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Gilera dna 50


Guest fredbike
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Hi people, im new here and have a huge problem, im just about to give up.


I have a gilera dna 50 that has troubles starting and when you do get it started it is constantly sputering at watever revs. I have bought new coil, ht.lead spark plug and cap, so unless the wiring loom is at fault the spark should be ok. my older brother has checked the fuel lines the carbs float chamber and air filter all perfect condition. He got it running the other day floorlessly for 20 mins by creating a vaccum in the fuel pipe (hes a genius ) and that was great till the next day rode it down the road half mile perfectly and then it splutted and died.


PLz any help would be much appreciated we are at a loss. thank you.

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Wrong section of the forum for a start fella.


How many miles is on it and how old is it?


How fresh is the fuel?

Have you cleaned your carb?

Cleaned Air filter?

Check your jets and make sure they are clean?

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Sorry weong section dont know how to move it, if i have to?


but yeah carb float chamber air filter jets are spotless.

fuel it about a month old in the tank.

and only done 2000 miles 05 plate


thank for replies.

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Hmmm, defiantly a strange one. Normally if you have done the above it should be ok. You can try draining the tank and put some cleaner through it.


When it splutters, does it just splutter as if it don’t want to go over a certain amount of revs??


What happens when your bike dies?? Rear wheel lock or?? Deos it start back up again straight away after?? Explain


Matty

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He got it running the other day floorlessly for 20 mins by creating a vaccum in the fuel pipe (hes a genius ) and that was great till the next day rode it down the road half mile perfectly and then it splutted and died.

 

You haven't explained the problem very well which makes it difficult for us to help you. I don't really understand what you mean by the above but my intial thought after reading it would be to try it with the fuel cap off and see how it runs then :?

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Sorry im not explaining very well it just hard to explain.


when the bike dies the rear wheel is not lockup it is still free to move, and when it splutters it spluters at all revs, as though the spark plug is struggling to spark well but i know it working fine as i have took it out and tested it.

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o yeah when i say vaccum i mean the fuel wasnt getting sucked through to the barral so my brother did it by sucking on the tube connected to the diafram.

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Right, well obviously it sounds like the fuels having a problem getting to the carb. First of all try the fuel cap off, if that doesn't work then I'd check the fuel cock (the bit where it comes out of the fuel tank)

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OK tryed without fuel cap same problems no change. Ill look at the fuel cock when i have some more time. But just a question ( im trying to learn mechanical stuff for my 125 next year ) Why would the bike behave differently with the fuel cap off?

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OK tryed without fuel cap same problems no change. Ill look at the fuel c*ck when i have some more time. But just a question ( im trying to learn mechanical stuff for my 125 next year ) Why would the bike behave differently with the fuel cap off?

 

They have an air hole in them, if its blocked the carb can't draw more petrol, obviously yours is fine, but its a quick easy check so it was worth a try. :D



Try the fuel cock next but make sure you've got no petrol in your tank

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ok i understand like putting your thumb on the end of a staw for of liquid the liquid cant move.


Yeah also will mention the fuel is definetly getting to the carb because when you take the fuel pipe of the carb fuel leaks out, so im gusseing its not the fuel cock either

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The thing is there is fuel coming out of the petrol tube connected to the carb beacuse i checked so at least to that point the fuels running fine.


Another idea my brother had was that i could be the timing as the splutter does not sound like a fuel shortage but like the spark if fireing at the wrong time,what do you think? cheers.

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you can find that out by taking plug out and turn engine over--when pison at top plug should spark


are all pipes done up and no kinks or nothing trapped ?

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ok i understand like putting your thumb on the end of a staw for of liquid the liquid cant move.

 

Exactly :D

 

The thing is there is fuel coming out of the petrol tube connected to the carb beacuse i checked so at least to that point the fuels running fine.

 

Yeah, i'd agree! :D


Maybe it is to do with the timing then, but I'm not too good at electrical stuff, but there again if its electrical it doesn't really make sense that when your brother made a vaccum it ran okay. Maybe you should try that again to make sure it wasn't a fluke, then you'll know if its a fuel problem or electrical problem.

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OK yeah did the vacum again it was just fluke, but what i have notied is that the is air buble that come through the carb up the petrol tube, and me brother said it might be the inlet manifold has a crack in the rubber so air would get in so ill check that as well as the timing thing (thanks for that).

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Timing can be checked (on most engines) by removing an inspection cap on the side of the cylinder head.


Behind the cap, you have a disk with a notch on the edge of it. You buy this special light gun thing, which you link up to the spark plug (somehow, never done it).


The light goes off everytime the spark fires. This acts as a strobe light. If the timing is correct, then the strobe should fire when the notch on the disk is in the exact same place everytime. This is a specific place, with a corresponding notch next to the disk. In low light, the notch appears to stay still. As engine revs increase, the notch appears to spread out.


It'll tell you how much it should spread by in your haynes manual.


If the engine won't start i guess just turn it over on the starter and make sure it's in the same place.

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