Andrew43 Posted June 6, 2012 Share Posted June 6, 2012 Hi, my boy has a YQ50 Aerox and had to have it brought back home on saturday on the back of the lorry. It was running fine, it has got a 70cc mollossi kit on it and all the rest of the things to make it go fast but i can not get it to start. I have a good spark, i have fuel getting to the carb, but the spark plug does not seem to get socked after kicking over! With further investigation i took the air filter off and it feels to me that it is blowing instead of sucking which lead me to the reeds...1 side was not seating and i cannot get it to seat...is it possible the block has deformed? anyway found another block which looked fine but still cant get it to fire.....any idea's? Thanks Andrew PS the bike is a 2005 model with water cooling Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 Andrew, first things first i must say that i'm not familiar with the scoot..,.but is there plenty of fuel in the tank i assume the fuel supply is vacuum operated?...if so check the vac line from the inlet manifold to the fuel supply tap, see it hasnt come adrift, split, kinked etc etc Link to comment Share on other sites More sharing options...
Andrew43 Posted June 6, 2012 Author Share Posted June 6, 2012 No no pipes split that i can see and yes full tank of fuel, i have had the carb off and cleaned and there is a new plug in it. Fuel is getting to carb chamber just not getting to piston! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 ahh there may be a problem there if you've had the carb off! am i right in thinking the fuel supply is vac operated? Link to comment Share on other sites More sharing options...
Andrew43 Posted June 6, 2012 Author Share Posted June 6, 2012 Yes vac operated....but the system has been completly drained and it has filled up by its own means Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 i dont get that, is there a prime facility on the tap? Link to comment Share on other sites More sharing options...
Andrew43 Posted June 6, 2012 Author Share Posted June 6, 2012 no nor do i!!!! What is making me think is the fact that if i pull the air filter off and put my hand over the end it feels like it is blowing not sucking Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 how do you know that fuel is in the carb, it isnt supposed to get there without the engine running (ON A VAC SYSTEM) and you had the carb apart so it's empty of fuel isnt it? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 so it will either need priming by whatever means was given by yamaha or you will need to take off the vac line from the manifold and suck on it to open the fuel supply and fill the carb Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 andrew i'm on my lunchbreak, cant wait long for replies! Link to comment Share on other sites More sharing options...
Andrew43 Posted June 6, 2012 Author Share Posted June 6, 2012 at the bottom of the carb there is a drain pipe and if it is pushed it allows fuel to pour out so fuel must be in chamber of carb Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 at the bottom of the carb there is a drain pipe and if it is pushed it allows fuel to pour out so fuel must be in chamber of carb sorry dont understand that, pour out of what? Link to comment Share on other sites More sharing options...
Andrew43 Posted June 6, 2012 Author Share Posted June 6, 2012 the priming of the carb came in the means of me kicking it over and turning over on electric start Link to comment Share on other sites More sharing options...
Andrew43 Posted June 6, 2012 Author Share Posted June 6, 2012 the chamber at the bottom of the carb has a pipe connected to it that is a drain...pushing it in allows the fuel to drain..so therefore there has to be fuel in carb Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 6, 2012 Moderator Share Posted June 6, 2012 ok then my last shot is suirt around 3cc of petrol directly into the spark plug hole snd try with that, the reed is an issue though, there will be a bend tolerance, off now Link to comment Share on other sites More sharing options...
Ryan09 Posted June 10, 2012 Share Posted June 10, 2012 Try the fuel directly into the cyclinder, it should start for a couple of seconds. At least you know the cylinder side of things is fine if it starts. My sister has a Gilera Dna and had a similar problem to this. I ended up completely stripping it and it turned out the vaccum hose had slightly melted on the exhaust so the fuel wasnt being sucked through properly. The fuel line had fuel in it going to the carb but because there wasnt enough of a vaccum there wasnt enough being drawn through to run the bike. Link to comment Share on other sites More sharing options...
Andrew43 Posted June 15, 2012 Author Share Posted June 15, 2012 Hi, Had a new piston kit fitted it was the rings melted to the piston and lost compression. Now done that and bike ticks over fine but when riding at 20mph+ it starts to hunt bad if u try to keep it to a constant speed. It will accelerate to good speed but continues to hunt. Any idea's anyone? Thanks Andrew Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 15, 2012 Moderator Share Posted June 15, 2012 could it be fuel starvation...indeed could that have caused the original piston damage? check the fuel supply flow to the carb and if good then perhaps a carb strip inspection and clean Link to comment Share on other sites More sharing options...
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