KymcoForum.com
General => Technical | How To => Topic started by: streido on May 27, 2012, 02:18:26 PM
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Been having bother getting a type K&N filter to work on my Agility 50. Was on 82 main with my stock airbox and ran great, swapped out to an open filter but just cant get the jetting right so i will run as good, or as i hoped better.
So far i tried
88, wouldnt run well at all, too lean.
94, still seemed a little lean.
100, ran ok but not as good as stock, seemed little rich?
96, i got the result below which i think is pretty close but still off im sure cos it still runs better on my stock filter and 82 jet .
A little rich i thought?
(http://i1193.photobucket.com/albums/aa351/streido/20120527_133925.jpg)
(http://i1193.photobucket.com/albums/aa351/streido/20120527_133937.jpg)
(http://i1193.photobucket.com/albums/aa351/streido/20120527_133946.jpg)
(http://i1193.photobucket.com/albums/aa351/streido/20120527_133954.jpg)
I am still not great at reading plug chops so if anyone who knows better than me can advise that'd be great.
Had read that when the ring is higher up the insulator its too rich? Should be at the very bottom of it? Not sure if this is right or not tho?
Also not sure why its not a complete brown ring all the way round the insulator?
Its frustrating tryiny to dial this in and get a little better performance, cant even get the same performance as stock yet :(
Beginning to think my little A50 just doesnt like free-flow filters at all no matter what jet i try ???
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thats a plug looks like something is missing wears the small metal peice that hangs above it.
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thats a plug looks like something is missing wears the small metal peice that hangs above it.
I "chopped" the threads off to do the plug chop so i can see the insulator to read how it was running.
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It does look rich in color but the blind spot is clean so it's not too rich by any means. What pipe is on it? You may be at the flow limit of that.
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Just memorize this...
Plug Chop Poetry
“Plug Chop Plug Chop Plug Chop” I cry!
“Until you learn to feel me,
You’ll have to do it by eye.”
When it's dirty and black, it's got the sh**s,
You have too much gas you are running rich.
When its hot and white, but looks pretty clean,
You're 'bout to blow your sh** up; you're running lean.
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Why is there a white spot? Did you do the proper plug chop procedure?
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It does look rich in color but the blind spot is clean so it's not too rich by any means. What pipe is on it? You may be at the flow limit of that.
Its still the stock pipe on it. It def lacked the power and response i normally get using the stock airbox and 82 main jet so im thinking its close but not right. :-\
Ran out of clean plugs so cant so anymore chops till i order some more. Just refitted the stock box and 82 jet again for now.
I really cant see me gaining any improvement in performance with this at all, it always feels worse no matter what jet i try in. The one aboce was almost as good as stock but unless it will give me a small gain then im staying stock. All i gives me at the moment is more noise which i dont really want :(
I did think maybe if i put more air in then i need more air out. My stock exaust will need replaced this yr so i tried drilling a few holes in the end to let more gases out, drilled thro at least 3 baffles inside too, but made no difference.
I really am at a loss and suspect i will be better off sticking to stock air filters. Just annoying cos Word swears by it and says it works well on his? Maybe a climate/altitude thing? Im not high up and normally its damp or theres moisture in the air.
Vivo, yes i did it as proper as i could. WOT for 2-3 miles once it was heated up, cut engine and pulled up, took out plug, cut it.
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Vivo, yes i did it as proper as i could. WOT for 2-3 miles once it was heated up, cut engine and pulled up, took out plug, cut it.
You used a new plug after the heat up?
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Yup. Brand new.
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That mocha color is ok but its supposed to be a ring. Maybe going a bit richer will give you the ring.
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That mocha color is ok but its supposed to be a ring. Maybe going a bit richer will give you the ring.
Thats where my confusion lies, why is it not a complete ring?
Tbh im thinking its prob not worth wasting anymore of my time or money on it now, i dont see it giving me much if any gains at all even if its perfect.
I've tried 13 diff jets so far ranging from 88-120 and cant figure it out, every time my performance is worse than stock ??? On flats its sometimes the same but on hills i lose anywhere from 3-10mph depending on the jet. Just feels like ive spent too long now on it and dont want to keep buying jets and plugs for chops so i may need to call it a day and forget about it for a while.
I assumed i would get a small but noticable gain in power with the open filter, seems like i dont tho and the noise is annoying too. Pretty embarrassing when you approach a bus stop and everyone turns to look at what monsterous machine is eating up the tarmac, only to tootle past at 30-40mph. My neighbours must hate my morning starts too when im going to work. :-[
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I would have to agree that the OEM is better for you right now. When you get a new pipe that will all change.
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I would have to agree that the OEM is better for you right now. When you get a new pipe that will all change.
Think your right. Need a new zorst by the end if the year anyway cos one that on now wont last much past summer/autumn. Will prob hang off and retry one i fit a Leo.
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You should not do a plug chop on a brand new plug. It wont tell you how youre really running, as you noticed incomplete ring. You should only change plugs after you swap jets, then ride on it for at least a hour, other wise your only seeing how your engine is running at WOT for a limited amount of time.
I would recommend buying a EGT gauge. A CHT is a good tool to have as well, but for instant A/F EGT is best.
Build an EGT for 30$
EGT Thermocouple K type for Exhaust Gas Temp Probe
http://www.ebay.com/itm/EGT-Thermocouple-K-type-for-Exhaust-Gas-Temp-Probe-/250787715391?pt=LH_DefaultDomain_0&hash=item3a641cd93f (http://www.ebay.com/itm/EGT-Thermocouple-K-type-for-Exhaust-Gas-Temp-Probe-/250787715391?pt=LH_DefaultDomain_0&hash=item3a641cd93f)
Digital DC Temperature Meter for K Type EGT Probe (F)
http://www.ebay.com/itm/Digital-DC-Temperature-Meter-for-K-Type-EGT-Probe-F-/250842647144?pt=LH_DefaultDomain_0&hash=item3a67630a68 (http://www.ebay.com/itm/Digital-DC-Temperature-Meter-for-K-Type-EGT-Probe-F-/250842647144?pt=LH_DefaultDomain_0&hash=item3a67630a68)
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You are the Man Love My... Guess what I just bought!
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Itll take a little while to get to you, maybe 3 weeks minimum, but seriously worth the wait.
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For 30.00 bucks it fits the bill.
I'm not planing on beating this build, and an egt is just what I needed. I have an MSD 4217 on the way, and I could NEVER get the right Ign curve without an EGT. Thank You!
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That looks a hell of a lot easier and more acurate than doing the plug chops. Will take a note of it and prob get one soon i think, for the sake o a few £'s its well worth it. Prob save that on new plugs for chops over time anyway.
Thanks for the info. Do you know if they come with instructions? Is it quite simple to work out how to use properly?
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It will run the coffee maker if you ask it to. Then it puts the lotion in the basket...
I imagine it's on or off. Maybe a peak hold feature? Plug, and play.
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So how would you know if the reading you get is the correct reading and the scoots set as it should be? Or am i just sounding like a total noob here?
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The exact number it reads is really irrelevant for the most part. It's the changes in temp. that matter. I think my melting pistons is related to the timing curve I asked Suitai to program in the CDI. By retarding some of the advance it is possible to move the heat into the pipe, and out of the cylinder. The important factor is the read time. Real time is crucial. By comparing rpm/temp a proper Ign curve can be built just for that set up. The HUGE side bonus is it dials in jetting exactly. You want a smooth climb in temps. with no peaks/valleys.
All that from a 30.00 tool.
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There's no standard reading for EGT. You have to incorporate this with your plug chop reading + egt to create a baseline. Get the proper reading on plugs then see what the egt is. Then that is your egt. You can start from there. You will know in the future if there is a problem if your set egt baseline reading is off. Different probe locations will even give you different readings.
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It is the best tool in my opinion for setting it up, as well as monitoring the engine.
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If you hit 1200+ degrees its too lean, youre running 400- its too rich, you can also be over rich and cause EGT temps to rise because of afterburn effect, but if you cant figure out youre that rich you shouldnt be working on it. The EGT is used to tune your carb to your pipe (Youre powerband) Close concept as a CHT. Only real difference its instantaneous of whats going on. Once you use it you will see very quickly whats right and whats not. It will let you know if your pilot isnt right very quickly.
My suggestion is if you dont have a lot of money and you cant read a plug chop, EGT, or CHT you probably shouldnt tune your own 2 stroke until you read more into it.
http://twostrokemotocross.com/2009/12/carburetor-theory-and-tuning/ (http://twostrokemotocross.com/2009/12/carburetor-theory-and-tuning/)
Best book in the world to read for new riders, and old. And its free, A must have for all 2t builders.
http://edj.net/2stroke/jennings/2stroketunershandbook.pdf (http://edj.net/2stroke/jennings/2stroketunershandbook.pdf)
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My Kymco is 4t LMK not 2t. Im pretty ok with tuning the Kymco, learned a lot over the last yr or so and do all my own work, repairs and servicing on it. I kinda got a good feel for it now and know from how it rides if its not right. Still learning new things every day tho, are'nt we all? :)
My Kymco's running great right now and is set almost perfect so if i was to take some readings at this stage i could then use them as a reference point in the future, if i have understood how you say its meant to be used?
I do own a 2t Vespa tho so im thinking it may be useful to get one and learn more about it as im sure i would use it once i start tuning that. I just need to make sure im clued up how it all works before i try use it to tune.
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Some of my old posts from another site I use to regulate. Unfortunately its geared more towards 2t. 4T is easier actually.
Generally, when in-cylinder temperatures increase, so do exhaust port temperatures. The exceptions to this are caused by things like having a lot of blowthrough at TDC following the exhaust stroke, where you get a lot of fresh air flowing through the top of the cylinder and straight out of the exhaust port. This obviously has a cooling effect on the gases being scavenged, and is most pronounced in 4-strokes when using a wide-overlap camshaft (often used specifically for this purpose), and in 2-strokes where the combustion system geometry has been designed to optimise scavenging.
Now, the effect of mixture on EGT:
With a very rich mixture, exhaust gas temperatures will be low. This is down to a number of factors, but the absence of sufficient air for complete combustion is the main factor. The flame front simply dies out. Also, the excess fuel has a high specific heat capacity, and is able to 'mop up' further heat, particularly in something like a Diesel engine where there are still fuel droplets present (the evaporation of these droplets requires energy input, thus lowering the surrounding temperatures). CO rather than CO2 is produced due to the partial oxidation of carbon in an oxygen deficient environment. This CO is then further oxidised to CO2 later on in the combustion process (say, when both valves are open, and there's a sudden influx of fresh oxygen). This resulting oxidation of CO to CO2 requires energy input, so temperatures are again reduced.
Moving on to leaner mixtures, more air is available to sustain a more complete combustion, and more fuel is burned, and temperatures rise, to a peak, when all the fuel is burned (obviously all the chemical energy held within is released as heat). The effects mentioned previously decrease, particularly as the oxidation of carbon is complete. Leaner still, there's excess air, which serves to dilute the hot combustion gases, and temperatures again start to decrease.
This is all quite high-level; there's rather a lot more with regard to heat release rates.
As for why detonation generally only takes out one cylinder:
The line between detonation and no detonation is extremely fine. It can take just a few degrees extra in cylinder temperatures, or a few tenths of a degree crank angle too advanced (for spark/injection) to cause detonation. As a result of cooling channel designs, and slight imbalances of flow between different inlet tracts, (not to mention different AFRs cylinder-to-cylinder caused by tolerances on the carburettors), all the cylinders very rarely operate at exactly the same timing/mixture/temperature. If you have a bad detonation, and take off the top of the piston on one cylinder, your engine will probably catastrophically fail pretty quickly on one cylinder before the others have even had chance.
As for what EGTs would do to warn you of detonation, well, I wouldn't rely on using them as an indicator. Firstly check your mixture. Secondly make sure you're not running at some silly advance anyway, and thirdly listen out for detonation. If you've set the engine up properly in the first place then there's no reason for it to start detonating during use. However, whilst leaning out during setting your engine up (and we're talking sensible AFRs here), you'll notice the exhaust temperatures rise, peak, and then start to fall. As you said, when they're falling, there's a good chance your detonating. This is because the shock wave caused by the detonation breaks up the boundary layer of relatively stagnant mixture which normally 'lines' the cylinder walls. As a result, the thermal transfer between the combustion gas and the (normally rather cool) cylinder walls (and by proxy, piston) rocket, until you start siezing little chunks of piston land to the bores and ripping them off. The exhaust gas temperature decreases when detonation occurs because some of the heat which usually goes out of the exhaust ports goes straight into the cylinder walls. So it's important to distinguish between exhaust gas temperatures (which essentially indicate mixture; the peak temperature is at stoichiometric) and 'general engine temperatures' (coolant and oil) which are drastically affected by any changes in friction between the piston and bore/liner.
Pre-ignition is when combustion (the rapid progression of a flame front through the end gas) occurs before (in time) the spark. This can be due to a number of factors, generally by 'surface ignition' where the charge is ignited by a hot surface (often a hot valve, the spark plug, or a hot spot on the bore or head, and occasionally by a glowing carbon deposit somewhere in the chamber). Note that surface ignition can also occur after the spark event; this is known (surprisingly enough) as post-ignition.
Knock (or detonation) is spontaneous combustion of some of the charge ahead of (in distance from the spark plug) the advancing flame front. (I'm assuming here that you understand (or can imagine) how a flame front propagates from the area around the spark plug, if not please shout!). As this flame front propagates, the gas which has not yet been ignited, is compressed, and as a result its temperature and density increase. If the conditions (temperature, pressure, density) of this unburned portion of mixtue are right for combustion, then ignition will occur. This resulting combustion advances MUCH (5 to 25 times) faster than the 'normal' flame front, and is sometimes severe enough to cause catastrophic failure (as I described earlier). This rapid combustion causes a high-pressure shock wave which gives knock its characteristic (onomatopoeaic!) sound. Knock occurs when this secondary, spontaneous ignition occurs before the flame front has reached it. In effect, there's a race between the normal flame front (propagating from the spark), and any auto-ignited areas of charge.
So, surface ignition (usually in the form of pre-ignition) can cause knock, by causing an abnormal combustion event ahead of the flame front. If the spark has already occured, and a normal combustion event taken place, but knocking occurs, this is known as spark knock, i.e. it has not been caused by surface ignition.
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There is blood running out of my eyes. Lots O big wurds in them.
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My suggestion is if you dont have a lot of money and you cant read a plug chop, EGT, or CHT you probably shouldnt tune your own 2 stroke until you read more into it.
Right you are Sir! and same with cars! tuning takes lots of time and money. That's why I love old-school-hot-rod-tinkering! No BBK, EGT, CHT, pork chop, and lots of O's. Just pure engine swap! Swap that 50cc with a 200... twist and go!
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But this is fun.
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This is why I wanted to post...http://thesensorconnection.com/egt-probes/gauges/digilite-2-dual-series-digital-egt-cht-pyrometer-gauge. (http://thesensorconnection.com/egt-probes/gauges/digilite-2-dual-series-digital-egt-cht-pyrometer-gauge.) It's the fancier version.
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sh**! http://thesensorconnection.com/gauges-pyrometers/all-gauges-pyrometers/sportduty-analog-egt-pyrometer-gauge-warning-max-temperature (http://thesensorconnection.com/gauges-pyrometers/all-gauges-pyrometers/sportduty-analog-egt-pyrometer-gauge-warning-max-temperature)