Fuel Mixture fuel mixture

Discussion in '2-Stroke Engines' started by pianoman8t8, Feb 4, 2007.

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  1. pianoman8t8

    pianoman8t8 Guest

    ok, so I've put on around 75 miles on my bike, and I was wondering when i should switch to a leaner fuel:eek:il mixture, and it's currently still at 20:1. I haven't even run a gallon of the 20:1 throught it yet, thought, but I was just wondering. Any ideas? I still have about 1/4 gallon left of the 20:1


  2. Steve

    Steve Guest

    I don't know the answer to your question, but I'm at exactly the same point as you are, and I plan to burn the whole gallon at 20:1 before I mix some fuel with less oil.
  3. Guest

    Guest Guest

    You could probably go to 32:1 after your first tank.
  4. I went thorugh about three gallons at 20:1 before I switched to 32:1 but like everything else with these things I can't say to what extent it is good for the engine either way.
  5. gone_fishin

    gone_fishin Guest

    i did a confirmed 20:1 of briggs & stratton for 200 miles, rode it hard but with respect, it's starting to feel really good and it's very reliable.

    i've just mixed my first gallon of 40:1, still briggs, it's weaning now and doing great. i changed my plug to a new ngk-b6hs with a hot gap, bumped the needle one groove richer, made a full-breather aircleaner. i should mention the muffler's been fully gutted from the get-go. it thumps very impressively, grooving in real nice now. i can feel enuff power to know i'll be able to use at least a 36 if not a 32 rear sprocket next month.
  6. chieflets

    chieflets Guest

    what notch have you got it on and your mixture screw up top how many turns from fully closed

    Just out of curiosity

  7. foyeburger

    foyeburger Guest

    im in the same boat . ive got about 300 miles on my 48 cc dax engine and was wondering the same thin . been using 20 to 1 was also wondering when to switch up. daxs phamplet that came with the kit says to bump it up to 25 to 1 after breakin . so whats 32 to 1 and 40 to 1 got me confusd im at ocean level so i dont think i need to change the needle in th carb a notch seems to work fine the way it is. larry ca
  8. gone_fishin

    gone_fishin Guest

    my dax 70 came with the needle on 2nd slot down. after a lot of messing with it i get my best performance on the 3rd one (i'm as sea-level as it gets)...beefier thump, i can roll at idle and it sounds pretty cool.

    the screw is for setting idle, not mixture...set it according to your own conditions.

    i use briggs & stratton "easy mix"...it comes in 3.5 oz bottle, i bottle to one gallon for actual ratio of 36:1.
  9. Blaze

    Blaze Guest

    I have over 200 miles on my bike, and I run it on 25:1 all the time. I guess I could probably get more performance by using less oil in the gas, but my plug isn't getting fouled up or anything, so I figure I will just leave it at 25:1. I have a cheap eBay engine, and I don't think it hurts to have the extra oil running through it.

    By the way, my mixture is set on the 2nd groove from the top (adjusted by moving the E-clip on the throttle needle).
  10. pianoman8t8

    pianoman8t8 Guest

    Also, I looked at the internet about my sea-level height, and Supposedly I'm around 140 ft. above sea level. It ran good on the 2nd groove (from the top), but better low-end power on the 3rd groove (from the top) but also less top-end, and it almost sounded like it mighta been flooding out on the 3rd when WOT.

  11. gone_fishin

    gone_fishin Guest

    i double checked & tried 2nd from top again. about the same as pianoman, except i get good top-end on 3, so i went back to 3rd from top.

    i think better performance is gonna involve going to 32:1, tho...get things a little more oily, like blaze says.
  12. chieflets

    chieflets Guest

    for extra 1km or 2km in top speed its not worth using leaner fuel I rather keep it at 25.1 and keep it safe.

  13. bamabikeguy

    bamabikeguy Active Member

    I'm trying something new on my personal engine. I had been using Stihl brand at 50:1, but my bikeshop guy, who also is the small engine expert in Decatur, gave me a few packets of Sten Mix synthetic, saying the muffler would stay cleaner longer.

    Very noticable difference, less smoke coming out of the exhaust.

    The thing I didn't like was how I had to drain the plastic packs into a bottle for on the road use, the packs are 1.8 fl.oz., and when I have to fill up on the road, I use the cap of the oil bottle as my measuring devise, 1 cap equals 3-4 cc.

    On the outskirts of Bayou La Batre, a guy gave me a nearly full bottle of what he called "the best synthetic", AMS Saber Professional 100:1 Pre-Mix.


    5 guys were gathered around my bike when he gave me the bottle, these guys are gulf fishermen. What they were saying was once the rings are seated, it didn't matter what mixture you used, 50/80 or 100 to one, synthetic simply took less to do more.

    That personal engine has over 5,000 miles now, has had the cylinder inspected by two small engine mechanics who both say the rings are in perfect shape, so I'm going to take the advise and stick with synthetics.
  14. Guest

    Guest Guest

    Amsoil 100:1 run at 100:1 will hurt your engine. It is a great oil but the reason we need richer oil concentrations isn't for piston ring lubrication, its that darn connecting rod bushing. If you are going to use Amsoil 100:1 you should run it at a 50:1 ratio.
  15. bamabikeguy

    bamabikeguy Active Member

    Thanx drew, I never DID go 100:1.

    GEBE has a 22 oz plastic tank, on the road, I divide it in quarters, add 1 capful (3cc) per quarter, which works out 50:1


    Last summer I went ahead and did precise measuring, with measuring cup, hypodermic needle and marking pen, to be sure to be able to measure 50:1 on the roadtrips.
  16. jaker

    jaker Guest

    ahh cool thats a slick idea marking the tank :)

    a little off topic but has anyone else here ever tried Sea Foam to remove carbon deposits and clean carburator?

    its recommended for all engines and i have personally used it on my drag raced 1986 thunderbird and when i put new heads on the 302 the cyl's were unmarked u could still see the factory crosshatchign all the way down and there was hardly any carbon buildup at all anywhere.

    as far as use on 2 strokes its more often used by ppl with 2strokes and my pal uses it all the time in his 110hp boat just add to the fuel as recommended.
  17. Guest

    Guest Guest

    Seafoam is a great product but best used to do a cleaning not as a preventative added to each tank (gets expensive).

    These engines are so easy to work on that pulling the head to clean the carbon off of the pistons is the cheapest and best route. You'll definitely know the extent of carbon buildup if you do this once a year or more depending on how much you ride your motor bike.

    I personally want more carbon buildup on my piston. I'll take any bit of help to up the compression ratio on our 6.6:1 engines :)
  18. chieflets

    chieflets Guest


    Shim the head slightly if there is room clearence

  19. jaker

    jaker Guest

    if u mean decking the cyl you had better clay it first to make sure u have enough room.

    i am not sure about this next bit of info but my logic tells me this..
    because of the way a 2stroke works the compression of the engine is limited to how efficiently it can pump air into itself
    based the fact that 4 strokes are better air compressers.. meaning to increas the compression on a 2stroke u have to tune intake port heads tuned pipe etc where as on a 4 stroke the mest effective way is to reduce chamber size.

    the reason a 4 stroke has more compression is because of the valve timing and having an extra stroke for intake etc....
    2 strokes rely on port location and becaue of this cannot fill the chamber as efficiently as a 4stroke

    reducing chamber size may help on a 2stroke but i imagine the chamber is pretty close to as small as it can be
    i have heard of some mod where they got a flap on the crank that forces the air into the port faster and increases compression