Carburetor question?? Help

[iagtroop]

Okay so i recently got a 1982 suzuki dr250. I have been battling what i believe is an air leak. It has a 34mm round slide mikuni. My question is this::: When i put a vacuum hose on the overflow valve coming out of the bottom of the carb and blow air into it the bike dies. Also if a plug the vacuum hose it will also decrease in idle until it dies. Could an air leak be coming from the overflow tube? I have been searching for a while trying to find this air leak so i am getting pretty desperate on what could be wrong with it. Anyways any help would help! This is her carby. Thanks alot

[img]https://i1378.photobucket.com/albums/ah109/iagtroop/SDC10669_zps4xght0il.jpg[/img]

[Tankie]

Is your problem that the carb is flooding?
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Always learning, everyday is a school day

[Triton Thrasher]

What makes you think there's an air leak?
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[Petemate]

[Hong Kong Phooey]

What are the symptoms under normal use?
Have you done anything to the carb, was it working before?
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'81 CG125, '97 FZS600 : '99 CBR600F4, '09 KTM RC8

[iagtroop]

I should have gone into more detail but i didnt want to bore you all with the whole story....

So i bought this bike and it ran great. I mean really great for a 35 yr old bike. I brought it home in my truck. Unloaded it and changed the oil the next day. Rode it for about 3 hours on trails around my house (still running unbelievably great). The next day i pushed it out of the garage, washed the mud off of it and now it runs like shit... It surges really bad at about 1/4 throttle and it will completely stall when i try to go up a hill.

SO i thought to myself..ok. No big deal i just got water in the tank or carb when i washed it. So i emptied the tank and put new gas, cleaned the carb, and the air filter. Nothing.

Since then i have bought a bowl gasket, new orings for all jets and mixture screw. and as you may be able to tell i put gasket maker between the head and manifold (not real pretty but it eliminates the possibilty of an air leak). After all these new parts the problem is still exactly the same as the day after i rode it for 3 hours.

In conclusion, I bought a bike that ran great. now it doesnt. It starts good and idles good until it gets warm, then the idle fluctuates and when i try to run it it surges bad at 1/4 throttle and will completely die under a small load (such as going uphill).

Oh yeah and the plug looks perfect to me... Im really confused. I can add a picture of the plug soon if that would help. Thank you all for the replies.

[Tankie]

From the picture it looks like you have two pipes in, one appears to be blocked off???
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Always learning, everyday is a school day

[jaffa90]

Why not make it act daft a bit then give it full throttle and remove the plug to see if it`s short of fuel?

[Suntan Sid]

If there was an air leak from the float bowl overflow then logic dictates there would be fuel leaking from the overflow.

https://i1378.photobucket.com/albums/ah109/iagtroop/SDC10669_zps4xght0il.jpg

The petrol tap in the photo looks as though it has a removable filter, have you cleaned it out?
Is the breather hole in the petrol tank free of crud, have you tried running it without the petrol cap? If it runs better without the petrol cap, then you need to unclog the breather.
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[mudcow007]

Isn't the blanked off pipe for a 2T feed?

Yam club talking about auto feeds

What condition is the plug, cap n' lead in?

[iagtroop]

Permeate,, that is what I thought too. It is vented to atmosphere.
I guess what I am trying to figure out is it even possible to have an air leak from an overflow tube?? I don't really see how but that is the only place that spraying cleaner cleaner has an effect on the idle.

Sutan Sid,, I don't really understand what you mean when you say if there was an air leak from overflow then it would be leaking fuel. Could my float level be too low that it is letting too much air in? Concerning the petrol tank filter... my fuel line is clear and I always have a steady stream of fuel to carb.

[jaffa90]

What is your problem?
The top of the overflow tube sits in the air space above the correct fuel level height.

[-]

[mudcow007]

My bad

They were 2 stroke earlier wern't they?

[Oldie]

Did you wash the bike with a pressure hose? Might not necessarily be a carb problem - maybe something like a cracked plug cap?

[iagtroop]

I the crimped tube was there when I bought it but I'm pretty sure it is for running a petcock that uses vacuum. for drawing gas.

The plug is new (added after the problem started). And the lead and cap look good. No cracks. But out of desperation I may go ahead and order a new lead anyways.

I didn't use pressure hose and I tried to not really even spray around the carb or engine. Just the tank and seat and rear fender.

Okay... so my problem is this. Bike starts great. Sometimes first kick. It idles great until it gets warm then idle fluctuates and when riding it surges really bad. I have sprayed all around the head and carb in search of air leak. I get no change in idle or anything until the carb cleaner drips down to the overflow tube and sometimes it will decrease in rpm and sometimes it will die.

I will ride it and then take a picture of the plug. Maybe that will tell you all something. It looks perfect to me though.

Thank you all for the help and patience

[jaffa90]

Picture!!!!
Use your nose to smell fuel or not, also your eyes to see if it`s wet with fuel or DRY.

[Suntan Sid]

If the bike is running lean, (ie you have an air leak), then the revs will drop slowly back to idle speed, compared to normal!
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[iagtroop]

Okay mates it was storming last night in Tennessee so I didn't get the bike out. I'll pull her out tonight and take a picture of the plug. Any advice on how I should ride it to get a good read on the spark plug?

[redeem ouzzer]

[Robby]

It was working fine. You washed it, it started running like shit. It's still running like shit.

I'm not all that convinced by your water removal method - fully draining a tank is always tricky, and it only need a few cc of water in the system to sit in your carb and cause problems.

So first off, turn off the fuel at the tap and drain the carb into a plastic cup through the drain screw and look for water in the fuel.

If there is no water in the fuel, spray WD40 into anything that looks vaguely electrical, and drench the wiring under the tank with it.

The bike was running fine, so there is no reason for a big problem to have happened so fast. Water in the wrong place is the best explanation.

[iagtroop]

i should have added. this all happened at least 3 months ago. so any water in mysterious places should have dried up by now.. Maybe.

Robby--- let me explain my water removal method. I removed the tank from the bike. Set the tank on blocks with a pan underneath it. Turned the petcock on and let the fuel drain from the tank until empty. Then i added a few more gallons, sloshed the tank around, and let that fuel drain completely from the tank. SInce the fuel looked good and clean i put it in my 4wheeler and have been running that 4wheeler ever since.

I have taken the carb off the bike at least 11 times (no exaggeration) and cleaned it with carb cleaner and pressed air. I put new orings on all the jets and the mixture screw. i put a new bowl gasket on. and i tried adjusting the slide needle up and down with no real affect on performance. (now the needle clip is where it was to begin with (in the middle))

I am pretty positive there is no water in the fuel delivery system.

Now tomorrow i will definitely try spraying down the wiring with wd40. Althought there is not much wiring to worry about since this bike has no battery, headlight, or accessories. there is just wire coming from the magneto to the coil. And i will definitely check that tomorrow.

Water in the wrong place is probablay the best explanation but i have seen air leaks happen out of nowhere in the past that is why i am trying to cover anything and everything that could be wrong.

I think the best thing i can do right now is order a new spark plug lead and find a way to test the coil.

[iagtroop]

okay mates. here is the plug. I ran her hard up a slight hill and cut the engine off at probably 5,000 rpm. It looks pretty good to me. Maybe a little rich???????? Im confused. oh yeah and it started 2nd kick after not being started in a couple weeks and it also idled great until it got a little warm

[img]https://i1378.photobucket.com/albums/ah109/iagtroop/SDC10679_zps1rpycasp.jpg [/img]

[Oldie]

When you stripped the carb did you actually inspect the jets for even small blockages? Just trying to get a clearer picture.

[Hong Kong Phooey]

Could be electrical, if you've got a spare coil and plug that's worth the swap.
Does the choke make any difference?
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'81 CG125, '97 FZS600 : '99 CBR600F4, '09 KTM RC8