ktm sx 105 2 stroke

[-LadyDirt-]

Before any rider (or racer) starts monekying with jetting or the gas/oil ratio - they should do a plug check. Knowing what is causing the plug to foul will allow you to determine what the fix for the fouling plugs is - too much oil or jetting. I'm always hesitant to cut back on the oil ratio, a standard 2 stroke ratio for anything from race bikes to weedeaters and chainsaws is about 40:1. Anything in the 30:1 to 50:1 range is fine IMO, but I would never go higher than 50:1 in any 2 stroke I own.

Not running enough oil will toast your motor and leaning down your bike because it is fouling plugs at idle is not a good idea unless they are certain it's the idle fuel circuit and not the main fuel circuit. Give your bike as much oil as it will take without fouling plugs when jetted correctly IMO. I have over 3000 kms on my one sled motor, popped the head off and measured the bores this year, new clearance on the pistons to the bore was 0.0039", I'm at 0.0040". Wear limit is 0.0048". Virtually no wear after 3000 kms and I use a regular everyday oil (Shell Advance regular - not the synthetic), not a fancy oil. Its about how much you use - not the type IMO. People who skimp out on oil typically wind up with motors as expensive paperweights. A well oiled motor is a happy motor.

I agree, I usually run 45:1..seems to work just fine but like we pointed out earlier, my bike only fouled plugs when it was idling so now that I learnt that I dont let my bike idle and it doesnt foul, but just for precaution my mechanic is going to have a look at the jetting now anyway just to make sure. I was running my bike richer with oil because I was just breaking in the motor, but I think if i bump it up to 45-50:1 it should be ok. I really dont ride my bike very hard.. not to its full potential anyway, but i'm sure as i get more used to it and become a better rider I will so as my riding style changes well then I guess I just gotta start paying attention to other things like jetting, oil ratio, plugs, etc. However, my mechanic suggested I put only KTM OEM parts, including spark plugs..which sucks cause I figured I'd try and get away with the canadian tire knock-off, but apparently that is a no-no haha, but I'm cheap..and really wanted to avoid paying $30 for a fuggin spark plug!

 

[Thunderr]

KTM only plugs? hmmm

I'll keep rolling with crappy tire.

Of course I'm on my 2nd plug in 3 years. Damn 4 strokes.

 

[-LadyDirt-]

Well I just put a KTM one in there when I rebuilt the motor, I think my mechanic is a bit too anal anyhow.. a spark plug is a spark plug..right? lol the NGK seems to be workin just fine

 

[Thunderr]

Not sure what plug my bike has in it.

Mo Potatoes bike (08 250 XCF-W) takes a NGK CR 9 EBK. That's straight out of the manual.

 

[Modman]

I agree, I usually run 45:1..seems to work just fine but like we pointed out earlier, my bike only fouled plugs when it was idling so now that I learnt that I dont let my bike idle and it doesnt foul, but just for precaution my mechanic is going to have a look at the jetting now anyway just to make sure. I was running my bike richer with oil because I was just breaking in the motor, but I think if i bump it up to 45-50:1 it should be ok. I really dont ride my bike very hard.. not to its full potential anyway, but i'm sure as i get more used to it and become a better rider I will so as my riding style changes well then I guess I just gotta start paying attention to other things like jetting, oil ratio, plugs, etc. However, my mechanic suggested I put only KTM OEM parts, including spark plugs..which sucks cause I figured I'd try and get away with the canadian tire knock-off, but apparently that is a no-no haha, but I'm cheap..and really wanted to avoid paying $30 for a fuggin spark plug!

Yeah I would agree with that except the spark plug comment - I have used everything out there and I will swear by NGK plugs. I have ran them in race motors for years and have never missed a beat. They do need replacing from time to time - but that is a standard maintenance thing. The jetting thing IMO is likely not your riding style as much as it probably needs the air screw cranked around a few turns or a smaller pilot jet to compensate for the higher altitude here. Because it's only fouling at idle, this is where I would start in the fuel range if your mechanic has not adjusted it. Typically its overlooked/not adjusted because no one rides around at idle but if you are fouling plugs at idle then its causing a problem and should be adjusted. That being said, if its not fouling plugs anymore and it's not too boggy off the bottom end, then ride it like you stole it and have fun!

 

[willmx11]

Mines a 2006. I've had it for ..9 months? And I am the 2nd owner. I have redone everything to this bike, complete brand new top/bottem end engine with maybe 20 hrs on it?, new brakes, forks, tires, and soon a new pipe. It's an amazing bike, and would no doubt kick the chit out of a 150r. Just depends if you want to go 2 stroke or 4 stroke but yes, I agree with WillJeff.. 2 strokes way more fun. It would be very hard for me to let this bike go, so the price would have to be right, and so far, its got over 4g into it. Mine keeps up to 125's my mechanic races 450's, and he even says that my bike scares him..but he's got it running pretty good. I am almost willing to bet that you would not find a decent KTM 105 for under 4g..and if you do..its likely because something is going wrong with it and your gonna have to dump money into it soon enough.. just sayin. BUT.. you could always look at KX 100's.... if you want something cheaper.

Well i think i wanna go 2 stroke and get the sx105 but there really hard to find. i cant even find one at a dealership brand new. and canada is really far away. But im havin a dealership look around for me.

 

[-LadyDirt-]

Well i think i wanna go 2 stroke and get the sx105 but there really hard to find. i cant even find one at a dealership brand new. and canada is really far away. But im havin a dealership look around for me.

Well you know you could save yourself the time, money and hassle and buy a Kawasaki KX 100.. its the same bike literally, just green.. oh..and CHEAPER!! That would have been my choice, and I almost bought one myself until I saw the KTM for sale for $1800.... $1800!! That is UNHEARD of! hahaha of course it blows up my first ride but meh, I have basically a brand new bike now for 4g, would have sucked if I paid 4g for it and it still blew up.. yikes. She will be getting a new pipe and plastics soon and eventually gonna try and do some black rims.

Good luck with your findings, I'm surprised there aren't more 105's in the states, there very hard to find here and when you do they are $$$...but I'd look at a KX100 if I were you..trust me man, your gonna save yourself a lot of money, im finding out the hard way just how expensive it is to maintain a KTM..parts are ridiculously priced and so is the bike..but I love it nonetheless..

 

[willmx11]

Well you know you could save yourself the time, money and hassle and buy a Kawasaki KX 100.. its the same bike literally, just green.. oh..and CHEAPER!! That would have been my choice, and I almost bought one myself until I saw the KTM for sale for $1800.... $1800!! That is UNHEARD of! hahaha of course it blows up my first ride but meh, I have basically a brand new bike now for 4g, would have sucked if I paid 4g for it and it still blew up.. yikes. She will be getting a new pipe and plastics soon and eventually gonna try and do some black rims.

Good luck with your findings, I'm surprised there aren't more 105's in the states, there very hard to find here and when you do they are $$$...but I'd look at a KX100 if I were you..trust me man, your gonna save yourself a lot of money, im finding out the hard way just how expensive it is to maintain a KTM..parts are ridiculously priced and so is the bike..but I love it nonetheless..

ok theres a 2004 on craigslist for $1800 ill prolly look at it. are they just as fast and powerful as a 105?

 

[-LadyDirt-]

ok theres a 2004 on craigslist for $1800 ill prolly look at it. are they just as fast and powerful as a 105?

For sure, I'd say..i've ridden a few and they feel just as snappy and torquey as mine, but their Japanese thats the only difference so everything is cheaper.

 

[willmx11]

For sure, I'd say..i've ridden a few and they feel just as snappy and torquey as mine, but their Japanese thats the only difference so everything is cheaper.

ok well idk know bout the kx 100 or sx105 now. my friend whos a really good racer he said those bikess are like time bombs you have to replace the top end all the time.

 

[-LadyDirt-]

ok well idk know bout the kx 100 or sx105 now. my friend whos a really good racer he said those bikess are like time bombs you have to replace the top end all the time.

lol ppfff...thats a crock..maybe if your racing them ya...but if your racing you have to put a top end in any bike all the time.

 

[willmx11]

lol ppfff...thats a crock..maybe if your racing them ya...but if your racing you have to put a top end in any bike all the time.

what if you ride about 2 to 4 hours about every other weekend?

 

[ktm 13-44]

what if you ride about 2 to 4 hours about every other weekend?

if thats the case, you will be just fine.

even if you have to replace the top-end, its SUPER easy and super cheap. on a small 2-stroke like that you'll be revving the chit out of it all the time. it wears on a bike, and parts have to be replaced from time to time. Just take care of it, do the regular maintenence, and you'll be just fine.

when you go to buy the bike, make sure you look for the right things. see if the oil in the gearbox is black. if it is the guy hasnt been changing it like he should have. smell the oil. if it smells burnt, stay away. remove the flywheel cover. if you can jiggle the flywheel at all, the bottom-end is on its way out. there should be no movement there at all. look at the forks. any oil on the fork tubes? Are there any "black rings of death" on the tubes? blown for seals.

just be smart about the bike you buy.

 

[willmx11]

if thats the case, you will be just fine.

even if you have to replace the top-end, its SUPER easy and super cheap. on a small 2-stroke like that you'll be revving the chit out of it all the time. it wears on a bike, and parts have to be replaced from time to time. Just take care of it, do the regular maintenence, and you'll be just fine.

when you go to buy the bike, make sure you look for the right things. see if the oil in the gearbox is black. if it is the guy hasnt been changing it like he should have. smell the oil. if it smells burnt, stay away. remove the flywheel cover. if you can jiggle the flywheel at all, the bottom-end is on its way out. there should be no movement there at all. look at the forks. any oil on the fork tubes? Are there any "black rings of death" on the tubes? blown for seals.

just be smart about the bike you buy.

ok. thanks for tips