Tohatsu M40C twin carburettor modification

[ice_spy]

It's been a long time in the planning, and even longer to find a confident welder to take on the job.
A lot of heat and alot of fill to be added, it was no easy task.
The motor now has direct intake runners, with the reeds now placed much closer to the crankshaft. The crankcase volume has been dramatically decreased, which should in theory supercharge the intake charge.
Carburettors are the same model as the m40c, however it now has reed stuffers.
The rear half of the motor is stock with no porting or modifications.
If it all works, another block will be built with +1 pistons, and some mild clean up / porting, depending if the power band needs to be moved to a higher rpm .
Has anyone done anything similar and could give any advice , help or constructive criticism with this build would be most welcome.
If it all goes to plan, my goal is to set a new APBA record for the kilo run at the Nationals.
Pics coming soon.

[ice_spy]

[Roflhat]

Loving your work

[ice_spy]

Thanks rolfhat, I managed to get in the garage tonight and gave it a final sand and a quick paint.

[ice_spy]

Block is together and sealed, stator and flywheel assembled, carbys sitting on waiting for 1x more reed stuffer and some new gaskets. Got to sort out timing lingage and throttle cable attachment. Found a clamshell 65merc cowling will clear the front carbys and not have to worry so much about custom bed plate and pan, with an extended cowling to suit. Its all coming together now.

[ice_spy]

Cleaning up the deck and head after the previous owner gouged it trying to remove it, also to remove any corrosion. Fixed up 2 snapped head bolts, and getting surfaces ready for the head gasket. Not sure i will mill the head down for squish yet, but its definitely an improvement if I do.

[ice_spy]

Modifications for the throttle cam, adapting the m40c throttle cam mount to the twin carb reed stuffer plate, so that it retains the original position. The top throttle shaft was replaced with the m40c shaft to utilise the original throttle lingage set up. Bolted together ready to be welded up.

[ice_spy]

After some mods to the oem bedpan I was able to go for a more sleeper look.

[ice_spy]

Going all out, got a spare head im converting to center fire. Has been milled for compression already too.

[ice_spy]

Mounted the starter, plumbed up the recirculating system. Tapped a brass tube in for the fuel pump and started plumbing up some lines. Its getting close now, dropped the head off to the welder today, as soon as that's ready, it should be time to fit the powerhead and give it test and tune.