuddyblooo wrote:I've learnt Yamaha had a recall on these motors to replace the inlet valves due to a manufacturing fault hence the revised part number and no problems on the last couple of years of manufacture of the TRX.

All I've ever heard is that they always denied there was a problem and then quietly fixed it with the revised part..

There was certainly no recall in Australia.

OK I'll dispell what I read in an article on the TRX as a myth and in hignsight I should have questioned Yamaha personally.