help

[jal123ddd]

hi all I am looking for some help here my sons py90 which is 4 stroke will not kick over ,checked the spark plug ,petrol , oil every thing seems fine I had it going once today with some effort and was running fine but just stoped and would not kick over agin any answers on this will be most welcome

[eastanglianbiker]

is the kick start working or when trying to move it it wont move ? if it is kicking over but wont start then check timing and compression both of which will cause it not to run if there not correct

[Tango]

and check valve clearances too......if they are too loose or too tight you'll have problems.....

[jal123ddd]

yer the kick start will move fine as it used to ,do not want to sound thick here but how do I check the timeing , valves ,and compression on it but I did for get to say that I adjusted the the other srew on the carb next to the idle screw which when I terned it it turned the revs up and down on the engine can this be the problem and as there got to be a run setting on it

[eastanglianbiker]

so it was running untill you urned screw on carb yes? when you turned that did it stop running and refused to restart or just not start next time you tried it?if it is the mixture screw you are talking about then screw it fully in and then 1 1/2 turns out that will be roughly correct and allow the bike to run if its going to as most are between 1 and 2 turns out as standard i am assuming you still have all the standard airbox and exhaust on the bike

[jal123ddd]

yes it was running well before I turned it and then it was having trouble starting but I do not have the original filter or exhaust on it but they are compatable to the py90

[eastanglianbiker]

have you check compression just to make sure its ok? turn mixture screw right in then out about 2 turns and see if it will start then

[jal123ddd]

tried the mixture screw 1 and half turns but still the same and I have now tried it two turns and still the same , but I have felt a diffance in the compression on the kick start as from before as there is not a lot of go in it ,it feels like it wants to go but will not

[eastanglianbiker]

when was the last time it had a new plug and have you checked the quality of the spark of the plug you have at the moment,you can check it by pushing the plug into the cap and then resting plug on engine and slowly kick bike over to see if its sparking

[jal123ddd]

did look at the spark plug but looked ok to me but I am no expert will try this tomorrow and let now of out come ,as I am up agin at 5 in morning to sunny Swindon for another day of work

[acting_strange]

If you believe it to be low on compression then you can try taking the plug out and squirting a couple of shots of oil down into the bore.....you then kick itt over a couple of times to circulate the oil onto the rings etc.....put the plug back in and try to start it....If it starts you have a clue as to the possible problem...if it continues to start then you have fixed the problem...

This used to be a problem with ford escorts and other vehicles..they used to "wash the bore" and lose comprsession...

[jal123ddd]

right ok done all you have said and it started twice but that was with the ckocke on and when I terned the ckocke off the bike just cut off and I did note that the kick start went all the way to the floor and I can push the kick start down with my hand with no effort can it be this , but sure the bike will not cut out if it is that can it

[acting_strange]

right ok done all you have said and it started twice but that was with the ckocke on and when I terned the ckocke off the bike just cut off and I did note that the kick start went all the way to the floor and I can push the kick start down with my hand with no effort can it be this , but sure the bike will not cut out if it is that can it

 

OK so how long did you run it for befoe you put the choke off?....was the bike warm?

Could you start it again after that, even with choke, without having to put oil in the bore?

[jal123ddd]

the bike ran for around 20 seconds or so and the bike started to go slugy and I put the trotle up and it just cut out and then would not start agin with or with out the choke it is doing my nut in now and it as not started from the other day

[rennie]

20 secs is probably not long enough before you turn choke off!

each bike is different but you usually have to turn the choke off gradually.

Sue's YBR takes about 5 mins to warm up from cold and won't go if you touch

the throttle. Most bikes will bog down/stall if you go straight to lots of throttle.

[Tiggie]

Very true. Lost count how many times my bike has cut out at the first set of lights because I was too eager to kill the choke!

[jal123ddd]

no the engine was not all that warm ether and I put a little in the bore can it be the timeing at all

[eastanglianbiker]

if the timing has never been messed with it should be ok unless its got the old type points fitted to it and not electronic

[jal123ddd]

tried agin today still want start do not now what it can be

[jal123ddd]

it the type that are on top and bottom of the head with the screw caps on them

[eastanglianbiker]

no points ign will be a set of breaker points behind the flywheel on the left had side of the engine i would of thought, when you look in the slots in the magento you wil see a set of points or an electronice pick up depending on which type it has if its points then it will have one set that will need a gap setting on them or if they have burnt out will need replacing

they will look like this http://www.ebay.co.uk/itm/YAMAHA-YA-7-A ... 714wt_1083

[jal123ddd]

hi to all that answerd my question thanks to all but all it needed was a new plug and the fuel screw adjusted thanks to all agin ,but I have a new question now which I have started thanks agin