Intake manifolds?

[pdxjim]

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.

[85RZwade]

These:

https://www.ebay.com/itm/402313191328?epid=239217658&hash=item5dabbc1fa0:g:w1kAAOSw4lte~MfP

I have a set on my RZ even as we speak.

[m in sc]

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.

[pdxjim]

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/

[rodneya]

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/

[m in sc]

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