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Thread: ESE's works engine tuner

  1. #26206
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    27th October 2013 - 08:53
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    Quote Originally Posted by SwePatrick View Post
    Actually yes.

    I dynoed mine 211 cc engine this weekend, a drop in peak power from earlier.
    But it was expected as i have been aiming for wider powerband.
    61.86hp at the wheel and 36.11nm, average power is 41.79hp from 6000rpm to 13000rpm.

    However, my first advice is make sure spark is in center of combustionchamber in all axis, XYZ.
    Index sparkplug carefully 'opening' towards boost.
    Then check your reed petals, i had a brand new v-force3 to test.
    16 pulls and the petals were soft as rubber.
    Best power and torque however with my heavily modified boyesen radvalve.
    0.45mm polini carbonit petals with no additional blades at all, no dampening petals either.
    std it's a '4 blade' setup, i´m running two big blades.
    Ported a lot and welded it straight(straight shot for the carb into cylinder)

    Try to map down where the engine is lean or fat in throttleregister.
    Then modify your meteringrod/needle in carb to suit this.
    Mine is very very crisp in lower throttleopenings, this doesn´t wet down the crankcase at all(no need to rev it clean).
    But i also as is running a Keihin PWM carb, they´ve got a separate idlesystem, i can let it be very lean on idle.
    As for now i run '100' jetsize on lowspeed and '245' on highspeed, and my homemade powerjet is fully open, dunno the flowrate on that.
    Powerjet is also located from bottom and up a third of carb bore.
    This to react early and maybe lean out more at top

    There are some more hp lurking in my engine as i´m a bit small on the carb(40.5mm as we speak)


    So my main advice is: spend a lot of time get the fuel distribution correct.

    Rgds.
    ok thnx. plug is central located on all axis. #9 heatrange. I haven't index the spark gap to the cylinder rear but ill look into it

    reeds are brandnew carbon fiber at .4mm thickness with no stiffners. reed block is ktm with some dividers removed for 4 large petals instead of 8 small

    carb is lectron 48mm with 2 powerjet. only adjustment is needle length and powerjet. ill try again Saturday to reduce the powerjet fuel. maybe the needle is flooding the crankcase at low engine speeds also

    do you have unburnt fuel from the tail pipe ?

  2. #26207
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    18th March 2012 - 08:35
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    Quote Originally Posted by peewee View Post
    ok thnx. plug is central located on all axis. #9 heatrange. I haven't index the spark gap to the cylinder rear but ill look into it

    reeds are brandnew carbon fiber at .4mm thickness with no stiffners. reed block is ktm with some dividers removed for 4 large petals instead of 8 small

    carb is lectron 48mm with 2 powerjet. only adjustment is needle length and powerjet. ill try again Saturday to reduce the powerjet fuel. maybe the needle is flooding the crankcase at low engine speeds also

    do you have unburnt fuel from the tail pipe ?
    Just a small amount when cold.
    When it is hot, just moisture(oil) like an normal petrolengine.
    I gained huge amount of torque with my ported boyesen reedcage.
    There is a lot of meat in those to get the shape you want.

    Why i advice to index plug is as it seems to run more clean, more crisp more response.
    seems to be more important than on petrol.

  3. #26208
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    28th November 2013 - 21:58
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    Quote Originally Posted by G Jones View Post
    OK - been a bit busy so missed this...
    I think "flooded" would be a slight exaggeration - lucky to get 2 or 3 bikes turn up these days - there was one reasonably successful guy running a Banshee motor - which was originally built by a well known UK "tuner" as a hill climb bike at something like 525cc capacity - that was running in our series as a 350...
    snip
    I did carefully say that I didn't know what I was talking about! Thanks for jumping in.
    Thanks too for the "tuner" comment - thought it was just me who didn't think he was some kind of 2 stroke genius...

  4. #26209
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    28th November 2013 - 21:58
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    Quote Originally Posted by G Jones View Post
    Any thoughts on crankshaft mass desirability ?
    Reason for asking - I just happened upon some crankshaft pictures - mainly for Italian scooters - seems to be quite a few being sold of what they describe as "Bell Type" - similar to the picture - any other thoughts on any disadvantages - or indeed advantages ?
    Attachment 331300
    Some Vespa cranks are like that because that's the induction system, of course...
    Not without precedent for TZs, though. The third picture is from a later article so the, not very clear, crank picture should show what he ended using i.e. pork chop outer wheels and giving up on the split crank idea.
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  5. #26210
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    24th January 2010 - 03:21
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    Quote Originally Posted by guyhockley View Post
    I did carefully say that I didn't know what I was talking about! Thanks for jumping in.
    Thanks too for the "tuner" comment - thought it was just me who didn't think he was some kind of 2 stroke genius...
    Well - I didn't mention any names but you instantly knew my train of thought ?
    Thanks for the (french) article - pity my schoolboy french is too many years ago - although I can pick up some interesting thoughts - the pork chop thing would appear to be an easy way to gain some case volume - although as Wobbly says - full circle is better - it may be possible to slim the flywheels (on the inside face) to the crank pin depth - and regain balance weight with heavy inserts - although more research needed there to understand whether it's possible to add enough weight in the space available...

  6. #26211
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    11th October 2016 - 21:23
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    Quote Originally Posted by Haufen View Post
    There is a rule of thumb, or more than one. But if you follow it blindly it might leave you with a damaged engine in the end.

    I'd make that a bit dependant on the drilling bits you have available. It is far easier to make a radius of 5mm with a bit that is 10mm in diameter than with one which is 7mm in diameter. Are you sure you need an exhaust port that wide? No time to go step by step (and probably learn much more during the process)?

    Other parameters influencing the port shape and max. width are:
    • cast iron bore or plated aluminum bore? If the latter: are you going to replate after grinding?
    • piston ring pin position (ideal: centerline midle of boost port).
    • Piston ring thickness (thin is better) and material (less width for cast rings).
    Cast iron bore, two rings, pins at the sides of the exhaust port (chord length between pins 35mm), ring thickness ~1mm (can't get more accurate measurement right now), don't know ring material.

    Step by step process seems like a sensible way to go...

  7. #26212
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    11th October 2016 - 21:23
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    Read everything I could find about the "leaning tower" scavenging here. Another Q, perhaps my search skills are not that great.

    I'm limited to old style piston with high dome (~20deg near the piston edge. there's 1mm flat before the dome above the rings). Would the aprilia style vertical angles of A&B ports have to be altered upwards by the difference of piston dome angle or kept the same?

  8. #26213
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    25th March 2004 - 17:22
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    So the rules? say you must keep this piston?
    Piston, rod, gearbox, really determine the revs you can pull.
    Don't you look at my accountant.
    He's the only one I've got.

  9. #26214
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    11th October 2016 - 21:23
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    Not the rules, but availability in this size. It's a father-son hobby project and learning experience more than anything else. DIY to see what we get done, instead of the simpler way to shelling out to get the same as everyone else. If we can beat some guys with "stock" parts, all the better.

    Trying to learn as much as we can, that's why we are here.

  10. #26215
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    3rd January 2012 - 01:25
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    Quote Originally Posted by Jannem View Post
    Cast iron bore, two rings, pins at the sides of the exhaust port (chord length between pins 35mm), ring thickness ~1mm (can't get more accurate measurement right now), don't know ring material.

    Step by step process seems like a sensible way to go...
    Cast iron bore is perfect, as it allows you to make nice radiuses between bore and port all around.
    The pin position however is a major drawback. how wide is the port at the moment? It might be worth considering to just radius the port edges if you can not move the pins. Your ring thickness should not be a hindrance for a wide exhaust port (if the pins are moved).
    If you have an old ring you can try to bend it (in stroke direction). If it bends, then 70% chordal width should be feasible, if it breaks then 65 is your limit.

    Quote Originally Posted by Jannem View Post
    Read everything I could find about the "leaning tower" scavenging here. Another Q, perhaps my search skills are not that great.

    I'm limited to old style piston with high dome (~20deg near the piston edge. there's 1mm flat before the dome above the rings). Would the aprilia style vertical angles of A&B ports have to be altered upwards by the difference of piston dome angle or kept the same?
    Your setup does not sound to be particularly high tech, thus using the RSA as an orientation might not be the best of ideas. From the descriptopn of your engine it sounds to me like some sort of "traditional blueprinting" would be a good idea and already provide a noticeable step up in driving performance.

    I would keep the vertical angles the same (I might even have asked the same question here some time ago), even with your 20° piston. Keep in mind that these angles are for a sqare engine configuration and thus the "correct" angle values for a short stroke engine are lower and vice versa for a longstroke engine.

  11. #26216
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    25th March 2004 - 17:22
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    I'd modify to try fit a cheap but big- leap- ahead mx piston. Even if it means matching Conrad. All these parts are cheap to replace once the initial machining is done and end result more reliable.
    Engineering beats clever portwork in many respects. That also makes for practical research experience. Let your son find the options and vet together.

    Light strong piston with low crown to pin height and thin ring. There's power through alternative part engineering. Else you are just following a well trodden part of std parts and consistent constraints, compromises and breakages if shoddy spinning metal.

    Wish I'd learnt that a lot earlier and spent more trying to ignore that lesson to run what I had again and again.
    Don't you look at my accountant.
    He's the only one I've got.

  12. #26217
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    10th December 2016 - 13:02
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    CTIS two stroke

    Hi guys .I have just come across this in a motoring magazine that comes to work
    Cant see it working to be quite honest
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  13. #26218
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    23rd September 2014 - 19:35
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    Quote Originally Posted by Jannem View Post
    Trying to learn as much as we can, that's why we are here.
    +1
    Best motivation.
    Check out my YouTube channel! - 2STROKE STUFFING -
    https://www.youtube.com/2STROKESTUFFING
    Two strokes & rum!

  14. #26219
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    11th October 2016 - 21:23
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    Quote Originally Posted by Haufen View Post
    Cast iron bore is perfect, as it allows you to make nice radiuses between bore and port all around.
    The pin position however is a major drawback. how wide is the port at the moment? It might be worth considering to just radius the port edges if you can not move the pins. Your ring thickness should not be a hindrance for a wide exhaust port (if the pins are moved).
    If you have an old ring you can try to bend it (in stroke direction). If it bends, then 70% chordal width should be feasible, if it breaks then 65 is your limit.



    Your setup does not sound to be particularly high tech, thus using the RSA as an orientation might not be the best of ideas. From the descriptopn of your engine it sounds to me like some sort of "traditional blueprinting" would be a good idea and already provide a noticeable step up in driving performance.

    I would keep the vertical angles the same (I might even have asked the same question here some time ago), even with your 20° piston. Keep in mind that these angles are for a sqare engine configuration and thus the "correct" angle values for a short stroke engine are lower and vice versa for a longstroke engine.
    Port is now 28mm, so there is room. Don't have extra rings to test. Piston is Italian GPM, and appears much more decent quality than the typical far east choices. Rings do not have a coating and look decent, but are magnetic.

    It's an AM6 cylinder with Suzuki piston. Stock the transfer timing is at 130deg and blowdown will not be staggering even with raised exhaust. Will see how it all pans out after we get it on the case, but expect to machine the lower end of the cylinder as the piston is little shorter than stock.

    The aggregate angle of the piston with the flat at the edge is ~15% and the 44mm is 4mm overbore with 39mm stroke. So the angles may be reasonably close after all. Basic trigonometry says 2mm per side you'd use 3 deg less angle for the new bore with original type piston.
    I appreciate the oversquare by boring out is not ideal with the implications to transfers. Two wrongs usually do not equal one right, but in this case higher dome and overbore impact to transfer angles may actually fit somewhat together. I'm however building a angled porting tool to adjust the transfers.

    Quote Originally Posted by F5 Dave View Post
    I'd modify to try fit a cheap but big- leap- ahead mx piston. Even if it means matching Conrad. All these parts are cheap to replace once the initial machining is done and end result more reliable.
    Engineering beats clever portwork in many respects. That also makes for practical research experience. Let your son find the options and vet together.

    Light strong piston with low crown to pin height and thin ring. There's power through alternative part engineering. Else you are just following a well trodden part of std parts and consistent constraints, compromises and breakages if shoddy spinning metal.

    Wish I'd learnt that a lot earlier and spent more trying to ignore that lesson to run what I had again and again.
    I wholeheartedly agree. I would have liked to use another piston which has much shorter compression height and 10mm longer rod, but it's out of the question because of the budget constraints. Without going into lengthy personal history, I can dedicate much more time than before and very little funding to my kids at the moment. Used to be vice versa. Life has it's surprises and the bad ones may be good ones as well. My 15yr son paid for the bike out of his own pocket and got much better one than he expected, because we could buy one previous owner didn't know how to fix and we did it together.

    I have a lot of experience in the 4-strokes, decent tools and even a crude flowbench which can be used to test basic wet flow, but 2-strokes are a learning curve.

  15. #26220
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    20th January 2010 - 14:41
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    Quote Originally Posted by guyhockley View Post
    Some Vespa cranks are like that because that's the induction system, of course...
    Not without precedent for TZs, though. The third picture is from a later article so the, not very clear, crank picture should show what he ended using i.e. pork chop outer wheels and giving up on the split crank idea.
    Pretty much every low powered two stroke up to the mid sixties was that design.
    Villiers or a victa lawnmower
    I refer to them as being Pork chop cranks.

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    But They found better power by filling them with all sorts of bits of epoxy or screwed or brazed on lumps.
    This was because they had poor port designs and short transfer timing.
    Yes large crankcases are in fashion as they work better with modern porting designs.
    For instance a TZ350 works better with the larger volume RD400 crankcases.
    But the large large modern crankcses still have smooth crankshafts with no cut outs to lesssen turbulence and fiction and pumping losses..
    Here are some pictures of how they should look. with 1mm clearance to the crankcase at every dimension
    https://www.kiwibiker.co.nz/forums/a...hmentid=330835
    https://www.kiwibiker.co.nz/forums/a...0&d=1438074109
    https://www.kiwibiker.co.nz/forums/a...hmentid=314111
    https://www.kiwibiker.co.nz/forums/a...hmentid=314108
    https://www.kiwibiker.co.nz/forums/a...hmentid=314093
    https://www.kiwibiker.co.nz/forums/a...hmentid=312225
    https://www.kiwibiker.co.nz/forums/a...hmentid=311364
    https://www.kiwibiker.co.nz/forums/a...hmentid=311365
    https://www.kiwibiker.co.nz/forums/a...hmentid=303952
    https://www.kiwibiker.co.nz/forums/a...hmentid=303485
    Quote Originally Posted by Katman View Post
    I reminder distinctly .




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