DR Carb Problem

I pulled out my old 1992 DR350SN after letting it sit for two years and decided I wanted it back on the road. After airing the tires and putting in fresh fuel I put the petcock on prime and put on my kicking boot. When I walked back over to the bike there was a puddle of gas underneath it. I turned off the petcock and rapped on the carb with a wooden mallet and tired it again, same thing. So I drained the carb, pulled the bottom of the carb off and cleaned the float, needle assembly and checked the o-rings and put it back together. Now when I put the petcock in prime it only leaks from the drain hose at the bottom of the carb. I pulled the bottom off again and checked if there was something stuck behind the drain plug, but that appears OK. So does anybody have an idea what is causing it to leak and what should I change out?

I pulled out my old 1992 DR350SN after letting it sit for two years and decided I wanted it back on the road. After airing the tires and putting in fresh fuel I put the petcock on prime and put on my kicking boot. When I walked back over to the bike there was a puddle of gas underneath it. I turned off the petcock and rapped on the carb with a wooden mallet and tired it again, same thing. So I drained the carb, pulled the bottom of the carb off and cleaned the float, needle assembly and checked the o-rings and put it back together. Now when I put the petcock in prime it only leaks from the drain hose at the bottom of the carb. I pulled the bottom off again and checked if there was something stuck behind the drain plug, but that appears OK. So does anybody have an idea what is causing it to leak and what should I change out?

Your float needle has a spring loaded contact pin that is most likley stuck which can raise the float level a substaintial amount. Make sure the spring loaded contact pin moves freely and springs back into the extended position. If that checks out then the rubber tip may have hardened up allowing fuel to seep by even with the float needle closed. :thumbsup:

put a new needle in it, mine did the same, it looked fine but that was the problem.

Also check the rubber o-ring under the needle seat. It can split and leak fuel around the outside of the needle / seat assy. One other o-ring fails as well, this one is on the plastic float cage assy. See ref #'s 19 and 24

http://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/26/Type/Motorcycle/MakeID/2/Make/Suzuki/YearID/33/Year/1992/ModelID/6162/Model/DR350S/GroupID/249166/Group/CARBURETOR_MODEL_L_M

One other common problem on the older DR350's is the vacuum petcock. The rubber diaphragm will rip allowing raw fuel to flood the vaccum line connected to the carb. Pull the vac line and make sure it is dry inside.

Change your engine oil, it is probably contaminated with fuel.

So I should order a new o-ring for the float and a needle assembly with a new o-ring. I had the petcock on prime, so I haven't had any problems with the diaphragm yet. I hope I can get it fixed as my DR will be a fun and cheap way to get to work which will save me some money. Thanks for all the help!

Also check the rubber o-ring under the needle seat. It can split and leak fuel around the outside of the needle / seat assy. One other o-ring fails as well, this one is on the plastic float cage assy. See ref #'s 19 and 24

http://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/26/Type/Motorcycle/MakeID/2/Make/Suzuki/YearID/33/Year/1992/ModelID/6162/Model/DR350S/GroupID/249166/Group/CARBURETOR_MODEL_L_M

One other common problem on the older DR350's is the vacuum petcock. The rubber diaphragm will rip allowing raw fuel to flood the vaccum line connected to the carb. Pull the vac line and make sure it is dry inside.

Change your engine oil, it is probably contaminated with fuel.

+1 Good point. My BST had this o-ring die from sitting around while I was playing with the FCR's. :thumbsup:

+1 Good point. My BST had this o-ring die from sitting around while I was playing with the FCR's. :thumbsup:

That kind of happened to mine as well. Two years ago after a knee operation my doctor told me I couldn't ride dirt bikes anymore because kicking the bike over was going to damage my repaired right knee. So I bought a new 2006 CRF450X (electric start) and a pair of Asterisk knee braces and my old DR350SN has been sitting ever since. I'm thinking about putting on some street tires and making it a Super-Moto type bike. It always was a blast to ride and I've taken it everywhere! See picture below:

dr_snow.jpg

A couple of questions here... Would those O-Rings or just a stuck float cause the bike to pour out gas continuosly while running. Mine will dump about a cup of gas during the time I would sit at a red light. It even pours out a line of gas while going down the road. My last shot of carb cleaner down the fuel tube seemed to help, but now it's worse than before. Can you access the above mentioned orings from the bottom of the carb while it's on the bike... or does it need to come out?

Thanks for the thread... it came at a good time.:thumbsup:

A couple of questions here... Would those O-Rings or just a stuck float cause the bike to pour out gas continuosly while running. Mine will dump about a cup of gas during the time I would sit at a red light. It even pours out a line of gas while going down the road. My last shot of carb cleaner down the fuel tube seemed to help, but now it's worse than before. Can you access the above mentioned orings from the bottom of the carb while it's on the bike... or does it need to come out?

Thanks for the thread... it came at a good time.:thumbsup:

Either senario will cause fuel to leak out of the overflow tube due to an excssively high fuel level. You'd be better off removing the carb but you might be able to pull off replacing the o-ring with the carb in position. Replace #24 and #19 below.

1910_9A.gif

Mine overflows with the engine off if the petcock is on prime. On my 1992 DR350SN you can loosen the two clamps on the carburetor (one in front and one in back) and then rotate the top of the carburetor to the right and you can pull the bottom off and access the o-rings. I pulled mine off three times in half an hour.

I had the petcock on prime, so I haven't had any problems with the diaphragm yet.

If the petcock diaphragm is torn, it will flood the vacuum line and carb with fuel regardless of what position you put the lever in.

I only stress this as a possibility because it has happened to so many people (myself included). You can go crazy looking for a "carb" problem only to find out it was the petcock all along. Better to rule it out first before looking elsewhere for problems.

If the petcock is not the problem, then replace the needle / seat and the two o-rings. Set the float height per the manual and test.

Change your oil. When my bike was leaking fuel, I drained 4 quarts out of a two quart system. It was about a 50/50 mix of gas and oil !

While you're in there be sure to clean the pilot jet, along with all other jets and passageways. Also adjust your float height back to spec as mentioned by jcalis above. c good

If the petcock diaphragm is torn, it will flood the vacuum line and carb with fuel regardless of what position you put the lever in.

I cleaned the old parts once more real good today to see if that would fix it before I have to order new parts, and it still leaks. But it only leaks in the prime position not the on or reserve position. So I put it in the on position and started it up and then it leaked when the engine was running but stopped leaking when I turned it off. I tried calling my local Suzuki dealership to give them my business and they said all the parts are discontinued with no new replacements. So it looks like I will try the online store that was suggested by jcalis and replace parts 19, 23, and 24. Is there anything else I should get?

Those parts should take care of the problem as long as the vacuum line is dry.

The only other problem could be a bad float or bent / broken metal tab on the float that holds the needle up against the seat.

I ordered the parts -two o-rings and the needle assembly- so I will post back when I put them in and see if they fix the problem. Thanks to everyone for all your help!

I have a similar problem.

1990 DR 650 with a 39 MM flat slide Mikuni. The carb is new but when running gas runs out the overflow. I took off the float bowl and checked the float, it works. I adjusted the float upwards to shut off sooner, still the same problem.

I looked at the vacuum line and it's dry.

When the petcock is in prime, it leaks out intermittently and this seems to help but not totally fix the problem.

The float bowl is clean.

Any ideas?

You may need to replace the same two o-rings I ordered. I'm not sure what part numbers you'll need for your carburetor though. Any DR650 owners out there that can help?

I disconnected the petcock/vacuum line and running in prime position has fixed the problem. I'll get a Raptor petcock and use it.

Now that I've plugged the vacuum line it seems to be running rich, so that tells something.

During the ride I noticed that it wouldn't take more that 1/4 throttle at less than 3000 RPM. That seemed funny so I checked the pilot jet. There was no pilot jet, it never was there, apparently.

I took an old jet and installed it and seems OK. Takes throttle at low revs, but is still hard to start, takes about 5 kicks.

I'll get the stock pilot jet and try that.

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