Is it possible to convert GV250 carb model (2007) to run an electric fuel pump?
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I think the Korean’s did a very good job with Mukuni Japan to make a “custom DF series” pump for Hyosungs.
The GV250 uses the same pump as a GV650 carby = it means the GV250 will not be able to max it out. The vacuum pump is poweful enough to run a 650cc already.
If it has problems, you can replace it (but they rarely fail except bad debris from fuel , crap fuel (e10) , or just simply very old age kicking in)
An electric pump would put more strain on the stator unit and the regulator because the regulator sits “under the seat” , it does not get enough air cooling , compared to a GV650/GT650 to cool down the regulator.
The “floats” for the carb can’t handle anymore extra psi , henceforward the “vacuum pump” works in “pulse fasion” , it pumps more as the carbs demand more.
For “simplicity” and efficiency , i would recommend less electronics on a carb bike , after all the stator it uses has less watts than an EFi model and it also has less poles than an EFi model.
The EFi models use electric pumps but they have updated stators to handle it and a 30A relay dedicated for a pump, it is resource hungry.
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here is a fun fact.
In 1999 – 2002 Hyosung “did” actually use electric pumps on their GV250 Aquila Carb models , which looks 100% like this one and they use a “special 1999-2001” bike harness to include the pump and the CDI would know about it too. Very very rare now, why ? = They discovered, stators would last longer and owners would have less maintenance jobs on the bikes if they contract Mikuni Japan to make them a vacuum pump.
This is when they started making intake pipes updated with vacuum holes for pump. Old rare models did not have vacuum holes to feed pipes to vacuum pump.
Nowadays, the Taiwanese seem to do these pumps for old scooters and their quality is not good. So if you find a pump like this, or similar, it will be made in Taiwan or China , (big problems later)
You want a vacuum pump to guarantee that you will not be stranded many miles away from home. In my years of riding Hyos , i’ve never had a rear pump fail on me.
Just the tank “TAP” is a common replacement item. (for good reason, bad taps cause engine hydrolocking , jammed carbs , seized motors.) so always make sure one every 2-3 months , remove the tank tap pipe and confirm it is not dripping fuel when engine is OFF and tap is OFF setting. Saves you in the long run!
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Thanks a lot for such an informative reply. Obviously going electric is a bad idea. The main reason which caused me to come up with this idea is because I have started to experience jerking while riding in a higher rev range. So far I have replaced the plugs, fuel filter and cleaned the air filter. I have also taken the fuel pump apart to see whether there was any particular dirt in it but everything seems fine. It also seems to pump out the fuel quite well proportional to the engine revs. The bike is used on a fairly regular bases so I don’t think that any fuel residues could have caused any blockages in the carbs and to be honest it seems that removing the carbs on this bike is quite challenging and I would like to consider this as a last resort. Has anybody experienced something similar to this? Any ideas what could be the cause?
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As per simon, start easy by investigating ignition parts.
But i would recommend removing carbs and please do not panic, follow these 2 guides below and TAKE YOUR TIME 🙂 , Rubber Intake pipes are very difficult to get now, so look after yours well.
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Thanks for your replies and encouragement guys. I will follow your advice and get back. As for the intake rubbers, well that is another concern because while I was replacing the plugs I noticed that they were in a reasonably bad shape so if I do end up having to take out the carbs I am going to need to replace those. Following Marcel’s remarks about availability I’ve had a quick browse on the internet and it does look like I might be in trouble. Do you guys have any recommendations about where I could possibly source these? Thanks again.
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Thanks for your replies and encouragement guys. I will follow your advice and get back. As for the intake rubbers, well that is another concern because while I was replacing the plugs I noticed that they were in a reasonably bad shape so if I do end up having to take out the carbs I am going to need to replace those. Following Marcel’s remarks about availability I’ve had a quick browse on the internet and it does look like I might be in trouble. Do you guys have any recommendations about where I could possibly source these? Thanks again.
i’ll always find a way to get intake pipes , believe me , my ebay is the one that has the most stock , and i’m always hunting. Do not worry but yes they are getting very difficult to get.
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Hi guys, just a short update from my end. Well I have checked the coil and plug resistance and everything seems fine there. I also noticed that the plugs were a sooty black. While I had the tank off I also had a very close look at the intake rubbers and they are definitely in bad shape. I came across some hints about checking these for possible vacuum leaks just by spraying carb cleaner over the cracks while the bike is running and observing any changes in idling. I haven’t done that yet, I’ll probably have time to do that later.
Am I right to assume that should there actually be vacuum leaks in the rubbers this could well be the cause of the symptoms I am experiencing?
I also came across some ideas of using some Super RTV silicone adhesive to block off any leaks should these actually exist. Has anybody ever tried this?
My plan is to check for leaks and should there be any, use some silicone adhesive to temporarily block these off to see whether this solves the problem. Then if it does, start looking to purchase replacement rubbers 🤞🤞🤞. Any thoughts on this idea?
Thanks again for all your help!
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Get a good quality motorcycle tyre tube and rubber glue in your country that supports “HIGH HEAT” , and wrap around the intake intake pipe and patch it careful , that should help give it more life until you get replacemennt rubbers.
Sooty plugs also mean air filter is dirty (causing rich condition) , if the coils and caps are okay. Try fresh CR8E plugs and ride a little bit, then see your true plug colors again.
Spraying carb cleaner at the intake pipes helps (it has o-Rings under it) , sometimes they need replacing like these below
Intake Pipe O-RING (Inlet Boot Seals) x2 – GV125 GT125 RX125 GV250 GT250 Hyosung
Also spray around the airbox on top of the carbs, incase airbox is not sitting on carbs properly. It might leak out air.
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Thanks Marcel, noted. Ok so the carb cleaner did prove that the bike does have vacuum leaks, so some basic repairs are next in line until I do manage to source replacement rubbers. Unfortunately ebay isn’t much help in that regard. Also while tracing the pipes in connection to air flow I came across this device and can’t really figure out what it is and does. Is there any way of testing this?
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Fake Emissions Device.
Very very useless on carb bikes.
Korea puts EGR (infamous name) but correct word is “AIS” / 2nd Air Valve to make bike emissions less in stricter EU countriesHere in UK we don’t care , we don’t get checked for emissions on carb bikes, so it is legal for us to remove it for now, thats why we sell the blanks
EGR Valve Blanking Plate / AiS Delete Block Off Kit – Various Hyosung Carb Models
Bike is happier = why? More vacuum energy is going to the fuel pump now , instead of sharing vacuum energy to pump , tap , and AIS(EGR) device.
The bike will make less pop sounds too. Exhaust may sound a tiny bit better.
1999-2002 GV engines did not have it.
If you remove it, make sure to blank the ports , like below
How to change Vacuum Lines on Hyosung GT125R GT250R & GT Comet (Air Hose Diagram)
Ignore the bike is a GT above ^ , the instructions also help GV bikes , they have the same engines and carbs (125cc GT/GV included)
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Well guys I have managed to apply a reasonably thick layer special silicone designed to resist heat over the cracks on the intake rubbers. Left it 24 hours to make sure it was dry and then went for a ride but unfortunately the problem persists. I have now ordered new rubbers (managed to source these from the US) quite expensive but I am going to have to attack those carbs.
Thanks again for all the support and information you have provided me with. I will post an update once I complete the next challenge 😓
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Well guys I have managed to apply a reasonably thick layer special silicone designed to resist heat over the cracks on the intake rubbers. Left it 24 hours to make sure it was dry and then went for a ride but unfortunately the problem persists. I have now ordered new rubbers (managed to source these from the US) quite expensive but I am going to have to attack those carbs. Thanks again for all the support and information you have provided me with. I will post an update once I complete the next challenge
Make sure to replace the “intake” O-Rings too! and keep us posted 🙂
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Hi Guys, well I am still waiting on the new rubbers to arrive from the US but it seems that I am not going to need them for now. 😀
Yes I have finally managed to sort out the problem. As I had mentioned in one of my first posts I had replaced the plugs, fuel filter and cleaned the air filter. Well the fact that the plugs were quite sooty kept echoing on the back of my mind because as Marcel had mentioned this is normally related to a dirty air filter. So I decided to carry out a small experiment. I cut out a small piece of towel the shape of the air filter and placed this instead of the filter. I went for a ride and was impressed at the improvement I felt. It was obvious that using compressed air to clean the filter wasn’t good enough. Kindly note that I would have also replaced this but the local dealer didn’t have any in stock. These people are more interested in selling new bikes then supporting the older models. 😡🤬
So now I needed to get hold of a replacement air filter, at least I managed to source this in Europe so it shouldn’t take that long to get here.
In the meantime I also tried to find some other information about the best way to clean a paper air filter and I came across an article saying that you could wash this with water and detergent so I decided to give this a shot and believe it or not it worked wonders.
At first I was thinking water and paper… But I was very surprised at how hard the paper in the filter was. I am not sure whether all paper filters can withstand this procedure, so if you do ever decide to give it a shot, this would be entirely at your own risk.
This is the way I went about it:
Find a container which can take the full length of the air filter an fill this with water and dish washing detergent
Let the filter soak for about an hour and after this grab the filter and start to move it around it the water just as if you are forcing the water through the filter.
Then get hold of a very small paint brush (something that will fit in between the paper folds in the filter) and run this a number of times through the folds in the filter rinsing the filter every time. You have to be careful not to go too hard with the brush keeping in mind that this is only paper.
After having done this with the brush, 3 times, rinse the filter in clean water and leave it to dry in the sun. You have to be absolutely sure that it is completely dry before installing it back and running the bike.
As I said this procedure worked perfectly for me and I only tried this because I didn’t have a replacement air filter available. So this is just an interim solution. Installing a new air filter is always the recommended solution.
I am also curious to know whether anyone has tried to rip out the paper of an old air filter and replace this with proper foam. Is this a good idea?
Well looking on the positive side I managed to source the intake rubbers for my bike seeing that these are now becoming very hard to come across. While on the same subject are there any other parts that you would recommend I stock for the GV250 carb model.
Thanks again for your support and advice.
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Hi guys,
Well I finally received the intake rubbers but unfortunately the seller sent me part no 13120HJ8201 instead of 13120HJ8204. He is claiming that the part should fit perfectly just the same. He said that part no 13120HJ8204 is no longer available from Hyosung.
The main difference seems to be that the connection to the emission device we had discussed earlier in this post is blocked off. No serious problem there.
But I also got the impression that the rubber might be bent at a very slightly different angle. I cannot compare so accurately since the old one is still in place. I must say that the part does actually have GV250 imprinted on it but I know that there were a few minor alterations on the bike since the original model was produced.
This leads me to my question, does anyone know whether these parts are a perfect physical substitute for each other?
Thanks for your kind support
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So I dont need to run a hose from the rear cyclinder to the gas tank. I only need to run the line from the front cylinder to the fuel pump. Im haveing totally dif issues but if thats the case then i would much rather do that. Currently i have front and rear meat at a T connection with runs towards the fuel pump but right before the fuel pump i have another T connection witch splits it an i attach one side to pump and the other to the left side of gas tank. Before this I had had a T right outside of rear intake witch i ran one hose to right side of gas tank the other one went across and connected with the front manifold and then over to the fuel pump but i qasnt sure on what tap it was supposed to attach to under gas tank. So i changed it to the way i have it now and it sounded better and and felt more responsive and then i filled the tank and i wasnt able to even to keep her idling. Dieing at stop lights unless i gave lots of gas shitty ride home thats for sure. But when tank got lower it got better so idk what the problem was. Its probably still there but currently I have no spark. Idk remember why but i disconnected the cdi and when i reconnected to go to work she wouldnt start. And reason is no spark. So something happened either unplugging or plugging cdi in. Im at a loss.
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Hey guys my name is Jarret and I just registered with hyoriders. I was actually trying to find out about possible aftermarket air intake or filter options for a GV250 when I came across this forum/thread(I’m not sure of proper terminology) but anyway as Marcel had mentioned about a version of carb model with electric fuel pump and how they realized stators would last longer without it…Well it just so happens I have one of those models that I bought back in December. It’s a 2002 GV250 Alpha and I’m currently going through that exact issue. My stator has gone bad and has left me stranded a time or two now due to battery dying and then of course dead battery=no fuel so I now know that I’m gonna see if I can’t try and convert to vacuum pump. I’m glad I came across this and look forward to exchanging info and such with u guys. Thanks for allowing me to join.
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Hey guys my name is Jarret and I just registered with hyoriders. I was actually trying to find out about possible aftermarket air intake or filter options for a GV250 when I came across this forum/thread(I’m not sure of proper terminology) but anyway as Marcel had mentioned about a version of carb model with electric fuel pump and how they realized stators would last longer without it…Well it just so happens I have one of those models that I bought back in December. It’s a 2002 GV250 Alpha and I’m currently going through that exact issue. My stator has gone bad and has left me stranded a time or two now due to battery dying and then of course dead battery=no fuel so I now know that I’m gonna see if I can’t try and convert to vacuum pump. I’m glad I came across this and look forward to exchanging info and such with u guys. Thanks for allowing me to join.
Let’s do it.
Make a new topic and we will follow it with you.REGULATOR upgrade is an ABSOLUTE key/ If anything electric needs upgrading, make sure it is a regulator (like the one you saw on the shop)
The grey ones are too small and got re-called by Hyosung , and they tried to amend with another black one, but the OEM Korea & China regulators are just not worth a fried bike!
Stator = Replace it. But if you want to test the stator health, I will show you in a separate topic you make.
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