Building a 290/390

[MustangMike]

Jeremy, congrats on the new job, that is great news!

I'm confused, do you have to pull the rear bar stud to replace the jug?

Also, are you using an OEM jug? I don't see any used ones on ebay!

 

[Adirondackstihl]

Jeremy, congrats on the new job, that is great news!

I'm confused, do you have to pull the rear bar stud to replace the jug?

Also, are you using an OEM jug? I don't see any used ones on ebay!

The rear bar stud goes through the chassis and is threaded into the block.
Yes, I'll be using a new OEM top end.

 

[fearofpavement]

The rear stud holds the pan in, it is possible to replace the cylinder without removing the pan but I never do because these can be challenging to get sealed up without having the complete engine out to clean up and get assembled properly. (I build the engine out of the saw, pressure test it the next day and then install the sealed up engine.)
I'm not sure why people are replacing the studs w/new. Even if you take it out with a Channellock, it can be gripped in an area that marring it up doesn't matter. (space on the stud that's taken up with the bar thickness). Most of the time I remove them by double nutting and always install them that way.

 

[Adirondackstihl]

The rear stud holds the pan in, it is possible to replace the cylinder without removing the pan but I never do because these can be challenging to get sealed up without having the complete engine out to clean up and get assembled properly. (I build the engine out of the saw, pressure test it the next day and then install the sealed up engine.)
I'm not sure why people are replacing the studs w/new. Even if you take it out with a Channellock, it can be gripped in an area that marring it up doesn't matter. (space on the stud that's taken up with the bar thickness). Most of the time I remove them by double nutting and always install them that way.

You're a better man than me if you can remove that stud with Channel Locks and not *f-word it up

 

[jmssaws]

I love these saws,I wish I had a building full. They sell like crazy,cheap and quite good really. I don't modify them just sell them. Kool thread

 

[MustangMike]

I think I like the double nut idea, thanks.

I requested a cylinder quote from Mark.

 

[Mark71gtx]

Double nutting works best for me. I have sealed them both outside of the housing and inside the housing. Either way can be challenging. It is challenging to seal it properly with the pan still in the housing, but it can be really annoying trying to get the sealed unit back into the housing as a unit as well. I am always paranoid that I am going to break the seal twisting the assembly back into the hole. They really could have designed these better...

 

[Adirondackstihl]

Double nut works........most of the time.

 

[Chainsaw Jim]

I promise you doubling nuts will not work on the ones that are glued as tight as they can get. You'll destroy the threads.
I've had them bastards need vise grips all the way until the very last turn. And when that happens the stud will get real ugly.
Then I did one that was just barely stronger than finger tight.
The advise for buying a replacement is so you always have one on hand for the bastard of the bunch.

 

[Adirondackstihl]

I promise you doubling nuts will not work on the ones that are glued as tight as they can get. You'll destroy the threads.
I've had them bastards need vise grips all the way until the very last turn. And when that happens the stud will get real ugly.
Then I did one that was just barely stronger than finger tight.
The advise for buying a replacement is so you always have one on hand for the bastard of the bunch.

Exactly why I said "most" of the time double nutting works.

The 1st one I ever done needed vice grips right to the end.

Along with the rear bar stud, I always keep at least 3 muffler studs & nuts on hand too

 

[Chainsaw Jim]

Yeah I forgot about those muffler stud bolts. Some of those crimp jobs hold strong enough to twist the ends right off when you add a little rust.
Also my comment was directed at others and not you, just to be clear. I got lazy and didn't use the reply function...my bad.

 

[fearofpavement]

On the stud, there's the space taken up by the bar thickness and the clutch cover thickness. That's plenty to grip it with a pair of 440 Channellocks and even if it's scored all up in that area by the time it's out, it doesn't really matter because it's not a critical area. I've worked on lots of these saws and can't recall ever having to replace a stud. Moving the chain adjuster pin out of the way and taking off the chain catcher is helpful too.

 

[angelo c]

Jeremy, are you going to provide details of the build?

Also, why does that piston say "45" on the top, aren't we going to 49?

Another member tells me these thing are not "fun to work on", any advice or comments on that?

Don't listen to him. Like any saw your first requires thought and patience. After that they go together like peas and carrots. The big complaint if you must do a complete "tear down" of the saw as opposed to just taking the head off.
It's a walk in the park compared to splitting a case to replace bearings and seals. Also you need almost zero special tooling to tear down.

Saw snobs abound...

 

[huskihl]

On the first one I did, a crushed 039 into an ms310 body, double nut AND vise grips on the bar stud at the same time didn't budge it, so they don't all come out without heat. I didn't wanna heat things up down in there, so I left the pan in the body and finagled the crank, sealer, and cylinder down into the saw and bolted it in. Pita, but it works. But next time I'd make every effort to remove the bar stud so I could build the motor in one piece, and then drop the whole thing in in one piece.

 

[VK Johnson]

You could try putting the barb in the freezer for a couple of hours to shrink it...then take it out and immediately drive it in.

 

[Lightning Performance]

I'm unclear as to what you are claiming here. Are you saying that there are different part number cranks with the different engines that have varying timing or that there are manufacturing differences in the cranks that result in timing variations?
Same for the cylinders, are you saying the 029S uses a different cylinder than the MS290 or that you found differences between them? All the MS290 cylinders I've had apart say 029 46mm and the MS390's say 039 49mm. And also I've seen MS390's with and without the decomp.

I never checked the crank part numbers. As far as I know they all interchange including the lower pan and chassis. Besides timing there is no physical differences to my knowledge. Some say they made a bigger carb for the 039.

How many different carbs are there? Walbro Zama others?

 

[huskihl]

Not sure if one they all had different carbs, but the 2 I had were different. They were both bigger than an 044 carb. Probably just jetting was different

 

[paragonbuilder]

I have a friend who has 3 029 supers. I made one into a 390 for him and muffler modded it.
He said it was obnoxiously loud and drank way more fuel but wasn't stronger...
Than he got some big logs... He likes it!


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[MustangMike]

Dan, did you use OEM parts?

 

[paragonbuilder]

Dan, did you use OEM parts?

No, I bought a huztl engine kit and used all but the pan. I did not want to pull the stud.
I would look closer at it now. Maybe clean it up a little...


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