Page 1798 of 1835 FirstFirst ... 7981298169817481788179617971798179918001808 ... LastLast
Results 26,956 to 26,970 of 27515

Thread: ESE's works engine tuner

  1. #26956
    Join Date
    18th May 2007 - 20:23
    Bike
    RG50 and 76 Suzuki GP125 Buckets
    Location
    Auckland
    Posts
    9,057
    Quote Originally Posted by speedboy View Post
    Quote Originally Posted by TZ350 View Post
    A RV 2T running with no RV, that is truly epic --- --- very much looking forward to hearing if it's ridable.
    Why Epic? A lot of people are riding with broken or missing reed petal -> Strange idle, weaker performance
    Why Epic .... well intuitively I have always thought you needed some sort of inlet valve timing control to make a two stroke engine work properly. My guess is most people think so too. It would be truly Epic and rather funny if we have all been clinging to a myth.

    Flat earth, center of the universe thinking and tuning myths abound, as an example, I have an old 500cc single cylinder motorcycle with an exhaust valve as large as the inlet and with the single exhaust port opening into two large exhaust pipes.

    Twin Port JAP.jpg an example of an early 500cc JAP racing single cylinder 4T engine with Siamese exhaust.

    It was an Epic step forward for 4T performance when the need for big exhaust valves and pipes proved to be a myth. Big exhausts must have intuitively seemed right at the time but as with so many intuitive faith based beliefs it was proved wrong and the change in understanding was Epic.

    There have been valve less single speed industrial 2T stationary engines that relied on inlet resonance before.

    My guess is that a no rotary valve or any sort of valve 2T engine could be made to work well if the inertia of the inlet stream could be varied to match the ramming effect required to keep the fresh mixture in the crankcase as the rpm varied. BrrmBrrrm.

    Something like a variable length, or variable area inlet tract or both might make a variable speed valveless inlet 2T work well.

    Variable area may not be that hard to do.
    - Team ESE -



  2. #26957
    Join Date
    4th May 2016 - 21:50
    Bike
    Bultaco Metralla GT
    Location
    Australia
    Posts
    72
    Quote Originally Posted by TZ350 View Post
    Why Epic .... well intuitively I have always thought you needed some sort of inlet valve timing control to make a two stroke engine work properly. My guess is most people think so too. It would be truly Epic and rather funny if we have all been clinging to a myth...
    I'd be willing to bet my entire personal fortune - and I own assets to the value of almost sixteen dollars - that it turns out the simplest way to make a two stroke easy to start and run well over a wide rpm range, both on and off the pipe is some sort of inlet valving...

  3. #26958
    Join Date
    30th April 2011 - 04:57
    Bike
    bsa. honda. aprilia
    Location
    england
    Posts
    326
    Quote Originally Posted by Frits Overmars View Post
    Frits is this explainable? there is obviously some way the cylinder is being filled with residual fuel to start combustion. angle of cylinder barrel? or is it on the pipe


    come on agnes... im up early for your next experiment

  4. #26959
    Join Date
    20th April 2011 - 08:45
    Bike
    none
    Location
    Raalte, Netherlands
    Posts
    2,287
    Quote Originally Posted by breezy View Post
    Frits is this explainable? there is obviously some way the cylinder is being filled with residual fuel to start combustion. angle of cylinder barrel? or is it on the pipe
    Anything is explainable (unless it's female) but for now I'll confine myself to guessable: I suppose there was a puddle of fuel in the crankcase, so an igniteable mixture could form. Compressing the cylinder contents and then releasing them through the exhaust port could create just enough mixture movement to get some of it in the vicinity of the spark plug...

  5. #26960
    Join Date
    22nd November 2013 - 16:32
    Bike
    STRIKE trike
    Location
    Perth, Western Australia
    Posts
    475
    OJ, you fibber, I would reckon that the left half of your Metralla head would be worth more than $16.

    As to full inlet control over anything else, I’m not so sure. What about an unthrottled inlet, whether 24/7 or not? Total flow thru the engine is by the height, hence timing, of the transfers. If some bloke in WA didn’t get distracted with work, kart preparation and local karting politics, we might find out soon. Hopefully.

    Agree with Frits, the only way it could have run is using residue fuel or unless there was some other hidden form of supply. Doubt it looking at the circumstances. Mind you, I wouldn’t be doing a “full Monty” ride without any undies on.
    "Wish I didn't know now what I didn't know then"

  6. #26961
    Join Date
    18th May 2007 - 20:23
    Bike
    RG50 and 76 Suzuki GP125 Buckets
    Location
    Auckland
    Posts
    9,057
    Quote Originally Posted by oldjohnno View Post
    I'd be willing to bet my entire personal fortune - and I own assets to the value of almost sixteen dollars - that it turns out the simplest way to make a two stroke easy to start and run well over a wide rpm range, both on and off the pipe is some sort of inlet valving...
    I very much expect you are right.

    Some time ago I was plagued by a bad resonance hole and blow back through the carb. I tried some experiments to see what could be done to eliminate it.

    My first effort was to close the inlet valve earlier. I originally started with the inlet closing at 80 deg ATDC and closed it earlier and earlier. Eventually I got down to 25 deg ATDC. 25 reduced the symptoms but did not eliminate them and 25 is ridiculously short and badly hurts power so no use at all.

    Length -1.jpg Length - 2.jpg

    The next move was to try a longer inlet tract. Adding the extra length worked much better than closing the inlet at 25 deg ATDC and the longer tract basicaly eliminated the blow back issue. But the plenum idea had other problems like fuel dropout upsetting the mixture, hence the interest in EFI.

    VariableArea - 1.jpg VariableArea - 2.JPG

    Later, with a carburetor I tried dividing the inlet tract in half with a butter fly at the carb end. The idea was to close half the tract off so as to keep the mixtures velocity up and use its inertia to ram the 6,500 rpm resonance hole and blow back out of existence. Then open the whole inlet area up for top end power.

    Blue Vtec Closed Red Open.jpg

    The idea worked pretty well on the dyno. Blue line is the valve closed. Red line is the full inlet tract area. Unfortunately the arrangement made for an impractically wide engine with the carb sticking way out in the breeze.

    BallValveInlet.JPG

    But I could put an inlet divider (or two) behind the EFI Ball Valve throttle body with a servo powered automatic stop that prevents the valve opening more than required for the current RPM.

    Two dividers would give three basic inlet areas. That way we may be able to have a series of inlet ramming resonant steps that more closely match the stuffing requirements of the crankcase over the full rev range.

    Who knows, if we get it right we may not need the rotary valve disk at all.
    - Team ESE -



  7. #26962
    Join Date
    20th January 2010 - 14:41
    Bike
    husaberg
    Location
    The Wild Wild West
    Posts
    8,108
    Quote Originally Posted by TZ350 View Post
    Why Epic .... well intuitively I have always thought you needed some sort of inlet valve timing control to make a two stroke engine work properly. My guess is most people think so too. It would be truly Epic and rather funny if we have all been clinging to a myth.
    .
    Running and starting whilst under little or no load is one thing, pulling itself into the powerband whilst under i would suggest is completely different.
    In the case of Adgnes though he has a trick up his sleeve (so to speak) the CVT which might allow it to work as it might be able to stay withing its resonant sped.
    Case in point, If the timing of the valve was not relevent then changing the timing of a disc valve would have little effect on the spread of power, yet we all know it clearly does.

    It did get we thinking though a spring loaded flapper valve in the inlet. might be a simple work arround.
    much like this. with the cable only operating at 3/4 revs or higher and the light spring at low revs....
    More research required...

    Kinky is using a feather. Perverted is using the whole chicken

  8. #26963
    Join Date
    18th May 2007 - 20:23
    Bike
    RG50 and 76 Suzuki GP125 Buckets
    Location
    Auckland
    Posts
    9,057
    Now that looks interesting, thanks.
    - Team ESE -



  9. #26964
    Join Date
    20th January 2010 - 14:41
    Bike
    husaberg
    Location
    The Wild Wild West
    Posts
    8,108
    animation_01.gif...............
    More research required...

    Kinky is using a feather. Perverted is using the whole chicken

  10. #26965
    Join Date
    1st May 2016 - 13:54
    Bike
    Vintage 2T
    Location
    Brisbane
    Posts
    144
    Valveless pumps are not unusual in other applications.



    Optimisation of inlet, outlet & pumping actions can only help.

    Cheers, Daryl.

  11. #26966
    Join Date
    23rd September 2014 - 19:35
    Bike
    Peugeot spx
    Location
    Norway
    Posts
    534
    Did anyone say blowback?



    I will make up a bunch of different length carb spacers to see where that gets me.
    Check out my YouTube channel! - 2STROKE STUFFING -
    https://www.youtube.com/2STROKESTUFFING
    Two strokes & rum!

  12. #26967
    Join Date
    23rd September 2014 - 19:35
    Bike
    Peugeot spx
    Location
    Norway
    Posts
    534
    Frits, I assume you've done more research than most on the subject.
    In theory could no valve be better than a properly tuned rotary valve for peak power and overrev?
    On the fence here. Keep on without the valve or not? It's interesting, but so is further testing with the valve and methanol/nitro.
    Check out my YouTube channel! - 2STROKE STUFFING -
    https://www.youtube.com/2STROKESTUFFING
    Two strokes & rum!

  13. #26968
    Join Date
    18th March 2012 - 08:35
    Bike
    Homebuilt chassi, Kawasaki 212cc
    Location
    Sweden
    Posts
    246
    I say buy a new valve and carry on hunting for power.
    This valveless is just a wild goosechase.
    That rejecting airmass you saw need you to get engine into tune before hitting throttle on dyno, in other words it will be really hard to get your roller start spinning.

    And by that,, pre heat pipe and incoming air in carb to about 450degree to get the pulsjet going in pipe then start engine

    Sounds to me it is a lot of work to be done just to get the moped rolling after been to the walmart for beers
    Need custom racing twostroke parts?
    Crankshafts, Heads, rotaryinlets or almost whatever.
    https://www.facebook.com/AMV-Product...9802399786466/

  14. #26969
    Join Date
    30th April 2011 - 04:57
    Bike
    bsa. honda. aprilia
    Location
    england
    Posts
    326
    I will make up a bunch of different length carb spacers to see where that gets me.[/QUOTE]

    well you gave it a try, i dare say you could play around with spacers and get it to run half decent but maybe it wouldnt be an improvement over the rotary valve. i suppose at the end of the day its how much time you feel you can invest in carrying on, which will decide if you continue. good video again

  15. #26970
    Join Date
    3rd January 2012 - 01:25
    Bike
    -
    Location
    -
    Posts
    179
    Quote Originally Posted by adegnes View Post
    On the fence here. Keep on without the valve or not? It's interesting, but so is further testing with the valve and methanol/nitro.
    Well, as you have come this far by now, why not try to do some dyno runs? You could use your starting aid to get the engine into the powerband on the roller and then remove it once you've reached a certain rpm. If this works, then proceed with some main jet changes. Do you have a solid baseline with the disc to compare your results to?

    If it is not going to work then you could also approach from the other side, by constantly elongating the timing on the disc well beyond what's normally used.

Thread Information

Users Browsing this Thread

There are currently 13 users browsing this thread. (2 members and 11 guests)

  1. diesel2

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •