xmoto 125 cc help

[sidewinder]

first off , what a great site this is , ive had some great instructions of removing the head and all sorts of stuff ok now to the niti gritty,
ok my bike was blowing alot of smoke , problem sovled got a new piston and rings happy days no more smoke and runs , always first kick , the problem i have is when i throttle on my bike isnt giving me the power , like its taking to much fuel(like riding with the choke on) it is not back fireing and and when had the head off i cleaned the vaulves and seats , now im not sure if its the carbie (which i havnt touched) or the timing maby its out a link , if so what would the bike be doing if the timing was out if this is the problem , i dont realy know how to describe it but some imput would be chocie

 

[china boy788]

when you changed ur piston, did you get a new barrel or hone the old one??

 

[sidewinder]

xmoto 125cc

no the barrel was fine no scores in it , just abit glased , i had alot of oils itin on the piston in the begining and was told by a local shop it was fine , so i went tto another and he said it was stuffed , so change out piston and now i got no power it still runns and changin gears up it still gos but lack of power , some times it stalls and thats not usual

 

[headsmess]

um...honing the cylinder is absolutely essential when installing the new rings...

its the "cross hatch" marks you would have seen in the bottom 30mm of the cylinder when you were looking at it... a bike shop shouldnt charge more than $5 for doing a simple hone...it takes all of 1 minute...

and once youve installed new rings without honing....you prtty well much need new rings again...

anyway... mstalling...did you make sure it was the correct piston for the engine? 52.4, 52.5. 55, 56, 60...etc etc etc? though, it wouldnt have fitted, or would be blowing a ton of smoke if it was the wrong size, so ok...

you may have the timing wrong.... flywheel with the T mark at 12oclock, cam sprocket with the lil dot at 9oclock.... if you cant see the dot...you put the sprocket on the wrong way round (will they fit on backwards? ive never tried....i might go check this out as soon as i log off)

other wise... you cleaned the valve n seats...how, exactly? they ideally should be reground to ensure perfect sealing... even a minor scratch can cause bad running...

how was the compression before and after? low compression means bad sealing...means low performance...

or...you may not have tightened the head nuts enough... and theres a leak there...can usually be heard though...and always best to change the head gasket anyway...

last point...new rings, honed cylinder.... break in!!!!! full throttle, high gears, max load. without over revving or sitting at one engine speed for too long...

hope it helps...

 

[headsmess]

you can put the cam sprocket on back to front holes line up....

ok, its only a few minutes to make sure the timing is set right...again...T mark on flywheel at 12oclock, dot on cam sprocket at 9oclock there should be marks on the case/head for a guide...

 

[sidewinder]

ok , didnt relise about the honing the cylinder, dos any one have any pics, of thiss x hatching and what it should look like ? and yes i did replace all gaskets including the head , the cams in the right way , to clean the valves i use a nylon brush you put in a drill and smicked if up with the valve in and then removed the valve and cleaned the back side of it , i did replace the valve stem seal as well ,

 

[sidewinder]

x moto

are there any chances , the cdi unit or coil could be stuffed , and if so how do i test these components?

 

[headsmess]

other than using new ones or ones that you know are good...


um, if i had a decent camera i could take a pic of the honing...

Google Image Result for http://www.detomaso.nu/~thomast/rebuild-2002/bore-honing-l.jpeg
gotta love google gotta hate pics that wont load directly

im gunna go with the lack of honing to be the problem...you said the bores glazed? that means the rings arent sealing...loss of power...

you could get away with just honing (ring a shop n see what theyll charge) and the same rings...if youre lucky

 

[sidewinder]

xmoto 125cc

turned out to be the timing had been put out bout an inch ) put back runs like new and power , hard to keep the nose down with the big pirreli tyre on the back thanks for your advise im sure i will be needing it soon