1900 cc engine conversion

[ChiefGunner]

I know we have a lot of “gear heads” here with much more experience than I have, so let me put forth a question.

We know that the new Venture motor uses hydraulic lifters which actuate upon TWO valves. These spring pressures are reaching “high performance” pressures which is why hot rod cars go with roller rockers. Because Yamaha has it this way it has proven to be a weak point with this engine.

The question then is.. Is it possible to have this engine re-done using roller rockers and solid lifters?  If it is, what are the pro’s and con’s?

[saddlebum]

On 1/31/2022 at 11:10 AM, ChiefGunner said:

I know we have a lot of “gear heads” here with much more experience than I have, so let me put forth a question.

We know that the new Venture motor uses hydraulic lifters which actuate upon TWO valves. These spring pressures are reaching “high performance” pressures which is why hot rod cars go with roller rockers. Because Yamaha has it this way it has proven to be a weak point with this engine.

The question then is.. Is it possible to have this engine re-done using roller rockers and solid lifters?  If it is, what are the pro’s and con’s?

I would imagine the Pros would be the same as with the Hot Rods. More positive valve action. Because in most of these setups heaver springs are used to eliminate valve float at high RPM's.

The Cons would be that the valves would have to be adjusted to a proper valve clearance at periodic intervals. Because the mechanical valve setup requires a given clearance versus no clearance required for hydraulic lifters the engine will run a little noisier until warmed up.

So the only advantage to hydraulic lifers is a quieter running engine and the elimination of periodic valve adjustments. 

The advantage of Roller rockers is reduced wear and operating friction. Elimination or reduction of valve float and improved performance.