The carburettors for this project will use the standard 36mm CV Keihin oem units found on the Honda VF1000F/R road bike models. They came to us looking very tired, rusty and crusty…

They were stripped down, cleaned and inspected. Rusty hardware was replated and the alloy bodies sent off for vapour blasting.

After reassembly they looked as good as new.

Anyone familiar with the early generation Honda V-Four knows how tightly packed the carbs are inside the vee of the engine. Seeing as this project is destined for the race track jetting changes will be common practice and with the limited space afforded by these carbs it was not going to be a quick nor easy task.

Honda themselves must’ve realised this same conundrum so they fitted plugs to the fuel bowls and caps on the vacuum chambers to make jetting and needle changes easier. Similar features were then standardised on the limited production VFR750R (RC30) model.

Such parts aren’t available for our carburettors so we designed and fabricated our own parts to feature the same access ports.

Fitting the standard production VF1000 air-box was not an option. It was too bulky for the space available. In order to fit the smaller frame and fuel tank of the FWS project bike we designed our own air-box and filter mount. We used a flat panel filter element that is specified for a modern liter bike producing over 190hp. That would be more than enough flow for this engine. The air-box needed to fit atop the existing plenum and it’s complex flange. My recently acquired 3D printer would be perfect for this type of task. After some initial trial fit ups in PLA a final design was arrived at and printed in ASA filament.

4 thoughts on “Carbs…

  1. Shawn Moynihan

    Beautiful work! I’m curious as to what kind of horsepower are we trying to attain? I was told by some mechanics that my VF1000R had no hope of squeezing out more power. Would love to see this making 150 at least!


    1. DonR Post author

      So would we! For now we’ll just focus on completing the bike and then iron out all the bugs. Once that’s all sorted we’ll start chasing horsepower.



    je suis admiratif du travail ! jai aussi supprimer la boite a air d origine pour mettre des cornets sur mesure, votre solution est super! vous pouvez faire encore marcher la 3 d pour me faire une boite aussi ?lol, continuez bien ce fantastique projet !


    1. DonR Post author

      At the moment it is just a prototype. It has not been tested for tuning performance, durability and temperature resistance although that shouldn’t be a problem. In the future it may be possible to produce more if it tests ok.



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