Yamaha TRX850 Enthusiasts Forum

Sorry for the long delay getting these valves made. They are now ready, I just need to pay for them and they will post them out to me.

I am currently unable to get online at home after having no end of ISP and pc problems so my posts may be infrequent and erratic for a while. Apologies in advance.

I will pm invoices out as soon as I'm able to those who have already put their names down for a set. I have a two or three sets spare that I'm happy to sell on a first come first served basis

Mark.

Excellent, thanks Mark.
Another job well done.
I'll await your PM..

Interesting reading the story on Cathcarts motor with the 2mm oversize valves and 12.5:1 flat top piston set up.
They used a std ECU and just retarded the timing by 4* obviously at the pick up from the crank to deal with the extra compression.

Can someone point me out the post where I quoted the cost of these valves so I can honour it.

Mark.

Price was in a PM

cobbadiggabuddyblooo wrote:Excellent, thanks Mark.
Another job well done.
I'll await your PM..

Interesting reading the story on Cathcarts motor with the 2mm oversize valves and 12.5:1 flat top piston set up.
They used a std ECU and just retarded the timing by 4* obviously at the pick up from the crank to deal with the extra compression.

Where can one find this write up bud

I found it on google.

sanddune51 wrote:Can someone point me out the post where I quoted the cost of these valves so I can honour it.

Mark.

Ok thanks to Cobba, for trawling through his pm's. I have quoted him a price of £93 for a set of 4, so that is the price for everyone on the forum. I should have these in my hand by the end of the week and will get firm postage costs for UK,Australian and European destinations which will be insured and signed for.

I will post up these details on this thread when I have them.

Mark.

If there is a set f these going I'd like to put my name down plz.......

I have replied to Phil by personal message.


Mark.

Is there still a set available for me?

Thanks
Bart

Set of 4, just exhaust valves then I take it?
Is anyone running with them yet?

Yet one of the lads racing his Trx here has set his up with the 2mm oversize exhaust valves on a std motor. Bit of head work and FCR's and Akra system.
I got an idea he found 93rwhp which it 3 - 6 more hp than most in similar trim without the valves.
I'm sure if he chose a free flowing exhaust he'll be close to 95...
Akra system struggles a little after 7,000rpm but plenty of balls at 4,000rpm.

Hmmm, a healthy power output but surely you would need some extra lift and duration on the cams to get the best out of them?

Quite a few factors start coming into play as I'm sure your well aware there Colonel Sanders..
What do you want out of your motor and what do you have to compliment???

You may find shrouding issues with the larger 2 mm valves so robbing Peter to pay Paul with Kent cams may spread a much more even power output throughout the rev range if that's your goal.
Or a Curmi has done using an Akra system with a std motor/2mm o/s valves.

Those I've spoken to who raced here on their TRX's back in the day had there bikes set up with 2mm oversize valves, Arias pistons, Over/V2 profile cams and Over exhaust all found between 112-116hp.
They all worked together well from 6,000 to 9500rpm.

Im tending now to change exhaust to an Over system because I'm loosing a couple of Extra HP in the top end due to the Akra exhaust. But i have oodles of the mid range being well complimented with the 1mm o/s valves, Kent cams, rolling mass removed internally on the motor and with the Dymag wheels so its a worthy sacrifice with the bike now being dedicated to more trackdays than on road riding.
( I'm putting out the peak Hp of a std Trx at 4400rpm / torque at 4100rpm )
So I'll feel I can afford the happy medium between outright horsepower and mid range grunt.