rse reed valve drill holes in piston or raise the piston skirt and extend intake port

[Fabian]

the only benefit Fabian has is a stronger idle.

and stronger low rpm torque

and

stronger midrange torque

 

[max350]

and stronger low rpm torque

and

stronger midrange torque

For once, I must agree with Fabian! If he feels that the engine gets stronger in the low and mid range, then probably no one here on the forum can have an opinion on just that engine right? Although there are various' theories about how reedvalve works

 

[Deleted member 12676]

ever hear of the placebo effect? If someone believes in a certain outcome then their body fools them with corresponding feelings that support their belief.
That also applies in the 2 stroke world.
I approach all tests with a neutral attitude and therefore do not fool myself. I also know that seat-of-the-pants tests fall into the placebo arena. So when I test for mid range power I find a long uphill and each test is started with a certain speed at the base of the hill. Top RPM tests are done with a speedometer to see the maximum speed. Here are my test results concerning this topic:

Crazy test #1003: add a reed valve to a piston port intake engine with extended intake (7.5" total)
Results: idled stronger with slightly better power taking off from a stop. 4% less top speed. no other power difference.

Crazy test #1004: put holes in the piston skirt so that now it is an extended intake added to a reed valve setup
Results: bad off idle power, 20% more top speed (+5.3mph)

Crazy test #1005: remove extended intake
Results: good power throughout rpm, gained .3mph top speed

http://www.motoredbikes.com/showthread.php?39470-Reed-valve-with-extended-intake

 

[Fabian]

ever hear of the placebo effect? If someone believes in a certain outcome then their body fools them with corresponding feelings that support their belief.

Have you ever heard of the 'Jaguar effect': where anecdotal evidence builds an immunity to aspects of Jaguar logic.

 

[Deleted member 12676]

I use the scientific method to test ideas.
I don't see how anyone can fault that logic.

 

[Fabian]

I can't wait till Headsmess gets his bicycle engine dyno built, then we can sort out what works and what doesn't.

I'm not sure how Headsmess could incorporate the technology into his dyno but there needs to be a knock sensor to pick up heat stress when replicating the effects of higher than normal engine temperatures, over longer running periods with wide open throttle and little or no airflow over the engine; a condition which more faithfully replicates the operational environment of these engines.

Short burst (dyno) runs won't uncover all the gremlins in the system.

 

[Deleted member 12676]

That's why the pros use a dyno only as a starting point.

 

[gamer121ps]

That's why the pros use a dyno only as a starting point.

you said its either piston port or reed valve, not both. are you suggesting that i drill the intake side of the piston to the point where the intake port is never closed off by the piston?

 

[Fabian]

If you have a reed valve installed on your engine, the piston no longer needs to control the intake port; with induction becoming solely a function of untimed vacuum control.

The problem with drilling the heck out of the piston is lack of redundancy. If a reed valve petal fails, the engine will not be able to operate from mechanical port timing offered by the piston.
For this reason it is wise to only have the piston port matched to the roof of the intake port, minimising port shrouding by the piston but still allowing conventional engine operation as a backup.

Having said that, i have "never" had a reed valve petal fail, but i like the concept of redundancy, because i travel to some off-the-beaten-track locations; out of mobile phone reach and out of easy access for emergency assistance.

 

[HeadSmess]

reed valve requires the largest opening possible. i would be setting the piston at BDC, scribing top of intake port, remove piston...and remove everything from below that line.... then chamfer edges nice to remove burrs and stress points...


hmmm...

just cus this video deserves another mention