Wiring I hate it, scares me to death, always has. Does anyone have experience of wiring Yamaha’s pre R1 engines? Basically, I picked up what the seller thought was a thunderace engine, although the code on it seems to imply it’s a late model FZR ex-up, although the carbs are certainly thunderace!

Firstly am I right in assuming the basic engine in both these bikes is the same, if so does this give me the option of using either ecu? Can I even use the earlier pre exup ecu and wiring for an even easier set up?

Does anyone out there have any experience of wiring these engines in a BEC set up? Just looking for the easiest route to a running engine!

What you want for easy peasy wiring on these engines is an ecu from a fzr1000 genesis. These are the early black engines. Bikes will be 87 / 88 era. The wiring is pos to both coils, neg to 1+4 coil, neg to 2+3 coil, crank sensor gnd and signal, pos feed to ecu, gnd ecu. Push button and go!

There are no interlocks, security, diagnostics or limp home to worry about.

4SV I think is the thunderace code, the thuderace does have a two bolt engine mount head casting.

Can I still use the thunderace carb’s, these (I believe) have a throttle position sensor, do I just ignore this?

yes, just ignore it.

I used a dyno jet kit as well, if you make your own exhaust and use no air box you will need it, I ended up with 170 on the mains and the needles ful rich.

Normally it would have an input into the ecu but early ones just use crank position / speed sensor