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Discussion Starter #1 (Edited)
Hi guys
Recently I went to a local mechanic to check and clean carbs on my AT. After he finished the job and reinstalled carbs on the bike the problem appeared as petrol started to leak from the tubes that needles slide into when it is on idle and slow rounds. It is only in the right hand side carb of front cylinder. Extra petrol is added in the cylinder and adjusting is not possible. Mechanic told me the tube where the needle is going into is damaged and it is not possible to repair anymore but I need to get other carburetor. What a disaster !? Nightmare started when I looked on the net and there is no carbs for RD03. I were checking on Keihin web site and there is nothing to find, no any information about RD03 carbs, not even the serial number or model name or maybe if some other bike uses the same carbs I could look for ....
Is anyone had similar experiences?
Is not it possible to change some part, jet or something and on that way to fix the problem?
To change the needles (appear they are different first and second)
To use the carbs from Transalp 600 or RD04? (I still prefer to keep my AT in original state)


Any suggestions, experiences, advice?
PLEASE HELP :sad1:
 

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Before you get too depressed, I'd suggest you check the needle valve (float valve) on that carb. It sounds a bit suspicious that it only happened after the mechanic did the work, and getting some dirt in the float valve is much more likely than damaging the jet. Unless he put something metallic in the jet, in which case I wouldn't let him near anything with moving parts. Even if he did, a damaged jet wouldn't necessarily cause petrol to flood that cylinder (unless it's really bad); it's easier to bend the needle than damage the jet, and the needle is replaceable. But it sounds more like the fuel level in the carb is too high, and that's controlled by the float and the float valve.

If you know carbs, please ignore this bit. As fuel fills the carb, the float rises with it and when the level is high enough, the float presses against a small needle valve. This closes the fuel inlet and so regulates the fuel level; it has to be just right to make the needle/jet combination work as intended. But the nose of the needle is tiny, and it's very easy to get a small piece of dirt in there (that's why there's a fuel filter). You'll often need a magnifying lens to see it clearly, and you should never poke it clean with anything metallic; a scratch on the seat will make it leak, so use compressed air or carb cleaner. The nose of the needle may have a small rubber tip, so be careful. Once you've checked the seat is clear, check the float height (have you got a manual?); you can adjust the height at which the float closes the valve by carefully bending a little tab on it, so it is also possible that this has got bent in reassembly. But don't adjust it unless you are sure it's wrong.

For what it's worth, my money's on the float valve, so please check this first before you buy another carb. Checking the valve should only cost you a few hours. If you haven't worked on carbs before, clean it thoroughly before you strip it; a can of carb cleaner spray is the best. Then be really patient and careful when stripping; there's nothing in there that needs any real force to undo. Take pics as you do it, and keep everything really clean. Check the fuel filter at the same time, they're pretty cheap, and let some clean fuel run through the lines before you reconnect. If it does turn out to be dirt, check your tank and petrol tap, and find another mechanic.:thumbup:

If it turns out that the float valve is ok, check the needle and jet with a magnifying glass before you condemn the carb. Check the needle for straightness and for scratches, it is precision ground and needs to be perfect. If in doubt, get a new one; it's much cheaper than a carb. They are different sizes for each carb; the rear one is slightly richer. I'd also check the diaphragm while you are in there, because they do deteriorate with age.

Sorry I can't be more specific, but mine's a RD07a and I don't know the RD03s so well. But I'm sure someone who does will be along soon. And if you haven't got a manual, get one.

Good luck.
 

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Discussion Starter #3 (Edited)
First I want to thank you because you were very specific thetimkirby, on your effort to explain in-depth. I am not an expert but I love to do a lot of work for all my bikes but if I am not sure about something or something is serious about engine I seek for professionals. Mikuni from my old Suzuki was ply for me but Africa is serious bike :) and beside it is a twin carb and I do not have synchronization gauge and my own ultrasound bath. (Although 25% acid solution over night and hose with water will do the job all the same) I did not touch this carbs since 40000km and still worked fine with small signs of "getting something wrong," I thought maybe the seals on the exhaust or springs and clutch basket .. this mechanic is on very good reputation in this region. many friends were there and I know the difference of their bikes before and after and I decided to visit him for the first time. Been there watching him working on my bike (quietly not to interfere :)) After reinstalling the carbs back and starting the engine he were tuning carburetors but it will not work as it should, than he called to show me the needle closed down on idle and I could clearly see how petrol leaking, dropping, sprayed around closed needle and have been sucked behind the bypass hole in cylinder. He tuck it of two more times and checking and returning. Called on phone somebody .. In meantime some friends of mine came with TDM, Super Tenere and AT RD04 .... Finally he said that on Africa this needle tube is not replaceable as on Super Tenera ... I can not say. .. Everybody can make mistake. And I hope he is mistaken with this, and I want to take of carburetors out myself and have look but since than, two weeks the weather is disaster, showers, rain storms and I must do everything in front of my apartment outside after my regular job ... I hope this weekend the weather will be DRY :) and I will have some news to write here.
Somme people have already told to this mechanic that I want to strip the carbs out myself, but whatever when all is settled I will return to him and tell him if he was right or wrong. Serbia is a small pond and I do not want the tails behind me, though i never said something negative about him.
Thank you again and still, if you stumble on some carbs for RD03 pls let me know. Maybe I will not need it but some friend may :)
cheers
PS: I have got manual two yrs ago, friend from Portugal :) Hallo to him too :)
 

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Not sure about the acid and water, sounds a bit extreme. What acid do you use?

Firstly, your mechanic may well be right and it maybe the jet is damaged, but I have to ask, how? The jet is a simple tube with parallel sides and holes further down, and it is pressed into the carb body. The needle is a tapered pin, with a very precisely ground profile, and it is this taper that does much of the mixture control as it is lifted in and out of the jet. For the jet to be damaged, either it has worn in use, in which case you would also expect to see a wear groove part-way up the needle, or it has been damaged in dismantling. (Wear on the needle is more common, and has a big effect on mixture and running). And if petrol is leaking out of both the jet and the bypass hole, then it sounds like the problem isn't just with the main needle/jet. One thing that affects them both is the fuel level, and that's down to the float and valve.

I still think it is worth checking the float and valve first, even if only to prove it can't be them. You don't need to buy anything to do this, you just need patience, care (and some good weather!). I'm not sure if you can take the float bowl off with the carbs in-situ; I've never tried, but that would avoid upsetting the throttle linkage. But don't be put off by the synchronising; you can do this quite effectively with a simple home-made manometer. It is just as good as a vacuum gauge, and more stable if you set it up right:

1 Get some clear plastic tubing, about 1m long, sized to fit over the nipples that screw into the side of each inlet tract. You need to source these, the holes have blanking plugs screwed in normally. I think they are a 5mm thread, but I'm not sure; they are common to a lot of bikes.
2 Connect one end of the pipe to each cylinder and make a U-shape with the middle of the pipe.
3 Put some oil in the pipe, so that the U-shape is filled half-way up each side. Gearbox oil is good, it helps if it is quite thick. It's easier to fix the pipe to a bit of wood or card, because you need to be able to see it while you run the bike.
4 You now need to partly flatten the pipe at the bottom of the U-shape; put a washer over the pipe with a screw in the middle. Tightening the screw will gradually flatten the pipe. This restricts the flow of oil through the pipe, but don't block it completely; it stops the oil level fluttering as each cylinder goes through it's inlet stroke.

When the carbs are reassembled and back on the bike, connect the pipe and start the engine. If one carb is open more, the oil will rise up the tube on that side (this is why you need to restrict the flow, or it will move too quickly). Adjust the throttle linkage until the oil is the same level both sides, and the carbs are synchronised. It's easier to do than it sounds, and if you search on here, you'll find a thread with pics showing you how. Bear in mind that this only synchronises the opening of the carbs, it doesn't directly affect the mixture.

If it does turn out that the needle/jet are worn, try putting a new needle in before you go for a complete new carb. Check it sits centrally in the jet; a really small bend or groove can have a major effect. Only if you are sure it's the jet try a new carb; any used one will be partly worn already, so try the easy/cheap stuff first. Be patient, and you'll learn more about your bike.:thumbup:
 

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worn needles and jet, will just make the bike run richer than it already does ,( my RD03 runs very rich and I will drop 120 main jets into it , when I get around to it, at the moment I just put up with 44 mpg )

for carb parts and ultrasonic cleaning etc. NRP are a good source of parts & advice

NRP motorcycle carburettor repair specialist

my prefered starting point if I have carb issues, ( this is usually the result of a bike being stored with fuel in it for a while ), is to run a high strength carb cleaner through it

with a few liters in the tank or a separate tank add a high concentration of carb cleaner to the fuel.. run the bike on tick over for a hour....:D:thumbup:


yes an hour :eek:

but keep an eye on the temperature ( good check of your thermostat and fans too ).






on tick over the small jet and passages are used and these are the most prone to blockages, if you ride the bike with the cleaner in , above 1/3 throttle you are on the main jet only, so just let it tick over as this cleans it.

Done this on a few of my bikes when I have had carb issues and it worked for me.:thumbup:


:thumbup:

As Tim said, looks like float valve hight issue to get petrol overfilling the bowl and flooding out.

I would not let a modern trained machnic anywhere near a carb....
 

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Discussion Starter #6
Tim, I thought of vinegar, but solution of 100% pure vinegar and water, 20% - 80%. This is comon used in ultra sound bath, I used that for servicing of diving equipment - regulators in diving center. Tomorrow I will dismantle my carbs and do everything as you said. I had a chance to see this hand made gauge for synchronising in friends garage but I think your hints are valuable cos he used water instead oil and about washer he didn't even think about :) I'll try it sure :)


Raymo, I never used before any kind of those additives, perhaps of my ignorance I was afraid to do so not to do some damage to some other place. But I will sure consider this, you know, when a men is drowning he grab even for a straw :) and will check the site you wrote. But tomorrow (Preferably during working hours) :) Is been long working day and tomorrow is brand new working day and now is after midnight :) And for several past years I had no much chances to use English so my brains are spinning and struggling now, need some sweet sugar and nutela maybe before going to bed :)
Thanks guys, I appreciate this
 

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Discussion Starter #7
I have been watching just now some stuff on you tube and something appeared to me, maybe I expressed myself wrong in terms... There is float needle and there is needle from the diaphragm. Well I was talking about this diaphragm vacuum needle and she is sliding towards jet needle and main jet.... The hole when needle is closed down on idle is leaking and behind you can see this butterfly stuff... just in case :) but in the morning I am taking out the carbs...

Raymo, but I use my bike whole year around, at least 11 months. Only the ice and below zero will force me to seat in my car and go to work. Every day use, traveling, holidays, going out... If I could pack my windsurfing and diving equipment on it I would be most happy :) Even for a dog I made special givi convertible top case :D
 

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Discussion Starter #8
:thumbup::thumbup::toothy10::cool:

Last weekend I striped my carbs out apart as I said I will do, and I checked all as you guys recommended to me. And you were all right! This ass of a mechanic were not have tighten the main jet!!!!!? He were taking out 3 times the carbs from a bike and from very beginning the main jet on front carb was so loose when I touched it with fingers it just dropped in. Cos it was in front of me on my table I took apart both carbs to check it all. After returned in the bike, made this tool for synchronising carbs from clear hoses and oil and soon the job was don!


here was a leak around the needle
IMG_20160507_094211.jpg

IMG_20160507_113333.jpg

the book the best friend :)
IMG_20160507_122508.jpg

the tool :)
IMG_20160508_112821.jpg

happy
IMG_20160507_183515.jpg

and finally, the same evening out for a drink with a friends
IMG_20160508_193537.jpg

Thank you guys for support
I appreciate this
cheers,
vanja
 

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Discussion Starter #9
[video]https://www.facebook.com/vanjasurf/videos/vb.1094982631/10206214277971291/?type=2&theater[/video]


short video from FB I have made when syncronising :)
 

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Discussion Starter #10
the bike is generally working fine but I must do some fine tuning of carbs later on. When I decelerate speed on exhaust are pops and bums, I guess lean mixture. Cos my AT is for Swiss made the slow jets are 35 instead 38 as on other xrv and because the air valve needle is on 1 3/4 turns instead as others on 2 1/8 turns. So I adjusted the valve on 1 3/4 as the book said but there are still pops ... Not a backfire witch is before carb... What is your opinion, should I tighten the valve to decrease the air? Apparently in the exhaust is extra unburned petrol ... Or maybe I closed to much the needle on floats and in the bowel is no enough of petrol? From about 6000 r/h witch is about 125 km/h the bike start to have kind of constant periodic "brakes" in speed, and as i speed up the timing in this brakes is more closer. Is it mean there is luck of petrol?

Before I do anything I want to buy one new CDI because on stroboscope I noticed every 5 sec or so there is a spark missing on one cylindar ( on rd 03 there are two separate CDI) probably cos this one CDI I have welded from behind :D cos it already malfunctioned previously :) And new air filter and petrol filter would be vise too :)
 
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