another tomos story

alright guys. I don't know much about these athena kits.

I got this tomos targa lx. I hope you guys can help.

I have spark, but I do not know how to tell if it's strong enough. to me it looks fine, it's a blue healthy large spark. I'm 99 percent sure I'm getting sufficient spark.

I'm getting compression.

now fuel. I cleaned the carb ridiculously meticulous. still not giving me any sign of life. what else could it be?

the plug is not wet after trying to start it. am I not getting fuel? the athena kit doesn't have reeds so I'm a little confused.

Re: another tomos story

Jason Luther /

i know this is silly, but is your fuel valve open? your plug should be wet if your kicking it over. pull the gas line off of the carb and see if fuel runs out. if so take the carb bowl off and see if its full, and if so see if your main jet is clogged. could you have possibly installed the piston upside down? -jason

Re: another tomos story

spray some Starter Fluid into the carb.. if it kicks over the carb is not delivering gasoline.

Remove the bowl (or open a drain if there is one) and see if fuel is in the bowl. If not, go back towards the tank and find whats stopping fuel flow.

Re: another tomos story

Don Pflueger /

a plug can have spark and still be bad. if the ceramic core has been burned, it may not be gettingg hot ewnough to fire the fuel/air mix. you should have an l86c plug. if not, your heat range is off.

HOW MUCH COMPRESSION???? and please do not tell me it blows your thumb off.

here's a simple test.

spray carb cleaner into the carb throat and try to start the engine. if it fires up, you have a fuel problem. if it does nothing, you have either a compression or electrical problem. so get a new plug and test compression.

also, is your piston installed correctly? if its upside down then it may not start.

Re: another tomos story

upside piston hahahaa oh man...looks like those "cutouts" in the piston serve more than one purpose..cooling AND to tell you which way is up!

Re: another tomos story

Jason Luther /

hey man, its been known to happen

Re: another tomos story

Don Pflueger /

yep, and its the most common mistake made when adding an airsal or other performance kit.

Re: another tomos story

Yeah...I put mine on upside down the first time...but it still started and ran shitty, spraying fuel back out the carb like a Windex bottle.

Re: another tomos story

Jason Luther /

thats was my next inquiry, will it run with the piston in upside down? i guess so.

Re: another tomos story

well I think it may be the spark. yes my fuel is on and I cleaned the carb ultra good. I tooke everything apart. see my compression tester won't fit in the really small hole. I need to get a different boot or make one or whatever. because I'm a little confused. we tow started it the other day. it would only run in the top end of 1st, and second was fine. it didn't run good, but it did keep itself going. eventually it died out .

Re: another tomos story

Don Pflueger /

could be a number of things wrong. try a new plug. you really need to know what kind of compression you have. other than that, you may have the piston upside down,incorrect carb jetting, a leaking base gasket, a bad crankseal, dirt lodged in a passage in the carb, really off timing, or something binding up in the tranny or on the crank (unlikely tho).

most times if a 2 stroke wont idle, its a leaky cylinder base gasket or bad crankseal, or dirty carb, or low compression. but if you cleaned out the carb well, and ran wire thru it, that kinda rules that out.

Re: another tomos story

I was told to NEVER run a wire through carb passages. I used carb cleaner and compressed air.

Re: another tomos story

Don Pflueger /

well, wire wont hurt a thing. this may i will have been doing it for 15 years proffesionally. and in that time i never had a problem. for 12 of those years i rebuilt at a minimum of 9 carbs a day. and thats not including the 3 years i spent working for a company called lubrizol where i worked in their carbeurator dept rebuilding rochester 4 barrel carbs that were used on test engines to test fuel additives, oils, and other various things. so whover told not to do that had better get some schooling in the small engine industry cuz every school i went to teaches this.

Re: another tomos story

I was told that you should not do do that, because many holes and jets in a carb are not perfectly round, but purposely different shapes and when dealing with very small holes it will distort the hole and affect the atomization of the fuel.

Re: another tomos story

it's a good idea to tell everyone not to use a wire or a tiny twist drill or a rattail file to clean a jet..

Those who know what they are doing already know a jet is easily damaged and will know why they were advised "Don't use a wire".

Those who don't know what they are doing will take your advice or suffer the consequences.

Re: another tomos story

Don Pflueger /

well, i dont know who told you that, or why. but holes in the carb bodies are drilled, not elongated, so they are in fact roune. look at a carb body closely and try to find a jet or passage that is not round, other than the throat since they are cast. i bet you will never find one. pull a welch plug out of a junk carb and look at how the passages are drilled. there is no way to make them oval, nor is there a benefit to making them oval. the only passage in a carb that fuel flows thru is the main jet. air is moved thru the circuits and atomization occurs in the carb throat and intake as the air and fuel tumble together before reaching the cylinder.

i should just host the zama carbeurator service manual for everyone to view the correct operation of a carb.

Re: another tomos story

On a microscopic level, one jet orifice can be smooth and another one rough. The manufacturer (hopefully) flow rates both jets. Both happen to deliver the same amount of fuel so are numbered the same, #xx.

Some "bull in a China shop" uses a wire and runs it through the rough jet.. result is they smooth it out a little and that jet now flows more than it should. Any slight reformation or deformation of the orifice, entrance , exit is gonna change it's flow rate.

Since everyone will read this thread, i guess the caution about not using hard impliments to clean a jet can now be dispensed with ;-)

Seriously tho i would sure encourge you to write a little primer on carbs and stuff and maybe submit it to the Resources section..

Re: another tomos story

Don Pflueger /

so how much difference do you think running a piece of wire thru a carb jet will make when the jet may be .08mm and the wire .04mm? non i bet. these things are not made perfectly. and even if you opened the hole up to .09mm, i doubt you'd notice any difference in performance whatsoever. this theory may hold true for something like the space shuttle, but not on a moped. its not like your running a rat tail file thru the jet. and ive found thousands of jets and carb bodies that had so much flashing in them it was a surprise they ever worked at all.

point in case;

tecumseh had a bad batch of carb repair kits. part number 31840. i noticed that when rebuilding carbs on the h60 model engine line that they had a hard time starting after repairs were made. here, the main jet has a hole in its side about the size of a human hair. i had to poke a piece of wire thru every jet i used to make sure they would work. i know this is a lawn mower engine, but these moped carbs are not built any better. neither are car carbeurators. ive spent a lot of years rebuilding carbs and kinda think of it as my specialty. and ive never once had a problem that was caused by running wire thru any hole in the carb body or its parts. if any thing, it made them run better.

Re: another tomos story

I agree that these jets are carbs and engines are crude. Sound principles and exacting technique are mostly wasted on a moped..

Obviously, you da man to write a tutorial about this stuff.. But if I had the knowledge to write it, i'd pretend the total stranger taking my advice was going to work on MY bike.

Re: another tomos story

Clean your petcock...learned that obvious lesson today.

Re: another tomos story

Shout it from the rooftops!! Clean thy Petcocks!

I know yer happy but.. jeeze.. hehe

Re: another tomos story

Jason Luther /

perhaps _that_ should be a lesson to always start with the most basic of repairs first. im sure even don has a few stories of hours wasted trying to fix something, instead of changing the plug or unclogging a gas line.-jason

Re: another tomos story

donp I'm not doubting you. Im just saying it does make an ounce of sense. the guy who helps me with this stuff is RICIDULOUSLY ANAL RETETIVE.

Re: another tomos story

Allen Murphy /

Anal retentive wankers are the WORST to work with-they make every job 3 times longer than it has to be!

And most of them don't know what the f**k they're doing, and use being AR as a means to CTA!

"Well, I followed all the instructions, and checked everything 25 damn times-why won't it work? Couldn't be anything I DID WRONG!" (Sure was, A-hole!)

Al Murphy

Re: another tomos story

Don Pflueger /

yea i do. mostly when i first started working on small engines. string trimmers always gave me a hard time. now they are no brainers.

Re: another tomos story

Don Pflueger /

and he doesnt know what he's talking about.

Re: another tomos story

well I would absolutely not say he is a bad wrench. he just is extrememly paranoid about cleanliness etc.

Re: another tomos story

Don Pflueger /

there is absolutely nothing wrong with being clean. but when he has the number of certificates hanging on the wall as i do, then i would listen to hes advice. but i do this on a daily basis, professionally for the last 14 1/2 years, and own my own small engine repair business. so i'm feeling more than adequetly inclined to tell you that using a piece of wire to clean a carb will not hurt a thing. the only carbs that doing this to will hurt them, is the walbra wta and wtb series where they have a diaphragm imbedded in the body under a brass fitting which works as a fuel pump and is non replaceable.

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