HJKO Posted May 15, 2019 Report Share Posted May 15, 2019 Hi guys/ladies, First time on the forum as I just bought me a 1995 Dnepr MT16 and from day 1 it seems I have trouble with the fuel supply to my carbs (K68).For some reason the fuel is not running into to filter house (first only on the right side, but now also on the left side!).But when checking the hoses and the fuel valve on the tank everything seems to be working fine. Fuel is freely running when disconnected from the fuel valve on the tank (with and without fuel filling opening covered), every hose is clean. The filters are not that clean, but I would expect the fuel to run down into the filterhouse even is the filter element should have been completely blocked. The day I got this bike I had problems this the fuel supply to the right carburetor, but I could drive with it. When running idle the motor would stopp after a long time running on idle. This problem disappeared when raising the rmp´s. So I drove it with a rather amount of RPM´s. I borrowed som carb tuning equipment to check my Idle balance. But now I do not get the bike startet due to missing fuel. Is there anybody out here who can help me with some good suggestions where to look to solve this problem?Looking forward to get this bike on the road...... Henk Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 15, 2019 Author Report Share Posted May 15, 2019 Hi, I found a little petrol in the filters, about 1/4 was filled up. It took only about 7 hours.So after my tour yesterday I closed the fuel valve, all fuel disappeared during the night (on the left side as the right side was almost empty). Why???Then when opening the fuel valve, it took about 7 hours to get a little petrol in the filters. So my question above is still the same. Any suggestions? Quote Link to comment Share on other sites More sharing options...
3 bike mike Posted May 15, 2019 Report Share Posted May 15, 2019 To me it looks like the filters are upside down ! are the marked which way up ?On my Dnepr MT9 the filters never fill up with fuel but the fuel flows through them none the less, Try disconnecting them just from the carb and see if fuel runs out of the lower pipe, With the fuel tap turned on of course . Hope this helps .. Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted May 16, 2019 Report Share Posted May 16, 2019 If the filters are clogged fuel will not flow into them well, there must be a working outlet for the fuel to flow into the filter. The hose is narrow enough that air will not easily go back up allowing the fuel to enter the filter. Also, if the carb bowls are full and the needle valve is seated no fuel will flow into the filters. A common issue if the petcock has rubber seals in it is that the ethanol in US gas will make the rubber swell which in some designs can choke off the flow. I don't know if the gas in your country has ethanol added or not. I have had some short term luck dismantling the petcock and putting some grease on the rubber parts but this is temporary as the grease will dissolve over time. If this is the issue replacing the petcock is the best bet. How clean is the tank? Dirt could be on the top of the pipes sticking up into the tank which will restrict flow. Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 16, 2019 Author Report Share Posted May 16, 2019 Hi, Thanks for your reply. There is no flow direction on the filterhouse. Looking at the paperfilter, it make sense it is installed this way. If now the filter collapses it will block the outlet, if placed the other way the filter would open up and all drit gets inside the carburetor. However I have to assume that the previous owner installed it correctly. I took the hose off and there was a tiny bit of petrol running. I guess when running the enige on high RPM´s the petrol it getting suck out of the tank. Yesterday when trying to start the enige, there was no petrol when pushing the "float activator" (is that what they mean with "tickling the carburetor"?)I was told to use the tickler before every start. This worked before yesterday. Tried to use the choke, but no help there either. Now is the weather nice her in Bergen, so I guess this is ok. You have no visual petrol running, but does it take several hours for the filter to fill up after you stopped the motor? Is that normal?Do you close the fuel tap directly after you stopped the engine? Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 16, 2019 Author Report Share Posted May 16, 2019 If the filters are clogged fuel will not flow into them well, there must be a working outlet for the fuel to flow into the filter. The hose is narrow enough that air will not easily go back up allowing the fuel to enter the filter. Also, if the carb bowls are full and the needle valve is seated no fuel will flow into the filters. A common issue if the petcock has rubber seals in it is that the ethanol in US gas will make the rubber swell which in some designs can choke off the flow. I don't know if the gas in your country has ethanol added or not. I have had some short term luck dismantling the petcock and putting some grease on the rubber parts but this is temporary as the grease will dissolve over time. If this is the issue replacing the petcock is the best bet. How clean is the tank? Dirt could be on the top of the pipes sticking up into the tank which will restrict flow.We have something here called: Shell V-Power Nitro+ Blyfri 98, this is ethanol free petrol with octane 98. Not sure what I have in the tank as it is half full. Quote Link to comment Share on other sites More sharing options...
3 bike mike Posted May 16, 2019 Report Share Posted May 16, 2019 Try and see if fuel flows out of the pipe when the filter is removed, Just drain it into a jar or something. that will tell you if the petcock is ok. must be on to do this !! while your there check to see if fuel stops flowing when the petcock is in the off position. Do it on both sides . If this test is all ok problem must be lower down, i.e. filters or carbs . hope that helps . Quote Link to comment Share on other sites More sharing options...
3 bike mike Posted May 16, 2019 Report Share Posted May 16, 2019 Another point... If fuel is not flowing when the pipe is disconnected from the filter and the petcock is in ON position. You could blow some air up the pipe, It may clear any blockage !! then you need to clean the dirt out if it works. Quote Link to comment Share on other sites More sharing options...
Northernduck Posted May 17, 2019 Report Share Posted May 17, 2019 Just adding to 3 bike mikes comments. His checks will tell you if it’s the petcock or something lower down. Your first post indicates that fuel freely flows from the petcock if the hoses are removed, it sounds like you’re problem is farther down, unless the petcock has become blocked with dirt since then. Do as 3 bike mike suggests. If fuel is available to the filters with the hose removed at the entrance to the filters then you can try disconnecting the hose from the outlet of the filters to see if this is the issue. If fuel is not getting through the petcock then check the petcock filter, and you should be able to see inside the tank with a light to see if there is an accumulation of dirt at the petcock entrance. Dnepr petcocks are notoriously undersized and can be modified if this is the issue. All orifices and standpipes can be drilled to larger diameter. If petcock and filters are not the issue, then the problem is at the carbs. Let us know how you progress. The ticklers manually depress the floats which is supposed to open the needle valve from the seat. A few things can go wrong here but let us know. Regards Quote Link to comment Share on other sites More sharing options...
racepres Posted May 17, 2019 Report Share Posted May 17, 2019 And when I tell folks I will Not use those little inline filters,..... I always hear, "never gave any problems"They work on a "pump" but always give me problems if Gravity fed... No Thanks. Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted May 17, 2019 Report Share Posted May 17, 2019 I'll have to say the filters work fine on my Ural, been running with them for 21 years with no issues. I can't say for Dneprs. Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 17, 2019 Author Report Share Posted May 17, 2019 And when I tell folks I will Not use those little inline filters,..... I always hear, "never gave any problems"They work on a "pump" but always give me problems if Gravity fed... No Thanks.Hi, there is quite a lot of dirt in the filters (my personal opinion) and as I am not sure about the NAS classification these carburetor can handle I prefer to have these filters in. Is it called NAS classification when talking about petrol and not oil?. I ordered new filters, hopefully this will help. Anyone know the max size of particles before the carburetor stops working. If it is a size bigger than the ones I find inside the filter I could get rid of the paper filter (and leave ut housing in the system). Next on the agenda is checking the tank, I need to find out where this dirt is coming from.But not today, today we celebrate the Norwegian Constitution Day here in Norway. Quote Link to comment Share on other sites More sharing options...
racepres Posted May 17, 2019 Report Share Posted May 17, 2019 And when I tell folks I will Not use those little inline filters,..... I always hear, "never gave any problems"They work on a "pump" but always give me problems if Gravity fed... No Thanks.Hi, there is quite a lot of dirt in the filters (my personal opinion) and as I am not sure about the NAS classification these carburetor can handle I prefer to have these filters in. Is it called NAS classification when talking about petrol and not oil?. I ordered new filters, hopefully this will help. Anyone know the max size of particles before the carburetor stops working. If it is a size bigger than the ones I find inside the filter I could get rid of the paper filter (and leave ut housing in the system). Next on the agenda is checking the tank, I need to find out where this dirt is coming from.But not today, today we celebrate the Norwegian Constitution Day here in Norway. On The British Bikes and especially on the Harleys... No Way.. The screen in the tank is all I need...actually the screen on the petcock in the Tank of the Ural seems to be just fine... Petcock from a ???? Suzuki maybe???On the Dnepr... is where I been experimenting... crud in tank, no screen on petcock... serious problems with them nasty little Filters...Probably the Crud from tank.. Trying a rather large filter [intended for the H-D] that is designed around gravity feed...Actually seeking an in tank Screen... Particle size that the carb/engine can swallow???? The Engine can take in and spit out a Hankerchief!!! BTDT..The carb??? probably not except at WFO, and Not thru the Bowl..Let's just say "alot larger than you may Imagine" Been my experience that if ya tickle the carbs, and fuel comes out... ya gots Fuel... also if it Quits, and you even suspect fuel, a quick reach down an press the "tickler" you should get fuel immediately... or yup, it is a fuel Problem... BTW... Did I mention that I despise them little inline fuel filters... and will/have gone to great lengths to avoid them?? Quote Link to comment Share on other sites More sharing options...
RussN Posted May 17, 2019 Report Share Posted May 17, 2019 The inline fuel filters on my Urals have glass cylinders. They never fill with fuel, and always allow free fuel flow through them!Not sure why, but that's how they work. So don't let the visuals confuse your thinking. Actual fuel flow through the filters tells the truth. You mentioned right cylinder fuel starvation after long idling. This is the first sign of fuel starvation from the petcock or tank.Make sure the tank vent is clear! It could be a small hole in the gas cap, or an internal pipe as in our Ural tanks. That pipe exits the bottom rear of the gas tank. Some riders have reported bugs building nests in those pipes, blocking them. Follow suggestions above for verifying fuel flow, starting at the pet cock and working down to the carbs.~RN Quote Link to comment Share on other sites More sharing options...
js69 Posted May 17, 2019 Report Share Posted May 17, 2019 The inline fuel filters on my Urals have glass cylinders. They never fill with fuel, and always allow free fuel flow through them!Not sure why, but that's how they work. So don't let the visuals confuse your thinking. Actual fuel flow through the filters tells the truth.Same with mine! Curious to know why they are not filled with fuel all the time Quote Link to comment Share on other sites More sharing options...
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