Engine Trouble Should cold starts improve?

Discussion in '2-Stroke Engines' started by Snarfu, Apr 24, 2012.

  1. Snarfu

    Snarfu Member

    My brand new build is a serious pain in the butt to start when cold. It's pretty new, only about 5 miles on it so far... Can I expect this to improve with more break in time?

  2. Al.Fisherman

    Al.Fisherman Active Member

    Most likely when you change the fuel mix. Start with 20:1 and go up from there, I use at the moment 32:1, and this year will go to 50:1.

    Decrease "pain in the butt"= Starting fluid/throttle body cleaner. I use it every time I start my bike up for the day. Cant peddle much (heart), and the engine will start up within 20'. Never had to use more then one application. Remember to turn off the fuel flow after shutting it down. I turn my fuel off about 500" before I kill it.
  3. Snarfu

    Snarfu Member

    Yep, having the same pedaling issues here. My heart's fine, but I live on a dirt road-- tough to break the land speed record on a 50lb bike. Starting fluid is a good idea- I haven't taken that step yet since I'm out of anti seize.
  4. Al.Fisherman

    Al.Fisherman Active Member

    Oh, and I start mine in the grass, as vehicles are in the driveway. 220#. OH and since this is in the 2 stroke forum, what is your power plant?
  5. Snarfu

    Snarfu Member

    My driveway is gravel, so it's no better than the road. Just tried the starting fluid with epic success!!! I did notice, though, that it takes 5 min or so for fuel to get from the tank to the carb. Checked petcock (really? Who named that thing??) and it's clear, so perhaps I live in a place where gravity isn't so tough after all.
  6. Snarfu

    Snarfu Member

    66cc skyhawk
  7. Al.Fisherman

    Al.Fisherman Active Member

    I always start out by opening the petcock, and hold the tickler down (opens needle to let fuel flow) to fill up the bowl. Then and only then hit it with a spray of starting fluid. In fact all my bikes have a small hole drilled into the cleaner cover. This way I can stick the nozzle in and spray.
  8. Snarfu

    Snarfu Member

    Now *that* is a good idea. :bowdown:
  9. Cavi Mike

    Cavi Mike Member

    The tickler doesn't make fuel flow in faster; it just holds the float down. The tickler is there to push the float down which opens the valve and allows the bowl to over-flow into the carb. If the bowl isn't full yet, the tickler does nothing because it can't reach the float in the first place.
  10. motorpsycho

    motorpsycho Active Member

    cavi mike is exactly right about the tickler.
    if the bowl is empty, fuel will flow into it as long as the needle & seat isn't stuck closed. holding the tickler down at that point does nothing because the float is already down and the needle & seat are already open.

    the stock petcocks (still funny) are **** and they are a very basic design with a little rubber diaphram inside....they flow very poorly.
    the best and easiest thing to do is remove the petcock (giggle) all together.
    go to the hardware store and get yourself a brass hose fitting and screw it into the tank in place of the petcock (yep, still laughing). Take that petcock with you to the store so you can find a brass fitting with hose barbs on the end. The brass fittings have the same threads, just match the size to the threads on the petcock.
    Then, get yourself an in line fuel shut off valve (that sounds better than petcock) for a lawnmower. you can get these at almost any auto parts store or hardware store for a few bucks. (i know that autozone sells them) this eliminates the crappy in-tank petcock all together, and the fuel will flow into the carb A LOT better.
    If you happen to have the same carb as I do, the carb has a fuel shut off built right into it in line with the hose fitting. so on mine, all i did was put the brass fitting into the tank in place of that silly pet-rooster, and i rely on the carb mounted shut off to do the job. Fuel flows like crazy with no restrictions for me, and when the shut off is closed, no fuel comes out, no drips, no slow leaks...it works great.
    I do have an in line shut off valve for a lawnmower on my other bike, and it works great too.
    Last edited: Apr 24, 2012
  11. Al.Fisherman

    Al.Fisherman Active Member

    Actually from the side seems to work out better (down tube not in the way, and I don't have to bend the nozzle). Since I get on from the left side, I now have the hole on the left side, seems easier.
    Last edited: Apr 24, 2012
  12. Fabian

    Fabian Well-Known Member

    There is another option, though it requires basic tools for the modification.

    Find a damaged 50 or 60cc chainsaw with a decompression starter button. Go to a welder who is good with aluminium and get him to build up a small area on the top face of the cylinder head that can take the length of the threaded portion of the decompression device.

    Drill a 2mm hole through the welded area to the internal cylinder head face.
    Now drill only the length of the threaded portion with a drill bit sized to be suitable to allow enough material for a bottoming tap to create a thread that matches the decompression button threaded length, plus clearance for the internal component of the decompression valve. Make sure the top surface of the welded portion is true and flat. Screw in the decomp and your starting issues will no longer be a problem.

    You can easily spin that engine till it starts.

    It's a bit of mucking about but it works a treat, especially if using a high compression cylinder head.
    Last edited: Apr 24, 2012