Broken reeds? This engine breaks whole reed blocks! 

As I mentioned a couple of videos ago, a dynajet model pulse jet engine's spring-steel reed valves have easily withstood 1400+deg. F temperatures while running on 90% nitromethane fuel (control-line speed; 200+ mph). The reeds have a pedal (like a daisy) configuration and have a relatively high aspect ratio; they cover multiple circumferential ports in an aluminum induction head, whose opening allows for a surprisingly good flow-rate. These reed valves are still available and can be easily adapted to your engine configuration. You can find multiple references to the Dynajet engine on the Google search engine. If you decide that you want to try these valves-I have them (new) and will supply them to your project free of charge. By-the-way a simple disc-retainer prevents the reed petals from over-opening.

"Manhood threatening music" hahaha 😅. Love your sense of humour!

Danke LANGTUNIG!!! Super Geil das ihr 2SS Sponsort! Danke auch an JEDEN anderen der die "Reise" ermöglicht! Vielen Dank!!!!!

Langtuning used to work 2 km away from me. What a coincidence 😂.

Can you hear it?? Drum valve, drum valve!! Seriously, I think that's the best solution in your boosted application. Especially the air volume level on this motor. It's pretty close now...

Good luck and greetings from the netherlands!

Music or no music, I'm invested

I very much appreciate your choice in music, ignore the haters.

Whatever music you want to use, use it. It's your channel. Usually the most annoying thing (for me) is how RU-vidrs tend not to be aware of "sound levels", although it sorts itself out in the end.

Look at the reed valve design used on 47cc pocket bikes. They use a curved stop block that keeps the reeds from over extending and breaking when they open. I fabricated some for use on my motorized bike. Haven't experienced reed failure since the addition of the mod. I posted this comment under another video but see it's more applicable to this one. ✌️

Its a port timing problem, i suggest you make the exhaust port open 1 degree earlier, maybe you eliminate the backfire problem.

Try TITANIUM REEDS but don't use CP Ti. ( commerically pure). You want something like 6-4 or 6-2-4-2. Something with some spring properties in it. Ti is very resistant to breaking. There is also several spring steels that would work great but they would require either you buy the material with a proper heat treat on it and then have them cut out by a shop with an edm or waterjet or you buy the material soft and then find a PROFESSIONAL heat treating outfit to heat treat them for you after they are done. There is no garage shop dunk it in a can of oil heat treat methodology when the risk of damage is so high if they get it wrong. Titanium could be machined as it would not need to be as hard as spring steel would need to be to make it strong enough. I mentioned 6-4 and 6-2-4-2 but do a little research as there is no doubt better alloys available these days. But Ti will not break unless something catastrophic occurs. But do NOT use CP Ti. It is too soft and not springy enough.

Made my day seeing this video posted thank you for the hard work!

I love the music... if it matters. I think your "cinematography" is more immersive with the music. But alas. ALWAYS happy to see you working on your projects.

What we would do back in the day when we would mod our dt50's, we would often use reed cages from 125cc bike's. Bit of fitting required but they held up well for us.

It's impossible to threaten my manhood. :P Play whatever music you want =)

you probably need aluminium reed cages and steel petals

You could remove the dump valve and just fit an adjustable blow off valve instead. This is how I run my supercharged MGB, valve bleeds off excess pressure in the event of backfiring.

highlight of the week

I wish I knew you IRL. You seem like you would make a good friend. I like you and your brain! Unfortunately I live in the US...

If you still want to bother with fiber reeds, machining an extra support into the cage at the middle of the reed is could help with the cracking by reducing the unsupported area. That way you could run custom metal cages still with the fiber reeds.

It's sounds like it's all coming together pretty well, keep up the good work, and you will make it

A 1976 CCW 440 engine from a John Deere Liquifire I worked on has aluminum reed cases and steel reeds with steel plates for limiting the reed travel. More models and years of snowmobile engine came with aluminum reed cases. They also are generally rubberized to create a very good seel and are large for the large displacement engines snowmobiles have. Cheap as well.

I'm wondering if it would be a good idea to put a burst disk, similar to the ones on supercharged engines, in the crankcase to prevent extensive engine damage when it backfires.

looking good!! so much potential

"Manhood threatening music?" Dude, I always love your music choices. Maybe that says something about my manhood...

After having watched the early stages of this build, this is exciting progress for some sustainable pulls and testing. I eagerly await the numbers this bold concept can produce.

Thank you! I love the work you are doing and sharing your amazing videos on Gan jing world. Welcome to the new world!

i think you should go for a larger reed cage. and steel reeds. in a boosted engine you should be able to overcome the larger size. but also since it's larger. there should be less stress on each reed. thus making it more durable. and with stiff enough reeds. it should be able to run on lower rpm to

maybe you should have the brake caliper at the bottom of the disc, and submerged in water. I dont exactly know what fading have for effect on your particular setup, but if it has an effect, power figues probably would be obscured and all over the place, right? water would both cool the disc, brake pads and your face when splashing around this summer =)

I'm assuming your misfiring at high RPM is related to your plug gap. 2 bar of charge is going to be really dense and quite difficult for the spark to penetrate. It.might just be a matter of closing your plug gap to like 0.8mm or even less.

Wow once you get a pipe it is gonna breathe by the look of the tubing you used. That was a lot of back pressure, great work, good luck and break a record!

Brilliant to hear you have got a sponsor for Bonneville, really look forward to seeing how it goes.

Endlich ein neues Video , greetz From Germania

I've used thin paint scrapers (spring steel) to make reed petals.

Great to hear that little motor singing again. Take a look at the old school Yamaha RT360 or DT250 reed block's, steel reeds, over engineered and made to last.

Enjoy this channel so much I click like before I even watch an episode

Put a pressure sensor on the Brake line will give you an indication of braking force , it will not be accurate but will give you a good base line for how hard your braking . Replacing the hand leaver with a longer unit (Screw/zip tie a longer arm) then use a spring to load the arm at a set distance will help , assuming pad wear is minimal for testing.

The mid 70's yamaha 250/350 had aluminium reed blocks with stainless steel reeds, and they were reliable .

If you intend on staying with the reed valves, I seriously think you need more blowdown area, it seems cylinder pressure is still way too high when transfers open, hence the broken reed cages.

Those notches in the one-piece reeds look like perfect stress risers. I wonder why they are designed like that.

I'd suggest a redesign of the piston top, replacement of intake and exhaust ports, no reedvalves at all.

A off the shelf option for the cage is the Boyesen Rad Valve as its fully metal , you could again get a Cr85 one and upgrade it to metal reeds when you liked ..

I think you should just use whatever music you want man, it's your channel after all. Super excited for this engine, can't wait to see it strapped to a chassis

Tells us about Lang tunings product and services. Thats what sponsors want.

I would try RVS Technology on the rotary valve. Should reduce the friction quite significantly!

Do you know what the crank case pressure is, you might need a smaller supercharger. As it is your cc pressure is 3 times atmosphere, no wonder the reeds keep keep on breaking.

Get your reed cages from Taiwan,Thailand, Japan. They make the most dependable parts I know of.

Maybe something is hitting your reed block or you have huge vibrations in the engine for it to break. You could rout a grove in the reed block and run an o ring in the groove and mounting bolts (retaining compound to lock the bolts) to help reduce vibration. Reed and carby would float then.

Maybe a reed cage with more support for the petals than only a bridge, will make the carbon petals possible. I think it is worth trying to make the Carbon petals work, but if you use the metal ones I would check on them every few minutes of runtime.

The reeds are probably resonating to destruction same as the tail feathers in an airplane , talk to an aeronautical engineer they deal with that stuff and in any materials you could think of , face it they balanced the SR-71 airfoils going probably faster than your reeds

First! Okay now to watch it and be back with any comments. Keep up the excellent work! You have done the final inspiration to buy a amr400 and custob mount to a 2 stroke I have for more looks than performance, project will be a cpuple years out before i start it but planning now will be key.

Use udahome (spelling) steel. Same material that shock shims are made from. A bridge in the center that is solid top to bottom. Makes two compartments.

Hey Alex, have you thought about a burst plate? They use them in some supercharged drag cars in case of backfires. It might be worth looking into, lot more compact and simple

So much pressure 🔥

Use a sparkplug similar to rotary engines, use an electric blower,turbo design, with electronic control of boost.

Make the lever for the brake longer, it will be more sensitive and easier to dial in.

BRUTE FORCE, HE WASN'T KIDDING !!

I’m thinking maybe steel reeds of the thickness you need won’t be able to work at the desired rpm, usually that’s why with high performance they move to composite material. Would a disc valve on either side driven by one shaft work? Maybe using a small bevel drive off the crank or off an idler pulley.

Hi Alex, outboard motor engines use reed valves

I forgot about backfire protection. Makes sense now. I would run a hose from between the carb and supercharger to the top of the dump valve so at part throttle the vacuum will help open the valve so it vents at part throttle to reduce intake temps when not at WOT. Might not be worth the effort but if it’s easy to add, worth a try. It’s looking much better with the bleed valve.

I always thought the “uniflow” design has major advantages in the power department

Is it possible to add a sparse support grid under the reed, or would that create too much extra turbulence

Maybe a solution for the reeds is also to make them diagonal with the raster of the carbon fibre . could change a lot

How about trying to double up on the reeds. If they are "tuned" to work without boost, boost might just need a stack of two, or three depending of boost levels. An easy thing to try out.

I still say in my opinion this engine should be fuel injected , 2 injectors, one spraying into the crankcase and one spraying into the transfers, it may even help the reeds live longer by only having fuel on only the one side of the reed.

I like what you are doing ! maybe a dumb question but, why reeds AND the rotary vavle ? seems to me, a rotary valve would be ideal, despite the limited Int/Exh timing. I wonder what Kevin Cameron thinks ?

To me it seems like the waste gate should be after the reed valves. You have no backfire protection with the waste gate before the reeds. The waste gate won't start relieving backfire pressure until the reeds are already broken. That's probably why they are breaking, the reeds are taking the hits from the backfires until they break. Just my thoughts.

Would a twingle setup be better for the boost since it's not possible for it to just blow the boost out of the exhaust? It would limit the exhaust some with the small diameter cylinders I guess.

Blingfactory makes aluminium reedgages, and steel reeds will be good way to go. It have enought flow to operate with them👌

In case of a musical interlude, might I propose the theme music from 'Shaft'? Manhood up to 11 😎

How about using the umm. I don't know the english word for it but spring steel might be the most understandable word😅 for the reed valve i mean. They might actually be that material anyways i don't know but it just crossed in my mind while drinking😅 allso just thinking how about make some tubing from that wastegate to the intake of the carburetor so it would work as bypass valve and recycle all the fumes instead blowing them outside... Sorry for my bad english😁 you'r doing great and your videos are the main reason i watch youtube🤘 never give up!!😎👊

I would try steel reed valves, or shim stock? Best wishes.

Just thinking laterally, if this is for a land speed record ,could you use a compressed air cylinder instead of supercharging. If it were fiberglass it would be light. If it were aluminium it could be incorporated into the bikes frame. I think there might have been some experimentation in drag racing where weight is important , but speed records not so much so.

Same thing happened here. Never had luck with vforce style reeds, too weak for serious application even just NA, tried boyesen with their normal style reed and are much better, even made more but power, it resists much more pressure they have double layer "plastic" style reeds, the only ones wich where able to resist in my 300cc 2 stroke modded engine application.

I really liked light jazz background music

Bring back the jazz ♥️

Pyrotechnik... Ist doch keine Verbrechen.... Wir werden dafür kämpfen und lassen Emotionen freien Lauf...

How do you like the idea of creating a 4-stroke 50 cc engine with 4 valves and turbo boost?I think the power will be about 7 horsepower

Rotary cylinder valve

I am so sorry I can't support like others..but I am on my seats edge to see what happens next

can you double the reeds up, like a car leaf-spring. thanks.

Would it be possible to run a mesh after the reeds to prevent fragments from entering the engine if you switch to metal reeds?

I am wondering what the best metal would be. Spring steel ?

If made from metal, then must be so sturdy that It will never break off into engine. Mabie a metal frame with much more supports, and keep the Reed material same?

Wonder if pieces of reed are what tear the exhaust ducting at about 7:44

I think that you're decieving yourself with the reed valves. The reeds aren't the problem, they're a symptom of another problem. There's a reason *why* you're getting backfires. I'm wondering if there's an overpressure event taking place inside the crankcase, which ends up holding the reeds open for longer than they should be. You could be experiencing a pressure wave being bounced back and forth all the way between the reeds and the supercharger, something that the wastegate can't deal with because it's too brief...until the reeds give up. Stiffer reeds isn't the answer, it'll make it worse. You need that overpressure pulse to go somewhere, so you may need more crankcase volume via a plenum chamber to even it out. We used to have similar problems on some Yamaha RD's we were tuning. The solution was to remove the balance pipe on the intakes and enlarge it quite drastically, forming a plenum chamber that bridged the seperate intakes. It still maintained intake balance, but it dramatically cut down on any rough running from unstable intake pressures. We learned the importance of critical volumes that day.

maddox pulse jets has the reeds you need

Try harmonic steel reeds, maybe with supercharged engine works better

Carbonfiber is bonded with resin... it is very possible that resin does not like nitromethane and alky + charge air temperatures might make own twist too...

vforce 2s for life

Thank you for no music, i prefer that

titanium reeds, it is half the weight of the steel, maybe akrapovič would like to help, gibe them a call

Forget the folks who complain about the music, make the content you want to make; doing that is what brought everyone here in the first place. Bring back the guitar, too. Do _you_, man. Would be cool to jam with you if we weren't so challenged by geography and a dash of crippling social anxiety haha

Try making Reed valves out of compresser valve plates from a truck those plates work hard and don't brake

Steve Tassinari at Moto Tassinari/V Force can fix this issue. Also, the first reed valves were made of aluminum.

Why don't you try poppet valves like they use in air compressors?

i used to come for the jazz... please bring the jazz back

Pray to god, is that an engineering concept?

Never ending story 2