Adly GTA50 Won't start when warm By mungus (Read 2,443 times)

[mungus]

Hi all, I wonder if anyone can help me? We have an Adly GTA50, 49cc 2 stroke. It has approximately 12000kms on it and has served us well. However recently it displayed a problem that has me stumped. When it is cold it starts and runs great, however once it is turned off it simply will not start again until it has cooled down and sat for a while and it starts and runs great again. 

I have cleaned every orifice in the carb including the starter and pilot jets a few times and replaced fuel lines and the fuel filter. There is plenty of spark and the plug isn't wet when it won't start. Today when I was playing with it I discovered that it will start when it is warm if I plug the air inlet on the air filter, basically flood it then unplug the air inlet again and turn it over for a while it will start again. I'm thinking that maybe there is a vacuum leak somewhere but can't find or think of anywhere that it might be. 

Any suggestions? Thanks for reading. 

[trashtruck12172]

have the valves been adjusted? sounds like there may be an air leak somewhere.

[cyborg]

One of the reeds may have a crack,,,,

[kz1000st]

Check the compression. Two strokes lose compression when hot. 7,200 miles isn't a lot but sometimes a ring cracks or the rings will wear out.

[mungus]

Thanks for the ideas guys. Will check over the next week or so and report back.

[mungus]

Reed valves are perfect, trying to get me hands on a compression tester now

[cyborg]

Could be crank seals went bad

[markymar61]

i have a ice bear trike PST50-12 im having trouble starting it, when its cool in the mornings it will start great, but when its hot and muggy it wont start. I have replaced all the fuel and vacuum lines don't know what else to do, it has 10,000 on it now once I do get it started it will start okay until it sets for 8 hours at work and takes maybe 20 - 30 mins to get it started if it starts at all any ideas. you can reach me at [e-mail] also thanx

[cyborg]

It's probably the valves,,, they need adjusting they are too tight

[crwford]

On the Ice Bear trike check the rubber intake make sure its clamps is tight and no cracks in it first before tearing hair out of you head.

[czmdiver]

Jul 17, 2017 13:50:05 GMT -6 cyborg said:

It's probably the valves,,, they need adjusting they are too tight

Its a Two Smoker.

[mungus]

Just an update. Replaced Crank Seals, they seemed Ok, but replaced them anyway since everything was apart. Won't start at all now. Spark is still good and fuel seems to be getting through to the cylinder Ok. Will probably go one step further and replace piston and rings.

At a bit of a loss at the moment, and pretty frustrated. Thanks for the ideas so far.

[cyborg]

Let us have an update when you can

[mungus]

For those playing at home kz1000st was very close. It was a cracked piston. Thanks to everyone who contributed to this thread for your help.

[czmdiver]

I can't see the crack since you took a picture on the Pin Sides of the Piston, or is that the crack from the bottom ring to the top of the Pin Bore?  I wish I had that in my hands to measure and lok at 
Ya when Clapped out they will rattle (slap) till they crack then bust the Skirt right off the Piston, Piston to Cylinder Clearance is Excessive when they rattle(slap) and way out of spec by the time they Crack a Skirt.