DR350 carb prob.

jsned

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#1
I have a 92 Suzuki DR350 (street legal version). I got it from my brother who bought it new. He has lost all the paper work, owners manual and so on. It has very very low miles on it but it has been sitting for three years or more. Anyway I changed the oil cleaned the air filter, drained the tank, refilled and it runs okay but when you shut it off gas pours out of the overflow. I first thought it was the float, so I took of the carb cleaned it checked the float and it seems okay.

I believe the problem is in the fuel petcock. It is the type of carb with the vacum line from the carb to petcock. There is no OFF, just ON RESERVE and PRIME. Before I try to buy the stock parts I was wondering if anyone knew of a better fix than going stock.

These bikes were once very popular so I figured some of you guys probably have heard something along the way.

Thanks Jeff
 

High Lord Gomer

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#2
I believe the floats should still handle shutting off the fuel. Have you tried hooking up the fuel line with the bowl off the bottom of the carb to move the floats by hand and see when/if they shut off the fuel? It'll be messy, but probably very informative.
 

Danman

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#3
Gomer is right. If I'm not mistaken the only time the petcock will flow without vacum is in when your in prime. All other positions you will need vacum in order for it to flow. If you have a mighty vac you can test its operation into a bucket realy easy. Just pull the vacum line off from the carb. Not sure how much vacum it takes, but you can also suck on it and see if it flows any. If you need a new one ditch the stock one. Get a manual one an plug the vacum line off at the carb. I have seen several people with that have had problems with the petcocks on the "S"model. Talk to the guys at Maximum-suzuki.com Someone with an "S" model will more than likely can answer you question about the petcock. If it has sat for any period of time you will want to clean out the carb real good. Also check the needle valve on it. If that is gummed up with old gas varnished gas it could be sticking. If the float has a hole it can sink and cause your problem.

If he spends any time on the bike off-road you might look into the T-vent Mod. It will stop the spuddering after hard landings and whoops.

Click me for more info on the T-vent mod.

If you have not opened up the Airbox and rejetted. Check out Kientech Jesse is the man when it comes to working on DRs. He talked me through a problem last year before dirtweek.

Good Luck.
 

jsned

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#4
The petcock was the oring that pushes against the tapered seat to shut off tthe gas was ripped. Easy fix. Stopped gas from free flowing in to carb no matter if bike was running or not.

Then the gas kept coming out of carb only when bike was running which told me it was something in bowl. The oring on the big brass part that the needle valve goes up into was eaten away. I dont know what the name of the big brass part was but it has 1.5 stamped on it. replaced it with new oring. Fixxed

Thanks for the tips, it runs real good now. No spitting or anything. Couple of little things I plan on doing first, alum bars grips, new cable for comp rel., gear it for the road a little bit better, eliminate some of the flab.

I dont plan on any serious offroad with it, (my KTM is for that) but I am going to call some of them guys you talked about because I know it is really chocked off. If anything I hope I can get it to start easier. Thanks again Jeff