Cut4fun

There is no outer plate with holes in it. That is the muffler itself with holes in it. The outer deflector just get the opening opened up like in my 390 thread.

136 I think is the 36cc Poulan made saw. I usually sale them for $50 to $75. A $100 is way to high unless you just need a spare of the moment like new one. .

I would have to have one in hand to tell you what drill bits I am using. I drill holes then use a dremel to enlarge them and widen them to my liken. Even the 2 oem slits. Dont forget to open deflector like shown on the 390 thread. Here is a stock muffler I pulled pic off net and added what to add in white. Now it is very easy to just look and drill the holes to fit inside the baffle which really is the saw waker upper IMO and the added smaller holes on the outside baffle. Carb tune afterwords which will be richer for sure on H side. Make sure idle is fine afterwords too.

Here is some info on ones I have owned and others I tested. Now I dont know which ones you can get over there. http://chainsawrepair.createaforum.com/ported-saws/chainsaw-tachometer-choices/

Thats what I am getting at. I have both SB saved if he needs numbers. I had to replace a intake on 357 that warped and have another new one still in package waiting for my 346 45cc IF. New updated replacement carb is a zama. Have those numbers too.

Is this a 50cc or the older 45cc 346? There is 2 service bulletins on the carbs and intakes on the older ones. If older saw it goes by serial number and back to date.

Another butt ugly 3750 60cc open port. Still waiting on oem ring. This is the 3rd one of these I have picked up and they run and cut with the 262xp MS361. Just a hair shy on the torque IMO compared to the 262xp. The 3750 actually handles better then the 262xp in a unbiased opinion of 2 of us switching saws back and forth one day cutting hardwoods all day.

I just checked and a oem muffler can be bought here for $25 USD.

Like you say norm is 80. But testing the 290 more toward 100 when more gains were found. Many I have found like more then norm. You dont know till you keep doing little more at a time. I do the 290 310 390 free for people, it's that freaking easy. But your on the wrong side of the pond. If they bring a beer to swig while doing so is a plus for all of us.

Make that holes. If you only have 2 slits on top of muffler from OEM. I open both of those and put 1 more in between those. Then I do 3 more below under baffle just like the top ones. Then I do 2 more bigger ones right in the middle of baffle. Then do the deflector as shown, by opening up outer part. It's not rocket science. % 80 to 100 for me.

No welding or brazing on mine. I dont like little pipes. Just a drill bit is all that is really needed on 290-390 muffler. Now I do use dremel on the deflector. If you dont require a spark arrestor, toss it. No need for small holes like that and wouldnt pass as a spark arrestor if required. Do you know how to re-tune a carb? Have you pulled the H or L side stop already?

I'm not a fan of these models but at least you got the 65cc top on the heavy beast. You can do a muffler mod on a MS290 310 390 in about 30mins. I have seen 23% quicker cuts on a 290 before. Just a tad less from the 390. If you want I will walk you through it in PM or emails. I have a thread on the 390 I did this year on Chainsawrepair site. I dont know if the embedded pics will shoow up. I know the photobucket one will. The 390 I didnt put the spark arrestor back in but I did on the 290 last year. Oh, Dont fall for that $100 muffler mod crap people sale online. Link 4 you. Stihl MS390 You will need to re-tune carb afterwords. Richer.

The 025 MS250 around here in hardwoods work best with 16" .325 RSC chain. Full 3/8 chain 7/32 cutter will make that saw a real turd. JMO. Now you might be able to run the picco 3/8LP PS3 chain if you switch bars and sprockets. I ran that set up picco 3/8LP PS3 5/32 cutter on a poulan 260 42cc and it would out cut the 025 with 325 rsc.

BINGO :thumbup:it has got to the point of childish IMO.

All of these are same kit. 034, MS340, 036, MS360, 360 , 064, MS640, 084 Hint hair dryer on ends attaching. added. Where I had bought one from for $8 USD. Just so you can see it. http://www.ebay.com/itm/034-036-064-084-MS-360-Stihl-Oil-Hose-Kit-New-/360290780660?pt=US_Chainsaws&hash=item53e30105f4

Yep isnt it easy to tell? I am usually just in the chainsaw board but for some reason I seen this checking in. It would be really neat to try one of those easy lift things with my echo PPT extend-able pole saw. But after the stupidy of this thread by said owner I wouldnt buy one

I'm guessing you are not a sponsor and you were trying to sale and push your stuff here. I only know of one site like that and I left there long ago. I hope this place isnt like that.

I owned 10 or so 372 in 70.7cc 74.6cc 76cc and 3 066 MS660 91.7cc. Like any saw with more cc size they shine once in the BIG wood with bar buried.

A guy I know did the same thing when a 650 was offered so much cheaper then a 660. Same dang saw just smaller bore. Like I said wear it out and then put the 660 topend on it for the $$$ saved from initial buy. [ame=http://www.youtube.com/watch?v=eJnNvq55H4k]Stihl 650 Chainsaw - YouTube[/ame] [ame=http://www.youtube.com/watch?v=HbgM2PPt5AA]Stihl 650 chainsaw - YouTube[/ame]

All of this was posted on Chainsawrepair site during a discussion we were having. Link to thread. 066 Stihl Even deeper inside the WJ carbs for you The carburetors of the WJ series have been designed for professional applications, especially for chain saws from 50 to 100 cc displacement. Technical Data: • Casting available in the following dimensions in mm: Choke Bore Venturi Ø Throttle Bore 22.19 14.29/15.08 19.01 22.19 15.88 20.56 22.19 16.67/17.46/18.26 21.43 23.38 19.05 21.43 • Mounting holes, distance between centers: 31 mm. • Metering system and fuel pump integrated in the carburetor casting. • Can be delivered with or without choke. • Adjustable high speed needles, idle needles and available idle adjust screw. • Available extras: speed governor, fast idle system. • Proper function in any attitude.

Stihl MS650 Specifications Walbro Carburetor Models: WJ-67 (MS650 Magnum BR) WJ-69 (MS650, MS650 Magnum and MS660 Magnum R) WJ-76 (MS650 Magnum BR) Weight for powerhead only: 16.5 lbs (7.5 kg) Displacement: 84.9 cc (5.2 cu. in.) Stated horse power: 6.4 bhp 52mm bore Stihl MS660 Specifications Walbro Carburetor Models: WJ-67 (MS660, MS660W and MS660 Magnum) WJ-69 (MS660 Arctic and MS660 Magnum R) WJ-76 (MS660 Magnum BR) Weight for powerhead only: 16.5 lbs (7.5 kg) Displacement: 91.6 cc (5.6 cu. in.) Stated horse power: 7 bhp 54mm bore Just like I posted above. 066 carbs. Walbro Carburetor Models: WJ-65 WJ-67 WJ-69 WJ-76

Why wouldnt it be? Just 7cc difference. The Dolmar uses same carb on 6400 64cc, 7300 73cc, 7900 79cc for 15cc difference. As soon as I get other laptop back I will get you carb numbers off the 650 660 IPL Oh you do know even the carb venturis on the WJ carbs on the 066 and MS660 are not all the same too, right.

The 650 is the 660 with smaller bore 85cc to go against the 385xp market at one time. Buy it for the cheaper price, run it, wear it out someday and you can bolt the 660 top end on it for the 92cc in the future.

Them things are everywhere over here. I passed on 2 of them for $150 apiece and another for $250 and just last month another $300 right up the road 30mins away. All of them within 1.5 hrs of my house. Underpowered for a 60cc saw, but collectors like them.

For hard working saws I tune H to 4 stroke out of cut but once in the cut the saw clears up and sounds like a mad hornet. L I adjust till I have good throttle response from off to full throttle is crisp and fast pick up. Now cookie cutting tune is totally different for short fast cuts when being timed or wanting to show off.