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Kenny O.
Kenny O., Motorcycle, ATV, Mules, Side by Side's Product Specialist. All Brands
Category: Motorcycle
Satisfied Customers: 953
Experience:  Worked for Kawasaki Motors as a Product Support Specialist (Factory Support) for 24 years
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I have a 2004 artic cat 50cc atv y6 put a new top end

Customer Question

i have a 2004 artic cat 50cc atv y6 put a new top end cylinder ,piston ,rings and gaskets have only 50 lbs compression and wont pull fuel into cylinder without hand choking or keeping carb partly closed with my hand,
Submitted: 6 months ago.
Category: Motorcycle
Expert:  Kenny O. replied 6 months ago.
HI Roger, my name is***** have a few questions before we get started.Top end was replace for what reason ?Was an oversized piston installed or just replaced with original size ?If original size was replaced, was the cylinder to piston clearance measured ?When it does start, how does it run?ThanksKenny
Customer: replied 6 months ago.
same problem low compression atv would start and you could take off and it would just get slower till it died put new cylinder and piston and rings but not sure what compression should be for this little two stroke but it will not run unless you force gas in cylinder by spraying or partially choking with hand and carb has been cleaned and float level checked
Customer: replied 6 months ago.
stock cylinder and piston
Customer: replied 6 months ago.
checked reeds and cleaned and closed position
Customer: replied 6 months ago.
i have worked on many atv but this one has me stumped ,i dont know if you are familiar with this particular atv but it also has a open port that looks like it should have something hooked to it on the intake side of carb ,dont know what purpose it serves but i know it shouldnt be open and i tried plugging it off
Customer: replied 6 months ago.
sorry for all the jabber but i also replaced crank seals
Expert:  Kenny O. replied 6 months ago.
OK, piston and cylinder clearance should have been checked, also the ring end gap of the new rings must always be checked, this will help you determine the wear on the cylinder if the cylinder is beyond service limit, and if for some reason its not enough then it needs to be opened up to insure that when the rings expand there is enough room for the growth.Just so we are on the same page, you know that there is direction on the piston, as I am typing you are adding more, as long as there are no grooves above the top of the exhaust port then you are OK, below since this is basically case inducted intake any thing below the transfers wont really matter.So if the clearance and the cross hatch in the cylinder is close it appears that this engine is not moving enough air, have ou tried checking the compression with the exhaust pipe off, have you puled the baffle and inspected for over abundance of carbon ?I would pull the pipe and then check compression and even try starting it with the pipe off (get you hearing protection)These are my initial thoughtsKenny
Customer: replied 6 months ago.
brand new cylinder and i checked ring gap in new cylinder arrow pointing dn toward exhaust and i did remove pipe and no change
Expert:  Kenny O. replied 6 months ago.
Suzuki has a similar engine configuration and as most of the manufactures don't really give you compression specs on this little engines, 50psi is low as I know the Kawasaki's and the Suzuki they are hard starting, those are usually up around 75psi.So we know that getting enough air (in this engine) below the piston and then if the transfer ports are clear (and the reeds are closing and not leaking back out) and you have a good ring seal, then what ever is on top of the piston is what you are going to have, just to test that theory, I would pull the carb and the pipe and check the compression and see if it comes up at all ? then if the same I would have to say something possibly;y something in the reeds, I know you say checked them, but that is main control and is responsible for the primary charge, if its not getting enough air pushed up and on top of that piston then there isn't enough air to compress ?Also make sure that the slide is all the way down ?Was this engine pressured and vacuum checked ?
Customer: replied 6 months ago.
i squirted oil in cylinder to raise compression and see if it helt but thats it i just know with that low compression it probably wouldnt pull fuel in either i wouldnt think
Customer: replied 6 months ago.
i will double ck slide tomarrow and reeds again and report back and do you know what might hook to the vacuum port on intake head side of carb
Expert:  Kenny O. replied 6 months ago.
To be honest on most of the "new" cylinders for the various manufactures they come with in my opinion to fine of a hone, I would always re-hone them to a 220 finish, it seems with a little courser finish the rings seated better and faster then verses a finer hone.Food for thought !Thanks RogerYes get back to me !Kenny
Customer: replied 6 months ago.
ok kenny will report back thx.
Expert:  Kenny O. replied 6 months ago.
OK, good

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