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Does 2 stroke = too smoke, always?

augustiron

augustiron

A firm member
Joined
Mar 5, 2003
Location
Truckee SF Reno
Moto(s)
All of them eventually.
Name
nope
So I am considering a 2 stroke dirtbike. again. My question is, do new ones smoke, badly? something like a NEW KTM 2T?

I had a 99 YZ250 that smoked like a mofo even with the ratio as low as it could go. It was a fresh rebuild and piston, etc. I had to get rid of it because me and the folks I ride with (wife) couldn't stand the smoke.
I have had a 4 stroke for the last 8 years and love it but want to play with something lighter and smaller. I don't have any good experience with 2 strokes.

I would like a new lightweight, smaller toy dirtbike and am looking at KTM freeride or 200 w/electric start but I don't want a smokebomb.

Any suggestions? (besides wiping the sand out of my vag? :twofinger)
 
A 2t that's running correctly smokes very little. At a motocross track you're likely to see zero smoke from 2t's as they run around. Riding trails, they do tend to load up a bit more, but make a point to wring 'em out wherever you can and they'll stay fairly clean. It was great riding last week with my 2t buddy. Whenever he ran out of sight, I could literally smell that I was still going the right way, even though I couldn't see smoke/dust. He was on an early 2000's ktm 250exc.
 
2strokeYardSale said:
...some smoke more than others...
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True. Eric's GG 250 runs like a dream, always has. Jetted nice and crisp, plug always looks great, never any fouling, never any carbon build-up on the piston, cylinder always looks perfect, not much spooge at all. It smokes way more than any other 2 stroke we've ever owned, and it's done it since the day it came off the showroom floor. Same oil, same mixture…it just smokes. Drives me nuts when riding behind him. I leave a gap so I don't have to smell it all day.




WoodsChick
 
my 07' ktm 300xc unknown hours doesn't smoke much once warmed up..hardly any.. I'm running rock oil 40/1
 
Port timing and squish can have a good effect on how well the mix gets burned. GG has notoriously bad squish and port timing (I know I have 3 of them). Ktm ports are pretty good but they run a big sqish. The street bikes are usually tuned better due to the high RPMs but can have it too. Pipe temps also contribute to how much makes it out the tail....Most of my bikes don't smoke much at all once warm but do on start-up, my biggest problem is I love that castor smell so as long as you're running a good pre-mix (Motul synthi has a good smell too) I don't mind it a bit...Dust is always more of an issue.
 
Also, not all smoke is fuel mixture related. If the trans side crank seal is blown it will smoke like a m-fer until all the tranny oil is burned, then it will seize. If it still smokes a lot after it's warmed up, sometimes just changing that seal can fix it.
 
My KDX is a bit sploogy, but runs great. I run a synthetic castor blend, as I love that castor smell. :thumbup
 
Lunch Box said:
My KDX is a bit sploogy, but runs great. I run a synthetic castor blend, as I love that castor smell. :thumbup
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I used to run castor in my `84 CR80 when I first started riding. I loved the smell but soon figured out it was giving me horrific headaches. Switched to
non-bean oil and the headaches went away. I love catching a whiff of it in the forest, though. Brings back super awesome memories! :love




WoodsChick
 
WoodsChick said:
I used to run castor in my `84 CR80 when I first started riding. I loved the smell but soon figured out it was giving me horrific headaches. Switched to
non-bean oil and the headaches went away. I love catching a whiff of it in the forest, though. Brings back super awesome memories! :love




WoodsChick
Click to expand...

The problem is that you would have to be behind me in order to catch a whiff. Something tells me that when we FINALLY ride together, you won't spend much time behind me. :laughing
 
elemetal said:
...GG has notoriously bad squish and port timing (I know I have 3 of them)...
Click to expand...


Yep. Those items were addressed shortly after bike was purchased brand new.
Also, no crank seal issues. It's still smokier than the rest of them :laughing




WoodsChick
 
Lunch Box said:
The problem is that you would have to be behind me in order to catch a whiff. Something tells me that when we FINALLY ride together, you won't spend much time behind me. :laughing
Click to expand...


Hah! You never know. Seems like every time I break bones I slow down just a little bit more. It doesn't stop me from breaking them again, though. Maybe I should just toss that idea in the garbage where it belongs? :ride




OldBrokenSlowChick
 
augustiron said:
Any suggestions? (besides wiping the sand out of my vag? :twofinger)
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Nope.... :twofinger :teeth

I am firm a believer in the proper jetting and lower flashpoint premix camp. If you are running the tight trails you are going to have to lean out your air screw, pilot, and needle to run relatively smoke free. Your engine has to run hot enough to burn the oil. The ONLY way to do that is to lean your bike out for that type of riding, period.

Changing the premix ratio, ie running less oil does what? 1st, it actually enriches the fuel/air mixture resulting in a cooler engine temp for any given rpm. 2nd, it provides less much needed lubrication to your crank. Sure, if you run some crazy lean oil/fuel mixture you may eventually get less smoke because there isnt any oil to burn. :thumbdown

Or, you can spend $10 on brass and a bit of time to lean out the pilot and needle and get a clean bike that runs great and is getting the lubrication it needs. I run 32/1 and other than cold, no unusual amount of smoke. :thumbup

I do have to clean my FMF turbine core often though as the swirling motion of the spark arrestor tends to suspend more unburned oil than a silencer without the sparky. Wish the FMF had a screen sparky instead.....

Oooops..... but back to the original Q. New smokers are no different than a properly running smoker from 20 years ago. My 02 YZ can run pretty clean when properly tuned. So wipe that sand out of your ...... :twofinger
 
New trials bikes and older ones don't smoke much at all, but we do run our mix at 90:1 or even 120:1:twofinger
 
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