My trek build

Discussion in 'Frame Mounted Engines' started by blacklabel7345, Dec 10, 2007.

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  1. started my build two days ago. Right now im fabing some cutom brackets to take care of the carb clerance issue. These things are lot harder to put together than i thought, but not to worry, the bike should be ready in a couple of days.

    one question that i cant find a straight answer to is do i have to put oil in the crank case and i i do:
    1. Were do i put it in
    2. what kind o oil do i use

    thanks all, willl have some pics and news soon

  2. JemmaUK

    JemmaUK Guest


    What engine are you using?

    If you are running a two stroke you mix the oil in with the fuel... mixtures vary from 16:1 to 50:1 petroil. On a two stroke you will destroy the engine in short order if you feed it with pure petrol.

    With the 4 stroke engines there should be an indication of where you put the oil in.

    good luck with getting your bike on the road.. :)

    Jemma xx
  3. im using an 80cc 2 stroke. I know that i hvae to mix gas 25:1 but no one said anything about crank case oil. I dont know too much about 2 strokrs, now i this thing was chevy powered it would be a diff. story ;)
  4. gone_fishin

    gone_fishin Guest

    as jemma says...your 2-stroke is lubricated thru the pre-mixed personal recommendation is 20:1 for break-in.

    i'm sure your work will be mechanically sound, but i think i should say that you may want to take it slow as you learn about operating one of these engines... spend some time searching out and reading the posts of the hundreds who've built before you. there's a big boost in overall happy-time-ness if you get it right the first time, and many (avoidable) pitfalls for the uninitiated :)
  5. azbill

    azbill Active Member

    the more you read, the better/easier your build will go
    and the easier it goes, the more enjoyment you will get out of your bike
  6. JemmaUK

    JemmaUK Guest

    Two strokes use a total loss system - there is no need to fill the crankcase with oil as you would a 4-stroke engine - lubrication is from the fuel/oil mix which is why fueling with pure petrol would destroy the engine.

    Use a good quality oil and when you've gotten it on the road run it for a while and recheck all bolts and connections...

    My personal machine is a GEBE 2-stroke (my second, the first got nicked)

    Have fun

    Jemma xx
  7. thanks everyone for the support. Im still having horrable clerance issues on my treck, but, hopefully ill get something figured out
  8. carb position

    i was looking around and went to the sppokytooth website and found that i can get an engine on something the size of my trek. now i can get the engine in quite nicely, but i have to tilt it. this brings my next question:
    does the carb have to be upright(bowl on bottom) or can i hvae it tilted a littlebit sideways? if i tip the engine forward a couple of degrees i hvae no problem, but this is a carb and the float is in the bowl and if i tilt it will it stilll work?
  9. kevbo

    kevbo Guest

    Note that you can't fill the crankcase with oil, because most (there are a few exceptions) 2-strokes use the crankcase to pump the intake charge into the cylinder. So any oil in the crankcase eventually ends up in the combustion chamber.
  10. noah

    noah Guest

    re: carb tilting

    Tilting carb slightly, very slightly probably won't affect too much other than looks but one option that worked for me was to take the bottom bracket from the front mount and to use it as a spacer for the rear mount on the motor side of the frame. Can you picture it... then you take the adapter plate and use that on the front... Mine went right down thru a water bottle screw hole on the front (after i drilled it out of course) , I hope you understand this, if not pm me for my telephone #....I have a trek 800 sport, a little older model.
    Last edited by a moderator: Dec 11, 2007
  11. srdavo

    srdavo Active Member

    it's never a good idea to drill a frame for the engine mount.

    I combined the threads you started today about this build. It's much easier to follow your build, with all the info in one thread.

    here's a link to some pics of a really tight build.

    Use search & have a look around. Lots of great ideas on mounting & manifolds here.
  12. im abandoning the trek idea. Going to use a beach cruzer from walmart. no way to fit the engine on th trek