YX 140cc modifications

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Will665

Will665

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g'day.
i recently bought the atomik nitrous 140m. i was just wondering if anybody else had or knows somebody who has a YX 140, i find it lacks torque at low RPM and i mainly ride track so i was wondering what modifications can be done.
 
racing cdi, ngk spark plug, performance coil, are the cheap mods.

irk/ork, big bore kits, high comp piston, performance cams, are the more pricey ones.

get a duel exhaust if u can, it looks sweet.
 
the reason why u might think it lacks torque at low rpms is probably coz ur in 4th gear goin 10ks den u expect it to do a mono........
 
nah turbos kick in later and he needs torque, maybe a supercharger??
 
ooooh, hows about a gas turbine running an air compressor, that gives full boost at idle...saw it on youtube:) sure, it was in a car, but hey! who cares?
 
I would go nitro!!!!!...thats allways a good choice!!
 
If it's got an IRK (Revs like a 2 stroke but also dies in the ass down low like a 2 stroke ) ... piss it off and replace it with a Lifan 150 ORK or a stock flywheel ignition ... IF it already has an ORK you'd need to fit a torquer cam ie Akunar A1 ... A different carb would help too ... such as a Keihin PD-26 copy which you can buy for $40 + postage off 4322g on ebay ... cheaper if you buy direct and forget ebay ...
 
makedonski said:
the reason why u might think it lacks torque at low rpms is probably coz ur in 4th gear goin 10ks den u expect it to do a mono........
Click to expand...
how old are you? 12? i find it lacks torque at low revs because it does... dickhead
 
Cactus Jack said:
If it's got an IRK (Revs like a 2 stroke but also dies in the ass down low like a 2 stroke ) ... piss it off and replace it with a Lifan 150 ORK or a stock flywheel ignition ... IF it already has an ORK you'd need to fit a torquer cam ie Akunar A1 ... A different carb would help too ... such as a Keihin PD-26 copy which you can buy for $40 + postage off 4322g on ebay ... cheaper if you buy direct and forget ebay ...
Click to expand...
thanks mate, yeah it doesn't have an IRK but it feels like it does. Still has the stock carby on it which looks like its junk. so i might give the keihin copy a try.
 
the real difference would make the cam....and a good carb off cause
 
This is the carb ... a KF-26 ...

BRAND NEW CARBURETOR 26MM DIRT BIKE THUMPSTER - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 25-Jun-09 18:30:37 AEST)

They're nothing fantastic to look at but he's after bottom end power for trail riding ... A friend of mine bought a new DHZ 125 and it has one on it ... I was surprised at how clean it ran and it pulled strong even lugging top gear to bed the rings in ... It started easily and idled spot on all day long too ... The mixture screw is underneath at the rear but it was easy to get at with a small screw driver ... I mentioned cams because I don't think he likes the cam in the YX140 ... that type of carb will help get back some of the off idle torque lost by the cam ...

There's also this 26 mm pumper carb from Elstars ... setting up the twin throttle cables would be a slight hassle but they'd boost bottom end torque for sure ...

Carburetor With Pumper, 26mm [pmpcarb] - $75.90 : Elstar Products, Factory-tuned Racing Motorbikes ATV (Quad Bikes), aftersale support, spare parts and accessories. An agent for Apollo motorbikes, Orion, Elstar Motorbikes Shineray. High-quality parts
 
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The carby on it is a Molkt 26mm, my mate tells me they aren't too bad so i might pull that off and give it bigger jets and see how that goes first, as well as having a look at the inlet manifold, failing that i think ill have to spend some money. cheers for the help guys.
 
PUT NITRO FUEL FROM A REMOTE CONTROL CAR IN IT.. thats what i did with my old orion hahahaha it went like a rocker.. before the engine blew up as well as the exaust stuffed up.. haha good times.,
 
hey mate, first of all im 16. Secondly if ur riding properly and it lacks torque, well maybe its because of your large weight. if u weigh between 50-65, lotta torque. 65-80, good torque, 80+ lacks torque. I think your in the lacks torque section mate. All i can tell ya is you got the wrong bike. 140s aint for u. If u want a mini bike that goes go for a 160 mate. Recently theres got 160 atomiks with the yx160 engine. Pretty sweet nd cheap. Cheers. :)
 
i was aiming the question to people who know stuff about these engines. i weigh 62KG so your wrong again. you clearly know nothing, first its because im trying to do mono's in 4th now i weigh over 80KG. i also asked what mods can be done not what new bike should i buy. dont post if your just going to post shit.
 
things to do.

race cams. some say akunar(has 3 or 4 styles/profiles) and tbolt(same deal, a few choices here)...all with various aims...some give low end torque, some give high end speed, etc etc... do a search, some surfing and some careful reading/cross referencing. some have decompression fitted, some dont...

or the gpx cams on ebay. what i got, and i can say theyre worth the cash. ive never tried the other brands.(and i havent tried them in a 140 yet, either) there is an issue with two different lengths of shafts, and two styles of bearings. so read, take notes, and make sure you get something that fits the first time...

IRK...dont bother. youll lose more torque with one. if you already have one fitted... try finding an ORK...

hi compression piston. same deal as the cams. do a bit of a search, get numbers and measurements right before spending money...especially if you have to wait three weeks for delivery from the US etc...

porting the head. something that some people cant do, and others can. be warned. carbide burrs cost a LOT of money. and its very easy to overdo it, and ruin what was a perfectly good head(and a $60+ burr)... remember, its easier to remove something than replace it... theres a thread here somewhere, useful, but not the most informative.... a good understanding of airflow/turbulence etc helps more...and a steady hand when you do get the die grinder out...

also theres grinding the valves into the seats. fiddling with ignition timing. changing exhausts/carbies.(usually after doing porting work)

other things like stroker kits, and BBK's...not really worth it. unless you get the engine rebalanced(same goes for a hi comp piston, engine needs balancing to cope with any extra/less weight)...feel capable of a complete engine strip down and rebuild?

just think, an engine doing 12 grand, has a piston that is accelerating then deaccelerating about 400 times a SECOND tdc to bdc then bdc to tdc.. twice a revolution....times that by the length of stroke, and youll realise that little bit of alloy is dong some serious work... hence the need for balancing...

anything else? um... not for now... just pray cactus comes and elaborates:) oh! gear ratios... usually limited to just sprocket sizes, but there are different gearboxes available... something i dont really know about, so i cant speak...

things like "racing" cdi's, unless theyre really good ones($100+), are a waste of money.... breather kits. what else? theres a few silly things out there... save your cash and do the real things....
 
Will665 said:
i was aiming the question to people who know stuff about these engines. i weigh 62KG so your wrong again. you clearly know nothing, first its because im trying to do mono's in 4th now i weigh over 80KG. i also asked what mods can be done not what new bike should i buy. dont post if your just going to post shit.
Click to expand...

I will answer this one simple, there is NOTHING you can do to boost the torque enough for it to make a difference. I have tried everything on mine and I have an IRK which makes it even worse. Just put up with it or get a bigger motor. I wouldn't waste my time or money doing anything to this as you can get a yx150/160 cheap as brand new now.

Throwing a new carb on, cdi and all the other stuff will help the motor run better but will not increase the torque by anything noticable. By the time you have spent money trying all that you will have spent close to a new engine.
 
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