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93 DR 350 Fuel in Oil

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I have a 93 DR350S. It wouldn't start and when I finally got it to run it smoked like a Banshee. I checked the oil and found it was extremely thin and smelled of gasoline. I did some investigating along with my suspicions and believe the vacuum petcock, which is junk and only has a prime and on position, is probably bad along with the carb float needle and seat, or seat o-ring. I have heard others experienced the same problem. Any suggestions, similar experiences, quick fixes, before I dump a hundred dollars on a petcock and new carb needle/seat combo. I have heard there is a dirt model petcock with an on/off/resv, instead of this ridiculous vacuum operated petcock, anyone know if it is interchangeable, if so what do you do with the vacuum line opening on the carb, how do you block it off, rubber nipple, RTV sealant, etc.??? Any help on this topic would be appreciated. :p:):)

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try and find another carb. off the dirt model? you might start with the float and make sure it works properly and that gasoline isn't running down into your cylinder and finally draining into the crank case. also pull the plug see if it's fouled. don't run it long, thin oil could damage your rings, valves, bearings etc.?????? good luck... :)

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I had the same thing happen on my '95 DR350se, I replaced the stock petcock with a high-flow unit from Pingel (www.pingelonline.com), although I do believe a stock dirt-model DR350 petcock will work also. I found that my problem in the carb was a cracked o-ring on the seat(the needle and seat themselves were fine to be re-used). As far as the vaccuum hose, just put a rubber plug over that port on the carb. Also, since you are going to have to take the float-bowl off, you might as well get a float-bowl gasket(unless you've already replaced it recently).

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I just checked, the Thumpertalk store has the Pingel fuel valve listed in the catalog, and the listed TT price is less than what I paid to get it from Pingel directly.

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This happened on my '97se too. I went with a dirt model petcock (the vacuum petcock is JUNK) but---that's not your only problem. You should pull the carb apart and check/replace the needle valve and check/correct the float level. I found that my needle had hardened compared to the new one and was letting fuel by the seat. Technically, you shouldn't get fuel in the cylinder/case even if your petcock is leaking.

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There may be one final issue in all this as well. On my street model there's a little brass tubing overflow in the foat bowl base that is intended to let any large amount of excess gas drain out the drain screw nipple on the bottom of the bowl casting. This is intended to prevent gas flowing into the cylinder just as you found. I take it the dirt models don't have that? Or if they do you may want to find out what's plugging it.

The other method for letting gas get by may be the diaphragm in the petcock. If that cracks and leaks it'll let gas run down the vacuum line and into the engine directly. If that's how it got into the engine then your carb may be fine and it's just the petcock.

That happened to me on my old CBR600F2 and it filled the cylinder. I hydraulic locke the bike upon trying to start it and was lucky that it was very close to TDC on that cylinder and didn't get much momentum up or it could easily have been bent rod time for me.

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I have a '99 dirt version DR350 that I just bought and the petcock is leaking on the tank. I took it apart and found it to be a very poor design. I plastic cone deverter, 1 o-ring, and the valve handle all held in with a set screw. I'll be looking for another unit to replace the stock valve.

Greg

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Thanks to everyone for all the replies. I am going to replace the petcock, plug the vent line opening on the carb and replace the needle seat o-ring. The only thing left would be the needle itself, however, I just had the carb apart to re-jet and it looked fine. I missed the needle seat o-ring and suspect both it and the petcock are partners in crime. Thanks again, I will post when back running and let everyone know how it turned out.

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Check that, I will plug the petcock vacuum line opening on the carb, for those of you who caught this mistake and are thinking, "hmmmmmm should that guy be working on motorcycles???"

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Well I don't know if you need to spend hundreds of dollars, I had the same problem and a week spring inside the pepcock was the cause of the problem. I had to re-adjust my float, and take apart the pepcock to strech

the spring, but I have not had a problem since.

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