YYIIIIIIHAAAAAA (I think :) )

[F-Type]

So, I've got one of these lemon-octanes. It's been mocking me since the beginning and I have tried everything in the school-book, well, at least the Savage Octane school book, over and over again. So in the end I came to the conclusion, it isn't any of those things that's the problem. Started reading in detail how an engine like this works, and what problems one can expect, or rather hardly expect. And eventually I found an article by some kind and knowledgeable person who had written about compression, not combustion chamber compression, but crankcase compression. So, a simple test and I could realise I had quite a blow-back from the crankcase, back through the carb and out to the air filter. So, the fuel-air mixture that is sucked in during the compression stroke, just gets blown out again the same way it came in, more or less, during the combustion stroke.

So, I installed a reed valve between the carb and the crank case. And guess what, after a year of frustration and a basically totally dead engine, it started. IT STARTED! and you know what! IT DIDN'T STOP! Not until I stopped it. And after i had stopped it, it started again in just a few pulls. So I stopped it again, and it started again in just a few pulls, same thing a third time. Unbelievable. I can hardly believe it myself as I write this!

It is way past midnight here right now, so further testing now isn't an option, especially as I have an early morning tomorrow with a long journey ahead for a week long trip.

So now I am frustrated about not being able to test the car more thorougly until more than a week away. :/

One thing that struck me in this, is that what HPI calls an "air restrictor", which I have never really believed in (I mean, who wants less air-fuel mixture in their engine?), isn't an "air restrictor", at least not in the way they make you believe. It is a cheap poor mans reed valve that really doesn't work very well, hardly at all.

I should also say that I tested to remove the reed valve and tried running the car again without it. It wouldn't start. Reed valve back on, and the car started in a few pulls.

Next thing will be to remake the throttle control, as the carb is now located a lot higher up, as it is mounted on the reed valve. I need to find a way to connect it to the throttle servo with the carb in the new high position. Any suggestions "on the fly"? So I have something to think about during next week

 

[J.LO's SAVAGE X]

well great job! Glad to hear! Help out your other octane owners and let them know!

 

[Jam Racing 1]

Pics Pics Pics. please when you have time a complete write up on this and finish testing. I am SURE other Octane owners would be very interested!!!!

 

[NightFlier X4.6]

Congratulations on what I hear to be a BIG victory!

 

[F-Type]

Thanks guys!

I'll try to manage to snap a few shots before leaving this morning, and then do a write up during the week.
Further testing must unfortunately wait until I am back home again in a week or so.

 

[F-Type]

Unfortunately I didn't get the opportunity this morning to snap any photos of the "prototype" setup. And I think I should do some further testing before doing a proper write-up of this mod.

But, in practice, it is a very basic thing, add a Reed valve between the carb and the engine (crankcase).

 

[smoose]

wow, mine runs with or without the restrictor in place, but did not notice any power difference, so put it back in. only difference was had to adjust the mixture needles to get to run without the restrictor. still great to hear you got yours running!

 

[smoose]

I also would like to see pics of the reed valve

 

[F-Type]

Good to hear yours is running. But didn't you have some issue you thought where related to combustion chamber compression?
That could be related to this.

There is a design in the crankshaft that is supposed to function as a reed valve, I think. Clearly yours is working, at least to some extent .
But I assume it puts high requirements on manufacturing to keep narrow tolerances, and one wonders about durability and how it affects engine power. In any case, I think that's where many of these engines fail. There's also a separate channel for the carb "pump" pulses. I tried to "identify" the pulses supposed to come from the channel but didn't manage. Instead I could see them in the air-fuel channel, where they're not supposed to be. Didn't seem to be any blocking in the pulse channel though. With the setup I have now, tested as per above, the carb pump pulses are taken from the air-fuel channel, which isn't supposed to work. But it does, and that, if anything, is a clear proof of the problems with my engine. And many more I am convinced.

Hope I am making sense. Writing on the phone so short and no pic references.
But check the octane engine exploded view in the parts list. And you'll see the crankshaft with an internal air fuel channel and a small opening where the air fuel mixture is supposed to enter when the engine is creating negative pressure in the crankcase, and to keep closed otherwise. It's the keeping close part that doesn't work. Simply too poor tolerances between the crankshaft and crankcase I assume.

 

[Alonzo-a2]

Czy ktos jeszcze zamontował zawór i posiada jakieś zdjęcie?

 

[Sandblaster]

Reed valves in two strokes has been around for a long time in dirt bikes, atv's etc. A big improvement in HP and performance. Reed valves is a science in itself.

 

[Lukasan]

Sorry to dig up this Thread can please anyone provide any details of this reed valve and how to add it?