Great video! Learnt a lot from this especially the fuel pump being vacuum and where the pressure comes from on the manifold, going to replace the pump and check the manifold seal. My Bike would start run for 30 seconds go lumpy and die, I stripped the carb, cleared the jets, replaced the diaphragm, changed the air & fuel filter and still the problem persisted. I was in head scratch mode too. Gonna get onto this right away. Well done mate, very well explained, good tutorial.
You are a diamond geezer! Problem solved. Do more of this. You deserve an Oscar for your delivery, explanation and teaching skills! Absolutely brilliant.
@@nickstanford3552 Haha that's great news, really glad it helped, thanks for letting me know, it makes it worthwhile, all the best and enjoy the ride 👍
I'm glad I watched your video, I've just got a pump to put on my dax copy. I was going to have a small hole in the inlet manifold. After what you just showed me, I will be drilling it to 3.5 mm. Great video thanks. 👍😎
Eeeeexacly the same problem!! Changed the intake manifold and when i revit it remains without fuel! This aftermarket intake manifolds are the problem! I was that stupid to throw away the old one to make the difference. I was thinking about the same vacuum hose that is to small. Thank you dear sir!
Great video and explanations! I recently fixed up a 350 Yamaha atv for my landlord which had the intake gasket problem. Unfortunately the previous owner had tried to fix it by cranking down the intake manifold bolts, which only bent one and stripped the other, and made the problem worse. It's an easy to look issue, so I'm glad you pointed it out! also +1 to the vacuum petcock issue.
Yes, SUPerb,Thanks ! and Cheers. Maybe the best, most informative repair vid I’ve ever seen. A very comfortable and accurate explaining style you have. Best.
Superb help !! I got the same problem my habana won’t go over 40mph ! Starts getting lumpy then won’t accelerate! Might be over heating or lack of fuel because of inlet manifold or pump 😢
Thank you very much , in the same position on my Aprilia Habana so hopefully once I check properly the problem all will be good again and back on the road here in sunny Ceredigion.
Where do you get your parts? Trying to give my 2001 Retro some TLC and the intake manifold looks very brittle ... scooterparts says it's no longer being produced. Along with a bunch of other parts I think I might need (still in the process of taking stuff apart and figuring it out) PS: Thanks for posting this video. Nice to see other people tending to Habanas aka Mojitos.
Excellent video, just wondering if you know what the thin transparent (stained reddish by fuel i think) pipes connecting to the carb do, there are three of them 🤔
Great videos thanks for sharing your thoughts and solutions I have been asked to work on an aprilia habana 125 that has no spark so I might need your help if I get stuck thanks again. 😀
I have a similar problem with my Yamaha scooter. The vacuum pump is high up on the tank near the saddle area. So, with no petrol coming out of my almost new petrol vacuum pump I'm going to have to check out, and hope my solution will be the same as yours.
Hi I'm so confused, I have a little Habaina 50 2003. When I fill it with fuel and leave it for a few days when I come back the fuel is no longer full I look in the opening and it's all gone I'd have to refill again approx it would take about 1 liter to bring it back up to top and then it will start
That doesn't sound good, the fuel must be going somewhere. If you can't see anything leaking out to the floor then check your oil level to make sure it isn't finding its way into the engine and mixing with the oil. It definitely needs investigating
Hi, just seen your video. I have a Pierr 125 Custom I’ve had it for 15 years And now every time I open up the throttle, it cuts out completely If I open the throttle gently a little It’s okay I’ve just ordered the new spark plug. It might be that if not I’ll move onto the fuel system. Any advice? Thanks, Darren
@@DE-jk6rd I would start with the basics first, check the air filter isn't clogged, spark plug, valve clearances etc. It sounds like its not getting enough fuel if its dying when the throttle is opened or too much air which could be a split in the carburettor diaphragm or a bad inlet manifold not sealing properly. Could also be vacuum fuel pump as shown in the video. It's hard to say without seeing it but go through a process of elimination and I'm sure you'll find the problem 👍
At the end of the video alot if fuel came out into the pan ate you had. Did you say that is too much causing a problem or this is OK? I lost you on that part
No that fuel is exactly how it should be. It supplies the carburettor and the excess fuel will flow back into the petrol tank which you can see when you look into the pipe where you fill your bike with fuel. Hope it helps
Hello brother. I love your vids. I have a question maybe you can help me with. Mine has a square mikuni pump. It just poors fuel when bike is not running just like a gravity fed petcock would do when it's turned on. Are the arrow sides supposed to hold vacuum? Cause mine just keeps pulling air through it when I apply vacume to it. Any help is appreciated. Thankyou.
Carbs check out with clean jets and clean all around. I tested the vacume port that goes to the intake on the bike. I used my vacuum/pressure gun and the guage slowly goes down. Is it supposed to hold vacuum exactly where I leave it without dropping on the Guage? The bike idles on and off choke but will not rev without dying.
Very interesting, I'm resurecting the same bike, didn't know what that green relay/ timer was for. good to know! Now if I can just find out why my dip/ main beam isn't getting power, I'll be right!
Like you I was searching the internet everywhere trying to resolve a similar starting issue on my bike and thanks to your video I was able to resolve my problem. Thanks a lot and appreciate your efforts creating this video!
Have a hyosung Aquila gv250 and a head scratcher as well. I'm goin thru the same issue. Im going to take the boot off and see if the vacume port is restricted. Do you know if they come from the factory restricted? Or do they get restricted over time??
It shouldn't be restricted from the factory, in my case it was an aftermarket part that had the restriction and caused my problem. If you're having similar symptoms to mine I would start with checking all your vacuum pipes for leaks or splits or loose fitting and then check the intake rubber boot to make sure it's sealing nicely around the carburettor and also good seal to the cylinder head. Hope it helps and let us know how you get on 👍
Okay yea I took boot off and doesn't seem restricted. Going to check hoses, o rings, and seals for vacume leaks and see what I find out on it. I noticed that the pump is pumping again. That's confusing me.
Thks 4 your video I have a Piaggio Zip 2T I think I have same problem whit my fuel vacuum I try to blow up the vacuum pipe no petrol not came out what you thing Thks
Hi, I have the same problem with cold starts. As you suggested I bought the green relay, I plugged it in and it still won’t start. Does anyone know what can be the problem. Thanks for your ideas
I just found this video as I'm having problems with my 1998 Aprilia Leonardo 150 scooter, there's very little fuel coming onto the filter. When you ride it in the normal flow of traffic it accelerates alright but as soon as you close and then reopen the throttle it bogs down and almost dies, and on occasions it does. What surprises me is the vacuum appears to be taken from the carburettor itself, a Mikuni BS 26, rather than the inlet side, it's just a rubber connector between the carb and head. I'm left with two possibilities, valve clearances which I did that not long ago, or a defective fuel pump which looks to be an absolute pig to get to as the tank sits under the frame rails so I'm not sure that I can get to the pump without taking the tank out?
Hi Graham, very hard to say without seeing it but lots to check. If the valve clearances are slightly too tight it could cause a lack of compression which could be it or you could try spraying some easy start or brake cleaner around the inlet manifold with the bike running to see if the revs rise which would indicate an air leak. Also the simple things like a dirty air filter or a worn out spark plug is worth checking. If all that is ok then maybe the carburettor mixture is too lean in which case and little 1/4 turn or so anticlockwise on the mixture screw might help smoothen it out. I would think that as it runs ok when out on the road that the fuel pump doesn't sound like the problem. It's a big list but hopefully it helps you out
@@motorcyclerevivaluk741 I rechecked the valve clearances and they were fine. I replaced the rotten hoses on the fuel pump in the tank and checked the pump diaphragm. I thought the rotten hoses were the problem as now much better fuel flow to the carb. But alas every time I give it wide open throttle for a few seconds once I shut off, slowing up coming up behind traffic or approaching a roundabout, as soon as I try and open the throttle again it dies.
Have you looked in the top of the carburettor to check the condition of the rubber diaphragm for splits and that its seated correctly? You can check the needle jet at the same time to make sure its ok. Also I believe your carb has a pump jet which should spray a small amount of fuel directly into the carburettor when opening the throttle, you should be able to see it spray if you can remove the air filter pipe and look straight into the carburettor whilst quickly opening and closing the throttle.
Not in this case, it's there because the fuel tank is below the height of the carburettor and it needs the pump to keep the carburettor supplied with fuel
After seeing this video I know the issue of my Ducati Monster 900 (1995) with a similar vacuum pump. You are spot on with the head scratching :D The motor runs, it revs, when I drive it dies… how does this happen?! Now I know. Thank you for this video!!!!
Thanks Maurice, hopefully it will help or least point you in the right direction. Its always worth checking all your vacuum pipes for leaks first before changing the pump. Good luck 👍
I got a problem with my scooter , i practice wheelys but my carb bowl is empty after 500 meters , my tank is in the back so the carb is not able to get fuel while wheeling ,i think about to install a pump like this , my issue is that the hose that connects to the crankcase is really thin and already connected to the carb , idk for what purpose , do you think i can use the vacuum on the top of the carb that is connected to the inlet ?
Hello nice video... My scooter only starts when i spray some cleaner at the filter... after it, it starts whole day only after night wont start can you help?
Hi thankyou, it's really hard to say without seeing the scooter. I would start by checking the electric choke and making sure it's connected properly and working. It could be a weak battery or even a leaking carburettor. Lots of possibilities but without taking it apart I couldn't say for sure but I think the choke would be my first place to check, hope it helps
Im going to check the vacuum port size like you did cause my boot looks just like yours. I have the same pump as you. Do you know if it's supposed to pump at idle? It dies at throttle and only idles but no change in fuel height in the clear line I'm using temporarily.
@@shanemyers4142 ok, if it worked ok before i would probably look inside the carburettor to make sure all is well. A good clean up inside and blow out the jets and check any rubber diaphragms for splits
@@motorcyclerevivaluk741 I got to thinking. There is a brass colored washer around the main jet. Have you ever seen those fail before. I'm wondering if fuel is getting passed the washer maybe and it's flooding it. I've been looking on line to see if one has failed on someone before to see what the symptoms would be but havnt found anybody yet.
@@shanemyers4142 they don't normally fail but it's worth cleaning as much as possible inside the emulsion tube where the main jet goes into, there are tiny holes in that tube that should be clear. Also if you have the carbs open it's a good time to test the needle valves are allowing the fuel in and also stopping it when needed. Just blow into the fuel line and flip the carbs upside down and make sure the floats move and stop the flow of air. How was the condition of the rubber diaphragms in the top of the carbs?
Wow what a good catch on that little pipe being clogged or something. I wonder if it was accidentally made that way even though it is metal. Either way it's still pretty cool how you found that problem. That was definitely not the common problem these scootershave. (or I least hope it's not) I have a very similar scooter/engine. I have a 2011 Foshan 150 Romeo. And lately I have been having problems keeping my bike running. After watching your video and while I have the carb off, I'm gonna check that manifold, under it, the O-ring, and see if anything looks bad. Thank you for showing and making that video. You seemed knowledgeable about that engine, carburetor and vacumm lines etc. I Truly appreciate you showing and making the video on TH-cam. Michael Merchant II
You're welcome, hope it helps. I think the reason the pipe was made that way was for use with a vacuum fuel tap which I'm sure it will work with but it doesn't make enough volume of vacuum for a vacuum fuel pump
Thank you that mate, it's given me the clue to sort my problem. The air flow nipple from my carb to the vacuum pump had a tiny backed off hole about .3 mm dia. halfway in, and seemed blocked. I used a nozzle cleaner and voila, I could once again see petrol filling into the clear part of the in-line filter. 4 kicks in, and the engine is running like new again.
Perfect I needed this video, I have the same issue with my gilera 125 st the fuel tank is located below the carb and im not able to get fuel up , I have replaced the pump and lines but its still the same , okay on small revs but no fuel at top speeds so I will check the manifold inlet hasn't got a restriction aswell 🙏👌
Sounds like the same problem, definitely worth checking that manifold both for a restriction in the vacuum line and also that the manifold is sealing properly to the head. Hope it works out for you 👍
@@motorcyclerevivaluk741 yes the vaulve on the manifold was restricted ! so I drilled it out and it is now working great with no issues 👌 thank you again for the video
Hi, i wonder if you could give me a little advice ? i have a 50cc 2 stroke with exactly this problem i've tried new plug , coil, carb, cdi unit, rectifier i don't know why i now have a funny feeling it could be the fuel tap is that a possibility ? . the bizzare thing is it ticks over lovely for as long as it wants but as soon as i accelerate it dies, if i play with throttle on the handle bars i can manage to get it to rev to the max but as soon as i let it idle it goes back to not accelerating and cuts out, also i have noticed that when i take plug out after trying to get it too run lots of steam comes out of plug hole. that seems to me like unburnt fuel ? is it ? i'm really scratching my head on what to try next ?
Its very difficult to say without seeing it. Which model is the bike? Is it water cooled or air cooled? You could try using a seperate fuel tank to the carburettor to eliminate the fuel tap and see if that works, also is there a fuel filter which could be blocked?
@@motorcyclerevivaluk741 hi, thanks for replying, its a 1999 peugeot Elyseo 50cc air cooled, very basic. i have run the scooter with and without inline fuel filter but there is one in the petrol tank attached to the fuel tap and several times when i have removed this it has come de-attached from the fuel tap but to cure this i have made it more secure and i have tried two different ones as i have a spare . i was going to do that today but weather stopping me lol. how would i know if the fuel is contaminated, the brand new plug is black and very damp like there is always fuel in there trying to burn.when i take off the fuel feed from the tank it seems to run ok but only for a short period until fuel runs out in the carb. the problem was there before this but i have now blocked off the oil supply from the pump to the carb and have put the oil directly into the petrol tank as the pump was not feeding the carb properly. In your opinion is a possiblity that the cdi unit could be faulty, even though i have tried a new one but i sent it back yesterday as the scooter still has the same problem, how would i know if the stator is faulty ? To me it definitely feels like the problem is fuel related - or vacuum !!! but i don't understand why when i remove the plug it is black and wet.What exactly does the reed valve do ? Its strange when i manage to feather the throttle and manage to make it rev, it can seem ok for a long time but when i release the throttle it goes back to the problem. a real head scratcher now
@@ginoginogino1968 hmm ok, I think the next step will be a compression test on the engine, It sounds like the compression is low and unable to burn the fuel properly, it's pretty normal on these engines and will probably require a new cylinder and piston. An easy way to test is with the kick-start, if it has good resistance then you have compression but if it is too easy or if you can use your hand to move the kick-start then compression is likely to be too low
@@motorcyclerevivaluk741 i have changed the block and head twice just to eliminate this, compression is between 80 - 120. ive been riding these scooters for over 8 years and so have many spare parts. it doesn't make sense that i can make it rev up high but when it goes back to tickover it cuts out when trying to accelerate !! im hoping that the fuel tap has an intermittent weird problem and hope the new one which i will receive monday will cure it. do you think it could have something to do with the electrical side of it ?
is it possible there could be a hairline crack in the casing somewhere, i did run the scooter for over 3 years a 70cc head and piston, but have now gone back to 50cc as the oil pump problem affected the block and piston.
![No more vacuum fuel pump problems! GY6 Won’t start: FIX! [PROBLD PULSER UNIT]](/img/n.gif)
Great video! Learnt a lot from this especially the fuel pump being vacuum and where the pressure comes from on the manifold, going to replace the pump and check the manifold seal. My Bike would start run for 30 seconds go lumpy and die, I stripped the carb, cleared the jets, replaced the diaphragm, changed the air & fuel filter and still the problem persisted. I was in head scratch mode too. Gonna get onto this right away. Well done mate, very well explained, good tutorial.
@@nickstanford3552 Very kind thankyou, I hope you get it sorted 👍
You are a diamond geezer! Problem solved. Do more of this. You deserve an Oscar for your delivery, explanation and teaching skills! Absolutely brilliant.
@@nickstanford3552 Haha that's great news, really glad it helped, thanks for letting me know, it makes it worthwhile, all the best and enjoy the ride 👍
I'm glad I watched your video, I've just got a pump to put on my dax copy. I was going to have a small hole in the inlet manifold. After what you just showed me, I will be drilling it to 3.5 mm. Great video thanks. 👍😎
Eeeeexacly the same problem!!
Changed the intake manifold and when i revit it remains without fuel!
This aftermarket intake manifolds are the problem!
I was that stupid to throw away the old one to make the difference.
I was thinking about the same vacuum hose that is to small.
Thank you dear sir!
Thankyou for the comment 👍 Glad it helped
Iam on my knees before you. Had for so long same problem, new pump, new intake, new carb.. respect, thanks a lot!!!
Glad it helped you 👍
@@motorcyclerevivaluk741 finally, so good to drive without stalling:D
Great video and explanations! I recently fixed up a 350 Yamaha atv for my landlord which had the intake gasket problem. Unfortunately the previous owner had tried to fix it by cranking down the intake manifold bolts, which only bent one and stripped the other, and made the problem worse. It's an easy to look issue, so I'm glad you pointed it out! also +1 to the vacuum petcock issue.
Glad it helped, thanks for the comment 👍
Yes, SUPerb,Thanks ! and Cheers. Maybe the best, most informative repair vid I’ve ever seen. A very comfortable and accurate explaining style you have. Best.
Very kind, thankyou, I only just saw this comment so apologies for the late reply
superb explanation of the fuel system. Thanks
Just was head scratching today on a oo habanna came across this video and I think this might be my problem,thanks.
Hope it helps 👍
Subscribed! Thankyou! More like this.
Thanks for your video.
Superb help !!
I got the same problem my habana won’t go over 40mph ! Starts getting lumpy then won’t accelerate! Might be over heating or lack of fuel because of inlet manifold or pump 😢
Could be lots of things, did the bike work ok before?
Fantastic video, just what i neede to sort my issues on my 50cc Habana. Same problem. Thanks for making the video!
Glad it helped, cheers for the comment 👍
Good stuff mate I’m about to pick one up later to fix for a family friend 👌🏻
Good luck, looks like you know your stuff so I'm sure you'll be fine 👍
@@motorcyclerevivaluk741 cheers buddy I’m uploading a video now about it 👌🏻
great! thanks for sharing
Thank you very much , in the same position on my Aprilia Habana so hopefully once I check properly the problem all will be good again and back on the road here in sunny Ceredigion.
Where do you get your parts?
Trying to give my 2001 Retro some TLC and the intake manifold looks very brittle ... scooterparts says it's no longer being produced.
Along with a bunch of other parts I think I might need (still in the process of taking stuff apart and figuring it out)
PS: Thanks for posting this video. Nice to see other people tending to Habanas aka Mojitos.
Try these guys, always been good for me www.racing-planet.co.uk
Excellent video, just wondering if you know what the thin transparent (stained reddish by fuel i think) pipes connecting to the carb do, there are three of them 🤔
Does Aprilia Habana have the same carburetor like Vespa ET4 125?
Also do you know what are the adjustment for air adjuster/mixture screw?
Great videos thanks for sharing your thoughts and solutions I have been asked to work on an aprilia habana 125 that has no spark so I might need your help if I get stuck thanks again. 😀
No problem, happy to help
I have a similar problem with my Yamaha scooter. The vacuum pump is high up on the tank near the saddle area. So, with no petrol coming out of my almost new petrol vacuum pump I'm going to have to check out, and hope my solution will be the same as yours.
I missed this comment sorry, did you resolve the issue?
Hi I'm so confused, I have a little Habaina 50 2003. When I fill it with fuel and leave it for a few days when I come back the fuel is no longer full I look in the opening and it's all gone I'd have to refill again approx it would take about 1 liter to bring it back up to top and then it will start
That doesn't sound good, the fuel must be going somewhere. If you can't see anything leaking out to the floor then check your oil level to make sure it isn't finding its way into the engine and mixing with the oil. It definitely needs investigating
Hi, just seen your video. I have a Pierr 125 Custom
I’ve had it for 15 years
And now every time I open up the throttle, it cuts out completely
If I open the throttle gently a little It’s okay
I’ve just ordered the new spark plug. It might be that if not I’ll move onto the fuel system.
Any advice?
Thanks, Darren
@@DE-jk6rd I would start with the basics first, check the air filter isn't clogged, spark plug, valve clearances etc. It sounds like its not getting enough fuel if its dying when the throttle is opened or too much air which could be a split in the carburettor diaphragm or a bad inlet manifold not sealing properly. Could also be vacuum fuel pump as shown in the video. It's hard to say without seeing it but go through a process of elimination and I'm sure you'll find the problem 👍
At the end of the video alot if fuel came out into the pan ate you had. Did you say that is too much causing a problem or this is OK? I lost you on that part
No that fuel is exactly how it should be. It supplies the carburettor and the excess fuel will flow back into the petrol tank which you can see when you look into the pipe where you fill your bike with fuel. Hope it helps
Sir my scooter keep shutting off what could be the problem
Can you give more information? There are lots of possibilities
I love you
@@tm9853 very kind, love you too 😊
What about vacuum pump swap to electric? :)
It's possible, just need to mount a low pressure electric pump near the fuel tank and connect a good ignition power supply.
@@motorcyclerevivaluk741 Thanks. It will be my weekend mini project 😉
Thank you very much, it looks like i have the same problem
Hello sir, great video, I am having this precise problem. May I ask where you got the vacuum fuel pump part from please?
I’ve liked and subscribed to your channel mate keep doing what ur doing it helps a lot of people that’s why I do it as well 👌🏻
Cheers, I need to keep making videos but never seem to find the time. Subscribed to you too, all the best 👍
Done the same boys keep up the work
Hello brother. I love your vids. I have a question maybe you can help me with. Mine has a square mikuni pump. It just poors fuel when bike is not running just like a gravity fed petcock would do when it's turned on. Are the arrow sides supposed to hold vacuum? Cause mine just keeps pulling air through it when I apply vacume to it. Any help is appreciated. Thankyou.
Carbs check out with clean jets and clean all around. I tested the vacume port that goes to the intake on the bike. I used my vacuum/pressure gun and the guage slowly goes down. Is it supposed to hold vacuum exactly where I leave it without dropping on the Guage? The bike idles on and off choke but will not rev without dying.
You shoot here alot of great information, thanks alot. i'll write down everything, you seem to be well experienced and thanks alot for sharing :)
Thankyou 👍
Very interesting, I'm resurecting the same bike, didn't know what that green relay/ timer was for. good to know! Now if I can just find out why my dip/ main beam isn't getting power, I'll be right!
Electrics can be a minefield on some of these older bikes, good luck finding the problem 👍
You’re a good guy thanks
Like you I was searching the internet everywhere trying to resolve a similar starting issue on my bike and thanks to your video I was able to resolve my problem. Thanks a lot and appreciate your efforts creating this video!
Glad it helped you, thanks for the comment 👍
Brilliant!! Thanks. Lots to go through on a gilera.
Good luck 👍
Have a hyosung Aquila gv250 and a head scratcher as well. I'm goin thru the same issue. Im going to take the boot off and see if the vacume port is restricted. Do you know if they come from the factory restricted? Or do they get restricted over time??
It shouldn't be restricted from the factory, in my case it was an aftermarket part that had the restriction and caused my problem. If you're having similar symptoms to mine I would start with checking all your vacuum pipes for leaks or splits or loose fitting and then check the intake rubber boot to make sure it's sealing nicely around the carburettor and also good seal to the cylinder head. Hope it helps and let us know how you get on 👍
Okay yea I took boot off and doesn't seem restricted. Going to check hoses, o rings, and seals for vacume leaks and see what I find out on it. I noticed that the pump is pumping again. That's confusing me.
Thks 4 your video I have a Piaggio Zip 2T I think I have same problem whit my fuel vacuum I try to blow up the vacuum pipe no petrol not came out what you thing Thks
Have to suck the vacuum pipe to make the fuel tap work not blow
@@motorcyclerevivaluk741 Hi Thks very much to reply yes and no petrol came out I order or ready the vacuum thank you again
Hi, I have the same problem with cold starts. As you suggested I bought the green relay, I plugged it in and it still won’t start. Does anyone know what can be the problem. Thanks for your ideas
I just found this video as I'm having problems with my 1998 Aprilia Leonardo 150 scooter, there's very little fuel coming onto the filter. When you ride it in the normal flow of traffic it accelerates alright but as soon as you close and then reopen the throttle it bogs down and almost dies, and on occasions it does. What surprises me is the vacuum appears to be taken from the carburettor itself, a Mikuni BS 26, rather than the inlet side, it's just a rubber connector between the carb and head. I'm left with two possibilities, valve clearances which I did that not long ago, or a defective fuel pump which looks to be an absolute pig to get to as the tank sits under the frame rails so I'm not sure that I can get to the pump without taking the tank out?
Hi Graham, very hard to say without seeing it but lots to check. If the valve clearances are slightly too tight it could cause a lack of compression which could be it or you could try spraying some easy start or brake cleaner around the inlet manifold with the bike running to see if the revs rise which would indicate an air leak. Also the simple things like a dirty air filter or a worn out spark plug is worth checking. If all that is ok then maybe the carburettor mixture is too lean in which case and little 1/4 turn or so anticlockwise on the mixture screw might help smoothen it out. I would think that as it runs ok when out on the road that the fuel pump doesn't sound like the problem. It's a big list but hopefully it helps you out
@@motorcyclerevivaluk741 I rechecked the valve clearances and they were fine. I replaced the rotten hoses on the fuel pump in the tank and checked the pump diaphragm. I thought the rotten hoses were the problem as now much better fuel flow to the carb. But alas every time I give it wide open throttle for a few seconds once I shut off, slowing up coming up behind traffic or approaching a roundabout, as soon as I try and open the throttle again it dies.
Have you looked in the top of the carburettor to check the condition of the rubber diaphragm for splits and that its seated correctly? You can check the needle jet at the same time to make sure its ok. Also I believe your carb has a pump jet which should spray a small amount of fuel directly into the carburettor when opening the throttle, you should be able to see it spray if you can remove the air filter pipe and look straight into the carburettor whilst quickly opening and closing the throttle.
Is that a raleigh bmx bike ?
Well spotted, raleigh nightburner
does a vacuum fuel pump increase accelerating or horsepower of a motorcycle
Not in this case, it's there because the fuel tank is below the height of the carburettor and it needs the pump to keep the carburettor supplied with fuel
After seeing this video I know the issue of my Ducati Monster 900 (1995) with a similar vacuum pump. You are spot on with the head scratching :D The motor runs, it revs, when I drive it dies… how does this happen?! Now I know. Thank you for this video!!!!
Thanks Maurice, hopefully it will help or least point you in the right direction. Its always worth checking all your vacuum pipes for leaks first before changing the pump. Good luck 👍
I got a problem with my scooter , i practice wheelys but my carb bowl is empty after 500 meters , my tank is in the back so the carb is not able to get fuel while wheeling ,i think about to install a pump like this , my issue is that the hose that connects to the crankcase is really thin and already connected to the carb , idk for what purpose , do you think i can use the vacuum on the top of the carb that is connected to the inlet ?
What scooter do you have Olaf?
Hello nice video...
My scooter only starts when i spray some cleaner at the filter... after it, it starts whole day only after night wont start can you help?
Hi thankyou, it's really hard to say without seeing the scooter. I would start by checking the electric choke and making sure it's connected properly and working. It could be a weak battery or even a leaking carburettor. Lots of possibilities but without taking it apart I couldn't say for sure but I think the choke would be my first place to check, hope it helps
I have the same problem, i will try it tomorrow. Hope it solve the problem. But anyway thanks for the tips ☺
Good luck 👍
Im going to check the vacuum port size like you did cause my boot looks just like yours. I have the same pump as you. Do you know if it's supposed to pump at idle? It dies at throttle and only idles but no change in fuel height in the clear line I'm using temporarily.
It should pump at idle, maybe more so because there is more vacuum at idle. Did the bike work ok before or has it been off the road for a while?
@@motorcyclerevivaluk741 yes I believe it worked correctly before it sat.
@@shanemyers4142 ok, if it worked ok before i would probably look inside the carburettor to make sure all is well. A good clean up inside and blow out the jets and check any rubber diaphragms for splits
@@motorcyclerevivaluk741 I got to thinking. There is a brass colored washer around the main jet. Have you ever seen those fail before. I'm wondering if fuel is getting passed the washer maybe and it's flooding it. I've been looking on line to see if one has failed on someone before to see what the symptoms would be but havnt found anybody yet.
@@shanemyers4142 they don't normally fail but it's worth cleaning as much as possible inside the emulsion tube where the main jet goes into, there are tiny holes in that tube that should be clear. Also if you have the carbs open it's a good time to test the needle valves are allowing the fuel in and also stopping it when needed. Just blow into the fuel line and flip the carbs upside down and make sure the floats move and stop the flow of air. How was the condition of the rubber diaphragms in the top of the carbs?
Sir is it possible to change the handlebars to onother handlebars or put a raiser under it?
Honestly I don't know, it's not something I've done before on this type of scooter
Wow what a good catch on that little pipe being clogged or something. I wonder if it was accidentally made that way even though it is metal. Either way it's still pretty cool how you found that problem. That was definitely not the common problem these scootershave. (or I least hope it's not)
I have a very similar scooter/engine. I have a 2011 Foshan 150 Romeo. And lately I have been having problems keeping my bike running. After watching your video and while I have the carb off, I'm gonna check that manifold, under it, the O-ring, and see if anything looks bad. Thank you for showing and making that video. You seemed knowledgeable about that engine, carburetor and vacumm lines etc. I Truly appreciate you showing and making the video on TH-cam.
Michael Merchant II
You're welcome, hope it helps. I think the reason the pipe was made that way was for use with a vacuum fuel tap which I'm sure it will work with but it doesn't make enough volume of vacuum for a vacuum fuel pump
You always have to check a casting. Obviously the hole was not fully open because of a casting minor fault.
Thank you that mate, it's given me the clue to sort my problem. The air flow nipple from my carb to the vacuum pump had a tiny backed off hole about .3 mm dia. halfway in, and seemed blocked. I used a nozzle cleaner and voila, I could once again see petrol filling into the clear part of the in-line filter. 4 kicks in, and the engine is running like new again.
Sounds like you have found the problem, good luck with it 👍
Great news, glad you got it sorted 👍
Perfect I needed this video, I have the same issue with my gilera 125 st the fuel tank is located below the carb and im not able to get fuel up , I have replaced the pump and lines but its still the same , okay on small revs but no fuel at top speeds so I will check the manifold inlet hasn't got a restriction aswell 🙏👌
Sounds like the same problem, definitely worth checking that manifold both for a restriction in the vacuum line and also that the manifold is sealing properly to the head. Hope it works out for you 👍
@@motorcyclerevivaluk741 yes the vaulve on the manifold was restricted ! so I drilled it out and it is now working great with no issues 👌 thank you again for the video
@@liambrown2712 Great stuff, glad you got it sorted 👍
Good job nice info
Hi, i wonder if you could give me a little advice ? i have a 50cc 2 stroke with exactly this problem i've tried new plug , coil, carb, cdi unit, rectifier i don't know why i now have a funny feeling it could be the fuel tap is that a possibility ? . the bizzare thing is it ticks over lovely for as long as it wants but as soon as i accelerate it dies, if i play with throttle on the handle bars i can manage to get it to rev to the max but as soon as i let it idle it goes back to not accelerating and cuts out, also i have noticed that when i take plug out after trying to get it too run lots of steam comes out of plug hole. that seems to me like unburnt fuel ? is it ? i'm really scratching my head on what to try next ?
Its very difficult to say without seeing it. Which model is the bike? Is it water cooled or air cooled? You could try using a seperate fuel tank to the carburettor to eliminate the fuel tap and see if that works, also is there a fuel filter which could be blocked?
@@motorcyclerevivaluk741 hi, thanks for replying, its a 1999 peugeot Elyseo 50cc air cooled, very basic. i have run the scooter with and without inline fuel filter but there is one in the petrol tank attached to the fuel tap and several times when i have removed this it has come de-attached from the fuel tap but to cure this i have made it more secure and i have tried two different ones as i have a spare . i was going to do that today but weather stopping me lol. how would i know if the fuel is contaminated, the brand new plug is black and very damp like there is always fuel in there trying to burn.when i take off the fuel feed from the tank it seems to run ok but only for a short period until fuel runs out in the carb. the problem was there before this but i have now blocked off the oil supply from the pump to the carb and have put the oil directly into the petrol tank as the pump was not feeding the carb properly. In your opinion is a possiblity that the cdi unit could be faulty, even though i have tried a new one but i sent it back yesterday as the scooter still has the same problem, how would i know if the stator is faulty ? To me it definitely feels like the problem is fuel related - or vacuum !!! but i don't understand why when i remove the plug it is black and wet.What exactly does the reed valve do ? Its strange when i manage to feather the throttle and manage to make it rev, it can seem ok for a long time but when i release the throttle it goes back to the problem. a real head scratcher now
@@ginoginogino1968 hmm ok, I think the next step will be a compression test on the engine, It sounds like the compression is low and unable to burn the fuel properly, it's pretty normal on these engines and will probably require a new cylinder and piston. An easy way to test is with the kick-start, if it has good resistance then you have compression but if it is too easy or if you can use your hand to move the kick-start then compression is likely to be too low
@@motorcyclerevivaluk741 i have changed the block and head twice just to eliminate this, compression is between 80 - 120. ive been riding these scooters for over 8 years and so have many spare parts. it doesn't make sense that i can make it rev up high but when it goes back to tickover it cuts out when trying to accelerate !! im hoping that the fuel tap has an intermittent weird problem and hope the new one which i will receive monday will cure it. do you think it could have something to do with the electrical side of it ?
is it possible there could be a hairline crack in the casing somewhere, i did run the scooter for over 3 years a 70cc head and piston, but have now gone back to 50cc as the oil pump problem affected the block and piston.