YZR125 big bore upgrade

[stuartadair]

Hello all,

I'm working on a Yamaha YZF R125 which has a holed piston. I've been asked to investigate putting a 150cc big-bore kit on.

Now, I've upgraded carb fuelled 125's to 150 before without issue but I'm not sure about fuel injected.

My logic is that the fuel system would only delivery enough fuel for 125cc, and upgrading to 150 would mean changing the fuel system.

What do you think ?

[_Iain_]

Give it up,

Rape a current generation crashed Rieju RS3 for its motor (identical motor, different electrics & a carb) I'd rob it for it's engine & loom and bin the rest. Stuff that in the yammy, then run that around de-restricted at 16.5bhp for a bit, then when you've got a bit of time & moneys Rieju will supply a 180cc kit for it. And race cams. And a load of other cool go faster bits, as they recycle the engine in a specced up form to go in their MRT200 crossers.

Trying to tune the EFI lump is pissing in the wind - even with a 150cc kit & power commander (read £700+) you wont see the power output of the carbed Rieju motor.
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[stuartadair]

Thanks Iain I thought as much.