372 xp help

[Klayton]

i got a 372 xp from my dad but the piston had broke in the cylinder. none of the piston had gone into the crank case so all i did was ordered a new piston and cylinder for the saw. i got the piston and cylinder from some guy on ebay. "the little red barn" is what the ebay shop was called. it was about 90 dollars shipping and everything. the saw ran like a champ for about one hour of work then i heard the piston start to come unravelled again. (ting ,ting,ting,) and i shut the saw off oppend up the top end and again the top of the exhaust side of the piston had broke off again. it looks like the rings are catching the bottom of the exhaust port and warpping the top of the piston. any help would be appreciated as to what to do now.
thanks , Klayton

 

[pioneerguy600]

Sounds like you bought an aftermarket piston and cylinder set. I would contact the seller and tell him what happened. If it is catching in the port that is a defect in my books.

 

[Klayton]

it is installed correctly

i have rebuilt about 6 dirt bike motors. never a chainsaw. but most dirt bike engines have the arrow also. SIDE NOTE: there was no oil sitting in the crank case. in dirt bikes there will be about an 1/8 of an inch to 3/16 raw oil sitting in crank case. dirt bikes have reeds and chainsaws don't so i know that there are some differnces but i thought i would see some oil. this saw was previously my dads and he did have someone work on it one time and i wonder now if they adjusted the carb. how do you adjust the carb to make sure it is not running to lean?

 

[pioneerguy600]

Insert a small slot screwdriver in the H adjuster screw and turn it in til it lightly bottoms out , keep track of exactly how many turns or part turns it does, then let us know what you found. Do this on both H and L screws.

 

[Klayton]

high and low adjust

i checked that out and it only has like a 2/3 turn worth of total adjustment. and it was about half way on that

 

[Klayton]

still need help

well i am having trouble figuring out if the piston kit was bad or if my dad had it tuned to lean or if the crank is bad. i dont think the crank is bad because it had no vertical slop that i can identify so...........???? i dont want to just buy another kit and hope it works. but i really love the way this saw runs

 

[blsnelling]

If the ring snagged, it's more than likely a defective kit. This is not all that uncommon with aftermarket kits. Buy a good used cylinder on Ebay and a new Meteor piston from one of our sponsors.

 

[half_full]

Anyone else thinking crank bearings? Pull the seals and check them. I got a parts saw that felt great but when I split the cases I was amazed to see the cage completely gone and the bearings bunched together. The crank seals can hide alot of play.

 

[SawTroll]

i checked that out and it only has like a 2/3 turn worth of total adjustment. and it was about half way on that

Sounds like you have limiters on the adjustment screws - you have to remove those to get a correct "reading".

 

[mdavlee]

It may be a combination of too lean and the port shape on the 2nd kit. Pull the limiters and figure out where the carb was set. You may be able to re use the original cylinder if there's not and deep scratches in the cylinder and save some money and keep a better cylinder.

 

[Klayton]

cylinder is shot

yeah the cylinder is shot i am sure of that. i am pulling up and down on crank arm and i can not feel any play in the bearings. i do not have the tools to split the case. is there any other way to check the crank bearings? by the way thanks for all the help guys