Yamaha TRX850 Enthusiasts Forum

Yep,am just back from Cuba and have just been and collected a big box of valves from a neighbour who had kindly signed for them fom the courier.

I just tried to upload photos using photobucket to post here but the site seems to be undergoing maintenance. As soon as its back up I'll post the photos in this topic for you to see. It took me ages to lay them out all neatly to photograph. They do look the buisness though

I'll make enquiries with my bank to find out if there is a cheaper way for you to pay the balance other than paypal but I can't guarantee anything concrete at the moment. For those in the U.K., that have ordered, I'm quite happy to accept a cheque drawn on a U.K. bank but will obviously have to wait for it to clear before I post the valves.

I know it seems to have been a long while for all of this to get this far. Thankyou to everyone for their patience and faith. I hope it hasn't been too sorely tested.

I'm sure photobucket will be back up very soon. I hope so as it took me ages to make use of it's simplest features


Mark

Ah, finally! It took aaaaages Just kidding, no worries mate.
Although I'm curious for the pictures, because I reckon you have about 100 valves now?
Now you have to pay attention, so you don't send like 10 exhaust valves to one person, and 10 middle-inlets to another person.

You're so right, I'm going to have measure and verify the length and diameter of every damn valve I send out so it might take a little time

Some of the new oversize valves



Five std valves (left) and five new oversize valves (right)



Std inlet v oversize (top) with std exhaust v oversize exhaust (below)


Sorry the last photo was blurry,the camera doesn't seem to want to focus . I'll try and bring my vernier caliper home from work tomorrow so I can show more clearly that the new valves are 1mm oversize. I never use it home,much prefer the feel and accuracy of a micrometer

If you'd like to pm me your delivery addresses, I can make a start on safely packaging up and addressing your valve sets for shipping off to you.


Mark

Ps. You should all have received my home address when I confimed your order.

Std Valves compared to Big Valves sat in the cylinder head that I'm in the process of modifying. Big valves are still sitting high at the moment as I haven't cut the seats yet.









Mark

The compression ratio will be up a bit with the flat surfaced valves - but do you think it will affect the swirl effect much?

Just curious, IIRC the middle valve is another art number when ordering from OEM motorparts. These all look the same?

Killerwhale wrote:Just curious, IIRC the middle valve is another art number when ordering from OEM motorparts. These all look the same?

The middle valve has a shorter stem. If I remember well, Sanddune mentioned this also earlier.
Otherwise, we have a problem!

Tarwetijger wrote:

Killerwhale wrote:Just curious, IIRC the middle valve is another art number when ordering from OEM motorparts. These all look the same?

The middle valve has a shorter stem. If I remember well, Sanddune mentioned this also earlier.
Otherwise, we have a problem!

Is the correct answer We have no problems

Mark

dandywarhol wrote:The compression ratio will be up a bit with the flat surfaced valves - but do you think it will affect the swirl effect much?

Swirl is primarily controlled by inlet port profile,bias and port bowl profile. Swirl can, in fact be measured. As I have absolutely zero facility to do this (in common with 99% of professional tuners),I'm unable to answer your question.I have never ever heard of valve face influencing swirl. 5 valve engines inherently have much less swirl than 2 valvers. We can only play with the cards we're dealt.

The compression ratio will be as high as I can safely make it. If anyone has a bit going spare,can they let me have it please,I'm going to be hard pushed to find all I'll need . Only calculation,measurement,a couple of "dry builds",machining and some more measurements will give me the answers.

Mark.

Just wondering as many manufacturers use piston bowl shape to increase swirl in the cylinder - the depression in the stock valve may be similar - I've really no idea

question - does the TDM 900 share the same valves as the 850?

Different last 2 numbers (ie *******- XX) s I recall,but yes they use the same valves.

Mark.

With these valves I have to alter the cilinderhead, so I will look into flowing the head now that I'm on it.
Another thing on my wishlist are different cams. And I think now is a good time.
I don't know which ones are still available. Any suggestions?
But I was wondering. If "race" cams use a higher lift than the standard ones, don't you risk that the bigger valves get slightly lower in the cilinders and hit the pistons??

Tarwetijger wrote:With these valves I have to alter the cilinderhead, so I will look into flowing the head now that I'm on it.
Another thing on my wishlist are different cams. And I think now is a good time.
I don't know which ones are still available. Any suggestions?
But I was wondering. If "race" cams use a higher lift than the standard ones, don't you risk that the bigger valves get slightly lower in the cilinders and hit the pistons??

The valves are closed when the pistons are at the top Tarwetijger

dandywarhol wrote: The valves are closed when the pistons are at the top Tarwetijger

I know they should be, but are you sure there is no risk valves and piston getting close together?
Like not on TDC but on its way and very close to TDC?