Jump to content
Sign in to follow this  

250sx too much oil?

Recommended Posts

Started my bike up today and like always starts first kick. After about a min it bogged and then died. I couldn't start it back up so I changed the plug and after a couple of kicks came back. Picture attached is plug. ImageUploadedByThumper Talk1397780644.382395.jpg

Share this post


Link to post
Share on other sites

Well...it's a MX bike....get on it and go....blow it it out.

The stock needle is poo..... Try 40 Nedw 170 main

Edited by E-TECH

Share this post


Link to post
Share on other sites

E-Tech is correct... its not the oil, its the jetting.  What bike, year, do you know your current jetting specs, pilot jet, main jet, needle and clip position, slide number, and air screw setting.  Give us the details, and we'll help you get it dialed in...  

Share this post


Link to post
Share on other sites

Both of my 250 sxs have 1 size under stock pilots to clean them up. Fouling hasnt been an issue since. Mine are offroad not mx ridden though.

Share this post


Link to post
Share on other sites

2014 250 sx

Stock jetting

Mj 158

Pilot 42

Air screw 2 turns

3rd pos

Based off the plug is it too rich?

Share this post


Link to post
Share on other sites

2014 250 sx

Stock jetting

Mj 158

Pilot 42

Air screw 2 turns

3rd pos

Based off the plug is it too rich?

Look in the back of your owners manual. It will give jetting specs for temp and altitude and compare. They seem to be pretty accurate.

If you are not keeping it on the pipe then the plug will foul. If you lug it a lot you might try to go 1 step leaner on the pilot jet? Maybe someone with more specific knowledge could correct me if I'm wrong? I've avoided messing with my carb until this year as it ran great with stock jetting.

Edited by poldies4

Share this post


Link to post
Share on other sites

Where I ride the stock settings are correct. My next tank will be at 60:1 ratio like the manual wants. New to riding, been 25 years lugging around too much I guess.

Share this post


Link to post
Share on other sites

Where I ride the stock settings are correct. My next tank will be at 60:1 ratio like the manual wants. New to riding, been 25 years lugging around too much I guess.

I did just notice you never mentioned what ratio you were mixing at. I run my bike 40-1 per the manual and all has been good. Make sure you use an oil designed to mix at that ratio as well. Congrats on the bike!

Share this post


Link to post
Share on other sites

I wouldn't run 60:1, regardless of what the manual says.  Stick with 40:1.  A few thoughts:

1. use the manual for jetting, and make sure your air filter is clean, and your silencer is not all carbon crusted inside.

2. a lot of bikes that are slightly rich respond well to just moving the clip one notch up on the needle

3. buy a JD jetting kit--quick and easy...

4. Is your bike due for a top end?  Sometimes the jetting gets a little sloppy as the top-end wears.

5. Maybe you just needed a new  plug. Plugs don't last forever in dirt bikes like they do in cars.

Edited by rpt50

Share this post


Link to post
Share on other sites

I would definitely run the ratio that is recommended by KTM. Then I would run the gas that is also recommended by KTM. Then I would follow the jetting specs that are recommended by KTM. Because it works! Follow the jetting chart for your elevation and temperature. It really is that simple.

Run good oil at the proper ratio with the proper jetting and your bike will run great. The stock needle is great IF you are at 2000' and it is 70°. If you are not at 2000' and/or it is not 70° the stock needle is the wrong needle. That is why it doesn't work. Changing the jetting means changing ALL the jets including the needle.

  • Like 1

Share this post


Link to post
Share on other sites

Air filter is cleaned after every ride and hasn't had dirt. Bike is new with only about 3 hours on it. 2014 ktm 250sx.

Here is your jetting chart.

14KTM250sxJettingChart_zps992f88ed.jpg

Share this post


Link to post
Share on other sites

I am running the stock setting which happens to work for where I ride which is milestone. The only thing is I haven't had a chance to ride at 60:1 which is what the manual says. I'm no expert but the plug looks really rich but I Havet been riding it hard yet.

Share this post


Link to post
Share on other sites

I would definitely run the ratio that is recommended by KTM. Then I would run the gas that is also recommended by KTM. Then I would follow the jetting specs that are recommended by KTM. Because it works! Follow the jetting chart for your elevation and temperature. It really is that simple.

Run good oil at the proper ratio with the proper jetting and your bike will run great. The stock needle is great IF you are at 2000' and it is 70°. If you are not at 2000' and/or it is not 70° the stock needle is the wrong needle. That is why it doesn't work. Changing the jetting means changing ALL the jets including the needle.

+1 great advice! Too many people apply their own philosophies without any specific merit to make their view valid based on data. Instead they use a gut feeling or apply some previous knowledge they think relates to the subject matter at hand. Unless you are certain of doing otherwise, stick with the info in the manual for the best practices when it comes to engine care.

  • Like 1

Share this post


Link to post
Share on other sites

+1 great advice! Too many people apply their own philosophies without any specific merit to make their view valid based on data. Instead they use a gut feeling or apply some previous knowledge they think relates to the subject matter at hand. Unless you are certain of doing otherwise, stick with the info in the manual for the best practices when it comes to engine care.

I agree that one should always follow the manufacturers recommendations, and I'm always amazed (and appalled) at the number of people who act as if the engineers that designed the bike know nothing, and they immediately start throwing money at the bike (revalves, pipes, head and porting, etc.).  The only problem here with following the manufacturer's advice is that KTM's advice on premix ratio is TRUELY odd.  I am not aware of any other two stroke product manufacturer that recommends such an extreme ratio.  Japanese 2 stroke MX bikes are all 32:1 (or very close, like 30:1).  My lawn care machines and chainsaw run on 40:1, and even my outboard motor and PWCs run 50:1, but they have an oil pump that increases the flow at higher rpm (the oil pump advances with the throttle), so the full throttle oil ratio offers more protection.  KTM's recommendations on everything else about the bike are very generic, but their oil ratio is way out in left field. As far as I can tell, a KTM motor is not made out of some special friction-free metal that does not need normal oil levels.   I think that is why you see experienced 2 stroke guys running different ratios.

 

Again, to the OP, I would stick with 40:1, and carefully look at the jetting chart in you manual (taking into account altitude and temp).  Pay careful attention to how the chart show progressively leaner settings, and you will be able to find one that works.  You may also find that your jetting needs change as your skill and confidence with the bike increases.  I help a lot of people with their jetting, and it's pretty common for folks to need a little bit leaner setting until they get used to the bike.

 

Another tip that might me useful is that you can use NGK BR8ES plugs.  They are a little taller so getting the plug cap on is a little tricky, but they only cost $2 at any auto parts store. 

 

Finally, no need to clean your air filter after every ride unless it is really dusty/silty where you ride.  KTM filters have a lot of surface area, and they seem to stay clean (airbox design??) compared to some other bikes.  I swear that my Suzuki air filter gets dirty with the bike sitting in the garage!  

Share this post


Link to post
Share on other sites

I agree that one should always follow the manufacturers recommendations, and I'm always amazed (and appalled) at the number of people who act as if the engineers that designed the bike know nothing, and they immediately start throwing money at the bike (revalves, pipes, head and porting, etc.). The only problem here with following the manufacturer's advice is that KTM's advice on premix ratio is TRUELY odd. I am not aware of any other two stroke product manufacturer that recommends such an extreme ratio. Japanese 2 stroke MX bikes are all 32:1 (or very close, like 30:1). My lawn care machines and chainsaw run on 40:1, and even my outboard motor and PWCs run 50:1, but they have an oil pump that increases the flow at higher rpm (the oil pump advances with the throttle), so the full throttle oil ratio offers more protection. KTM's recommendations on everything else about the bike are very generic, but their oil ratio is way out in left field. As far as I can tell, a KTM motor is not made out of some special friction-free metal that does not need normal oil levels. I think that is why you see experienced 2 stroke guys running different ratios.

Again, to the OP, I would stick with 40:1, and carefully look at the jetting chart in you manual (taking into account altitude and temp). Pay careful attention to how the chart show progressively leaner settings, and you will be able to find one that works. You may also find that your jetting needs change as your skill and confidence with the bike increases. I help a lot of people with their jetting, and it's pretty common for folks to need a little bit leaner setting until they get used to the bike.

Another tip that might me useful is that you can use NGK BR8ES plugs. They are a little taller so getting the plug cap on is a little tricky, but they only cost $2 at any auto parts store.

Finally, no need to clean your air filter after every ride unless it is really dusty/silty where you ride. KTM filters have a lot of surface area, and they seem to stay clean (airbox design??) compared to some other bikes. I swear that my Suzuki air filter gets dirty with the bike sitting in the garage!

You mentioned the br8es. I went with the br8es when i picked up a extra plug for the first 250sx i bought . When i saw the price on a br8ecm, omg ! i refused to buy it .

On subject though..id never run 60:1 on any performance 2 stroke. I run 50:1 for trail riding, 44:1 for harescramble or gp. I dont change jetting as i change ratio, never found it necessary.

Share this post


Link to post
Share on other sites

I agree that one should always follow the manufacturers recommendations, and I'm always amazed (and appalled) at the number of people who act as if the engineers that designed the bike know nothing, and they immediately start throwing money at the bike (revalves, pipes, head and porting, etc.).  The only problem here with following the manufacturer's advice is that KTM's advice on premix ratio is TRUELY odd.  I am not aware of any other two stroke product manufacturer that recommends such an extreme ratio.  Japanese 2 stroke MX bikes are all 32:1 (or very close, like 30:1).  My lawn care machines and chainsaw run on 40:1, and even my outboard motor and PWCs run 50:1, but they have an oil pump that increases the flow at higher rpm (the oil pump advances with the throttle), so the full throttle oil ratio offers more protection.  KTM's recommendations on everything else about the bike are very generic, but their oil ratio is way out in left field. As far as I can tell, a KTM motor is not made out of some special friction-free metal that does not need normal oil levels.   I think that is why you see experienced 2 stroke guys running different ratios.

 

I understand the desire to consider other options when seeing something foreign to what they've done in the past, but it's poor advice to deviate from the recommended ratio and hypocritical to your statement "I agree that one should always follow the manufacturers recommendations, and I'm always amazed (and appalled) at the number of people who act as if the engineers that designed the bike know nothing"

 

For example, with the 150sx, KTM recommends 40:1 in the manual, then on the 250sx it's 60:1. Are we saying the engineers are correct for applying 40:1 on the 150sx and incorrect when it comes to the 250sx at 60:1? Clearly these recommendations come from much research and testing, and to assume otherwise and come up with your own practice is simply not wise. The problem is that as soon you start deviating from the manual, you then start opening up a rabbits hole of other things that need to be considered, i.e. jetting specs, engine maint scheduling etc...  The books jetting specs would likely no longer to be valid and then you'll have to figure out and determine the long term impact improper jetting may have. In terms of lubrication, moving to 40:1 is likely to have very little impact on the lubrication on the engine, and it's likely to have a greater impact on whether you are running the engine too lean...which over time will have a much greater impact on the longevity/reliability. Moving to 40:1 will make your bike run lean and that's certainly not wise in terms of proper engine care.

 

My advice is not to make up your own advice, not unless you are an engineer and you have done deep research/testing into the specific engine/machine you are referring to. Otherwise you are just being reckless with your advice.

Share this post


Link to post
Share on other sites

 

I understand the desire to consider other options when seeing something foreign to what they've done in the past, but it's poor advice to deviate from the recommended ratio and hypocritical to your statement "I agree that one should always follow the manufacturers recommendations, and I'm always amazed (and appalled) at the number of people who act as if the engineers that designed the bike know nothing"

 

For example, with the 150sx, KTM recommends 40:1 in the manual, then on the 250sx it's 60:1. Are we saying the engineers are correct for applying 40:1 on the 150sx and incorrect when it comes to the 250sx at 60:1? Clearly these recommendations come from much research and testing, and to assume otherwise and come up with your own practice is simply not wise. The problem is that as soon you start deviating from the manual, you then start opening up a rabbits hole of other things that need to be considered, i.e. jetting specs, engine maint scheduling etc...  The books jetting specs would likely no longer to be valid and then you'll have to figure out and determine the long term impact improper jetting may have. In terms of lubrication, moving to 40:1 is likely to have very little impact on the lubrication on the engine, and it's likely to have a greater impact on whether you are running the engine too lean...which over time will have a much greater impact on the longevity/reliability. Moving to 40:1 will make your bike run lean and that's certainly not wise in terms of proper engine care.

 

My advice is not to make up your own advice, not unless you are an engineer and you have done deep research/testing into the specific engine/machine you are referring to. Otherwise you are just being reckless with your advice.

 

Dude, if you read my post, you will note that it discusses adjusting jetting, and of course my bikes are jetted for the ratios I run (40:1 and 32:1).  All I'm pointing out is that KTM's ratio recommendations are significantly different from other manufacturers.  I don't know why they suggest that ratio.

 

I do not think my advice is "reckless" either.  Even a cursory examination of owner's manuals from different manufacturers and professional publications related to 2 stroke performance will reveal that ratios between 24 and 40:1 are by far the most commonly recommended.  Even though I have a lot of experience myself (running smokers in various forms since the 70s), I always base my procedures on manufacturers recommendations and professional publications written by those with more knowledge than myself.  I choose not to follow the 60:1 ratio recommendation in my KTM manual however, simply because it deviates so significantly from widely accepted 2 stroke practices.  

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×