Homemade reed valve, the search begins

Discussion in 'General Questions' started by David Bogle, Apr 10, 2016.

  1. David Bogle

    David Bogle Member

    Have any of you ever built a homemade reed valve? Know of any good descriptions of the process? Have any pics, videos or links? At best I've been able to find discussions about the best materials to use.
     

  2. butre

    butre Well-Known Member

    I like using stainless steel shim stock for the petals and mild steel for the reed cage
     
  3. David Bogle

    David Bogle Member

    Do you have any pics of your craftsmanship?
     
  4. butre

    butre Well-Known Member

    it's somewhere in my parts bucket, I've been using an RSE valve for the past year. my design was similar to Arrow's valve, just with more steel
     
  5. HeadSmess

    HeadSmess Well-Known Member

    why the obsession with reed valves?

    what propaganda have you been reading?

    i recall an estonian posting a thread years ago with a vid of some estonian MB racing, where people where hacking into the crankcases and welding in manifolds for proper reed cages from REAL engines...but havent ever been able to find the thread again...

    if it isnt feeding directly into the crankcase...forget about it. half piston port, half reed valve is doing nothing but wasting time and money. all you are doing is placing a restricted passageway onto an engine with an already restrictive intake port.

    typical chainsaw/brushcutter easily out performs the HT engines, but still use piston ports 99% of the time.

    sheesh, i even figured out a decent way to do drum/disc induction but yeah...why bother? save up and get a denardis.
     
  6. David Bogle

    David Bogle Member

    Obviously you're not familiar with my postings or as you put it
    "My obsession"
     
  7. HeadSmess

    HeadSmess Well-Known Member

    true that, i got confused with someone else :)


    my bad...

    still...they aint worth it...unless you feel like seriously modifying the crankcase.

    modified a cylinder at one point to take the reeds from the lil CAG 49cc pocket rocket motors.

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    i thought they were a good idea at one point myself...

    can you tell this project was what made me convert my mill to cnc?

    and can you see the minor stuffups that prevented it from ever being finished? :D

    the first and biggest one was using the handy chunk of alloy i had lying around rather than get something slightly thicker... 3mm more and it might have worked. i took one cut too deep, broke through.

    think its all still in a box somewhere but then again, i probably scrapped most of it.

    i have a niggling memory about the reed cage breaking in the final stages that finally had me move on to other things...
     
    Last edited: Apr 13, 2016
  8. David Bogle

    David Bogle Member

    My obsession is with learning how to make my own parts instead of buying everything, I'm curious about what works or doesn't work for others
     
  9. lazylightning@mail.r

    lazylightning@mail.r Active Member

    Hi! I'm in the process of a build and it will have a homemade reed house. The actual reed (w/reeds) is something I picked up at the scooter shop. A four petal job for $10. I may change the metal petals to some carbon 0.5mm in thickness. I'll send some pictures when it wil be ready. You will have to port the piston or the reed will be of no use. A reed plus a speciafically tuned torque pipe will do alot to boost power, but you will have to increse the flow volume of those transfers and move them towards the intake side without getting too close to the piston ring pins paths. A third port will be needed for sure. The intake diameter should be wider than stock, as should the carb diameter. The maximum carb size is 21 mm for a 66cc engine when using a reed. A 22mm can be used on a piston port 66cc engine. I am using a conrod and bearings from a Yamaha Jog, it is 5mm shorter, so I have to lathe 5mm from the bottom of the cylinder using a special cylinder holder that I made. I also had to remove some metal from the bottom of the piston so it doesnt hit the flywheel when using the shorther Yamaha conrod. Here's some pictures of what I got going so far.
     

    Attached Files:

    Last edited: Apr 16, 2016
  10. lazylightning@mail.r

    lazylightning@mail.r Active Member

    more pics
     

    Attached Files:

  11. David Bogle

    David Bogle Member

    Very impressive, have you used a reed valve in the past?
     
  12. lazylightning@mail.r

    lazylightning@mail.r Active Member

    No it will be my first time though. I have been studying it a long time. Of course it would be better to have a reed feeding directly into the carters. But in reality even if you do this, there is very little room to make a third port coming up due to the limited mating surface area of the cylinder to the carters. I have been able to greatly widen the transfer volume/width and window length. This will help me get alot of charge through the two side ports, but I have outer transfer walls of about 1 mm in thickness before the fins start. It takes a steady hand and eagle eye. If you go to far, you will have a hole in the cylinder. Since I was going to lathe off 5 mm from the bottom, I just sliced off the bottom fins and welded some extra aluminum to the transfer outer wall area and then lathed it down to have a wider mating surface. I widened the transfers flow area after doing that. My transfer walls on my carters have had extra aluminum welded to them a long time already. I just added a little layer of jbweld inside here and there so they would match up exactly to the transfers on the cylinder.
    The best final solution would be to cast your own cylinder with good flow area ports/transfers and cut an insertable hardened instrumental steel cylinder (with thin little bridges for your wider/longer ports and transfer windows) and press it into the new custom cast cylinder. In that case it would be important to realize that grinding or dremeling such a super hard steel will be nearly impossible unless you use diamond bits. So you should get it designed right the first time. Little bridges may need some little walls that start off sharp like a knife and divide the flow before reaching the bridge. This will make it gradual and prevent the charge flow from hitting a flat and sudden inside of the bridge wall. This will need to be desigined into your cast though, and by all means it needs to be in perfect alignment with the bridges on the hardened speed steel cylinder. Such a cylinder would be worth the work though. Maximum flow area and a good size flow area in the third port and a steel cylinder that will never wear out. Welding a reed box mount(in two halves) onto the two halves of the carter will require some patience and good judgement in design and execution. I try to enjoy such things, then I begin to get good results ;-)
    I use some of these too. They make an engine perform alot better. More power, more peace of mind, more miles of racing it like a madman. http://www.techlinecoatings.com/hi-performance/bs-internal-engine-coatings.html
    I use the DFL-1 dry lubricant coating on the pins and piston skirts and the CBC1 thermal barrier for inside of the head and on the piston crown. It looks as though CBC1 is now replaced by CBC2, but it is also now available to the genreal public. Parts have to be sandblasted with a specific abrasive grit size, preferably using aluminum oxide as the abrasive. 20 psi for aluminum and 40 psi for steel. Then wash with acetone and do not touch with bare fingers or anything but a really clean cloth before applying coatings. The skirts have to be taped off before applying the ceramic thermal barrier to the crown and after that application, the crown needs to be taped off so the skirts can be sprayed with a single thin layer too. So use surgical gloves when handling so to not screw it up. When it is good and dry, it then goes into an oven for an hour at 350 F. The oven or grill should not be used for food again after that though.
     
  13. lazylightning@mail.r

    lazylightning@mail.r Active Member

    I almost forgot. To get a good flow area up from the bottom end through a third port in a newly casted cylinder, some modification will need to be done to the carter halves. This will mean moving at least one bolt to another location away from the cylinder mating area. This will mean adding some meat to it as well. Welding on chunks that you can machine later. That will still probably be easier than casting and machining the casts of some improved carters with bolts in different places and a direct reed intake mount. At this point, you will really save alot of money if you have learned to use TIG well enough to do it yourself. A good tip with using TIG on aluminum, is: Always warm your metal up a bit with a torch before trying to weld aluminum to aluminum. Dont make it real hot, not red! Just hot enough. The aluminum will take it alot easier and you wont have stupid globs that don't know where to go. Always practice on the same metal or type metal (an old broken carter and your donor metal) before trying it on your real peice. Don't work more than an hour. When you are tired, you have less concentration and less will. Save up energy and find a good day for your masterpiece to avoid sad or angering drama :)
     
  14. David Bogle

    David Bogle Member

    Sounds very labor intensive, do you race?
    Have you ever thought about making a YouTube video?
     
  15. lazylightning@mail.r

    lazylightning@mail.r Active Member

    I'll make a video for sure. Last summer I wanted to show off how I got my bike tuned while we were on vacation and it started cutting out the first day I tried to film it. It took me two weeks to find the broken wire inside of the insulation. Never got it running well again. We don't have any race tracks or races here. I do like to push it to the max all the time though. LOL! Top speed is still like 60 - 70 kph depending on what size rear sprocket I use. It sounds bad and takes off like a rocket though)))
     
  16. David Bogle

    David Bogle Member

    Hate to change the subject but with all the technical knowledge you have I guess you'd know a lot about porting as well, do you know a technique that isn't overly complicated that would give a moderate but noticable increase in power?more than just chamfering the edges.
     
  17. butre

    butre Well-Known Member

    widen the ports and install an extra base gasket
     
  18. HeadSmess

    HeadSmess Well-Known Member

    getting a decent tuned pipe is always going to make the biggest gain...
    top speed of 60-70kph... sounds like a lot of work to get a 66 to do what my lil 48's did, which didnt need any work at all? other than removing casting flash from the ports.
     
  19. lazylightning@mail.r

    lazylightning@mail.r Active Member

    Don't forget to buy a decent ignition block. Like the Jaguar ignition system for example. Otherwise your bearings will wear out real fast with any performance improvements. The stock ignition system is made to slow you down or kill the bearings since the Chinese manufacturers do not want you tuning these things to go fast. The factory owner was not at all shy about this. He meant that he will lose markets if they are banned in more and more countries. That is the reason they put a speed governing balance onto the crank as well.
    In addition to what was already mentioned here, you could widen depth/diameter of the transfer channels and bring them forward towards the intake without crossing the pistons ring pins paths. You should make sure the gasket is trimmed so as to not restrict flow within the transfers. A bigger carburator. A 16 or 18 mm would be fine. Take the head and rub the inside part on sandpaper on a flat hard surface making circular motions. I brought mine down to the fin level. Increased compression will help.
    I did and experimental modification of the ring end gaps by adding a thin layer to the ends of the rings. After working on them under a microscope like setup, I was able to bring the end gaps into perfect spec.
     
  20. lazylightning@mail.r

    lazylightning@mail.r Active Member

    Your 48's could do what my 66 could do with nothing more than removing casting flash from the ports? Wow! Challenge accepted! Breaking laws of physics will be alot harder than you think! I plan to get my 66 up to about 15 HP without going over 9000 rpm's at maximum speed. A little 48 with restricted flow volume will not even get anywhere near 10 HP. At least I will know that I have exploited every mod possible to squeeze as much power as possible from any 66 cc engine without making a high rpm noise machine out of it.... I'll bet my tuned pipe is better than any decent tuned pipes that come off the shelf ;-)
     
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