as above i just got a new piston and it seems stupidly tight all the sizes are the same and its the same piston ,also 1 ring was thicker than the other the thicker ring would only fit the bottom i have put the piston in the cylinder in the hope that it sat in there for a few hours will aid re fitting it
Make sure that the piston has been installed correctly. The arrow should be pointing towards the exhaust port. Since the piston is not actually circular it's more of an oval shape.
had this when i rebuilt my cr, piston ring end gap may need adjusting if its too small, take the rings off and see if the piston slides in the barrel nicely, if it does then its the rings that are the problem
the 1st groove in the piston was way to tight and the ring wouuldnt go in so i put the other one in there and that was to lose so i swapped them over and they seem to be the right way but that would contradict what calum said?
id think it would be the thicker ring on top for compression and the lower ring to control the oil on cylinder walls? could be wrong though, when i did mine they only fitted properly one way
Bottomnring is thinner one with expander ring, top is thicker ring. Otherwise you have fitted incorrectly. As advised by a motocycle engineering company that also builds and races engines.
1 of the most important installaton parts on a 2 stroke is to check the ring end gap
ALL IN THE HAYNES MANUAL
ALL EXPLAINED IN THE MANUAL
INSTALLATION TIPS AND HINTS ALL IN THE MANUAL
have you read the manual cover to cover b4 , dont mean to sound like a dick but this is where every 1 goes wrong they dig in and crack on thinking they no , but in the long run end up causing more dmage than good
all the piston to bore clerances are in the manual to check, just coz a company does the work u should always double check it, iv had a rebore done b4 by a big compny and got it back and checked it and it was incorrect so they got it sent back to redo...
if u put a piston in thts to tight it will lock up as soon as it starts its thermal expansion cycle...and cost u another top end, so a simple 2 second check can save you 200 quid
the rings are a different cros sectional shape both
on every forum theres loads of same people, no offence ment to them but , wen ever u buy some thing u get an instruction manual, no **** reads em thinkin there hard then fry there heads then end up hiding in toilet reading it like its a sin,
all manuals are there for a reason use them
every single thing is in them maybe sumtimes not best explaned like but its there
if ur the kind of person who wants to ride and park up a bike dont buy a 2 stroke....
these are not just simple bikes there complex machines and to work on them u have to work on them right, simpleist little lazy arse bodge can lead to hours/weeks of stress and unhappyness mostlikely ending up with the owner selling the bike
if u want to work on any bike/car u need to do ur homework,
if i get a new bike/toy or what ever before even riding it using it iread as much/watch as much info as possible, manual is in my **** house/car /van, u can never learn to much about any thing
other books are good to read like "basics of a 2 t motor" carburation,exhausts,these things need to have a number of specifics that all need to be extreamly in sinc to run correctly
as soon as a bike leaves a factory its messed with,touched, not 1 bike will ever be set up the same any where, (Bar race team)
u need to get to no your bike inside out
once u do maintenance changes over nite, it becomes part of you
noises/vibrations.......
but it all depends on the person, if there lazy there lazy, intrested or not
its ur wallet at the end of the day
i try to do things right once,may take a little longer but piece of mind is a great feelin
