I think when building my LC motor, I hogged out too much of the ID of the intake manifolds to fit the PWK's and match up with the Vforce3 cages.
Basically, I removed the step that the carb butts up against inside the manifold so the carb goes in a bit further and fits more securely.
My theory is this step from the 28mm ID of the carb to 34mm OD of the carb/ID of the manifold is causing turbulence, or slowing the flow at low vacuum/RPM, and causing tuning issues down low.
Does this sound plausible?
If so, which manifolds do I need to replace them with so I can start over?
Needs to fit the larger RZ crossover, and ideally have no ears so they fit flat against the Vforce3 cages.
These:
https://www.ebay.com/itm/402313191328?epid=239217658&hash=item5dabbc1fa0:g:w1kAAOSw4lte~MfP (https://www.ebay.com/itm/402313191328?epid=239217658&hash=item5dabbc1fa0:g:w1kAAOSw4lte~MfP)
I have a set on my RZ even as we speak.
there should be a lip seal that the carb 'snaps' into in the intake. it doesnt need to go further than that. id get some upp intakes from john at economy.
Tough to tell from the pics, but do these have the ears on the back?
https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/fuel-and-airintake/manifolds-yamaha-rd250350400r5ds6ds7-parts/manifolds-for-26-28mm-carbs-vm-tm-pwk-pj-with-boostcrossover-holes/
I really like these, but it looks like they are out of stock.
Dont have a crossover, but it is basically just a gimic that adds places where you van get an airleak.
https://drivelineperformance.com/billet-intake-manifold-kit-stock-26mm-28mm-carbs-carburetors-yamaha-banshee-350/ (https://drivelineperformance.com/billet-intake-manifold-kit-stock-26mm-28mm-carbs-carburetors-yamaha-banshee-350/)
Quote from: pdxjim on August 21, 2021, 07:40:41 PM
Tough to tell from the pics, but do these have the ears on the back?
https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/fuel-and-airintake/manifolds-yamaha-rd250350400r5ds6ds7-parts/manifolds-for-26-28mm-carbs-vm-tm-pwk-pj-with-boostcrossover-holes/
nope
just match them to the cage (via the gage). i run these on 2 bikes