Fuel stand-off - intake reversion - what are the causes? 2

[v114]

A while back, I posted some questions related to a v-twin I am working on.

Here is another puzzling one. The engine is a v-twin, dual overhead cam, 4 valve configuration - designed from a clean sheet of paper - not really a copy of anything.

The motor has severe intake reversion that comes on at around 4-5k rpm. At the same time, the engine will not make peak power past low 5k rpm.
Things tried have been:

1. Cam timing and duration changes - we have been all over the map with possible changes and combinations and the engine does not really respond positively or negatively to cam changes.
2. Intake manifold configs: dual IR runners, one carb to divide to either cylinder, 48mm and 56mm throat carbs. All had reversion.

Is it safe to say that the engine will not be able to realize its power potential unless the reversion goes away? Also, what other factors could contribute to reversion besides cams and intake systems? Really look forward to some experienced opinions on this topic.

Thanks

 

[wwest]

Have I missed something or have you NEVER removed the, any, exhaust stack/pipe/retrictions to see if the problem might lie there..??

 

[XXXLR8R]

I believe they use 1.90" diameter head pipes almost a meter long... no mention of Pat's suggestion to run a pair of 2.25" pipes 40" long, though.

V114 - IMO you've stacked the deck against yourself with your novel engine design.

What did you discover in the combustion chamber design?
Have you considered a dry-flow intake tract?

Si Vis Pacem Para Bellum

 

[VRC]

V114
Have you made any progress on the reversion or did you shelf this project?