372xp scored piston and cylinder

[mkinslow]

Alright gentleman and ladies if your present. New member here with a question. Got a used 372xp for a good deal about a week ago. Been trying to start it but no luck. Did the usual trouble shooting got fuel got spark and it's in ti. Rebuilt carb also and its adjustment is close enough it should start. But want lol. Noticed screen was missing on muffler so decided to pull it and make sure one of those dang little dirt dobbers hadn't built a nest. Took a look inside at cylinder and guess what. Scored piston cylinder isn't tobad . Just need an opinion on getting a new piston and rings and honing cylinder or what you guy's think. Thanks for your time.

 

[mkinslow]

 

[Adirondackstihl]

New piston and ring.
Clean the cylinder up.

 

[mkinslow]

I thought about that but I've also seen whereI can go to 52mm kit for around 80$and under. Its probably gonna be mostly something to play around with cuz I've got a 346xp and a ms170 that does most of my work. Just can't make up my mind stock or heat it up a little

 

[MGoBlue]

My vote... stay oem cyl. Break out the

 

[Chainsaw Jim]

What Adirondack said....That cylinder has very little use on it. All the factory hash marks are still visible. A little muriatic acid on a q-tip will eat the aluminum off the bad spot. It looks like there may be no scoring at all on the cylinder.
If this was a cheaper beater saw then go aftermarket on a piston. But it isn't, so spend the $85 on oem.

 

[mkinslow]

I may stay oem for now. I read they have plenty of power stock with certain mods andall. my 346xp rips so this one has got to be a hoss

 

[mkinslow]

Do y'all use cylinder hones or something more accurate to clean up the cylinder. I've used the hones on bigger engines but not on a saw engine

 

[Poleman]

Stay away frome hones....use sandpaper and a mandrel on a drill and by hand also works...just takes a little longer.
Make sure you get any and all of the transfer off.

 

[Full Chisel]

Stay with OEM for sure...look up Mastermind's method for removing transfer.

 

[mkinslow]

Ok ill stay away from hones I figured they would be quite aggressive on these cylinders anyway. Ill do the sandpaper mandrel more than likely. I just keep thinking on the 52mm kits

 

[Adirondackstihl]

Your 50mm OEM is 99.9% likely to make more power than the big bore garbage. Keep it OEM.

 

[Whiskers]

Don't forget to figure out what caused the failure otherwise you'll be doing it all over again. By the looks of things it could be the recoil side seal leaking.

 

[Adirondackstihl]

Here ya go....

http://www.arboristsite.com/community/threads/how-to-remove-aluminum-transfer-without-acid.248325/

 

[Adirondackstihl]

Don't forget to figure out what caused the failure otherwise you'll be doing it all over again. By the looks of things it could be the recoil side seal leaking.

Or decomp

 

[Blade]

I thought about that but I've also seen whereI can go to 52mm kit for around 80$and under. Its probably gonna be mostly something to play around with cuz I've got a 346xp and a ms170 that does most of my work. Just can't make up my mind stock or heat it up a little

If you are going down the 52mm big bore option, just a few hints on what to avoid.

A few customers have brought in these Chinese aftermarket kits, with quality ranging from average to very poor. Piston rings were complete rubbish, many of the cylinders had off-set or out of shape inlet or exhaust ports. Also many of the threaded holes for the AV mount spring and decompression valve are extremely poorly cut, and once again quite often off centre.

If a customer wants to go down the 52mm big bore pathway, I'd strongly suggest purchasing the Italian manufactured kit. I find these to be of very similar quality to OEM piston & cylinder kits.

 

[jmssaws]

Sand the transfer off, it's almost impossible to sand through the plating. The oem will make considerably more power than a aftermarket one all u need is a 40$ meteor.

 

[mkinslow]

Alright sounds like I will be staying with oem and checking the recoil side seal. Thanks for everyone who has helped with your knowledge and opinions. What's the easiest way to check those seal out. O and I want be going away anytime soon I love this site and working on these saws like I learned from my grandpa. Ill keep everyone posted threw out the process just be patient with me on time

 

[Whiskers]

I'd check the whole saw for leaks, pressure and vac test.

 

[mkinslow]

Alright