Yamaha TRX850 Enthusiasts Forum

can i fit a tdm 850 in to my trx 850 ?????

You can if you have the time and skill, and you want less power!

TDM850 engine can be a direct replacement as I know. Camshafts (4NX121710000 and 4NX121810000) are identical, so if it's not tuned TRX then no loss in power.

hi thanks for the replies ,
i have had a look at the wire diagrams for the trx and the tdm and they are different
my trx is a 1997 and the tdm is a 1993 do you think this is still a straight swap, and can i still use my cdi unit.

Harsh850 wrote:TDM850 engine can be a direct replacement as I know. Camshafts (4NX121710000 and 4NX121810000) are identical, so if it's not tuned TRX then no loss in power.

hi thanks for the replies ,
i have had a look at the wire diagrams for the trx and the tdm and they are different
my trx is a 1997 and the tdm is a 1993 do you think this is still a straight swap, and can i still use my cdi unit.

markymark wrote:

Harsh850 wrote:TDM850 engine can be a direct replacement as I know. Camshafts (4NX121710000 and 4NX121810000) are identical, so if it's not tuned TRX then no loss in power.

hi thanks for the replies ,
i have had a look at the wire diagrams for the trx and the tdm and they are different
my trx is a 1997 and the tdm is a 1993 do you think this is still a straight swap, and can i still use my cdi unit.

1993 you say, I think that's a 3VD TDM with a 360 degree crank. Only the later TDMs, from 1996 and on, code 4TX have the same 270 degree engine as the TRX.
I think you can still mount a 3VD into your TRX frame but you'll need the CDI from the TDM too.

Also mention that the oil reservoir of the TDM (both 3VD and 4TX) are different to the TRX (it's on top of the gearbox).
Codes for the TRX are 4UN (Europe) and 4NX (Japan).

The gear levers are different too, the TRX doesn't have the bottom hole in the alternator cover drilled out and the shift shaft is longer.