Yamaha 5PW engine. Will it run on carbs?

[Ivaan7]

Hi,

My current set up is with the 5JJ engine on carbs. This engine now has low compression and is breathing heavy from the crankcase.

Looking around at replacements. The 5PW engine is basically the same, but with fuel injection.

Can these engines be run on the 5JJ carbs?

Thanks,

Ivaan

[mikeveal]

I've a 5PW & yes, I believe it's essentially the same engine.

[Tim.C]

A friend of find did the opposite and found that the spacing for the carb/ITBs is ever-so-slightly different and hence the throttle bodies kept wanting to fall off.

[Ivaan7]

After some further research......
The 5PW head is different from the 5JJ. The inlet ports are shorter, and I don't think that the carbs will fit. Also, the top mounting point on the LHS of the head is in a slightly different position.
To use the 5PW engine, I'd have to use throttle bodies. This would in turn mean changing the fuel pump, fitting a return line, plus changing the tank. Then I'd need to add the wiring loom and Controller. Then alter the engine frame for the different pick up point.
I've decided to re-furnish the 5JJ head and use this on the 5PW block. Then I can stick with the current carb set up.