Anyone work on an MS290?

[TheSnake]

Are thes bolt supposed to be self-tapping?

 

[TheSnake]

I was instaling an 039 cylinder and the bolt holes are smooth.

 

[TheSnake]

Someone told me to drill hole in the muffler. How big and how many?

 

[Black Dog Chainsaw]

Nope none of us have ever worked on one of those...

 

[TheSnake]

Nope none of us have ever worked on one of those...

OK well tey are pretty common saws down here.
The bolt wont really go in.

 

[mortalitool]

The bolts install from the bottom on this saw. The cylinder itself is tapped.

Sent from my VS980 4G using Tapatalk

 

[Black Dog Chainsaw]

PSYCH!

I put a 3/8" or maybe even bigger hole in the square dished out area on the muffler. That leaves a strait shot from exhaust outlet through the muffler. You'll probably want to grind your muffler cap/cover open too.

I would pre-tap the holes in the cylinder myself before the install.

Also check your impusle nipple to make sure it wont pull out/fall out of the cylinder. If it does use a very very very light coat of sealant, stick it back in, and use a punch to peen the aluminum around the base. This will expand the aluminum and lock the impulse nipple in place.

Make sure to run your sealant (dirko, yamabond, hondabond, etc) into the corners of your seals a little and remember a little goes a long way. you don't need a thick layer b/c the cylinder will pull down and squish it all out anyhow.

I also recommend not using the supplied Chinese rings on the piston and to go with Cabers instead. I know it's probably too late in the game for that but I have had several sets of cheaper rings loose their tension after a couple heat cycles and drop the compression 20-30 lbs.

And of course go back and find out why your saw torched itself. If you don't know I recommend new fuel line, impulse line, fuel filter, and a good long inspection of the intake neck. Also check your crank to make sure there was no damage to the main crank bearing (i've missed that before once and wont do it again!).

Lastly, I recommend retuning the carb to 1:1 turns out so it doesn't lean seize while it's sitting idling.

 

[Black Dog Chainsaw]

The bolts install from the bottom on this saw. The cylinder itself is tapped.

Sent from my VS980 4G using Tapatalk

Some of the Chinese cylinders don't come pre-taped so you have to do it yourself... I chase the threads on all the 029/390/039/310/290 cylinders with the correct tap whether they come threaded or not.

 

[Black Dog Chainsaw]

Almost forgot....BE CAREFUL OF THE GROUND WIRE SCREW THAT GOES INTO THE CYLINDER!!!!

Most of the AM cylinders are drilled and taped for the ground wire but 85% if them are not deep enough for the OEM screw! You'll end up wanting to over tighten the screw and it will brake off causing you more headaches than you already have.

Welcome to OPE...

 

[Milkman31]

The cyl bolts are self tapping. Use the case spacers or washers to mock up the jug and crank cover to let sealant set up over night then take the bolts out and install in the case.

 

[Black Dog Chainsaw]

The cyl bolts are self tapping. Use the case spacers or washers to mock up the jug and crank cover to let sealant set up over night then take the bolts out and install in the case.

That's why I pre-tap... Yes the bolts are self tapping but cutting the treads in first will help direct the bolts when you assemble. Also it removes any chance that the self taping bolts run sideways or heaven forbid breaks off one of the cylinder ears.

Put it together all at once in the case and re-assemble. If you use a good sealant like the ones I mentioned above you can trail start the saw right away as soon as it's assembled. I literally broke into the 300's somewhere on this series of saw builds this last year. I can do these in less than an hour with muffler mods and re-tuning the carb so it's close. I haven't had a bad build on these in a looooooong time. Not saying pre-assembly and then main assembly doesn't work, but it takes longer and you'll get the same result.

 

[MustangMike]

One of the tough (and different) things on these is the rear bar bolt goes into the engine block, and you rarely get it out w/o ruining it. Putting them together is like a jig saw puzzle, not my favorite saw to work on. The correct order is important, or you will be taking things apart again.

 

[Dub11]

When I removed my rear bar bolt I went in first to pop lose the threadlocker they it came out lickidy split. And If you going to do more hold up becauses Bruce from Hlsupply said there working on a pop 039 kit!!!

 

[Khntr85]

Almost forgot....BE CAREFUL OF THE GROUND WIRE SCREW THAT GOES INTO THE CYLINDER!!!!

Most of the AM cylinders are drilled and taped for the ground wire but 85% if them are not deep enough for the OEM screw! You'll end up wanting to over tighten the screw and it will brake off causing you more headaches than you already have.

Welcome to OPE...

LOL I had one brake off in a damn ms250 hutzl engine a few weeks ago man was I pissed!!!!... damn near took it out back and shot the damn thing.....believe it or not they sent me a new cylinder without any hassle!!!

 

[67L36Driver]

I've done a couple Farmertec MS390 engine installs and the crankcase bolt threads are way different than OEM bolts.
Use the Farmertec screws.

 

[Adirondackstihl]

That's why I pre-tap... .

I sure would like to see that tap.

 

[super3]

That's why I pre-tap... Yes the bolts are self tapping but cutting the treads in first will help direct the bolts when you assemble. Also it removes any chance that the self taping bolts run sideways or heaven forbid breaks off one of the cylinder ears.

They are not all a thread you can tap for. The last 2 I did were a fast thread wood screw type bolts in the factory cyl. I tapped and replaced them with socket head allen.

 

[TJ the Chainsaw Mechanic]

Nope none of us have ever worked on one of those...

I don't know about you Makita guys.