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DT200R difficult cold starting

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Browncoat, Mar 20, 2010.

  1. difficult is an understatement.. when the engine is cold the only way I can get it going is to remove the plug and squirt some fuel into the bore the when I kick it over it will fire a couple of times then die, I have to repeat this process about 3 or 4 times before it stays running. Once it is going it goes well and it will start easily up to a few hours after I turn it off.

    Any suggestions as to what I should be looking at?

    I put a new piston and rings in it a while back and had it re-jetted(larger jet) at the bike shop cause the old piston had a hole burned in it from running too lean. so the carby was cleaned and rejetted by a "professional".
  2. I'd start with a compression check on the cold engine. If that's OK I'd move on to the fuel system/carby.
  3. Make sure the choke (or whatever cold start device the carb has) is working properly.

    In my experience, lack of compression is more an issue with warm/hot starts, so, from the symptoms described, I'd look at cold start mixture first.

    I have vague memories, though, that crankcase compression can cause cold start problems with a stroker.
  4. Thanks guys, i'll do a compression check though with having just put new piston and rings with a hone on the bore I would hope compression is fine.

    What exactly should I look at with the choke/cold start mechanism?
  5. Depends on what it's got. I'm not familiar enough with the DT to know what sort of carb it has or where it lives. However, I'd start at the choke lever and make sure it actually is pulling the cable. Then I'd trace the cable to ensure it's not broken, kinked or pinched anywhere, so that movement of the lever is transferred to whatever mechanism lives in the carb.

    Beyond that, I can only geuss. However, I've come across a number of 2-stroke carbs where the "choke" operates a plunger in the carb body that allows fuel to reach a separate cold-starting jet. If this jet or any of it's associated passages is blocked, the choke won't richen the mixture and you'll certainly have issues starting from cold. From memory, mine were always housed in the float bowl, but none of those carbs was Japanese.
  6. Yeah the Dt has a choke which operates a plunger in the carby body. Curious though, if you read my initial post you may note the carb was cleaned and rejetted by a professional at a bike shop. They charged an arm and a leg and I am loathe to go back.
  7. Thinking about this more I think the choke must be working because when I squirt fuel into the bore to get it going, when it finally gets going, with the choke on it idles higher and when I turn the choke off the engine idles back down to normal.
  8. Many choke mechanisms provide for a fast idle, independently of the mixture enrichment.

    Personally, I set no store in the competence of "professionals" on the whole, having seen numerous horrors perpetrated by the supposedly qualified. That's not to say there is anything wrong with your carb, but I wouldn't necessarily rely on it.
  9. It MUST be a carby float level issue.. I cracked the drain on the float chamber and drained a small amount and it started fine. I have repeated this process many times and it will start easily every time now if I drain a little from the float chamber.

    Strange.. it seemed like it wasnt getting enough fuel but it must have been getting too much. Yet it would start if I removed the plug and squirted some fuel into the cylinder...

    Oh well, I'm confident that I'm on the right road now.