Stihl MS290 Big Bore

[user 122190]

Filed and sanded the intake, exhaust, and the cylinder ports. They were probably okay, but now they definitely are. The first seconds of a fresh motor are critical. Smooth, lubed, and no burrs will make a new motor tight and wear properly to last a long long time.

I'm getting tempted to do this now, but share the photo progress during Christmas time. It would be a Christmas present to my BFF @cuinrearview, so he can second guess me and lay his doom and gloom predictions on the project. For New Years, I can post a picture off the internet of a destroyed 290, claim it blew up instantly, caught fire, killed the dog, and get his New Year off to a great start.

 

[user 122190]

I hope he doesn't read this, and spoil the present, or maybe he will forget. Never mind Timmy, just kidding.

 

[cuinrearview]

Hmmmm..... obsess much? I've never had anyone man-crush me, and I've got to say it's creepy. Maybe time to add my first member to the block list.

 

[user 122190]

Your in my thread. You don't find me trolling your threads. Still with my good looks, I can't blame you for getting crushy on me.

Hmmmm..... obsess much? I've never had anyone man-crush me, and I've got to say it's creepy. Maybe time to add my first member to the block list.

 

[Ryan'smilling]

Yeah there are lots of stories out there about the quality and longevity of these aftermarket parts. The other day, I was reading one scathing review of a similar big bore kit. "POS, the camshaft seized up in 5 minutes" LOL, the biggest critics often have limited or zero mechanical knowledge.

I did order a new intake boot for the build, from Amazon for $10 and change. For grins I looked at BaileysOnline.com for a Stihl OEM, and it was over $50. Really? OEM is 5 times more expensive, 5 times better(?), for a piece of rubber tubing.

Bailey's isn't a stihl dealer. They'll happily walk down the street to a stihl dealer, buy parts, mark them up, and ship them off. So using Bailey's prices to price stihl OEM parts isn't very effective.

 

[user 122190]

Bailey's isn't a stihl dealer. They'll happily walk down the street to a stihl dealer, buy parts, mark them up, and ship them off. So using Bailey's prices to price stihl OEM parts isn't very effective.

I didn't know that. They have quite a markup. They could use some competition. Or they must be doing something right.

 

[boomeradf]

I didn't know that. They have quite a markup. They could use some competition. Or they must be doing something right.

They state they aren't a dealer.

 

[a. palmer jr.]

I've ordered several aftermarket pistons and cylinder kits from Vostore on ebay and have yet to have any trouble with any of them. Maybe I'm lucky or don't use my equipment as hard as others...

 

[user 122190]

It is the old axiom repeated by most all mechanics.

Good, fast or cheap. You can pick only two, not three.

Buy an aftermarket part and spend some time with it. File it, sand it, inspect it, and decide to use or reject it. Even OEM factory parts need to be looked over carefully. They are ALL quickly pooped out and boxed for shipping, and if lucky only briefly looked at by a trained factory worker.

I've ordered several aftermarket pistons and cylinder kits from Vostore on ebay and have yet to have any trouble with any of them. Maybe I'm lucky or don't use my equipment as hard as others...

 

[FlyingDutchman]

Got the parts finally. Droopy cooling fin- afraid to bend it back. Ports are crappy and need cleanup. Several other little imperfections that may need attention on assembly

 

[a. palmer jr.]

If you bend it back it'll probably snap off. I guess you can always return it..

 

[kevin j]

It is the old axiom repeated by most all mechanics.

Good, fast or cheap. You can pick only two, not three.

Buy an aftermarket part and spend some time with it. File it, sand it, inspect it, and decide to use or reject it. Even OEM factory parts need to be looked over carefully. They are ALL quickly pooped out and boxed for shipping, and if lucky only briefly looked at by a trained factory worker.

There is an old adage:
Pick one, manage two.
Pick two, and the third is uncontrolled.
Pick three and not get any of the three.

Another:
You don’t always get what you pay for, but you rarely get what you don’t pay for.

 

[user 122190]

Damned if you do, Damned if you don't.

There is an old adage:
Pick one, manage two.
Pick two, and the third is uncontrolled.
Pick three and not get any of the three.

Another:
You don’t always get what you pay for, but you rarely get what you don’t pay for.

 

[user 122190]

Or you can realize that it has no effect, nor will it be seen once assembled.

If you bend it back it'll probably snap off. I guess you can always return it..

 

[ssm1699]

As you can tell by my signature, I rebuilt my 029 Super and put a 039/MS390 top end on mine. It was a farmer tec kit and it is still running good, to this day. I haven't been nice to it either. It got it's break-in, slabbing an ash tree truck. My 20" bar was buried in this trunk and had to be cut from both sides of this trunk. I can guarantee that I didn't inspect my piston or cylinder when I put it together. It probably had some issues with not having nice edges on all the transfers, exhaust and intake ports. But the sucker runs beautiful and has done everything I have asked of it, plus more. I am still running the original carb that came on my saw, but rebuilt it and tuned it richer, for the larger displacement. It could probably use being tuned again, since I haven't leaned it out from the rich settings for break in. I wouldn't worry about using an AM P&C. @a. palmer jr. and I have talked about these saws, as well as the farmer tec P&C kits, in other threads. I obviously am not to worried, since I built one of the Huztl/FarmerTec MS660 kits. It runs strong too.

 

[a. palmer jr.]

My 390 has really held up good in the back of my garage...

 

[FlyingDutchman]

I didnt figure the fin droop was that big of a deal. Just... Made me nervous right off the bat.

Everyone still throwing away the farmertec wrist pin clips and using Stihl ones?

 

[FlyingDutchman]

I didnt figure the fin droop was that big of a deal. Just... Made me nervous right off the bat.

Everyone still throwing away the farmertec wrist pin clips and using Stihl ones?

 

[ssm1699]

I used the farmertec clips, as they were, in my rebuild. With my 660 build, I just cut the ears down for that build.

 

[ssm1699]

One thing I have been contemplating is that I found on eBay, @Definitive Dave is selling a cross brand pop up piston for the 039/390. I just am not sure if I want to tear my saw down just for a pop up piston. Of course, I never checked the squish on my saw after I rebuilt it. It could potentially do even better, if I have a really poor squish right now, by getting that piston and putting it in.