Hey people, I have a 140cc bigoot with a brand new 140cc yx engine, i put all the bits together (carby accellerator cables and stuff) and then kicked it and it ran fine, i took it for a ride and it was very good, Then a couple days later i rode it and it started backfiring and splattering, so i changed the carby and cleaned it then changed the spark plug and had a good spark but still backfires, i then thought it was the carby and bought a new OKO RACE CARBY 26MM and installed but did the same problem, i then changed the coil but still no difference, i then changed the cdi and the same thing happened so i changed the wiring harness and the same problem occured, I got f*****in pissed so i changed the magneto and stator but still the same problem, I can start it fine on choke but when i change to normal it cuts out, ohhand i also changed the fuel and oil, and kill switch, what do u think the problem is.
140cc Bigfoot wont start/backfires a lot when started
- Thread starter Mxrider23
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rotn50
Master Spanner Spinning Moderator
Mate have you tried the fuel tank to check for cheap chinese plastic, which at times im sure the chinese use every 1 in 50 fuel tanks for a bin in the factory, pull the fuel line off and screw the tap out and the in tank filter is screwed to it, even though you changed carbs what was the slide needle setting(pull the slide out and remove the cable and spring and push the needle out, there is 5 settings, the lowest is richest and the top setting is lean, My 125 lifan did the same so i richened it up by putting the clip on the lowest setting on the needle and it never missed a beat from there on in, Hope this helps.
Im in brisbane, would that carby seting thing help the bike stop backfirin,cause with my bike i start it and it only works on choke and even then it backfires but the second i change it to normal it dies and splaters, also one day i was ridin it fine then literally the next day it stuffed up so i bought a new carby (oko 26mm) and still was gay, also i have pulled engines apart and fixed them like the timin and stuff as i have worked for three shops but i havent ever done valve clearence, how do u do it(the engine is also like 3 days old could it still be the valve clearence???) thanks.
Mate the best way to get the carby working properly, is to play with it. if the engine is 3 rides old, first thing i'd suggest is that your needle is off the mark... I thought you had played with it a bit, but doesnt sound like much adjustment has been done...
And yes, it's possible that from the factory your valve clearances aren't right. Quality control in china isnt always great...
have a look through the two threads below, they'll give you some ideas on getting the OKO 26mm right, and how to do your valve clearances...
http://www.miniriders.com.au/carby-...-rock-buying-oko-flatslides-5.html#post238245
http://www.miniriders.com.au/motor-tutorials/20425-good-guide-adjusting-valves.html
And yes, it's possible that from the factory your valve clearances aren't right. Quality control in china isnt always great...
have a look through the two threads below, they'll give you some ideas on getting the OKO 26mm right, and how to do your valve clearances...
http://www.miniriders.com.au/carby-...-rock-buying-oko-flatslides-5.html#post238245
http://www.miniriders.com.au/motor-tutorials/20425-good-guide-adjusting-valves.html
headsmess
Miniriders OG
^^^^^total agreeance with the valve clearance^^^^
sounds like it's running lean? Check your fuel filter, if you have one,try bypassing it. if that doesn't work remove your petcock and check the filter on that. seems wierd that it happened all of the sudden, something probably got stuck and blocking off your fuel supply, open your carb drain screw and see if petrol is coming out at a decent speed.
the rubber inside the fuel cap disintegrates so that can easily get lodged in the fuel lines/filters.
the rubber inside the fuel cap disintegrates so that can easily get lodged in the fuel lines/filters.
Yeh i tried all the things to do with the carby and electrics like i now changed the fuel tank and the fuel lines and the filter and it still backfires, also i changed the spark plug and the leads and coil and cdi but still the same prob, i think it can only be the valve clearences and i will do them tonight or tomorow, also does anyone know what the valve clearence gaps are supposed supposed to be for a YX 140cc thankyou.
Yeh i would have done the valve clearences but i have never had to ever to them on any bike and i have worked at moto shops as a full time mechanic and still never had to do it and i have also been there for 3 years now. I now got a car mechanic and he had a look at it and siad that it was the valve clearences and that the TAPPITS were too tight and that when you move them there should be a small nocking noise, and that means that they are good and that the noise should also bevery faint and not too loud or not too much play in it, i havent yet started it as for some GAY reason the electrics burnt out on the bitch and the coil, leads, cdi, wiring harness and stator burnt out so no i have to buy some more f*********king parts for the bitch, also the engine was BRAND new and i payed $850 for it as it is a 140cc GPX 18hp engine cause all the cams and shit as well as the valves and the Ports were machined out and bigger and now i have to spend another $200 on the complete electrics for the bitch.Does any one want to buy it say an offer and i might sell it once its done and i get the electrics, also it has fast ace rear suspension, sports cdi, The 250cc cdi, pro tapers and quarter turn throttle as well as OKO 26mm race carbie Brand new , and aslo uni filter new oil cooler that is coming from ebay and monster energy sticker kit and pro taper grips, also comes with a good brand new not even used VonZipper bushwick googles cost me 120 and a m2r helmet good condition as well as body armour. Say a price and ill think about it.
I bought the stator with the magneto from a shop on moss street in brisbane for $ 90 then i had to buy a new coil $25,cdi (race) $40 , kill switch $15, wiring harness $25. So it all add up to 200 and the coil was also a race coil, and all this was from a shop called Yamoto on moss street.
Monster energy kit? No Sale!!!!
headsmess
Miniriders OG
yamoto!!!!!!! AAAARRRRGH!!!! OHH finally, i fixed it , it was the valve clearences, my mate is a car mechanic and he told me to make the clearences 0.008 and i did and then i made it worse, i tod him u guys said to make it 0.004 and he said that it is not enough, but i did it anyway and it bloody worked OHH i soo fricken happy
