Convert MS 290 with new Cylinder to MS390

Can I convert MS 290 with new Cylinder to MS390

Hello all, I am new to the site, but have seem some excellent questions and answers.

I have a question to many of you out there.

I have an MS 290 saw that has, excuse me if I do not have proper terms here, a vacum leak between the pan and cylinder head. The model and part numbers for the MS 290 are the same for the MS 390.

My question is this. Is it worth gonig to a new cylinder that is for the MS 390, and it apparently fits on the same pan as the MS 290. That way for a few hunder bucks and change I end up with a much better saw than buying a new one??

I have service manual and parts manual and have never really messed with saws but am wiling to try this myself? I have some time and am interested?

Any ideas??? Good, bad??

Thank you all

The 290 is a decent saw for its intended purpose BUT it is generally not worth re-building as the repair cost is so close to replacement cost. WHy spend a few hundred dollars on an 029/290 when a new one is $299.00? When you get a new one you get a new bar and chain and have your old saw for spare parts. I would not put a new cylinder on a 290. Buy a new one and keep you eyes peeled for a 290 or 390 that got crushed by a tree, usually the engine will surive. Use the crushed saw to re-power your 290.

Oh yeah, Welcome to the forum!

Just thinking currently. I would like a bigger saw but that is 400-500 depending upon where, what etc.

Correct on dollar amounts being almost exact to the repair of parts.

Guess I have been watching too much Monster Garage, or Orange County Choppers.

But have time on my hands and thougth a tinker project might turn out a larger saw??

I bought 2 used 064's (85cc) for $200.00 each. First one was beat with an ugly stick but ran well, sold it to finance another purchase. Later bought another one in much better overall shape. My point? If you are willing and able to tinker, a 'larger saw' can be had for what you are thinking of spending on your 290. You could posibly do what you are thinking if the crank and rod are the same between the 2 saws, but again it's not something I would do, I would do it with cheap used parts though.

Crank and rod, bottom pan, and all other parts are all the same. Just the bore and size of the cylinder are different.

I have not yet decided. But who knows. I could afford to just replace the 290 with a new one for another fifty bucks. But getting a bigger saw for same price is kind of interesting, plus the experience of working on saw.

Thank you for the info and ideas.

This seems to be a great forum. There is great information here.

If any one was looking to go to a slightly bigger saw for pine, cedar, and fir, what might be a good saw to look for in the bar range of 24-30"?????

I picked up a new aftermarket jug and piston for the 29 a couple months ago on ebay for $45. Well worth that price to rebuild, IMO.
-Ralph

Did you need the special tools for ring compressor and seals etc?

Seems like a fairly simple replacement and a four or so hour job to accomplish.

I might look into the same size head and piston.

a vacuum leak between the pan and cylinder head.

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I would have to wonder what part is causing the air leak? Could be jug base is not flat or it also could be crank case base is not flat. 029/039 do not use a conventional crank case. Could be something else such as lean carb causing very hot running conditions.

Next question is did the air leak cause a meltdown such as burned piston.

I have a older model 029 in the collection it been an OK saw but I defiantly would not spend more than a hundred dollars on parts... it just would not make much economic sense. I kind of consider it a throw away chainsaw if something major happens. On the other hand I've also done a bunch of things that did not make much economic sense.

I would assume that the mix may have gotten lean. Not sure however why. Put away wet one to many times I am sure by previous owner. Did not take care of much actually.

Piston looks good does not appear to be scored, however going to check further upon full tear down.

I was just thinking of making a bigger saw, which does not make economic sense, correct. But since the jug fits on the same base sounded king of fun to make a hot saw.

So really fishing for a fun thing to do. Why do we waste money on autos, with fancy rims, and flashy stuff especially on 4x's. Kind of same deal I guess.

I have a good cylinder and piston from a 390 I would part with. The saw was run over and the cylinder has a broken fin or two, but the bore and piston look good. Shoot me an email if interested.

FishhuntLA said:

If any one was looking to go to a slightly bigger saw for pine, cedar, and fir, what might be a good saw to look for in the bar range of 24-30"?????

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AN 044 or 046 would probably fit the bill quite well.

TonyM said:

I have a good cylinder and piston from a 390 I would part with. The saw was run over and the cylinder has a broken fin or two, but the bore and piston look good. Shoot me an email if interested.

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Fishhunt (that sounds familiar ) I'd take him up on this. If Tony will part with this for a good price, it would make the rebuild more cost effective, and worth your while.

Jeff

I Have Done Two Rebuilds In The Lat Month Or So... The First Was A 362xp That The Crank Got Broken On The Out Side Of The Case.......put My (that)top End On A 372xp Bottom End (with Crank) I Got On Ebay For Like 35 Bucks Including Shipping...in Awsome Shape. That And A New Head Gasket And I Was Done.
The Other One Was A 365 That One Of My Guys Dropped A Tree On Or Something (still Not Quite Sure) But Completely Busted Both Sides Of The Case. Found A 365 On Ebay Same Deal Whole Case With Crank For Just Less Than 30 Bucks. They Both Run Great. Saved A Ton Of Cash On Those Two Saws. As Apposed To Buying A Crank For One And Both Halves Of The Case For The Other.
Little Advise Change The Fuel Filter If It Has Been Sitting Fir Awhile....

I sold the piston/cylinder to my neighbor with an 029. I put it on for him. Very easy. The 039 Piston goes right on the 029 rod. I put the fully adjustable carb from the 039 on as well, and did a minor muffler mod. My neighbor likes his 029 a lot better now! Now he just needs to switch to 3/8 chain, since he wants to run a 24" bar. Sorry FishhuntLA, the parts are no longer available.

Glad to hear you found a home fo rthe parts Tony! Its good to know that the swap will work with no problems.. I was curious about the 029 carb being large enough for the 039 setup.. I assume thats why you swapped carbs too??? I wonder what would happen if the 039 stuff was run on the 029 with the 029 carb.??


Ron

I beleive the 029 and 039 carbs are the same. I decided to use the 039 carb as it still was fully adjustable without limiters. The newer MS290 carb had the limiters, and I thought the adjustment would be necessary to have with the muffler mod. I could have used the MS290 carb and made it work, but why bother, when I had the 039 carb right there, and the carb has to come off for a cylinder change anyway.

Well I that is too bad. I just got home and was going to email you to pay and mail them.

Well I guess I will just buy new one and go from there.

Erik

Here's a jug and piston from a 310. It ain't a 390, but it'll fit. Just saw it, and thought of this thread. And the seller is very, very good to work with as well.

Jeff

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=79669&item=4373316321&rd=1

Thanks for the link Jeff..

I assume this is a direct swap also then??
I didnt realize there where other choices than the 029/039 interchange.. Any otheres i should be looking for to put a 029 back together???

thanks
Ron