Big Inlet and Exhaust Valves (+1mm)

[Mincehead]

Mark has already posted about the valves on the TDM forums too.

[Tarwetijger]

Mark has already posted about the valves on the TDM forums too.

Acknowledged!
So, posted on two dutch forums.

[Mincehead]

[Killerwhale]

Okay, first: I'm interested in a set too.

Then: If the valves remained the same over some models, these bigger-valves-set can also be used on TDM850 and TDM900's?
If yes, then the market is just getting bigger Sanddune51!

Read up that some dudes in OZ found 7,7HP on a scrambler 900 with minimal loss in low down tourque.
As i´ve won some dosh recently i´ll take a set...if poor gains i got fresh valves anyway!

[Mincehead]

On the horses Kw?

[Killerwhale]

On the horses Kw?

1800£ on harnessracing yes

[Mincehead]

Very nice, I don`t do gambling in general, well apart from with my life when the red mist descends.

[Kenny]

Are you porting your heads to old school spec or to the new way of thinking with high velocity smaller ports?

[Killerwhale]

Are you porting your heads to old school spec or to the new way of thinking with high velocity smaller ports?

Mine are vel ported on the exhaust side, full race port with piranha teeth in the inlet.

[sanddune51]

I've been away from my computer all weekend but am really pleased to see that things have really moved on.



Firstly a very big thankyou to "Tarwetijger" for posting a link to this thread on 2 Dutch forums . That has already produced another taker from the Nederlands.

I can tell you all that we now have 9 sets of valves spoken for from all over the world ,so it's a case of "when" and not "if" now. Thankyou to to everyone who has so far put their name down for a set.
Also thankyou to all those that have contributed to this interesting thread(don't stop). I hope perhaps in the future we'll have a lot head and port photos showing the ways people have modified their ports together with dyno results for different cams and compression ratios.

Mark.

Ps. I'll come back to discuss Tdm900 valves shortly when I've collected the part numbers.As I understand it the 900's have the same generic part numbers but with revised suffix numbers. But, as has been mentioned before Tdm'ers don't generally tend modify their engines(unless they put them in "proper" Yamaha trellis frames )

[Kenny]

Are you porting your heads to old school spec or to the new way of thinking with high velocity smaller ports?

Same to sanddune51 please

[sanddune51]

I have already ported my head using the same technique I use on all the heads I have ported. This did not include using "JB Weld" or similar on the floor of the ports to reduce the port diameter to speed up the gas velocity.
This technique seems to have a lot of merit,but I feel it would be too much of an experiment for me at this time.

Mark.

[sanddune51]

Sorry. I had just duplicated the above

Mark.

[Fritz Trix]

I'm also interested in a set
And i posted it in the german forum

Fritz

[sanddune51]

Fritz,

Thankyou for your interest,I'll add your name to the ever growing list, and thankyou also for putting out a shout on the German forum .

Mark.