346xp Scored Piston

[Mtnyota]

Yes I bought a mityvac for the vac test. I'll recheck to see if and thing loosened up and caused a leak. I had the cylinder pretty slick out but I guess it could be.

What is the consensus on the kafar p/c kits off eBay. Once I figure out the cause for sure.

 

[lone wolf]

Yes I bought a mityvac for the vac test. I'll recheck to see if and thing loosened up and caused a leak. I had the cylinder pretty slick out but I guess it could be.

What is the consensus on the kafar p/c kits off eBay. Once I figure out the cause for sure.

Prob China crap I hate doing things twice and wasting money!

What model Mitivac 8500?

 

[rob066]

That saw is likely too new to have a major air leak, so you're probably right. My old one has never had one, except where the carb bolts to the intake boot flange, an easy fix. You should be good to go after getting it together and re-tune.

I have a 385xp that wasnt running right. It was fairly new. The compression release was leaking. Im glad I have the knowledge in saws to reconize it wasnt running right before it became a burn up victim. It now has a plug in it.

 

[Mtnyota]

It's a mityvac mv8000.
The spark plug is a NGK BPMR7A

 

[Mtnyota]

Update: Did a vacuum test tonight and the vacuum dropped from 12 inHg to 3.5 inHg in 5 min. I don't have a air compressor at home, but using a foot pump I was able to find that the decompression valve was leaking.
It seemed to be a pretty small leak, so I'm gonna take it to work tomorrow and hook it up to the compressor with regulator set at 7psi to see if i can find any other leaks.

Rob066 where did you get a plug for the valve?

Thanks for all the help guys.

 

[A.E. Metal Werx]

Most stihl dealers carry the plugs, I've always got lucky that my husqvarna dealer had them on hand. Lots of people don't want to spend the $$ to replace a part they never use. That's why many dealers will stock the plugs.

 

[SawTroll]

Most stihl dealers carry the plugs, I've always got lucky that my husqvarna dealer had them on hand. Lots of people don't want to spend the $$ to replace a part they never use. That's why many dealers will stock the plugs.

Yep, those plugs are easy to get, and most of them are the same, basically. Most IPLs for saws with decomp valves list them, as an alternative.

 

[lone wolf]

Update: Did a vacuum test tonight and the vacuum dropped from 12 inHg to 3.5 inHg in 5 min. I don't have a air compressor at home, but using a foot pump I was able to find that the decompression valve was leaking.
It seemed to be a pretty small leak, so I'm gonna take it to work tomorrow and hook it up to the compressor with regulator set at 7psi to see if i can find any other leaks.

Rob066 where did you get a plug for the valve?

Thanks for all the help guys.

Wait a minute wouldn't that be a pressure test? Any way just rip the whole thing down and put new crank seals and all the gaskets then DO A VAC/ PRESSURE test and I mean both!

 

[Mtnyota]

I did do both. I saw the vac test leaking down so I did a pressure test to try and find the leak

 

[lone wolf]

I did do both. I saw the vac test leaking down so I did a pressure test to try and find the leak

Vac test leaking indicates bad crank seals to prove it put a gob of grease on them and it will seal this is not a fix replace them. You cant find bad crank seals with pressure test normally because the pressure pushes the inner lips out and make them tighter where as the vac test will pull them in and if bad they will fail. Sounds like you need seals.

 

[Mtnyota]

Thanks for the tip on the greasing the crank seals. I greased them and the vacuum held. After finding this I tore down the saw the rest of the way. The damage isn't as bad as last time. There is a 3/8" wide area were the scoring is bad. I think it should clean up agian.

View attachment 253395

View attachment 253396

So now I need to order a metor piston kit, oem cir clips, base gasket, crankshaft seals, and decompression valve plug. I was looking on baileys and they list (2) part numbers for the 44mm piston. MPA PC2095 and MPA PC2095B. Does anyone know what the difference is?

 

[GBD]

I think I lucked out. The cylinder in my newbie opinion looks like it should be fine. Ive still have some transfered alum to removed, but I think it should be good. I plan on getting the meteor piston kit and putting it back together. Is there anything else I should order/replace while I'm in there? I ordered a tach and I'm thinking about an unlimited coil.

Remember to clean out all the debris from the exhaust channel and muffler, otherwise it may be sucked back in scoring your new piston.
BTW: Is this really an OEM cylinder?

 

[Mtnyota]

Will do. Yup it's a mahle cylinder.

 

[nmurph]

Here's your next piston-

Replacement Piston for Husqvarna 346XP

This piston comes with Caber rings and circlips that don't need to be replaced with OEM.

Seals

Replacement oil seal for Husqvarna / Jonsered

Replacement oil seal for Husqvarna models 353, 346XP, 570, 575XP and Jonsered 2149, CS2152, CS2153, 2073, 2083.


Decomp

Replacement compression realease valve

(or PM you address and I will send you a decomp) I didn't have but a second to seach, but I was thinking Sal had a decomp plug...call him, he will help you.

Order today and you will have it bf the end of the week.

Omit the base gasket- you can nearly always get away with this on 346s's though they sometimes require a drink can gasket to give you enough squish.

 

[lone wolf]

Thanks for the tip on the greasing the crank seals. I greased them and the vacuum held. After finding this I tore down the saw the rest of the way. The damage isn't as bad as last time. There is a 3/8" wide area were the scoring is bad. I think it should clean up agian.

View attachment 253395

View attachment 253396

So now I need to order a metor piston kit, oem cir clips, base gasket, crankshaft seals, and decompression valve plug. I was looking on baileys and they list (2) part numbers for the 44mm piston. MPA PC2095 and MPA PC2095B. Does anyone know what the difference is?

Ask Baileys.

 

[4492011]

Thanks for the tip on the greasing the crank seals. I greased them and the vacuum held. After finding this I tore down the saw the rest of the way. The damage isn't as bad as last time. There is a 3/8" wide area were the scoring is bad. I think it should clean up agian.

View attachment 253395

View attachment 253396

So now I need to order a metor piston kit, oem cir clips, base gasket, crankshaft seals, and decompression valve plug. I was looking on baileys and they list (2) part numbers for the 44mm piston. MPA PC2095 and MPA PC2095B. Does anyone know what the difference is?

It looks like they have some different sizes link Piston Kits for Chainsaw Mod.346XP new

 

[lone wolf]

It looks like they have some different sizes link Piston Kits for Chainsaw Mod.346XP new

I don't understand that. You mean the oversizes that are smaller than the stock size WTF?

 

[4492011]

Yea I thought that was kinda weard too they are listed as oversize but the measurements they give are undersize.

 

[SawTroll]

Yea I thought that was kinda weard too they are listed as oversize but the measurements they give are undersize.

To me, it makes sense that the piston diameter is a little smaller than the bore, that's why they have rings.

 

[Mtnyota]

How do you know when you have all the transferred al off?