Big Bore kit worth it?

I modified the muffler today on my 290 along with a good tuneup and it woke it up pretty good.

I found on eBay they are selling 47mm bore jugs/pistons for around $100. Stock is a 46mm. I think it works out to me the same jug as a 390 saw, though I dunno if the stroke is the same on the 2 saws?

The problem I always have with upgrading average gear is that for the money invested I could buy better. For example, if you sold your 290 and added the $100 to what you get for it, you'd probably be able to pick up a nice used pro saw. I've seen nice 361s around here for $350-400. My $.02.

S

I thought I read that Baileys will be selling a new 390 kit for the 290/310/390 platform this year. Searching for link....

EDIT: This link has the kit's status as of April 18, 2012. http://www.arboristsite.com/baileys/151020.htm

There was another link somewhere talking about likely price.

I heard on some of the big bore kits the intake port is too flat across the top and it can break the rings under some conditions. While you can put more of a radius on you are also changing the port timing. The BB kit for the 2171 is one and my brother is going to radius his before he puts it together.

Billy

for a 290 used as a general woodcutting saw, I would say no to the big bore kit. Now if you have a 440 or bigger saw and you are looking for more power, then a big bore kit may be worth it. The muffler mod works wonders on these newer saws ( we have to remember that the saws made nowadays are under very strict EPA rules and regs, and the manufacturers are forced to constrict the airflow on modern saws). Just don't make the muffler outlet TOO big, or it can make the saw run like chit!!

Muffler outlet I made as big as possible without cutting the baffle. Also took out the screen. Runs fine after I turned the high mixture out about 2 turns and dialed in teh low and idle speed. Would barely run after I threw the muffler on and fired it up to adjust.

Ideally you want the muffler outlet just slightly smaller than the exhaust outlet on the jug. Two cycles like a little bit of backpressure. But if it is running fine for ya, run it....

Bailey's sells a complete aftermarket engine ($150.00) for the 290/310/390 and it's the 390 spec. Making a 290 into a 390 is a big upgrade and the aftermarket kit is the way to go IMO if you already have a 3/8" B&C on it.

http://baileysonline.com/itemdetail.asp?item=SBN 390&catID=



BTW: 47mm is not worth the $$ IMO. Go big (49mm) or go home!

There's still plenty of backpressure with the baffle still in the muffler. I used to have a weedeater I ran for several years with no muffler at all, never was able to kill it. Tossed it after got ran over (yeah great place to put yard equipment is in the weeds right behind a D8 dozer.

Dunno what he's cutting there, but if my 290 took that long to get threw a log I would have tossed it deep into the woods by now! I'd still be trying to cut the firewood I burned last year hahaha.

Yeah 3/8" chain, is there anything else?

Gotta agree it is kinda slow, the chain looks dull. Hard to tell from the video but it doesn't look like the usual jet of confetti sized chips pouring out of the saw, more like clods of dust. Sounds decent though.

That's Brad Snelling in the video....one thing is for sure, the chain is sharp and it's dumping chips. Imagine that was an initial run so the rings need time to seat. I've seen the video before and though if someone gave me a blown up 290 it would probably be worth putting that big bore kit in for $150.

Looks plenty sharp to me. That log is dry as a bone...which means it will throw some dust in addition to the chips and it is probably much harder than your average green tree.

He's also not really leaning on it. Remember those are initial break in runs and not race passes. I would agree that the saw probably has some breaking in to do.

Sleeper 290 is just about as cool as you can get! 100.00 be at-least a couple 100's worth of fun....

Yeah, I think I'm going to wait till I kill the motor and go from there, $150 is a bunch of money to put into a $400 saw.

This is why most do not do it to a 290. Now keep an eye open for a 390 parts saw.

A sleeper saw would be fun to have though. I'd love to be able to cut near as fast as my brother with a 460 hahaha!

Hmm... Tim, what's up your your saw? Yeah I dunno man, better trade trade pile of junk in! hehe

Most video's like that showcase a saws potential, so why do a video if you are going to baby it or before it's ready to run? I guess only the video producer can answer that.
It doesn't take that much to seat rings and be ready to cut full bore for a video.

If that is meant to sell the kit I think a lot of people will be confused, heck my 180C is faster than that.

It is probably worth it to take a 290 out to a 390 so yea, I would do it.

Only one way to beat a 460..........Its going to take More cc's!

So fit an 880 motor on a 290 your saying?

No just more cc's than a 390 has...70+ would be a good starting point. ( Oh and I hope no one brings up a pipe for play 361) With a sticker saying 460 killer!

Havent seen that in 20 yrs.

I can't vouch for whats going on in that vid but I know Brad personally. He knows his stuff. The BB kits on various saws have been discussed many times. One reason I have never done it is because of just what you saw. Eric Copsey talked about the kits at one of my GTGs and said they rarely improve a saws performance. I would much rather spend the money on a professional port job.

I am curious as to what the power output of that aftermarket engine is compared to a genuine MS390.

Not sure how the mfgs check pto hp on their saws but in the field we just do timed cuts. If the saws cuts slower than it obviously has less power. For this to be relevant you need to use wood sized for the saw to take advantage of the torque bigger saws have.