Reed valves and inlet duration.

[Theon]

Any Tips on ideal inlet duration for my motor with an RSE Reed Valve?
I've seen people have cut windows in pistons, to increase inlet duration, is this the go, or is it unnecessary?
Thanks for any advice,
Theon.

 

[GearNut]

The window in the piston is for a boost port, a 3rd. transfer port.
Simply cutting a hole in the piston will help, but why not get the most benefit from it?
Do a web search for more info.

 

[Theon]

Cheers Gear nut, web search was my next step,
Just thought someone here would have some experience in getting the most out of a reed valve.
I've heard you can go to far with drilling holes in pistons, I've also read some where about boost ports with reed valves, not sure I want to bother with that though, keen for others experiences.

 

[Theon]

Been doing a little research,
Seems that 170 deg inlet duration is recommended.
And getting primary compression as high as possible also important, The reed valve I have does not protrude into the inlet port and so I'm working on stuffing the cases as much as possible to compensate.
I have been working on my own Reed valve design, but am curious to try the RSE first, as it does look very nicely made.

 

[sublunacy]

jaguars ridiculas website is pretty convincing lmao

depends wich carb and exhuast and gear ratio. 170 degrees means nothing till you think like your engine. boost ports will frankenstein the 66cc w a piston window. case port reeds like an arrow steetracer cannot take boost ports at all.

im not saying anything more as my ideas for the last 6 months get systematically stolen then waved in my face. i wish i could help but filling wallets takes the cake theon no offense this time.

 

[2door]

"stuffing the crankcase" ? I sincerely hope you're not going to try using JB Weld. You'll be sorry.

Tom

 

[MotorBicycleRacing]

"stuffing the crankcase" ? I sincerely hope you're not going to try using JB Weld. You'll be sorry.

Tom

I got this from the other forum.

Insulting offers will be cursed to everlasting flames. I have spent untold hours getting this engine just right. The cylinder lost some flakes of chrome lining when part of the JBWeld I had glued to the interior of the crankcase (for more crank pressure) came off and got chewed up in the engine. Still runs great though.

Special quote for 2door

 

[Theon]

No I won't be using JB weld, I'm making aluminium plates.
It looks from the forums that I'm about 2 years to late to be at the cutting edge of reed conversion development.
So surely someone here has some advice other than not using JB weld.
Never mind I don't mine experimenting.

 

[Theon]

My new crank from RSE is quite a bit narrower than my other 40mm cranks.
with only 6mm between flywheels as opposed to the usual 12mm.
Allowing for 5mm plates to be mounted to the cases.
This should give me considerably more primary compression.

 

[sublunacy]

pretty nice. i recomend testing the assembled block by filling it w measurable amount of premix. if your happy it cleans dirt away aswell.

good luck!

also please test the crank balance bobweight

 

[headtrama]

My new crank from RSE is quite a bit narrower than my other 40mm cranks.
with only 6mm between flywheels as opposed to the usual 12mm.
Allowing for 5mm plates to be mounted to the cases.
This should give me considerably more primary compression.

How are you going to hold those plates in

 

[Theon]

Plates are a very slight interference fit, then glued in with Loctie 3805.
This will be 3rd Trial with no problems on the other two.
Removed Old plates from cases before installing wider ones, they were stuck good, and first attempt, so hopefully did a better job 3rd time.
Have chosen my inlet port timing, but seeing your all so secretive...
I'm reusing my lightened piston for this and have drilled a couple of nice big holes in it. I got a felling this things going to scream!

 

[sublunacy]

thanks theon. i appreciate the confidental very much here. and yes screaming power wheelies are your future piston looks identicle to mine btw. see how the pin is not affected in strength plus a bridged window including a gradual intake port opening and closing.

this thing is really going to haul the mail

 

[Theon]

And Thank you Sunbluacy, for being the only one here so far to offer me 'the' advice on the subject, I was looking for. And although I don't always follow advice 'by the letter'. I see that you are correct and likely a wealth of knowledge.
Thankyou for your support.

 

[sublunacy]

theon is getting a sublunacy reed kit sent to australia tmrw.


thank you and congratulations!

 

[Theon]

And this I hope to squeeze on to the Phantom, Then I'll have to Strap the **** out of them both and report.
Cheers Sunblunacy.
Will be running very similar engine mods on both bikes, So will get a good comparison test.
Stay tuned!

 

[mech_engineer]

You can run case inducted 180 duration but is less because @tdc and bdc take a few degree is like 170 for 8k rpm you need a 2.75cm^2 mean area but mean area at case induction means area because is the same area all the time and dont change like in the cylinder port

 

[mech_engineer]

The problem with this engine: the intake port is to small..

 

[Theon]

That's not the only problem with these engines, but it's what I've chose to work with.
Have you any recommendations on port sizes and timing?
I've been quite happy with my results so far, after all it is only a push bike doing 70-80 Km/hr.
Mostly wanting to increase my low to mid range torque, not really after anymore top end.

 

[mech_engineer]

Rpm port duration and type of power band you want? With these i will give you the mean area needed

 

[mech_engineer]

For low mid you need to increase the transfer port time area and reduce the exhaust time area...in other words port the transfer ports for more area and duration(can change timing in piston) i have 168 @ exhaust and 140 @ transfer going to change the intake to case inducted for 8k rpm intake area needed is 2.75cm^2 @ 180 duration. I have read a lot of the tuners book and i am good with numbers. i can obtain the mean area needed for the duration u got or can give you the duration needed for the mean area u got. There no space in the cylinder to obtain a good intake port but if you do it you can compromise the piston shape because you need to cut too much of it and the holes at the skirt not give the area needed also