KTM 300 exc = info needed

Hello all. New to the forum here. I have been riding since I was 10, am 26 now. got out of riding 5 yrs ago to raise my son & am now gettin back into this wonderful hobby & so is he! = Got him a Yamaha pw50 :thumbsup: . I have never really added anything aftermarket wise to my bikes as far as engine upgrades go... So here is my situation. I bought a 2001 KTM 300 exc last week & had 2 order some things = new levers, some bolts, seat bracket, new chain glide, rear tire etc. When I looked @ the bike it had an aftermarket FMF Gnarly pipe but no silencer on it. BUT the pipe was all bent up from being laid down & was ALL out of whack! I ordered a new FMF Gnarly pipe & a FMF Powercore 2 silencer for it. After installing EVERYTHING including the new exhaust it smokes quite a bit but not AS bad after it warms up. Was wondering if this could be a jetting issue. But it didnt smoke w/ old exhaust on. I did have to adjust idler screw a bit as it didnt want to idle really w/ new exhaust. I am still running the gas that was n it when I bought it & he was running a 40:1 ratio using AMSOil. I am switching to Lucas 2 stroke oil when I fill up next. Just didnt know if I should try 2 rejet it, try new mix ratio, try higher octane or all the above :excuseme: Was just seeing what anyone had 2 say. If it is a jetting issue I will be going w/ the JD Jet Kit. Thx in advance, Steve :usa:

How long has the bike been sitting? How old is the gas in the tank?

If it was me I would dump the gas in the tank and start with a fresh mix, if it's still smoking excessively then I would look at the jetting. I don't remember if you have to re-jet for a gnarly though.

How long has the bike been sitting? How old is the gas in the tank?

If it was me I would dump the gas in the tank and start with a fresh mix, if it's still smoking excessively then I would look at the jetting. I don't remember if you have to re-jet for a gnarly though.

I looked @ it & bought it last Tues = April 9, 2013. It was cold b4 he started it then because I felt the head on the motor & it was cold. It has sat n my garage since & I fired it up a week later April 16, 2013 after the new exhaust was put on. I couldn't tell you how old the gas is in the tank. I will drain the gas & start fresh. Just don't get why it didn't smoke @ his house. Like I said I put the exact same pipe on it that was on b4 BUT it didn't have a silencer so I went w/ the FMF Powercore 2..

Agreed.

Dump the gas in the tank and carb, then clean the carb to make sure there is no gunk in there, start with fresh mix, at the proper ratio, and see what happens. Jetting may be odd, and with a new pipe you always want to check the jetting. At times stock/old jetting will work, and at times you need to redo the whole shebang. It just depends on the pipe. If none of this cures the issue, check back in with the details of what has been done. I advise the JD Jet kit nomatter what. everyone who owns a 300 and uses the JD kit seems to be more than happy with the results.

Edited by The 300 Guy

Agreed.

Dump the gas in the tank and carb, then clean the carb to make sure there is no gunk in there, start with fresh mix, at the proper ratio, and see what happens. Jetting may be odd, and with a new pipe you always want to check the jetting. At times stock/old jetting will work, and at times you need to redo the whole shebang. It just depends on the pipe. If none of this cures the issue, check back in with the details of what has been done.

Will do. Just got home from work & will go drain the tank & carb & open er up & see what the inside of it is like. I wont know 4 sure as I am getting the new mix in the morning & heading to my property 2morrow & will ride it & see how it does... Thx 4 the tips guys

Will do. Just got home from work & will go drain the tank & carb & open er up & see what the inside of it is like. I wont know 4 sure as I am getting the new mix in the morning & heading to my property 2morrow & will ride it & see how it does... Thx 4 the tips guys

Anytime.

Will do. Just got home from work & will go drain the tank & carb & open er up & see what the inside of it is like. I wont know 4 sure as I am getting the new mix in the morning & heading to my property 2morrow & will ride it & see how it does... Thx 4 the tips guys

That's what it's all about my friend, riders helping riders :thumbsup:

Anytime.

That's what it's all about my friend, riders helping riders :thumbsup:

:thumbsup:

Ok, drained the tank, took carb off, drained & tore it apart. It is clean as a whistle... Put carb back together & put back on bike. Will post an update on the new mix using the Lucas oil when I get home Sat or Sun...

Agreed.

I advise the JD Jet kit nomatter what. everyone who owns a 300 and uses the JD kit seems to be more than happy with the results.

How do you know which jets 2 pick :excuseme: Like I said I have never added aftermarket engine stuff 2 my bikes so this is an all new game 4 me. I ask the "which jets 2 pick" question cause looking @ the JD kit online there looks 2 b several 2 choose from in a package so I'm assuming they are different sizes...

Also, should I b running premium gas n that bike?

Edited by stevekx500

The JD kit comes with detailed instructions, I am told. You go by your location and what you have on your bike, and you can get in touch with JD Jetting for them to help you out. This I have heard from all that have used the JD kits, and all have been truly impressed.

As for what gas to use, lower octane ratings have more debris and are less refined, so they are said to produce less "bang for your buck", while the higher the octane you use the cleaner it is and thus the better burn for your bike. Some say that you will have far less carbon build up on your bike as well using higher octane ratings, but that is not always the case as it has to do with your jetting and proper use, as well as proper specifications. Carbon build up at the piston top/dome is due to low temps, rich mixtures, and light load operation, or if it is on the sides of a piston it is due to bad ring seal or improper oil.

I have used all octane ratings with good results, so that is up to you, but in truth the higher octane is refined more.

The JD kit comes with detailed instructions, I am told. You go by your location and what you have on your bike, and you can get in touch with JD Jetting for them to help you out. This I have heard from all that have used the JD kits, and all have been truly impressed.

As for what gas to use, lower octane ratings have more debris and are less refined, so they are said to produce less "bang for your buck", while the higher the octane you use the cleaner it is and thus the better burn for your bike. Some say that you will have far less carbon build up on your bike as well using higher octane ratings, but that is not always the case as it has to do with your jetting and proper use, as well as proper specifications. Carbon build up at the piston top/dome is due to low temps, rich mixtures, and light load operation, or if it is on the sides of a piston it is due to bad ring seal or improper oil.

I have used all octane ratings with good results, so that is up to you, but in truth the higher octane is refined more.

Ok, quick update... Fresh gas over the weekend w/ a 40:1 mix of Premium gas & Lucas 2 stroke oil. Still smoking. guess I will be ordering the JD jet kit n the next couple of days...

Most 2t bikes, even properly jetted ones will smoke on start up, some more than others. Is yours doing this and clearing up some when warm, or just smoking bad all the time?

I have an 2000 300 EXC. these bikes are a bit finicky to jet, but the hard work has been done by those who owned these bikes prior to us...

]1st you are correct in dumping the gas and using what brand you prefer, and the mix level you prefer. Yes two strokes will smoke... My advice is to ride the bike before you start making jetting changes. You need to get the engine warm / hot before you'll see the smoke to dissipate. Ride the bike and then if needed we will help jet the bike to get the proper performance out of the bike.

As far as jetting goes, I didn't go with the JD kit. I purchased some jets and a different slide based on research I did on this and other forums.

Again I strongly suggest you ride the bike a few times, and then based on what you feel needs changed, we will help you get the most out of the bike.

BTW the 300's are so much fun... My bike is perfectly happy when putting around with the kids, or the old fart on their quads. But when I want some arm ripping fun, all I have to do is twist the throttle, and hang on... It truly is a do all bike.

Edited by eprovenzano

I have an 2000 300 EXC. these bikes are a bit finicky to jet, but the hard work has been done by those who owned these bikes prior to us...

]1st you are correct in dumping the gas and using what brand you prefer, and the mix level you prefer. Yes two strokes will smoke... My advice is to ride the bike before you start making jetting changes. You need to get the engine warm / hot before you'll see the smoke to dissipate. Ride the bike and then if needed we will help jet the bike to get the proper performance out of the bike.

As far as jetting goes, I didn't go with the JD kit. I purchased some jets and a different slide based on research I did on this and other forums.

Again I strongly suggest you ride the bike a few times, and then based on what you feel needs changed, we will help you get the most out of the bike.

BTW the 300's are so much fun... My bike is perfectly happy when putting around with the kids, or the old fart on their quads. But when I want some arm ripping fun, all I have to do is twist the throttle, and hang on... It truly is a do all bike.

Funny you commented 2day cause I FINALLY got 2 get some seat time n on the bike this afternoon :ride: & all I can say is WOW!!!!! :jawdrop: That bike is impressive!!! I have owned several bikes over the yrs & this is my 1st KTM & man is it a blast 2 ride! After getting it warmed up I hit the open area 2 warm myself up then hit the trails. As far as running ok it seems fine. Idles fine in & out of gear & the power is there when I need it = no lag or nothin, like you said just twist & you got a rocket on 2 wheels! I will put several more hrs on it & see how it goes. Thx for the advice :thumbsup:

Most 2t bikes, even properly jetted ones will smoke on start up, some more than others. Is yours doing this and clearing up some when warm, or just smoking bad all the time?

It doesn't smoke as bad once it warms up. I finally got 2 put some seat time n 2day on it :ride: & it seems fine now. Isnt smoking as bad as it was the other day so I think it will b ok. Just bothered me cause all the other 2 strokes I've owned n the past didn't smoke @ all... & if they did it wasn't much. The bike is a BLAST 2 ride. Like riding a feather w/ a motor! I have rode a couple KTM's n the past but didn't "push it" cause I didn't want to wreck the persons bike & this is the 1st 1 I've owned & man it's a LOT of fun when u get on it on the trails!!!

Edited by stevekx500

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