Yamaha TRX850 Enthusiasts Forum

hi all new here so be patient this has probably come up a hundred times already . but tdm lower engine and barrels so 900cc and six speed box with trx heads cams etc any advantage / problems ?

search is your friend

try tdm900 as a key word

ill give you a tip.. tdm / trx heads are 100% identical. the difference is cams and valves. But for the sake of the arguement, valves in this case are so minor, its not worth looking into.

If you REALLY want 6psd + 900cc.. get a TDM900 motor, get some kent cams, get a PC3 computer, dyno tune it, your away..

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EDIT
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Turns out they aint identical.. i made a post with pics about this to clarify

Quant,

So what are the differences, as i am looking for a TDM900 motor at the moment..........I have a cunning plan

differences between TDM900 / TRX850 ?

obviously injection, and you get a 6th gear.. altho top end speed is the same. Power is also the same, just the torque curve changes.. This is because you can only pass a limited ammount of air thru 38mm holes, so carbie or injected, your still only able to suck thru certain CFM..

is that what you wanted to know ?

yes thanks. I thought it might be something a little more sinister.....



so the cunning plan for next year.....

TDM 900 motor.
Carillo rods
JE Big bore...927cc
Vee Two cams
TRX Head gas flowed
FCR 41's

Should go well

Ooh, do JE do big bore's for the TDM now? How you gonna get round the ceramic liner?

You'll be wasting your money with the rod IMHO

And the TDM egine doesn't just drop straight in - go and have a look / measure and pay particular attention to the top mounts

Yes JE do a sexy 927cc big bore for the tdm900 - £250
I want the rods, as i still want to rev the motor....£200 each
Liners no problem apparently...£400 a go

I have the carbs on order.
Got the Vee Two Cams
Gas flow is arranged for Xmas.
So hopefully by end of next year it'll be finished...

927 ? interesting. I wasnt aware they were doing it. Might have to investigade the barrels and what not. Seems quite large and wouldnt provide much wall thinkness.. Which means some heavy machining would be in order.

Basically, the TRX850 block is different to the TDM900 so you would have to source some barrels. Ill see if i cant get some measuring done on it..

As for the bore liner. i will say this once again YOU DONT NEED IT IF YOU HAVE THE CORRECT PISTONS AND RINGS. Im sick of ppl thinking its some damn voodoo that you need else the bike will instantly melt / burn more oil than fuel / whatever.

phuk72 wrote:Ooh, do JE do big bore's for the TDM now? How you gonna get round the ceramic liner?

Don't TDM's run plated Ally barrels? If so the barrels will have to be bored out, re-plated and re-honed to suit the bigger pistons....

philk wrote: Liners no problem apparently...£400 a go
.

OK my bad, when i was refering to liners, I actually meant , bore out/ re engineer the TDM900 barrels and replate the bores.

thats what i did to my spare engine to get it to take 900cc..

Punched out the old sleeves, bored out the block, made new sleeves and pushed those in. im NOT using the coated TDM ones.

honkdawillydahonk wrote:

phuk72 wrote:Ooh, do JE do big bore's for the TDM now? How you gonna get round the ceramic liner?

Don't TDM's run plated Ally barrels? If so the barrels will have to be bored out, re-plated and re-honed to suit the bigger pistons....

yes to the above. apparently there is a 960 kit fer the 900 motor too, oil try and find out some more.