How to increase throttle pickup without modifying the muffler

MrDiesel

Hi All,

Im not sure if these are dumb questions or not but ill give them a go.

I have a husky 338 and a 346xp which are the two saws i use most frequently. I want to increase the pickup of the saw but i dont really want mod the muffler (unless necessary) due to the excessive noise.

So.... Here is what i have been able to find from other forums ie RC cars, trailbikes, go carts etc

Method 1: is to replace the gasket between the piton and the main body of the power head with a gasket made out of a thinner gasket paper.

Method 2: is to port the jets??? Im not to sure what this means but it sort of sounds like rounding the sharp edges off everything involved in the carby to piston area to improve the venturi effect

Method 3: Replace the fuel filter and fuel lines with larger diameter lines to reduce friction. At the point of conection to the carby a small g clamp is used to seal the connection

So.. Does anybody think these will help or should i go straight to a modded exhaust?

MrDiesel

Method 4: Replace the carby with a Tillotson HU carby for the 338 and a HE for the 346

SawTroll

I am not sure what you mean by "increase throttle pickup".

If it is about accelleration/throttle responce, if may be enough to richen the "L" on the carb a tad. The 346 should be excellent in that regard stock, if it isn't, something is wrong!

nmurph

i'm not sure what the OP means either????? a 346 is about as snappy as it gets. the problem with these saws is that no matter what you do to the carb or base gasket, you still are limited by the restrictive muffler. a muffler mod on a 346 really makes a difference, and you should be wearing ear protection anyway, so the increase in sound is not that noticible.

Wildlife

Method one? heres a thought ! T get that gasket off a few 2 stroke motors you must remove the pot(cyl)Then PICK the clip out of the piston & get the gudgeon out so the piston can be removed to get the base gasket off the case as it wont (often) pass the piston.But... once the pot is off get 0.050" skimmed of the the seat by a tradesman with a lathe & watch the compression ratio hit the limits(check the piston wont strike the top first!) Method two? Buggering about with the carby????? may as well have a crack at neuro surgery while one around in pandora's box.NO!get that different carb most recommended Method three? Exhuast mods are the easiest to try the most effective and the easiest to reverse if its a flop.I found taking the Muffler off made a (2 stroke)motorcycle I had slow ,so there are limitations . One might also get the barrel ported for performance .? however there are parameters already set at the factory tht cannot be passed without ruining the performance ,so get it done where they gaurantee the work in some way or its open season on failure to improve your saw.
As for my preference .. 2strokes like fresh filters, expansion chambers to accelerate, & big bore kits are a bolt on H.P. gain without YOU doing all the research & development. MORE POWER to yuh buddy

windthrown

Haysous Christ? Man, what a TW alias... also your NZ accent is too thick for me to comprehend up here stateside.

Increasing the compression of the saw is not the best place to start with modifications. If it stays all choked up you are not going to get much of a gain from doing that, and you are going to change port timing by dropping the squish. Some porting is typically required if you are going to mill the cylinder or thin the base gasket to restore the proper timing. Re-jetting the carb will be useless if you do not port the exhaust and open the muffler up. Otherwise you are just going to run richer. If you want more power, you need more air/fuel mix burning in there.

Wildlife

Yeah well its time to cut the crap,I was chucking off at mr deisels advice to put a thin gasket on,Yur RIGHT it alters the ports as I inferred in the bit on porting ,.With that level of understanding yuh best not "fu.." around with the carburettor either I'd say?so yeah,the muffler is the real place to do yur learning in reality or get a pro ,to get stuck into ports & jets! "Keep it simple , stupid"( to coin a phrase )AND in closing your responding to the wrong author in this thread but after all it is BRAILLE WEEK all over this forum.I have had some good advice and yur not wrong about that detail so ... KNOW ANYONE WHO CAN MAIL A BIG BORE KIT for a MS660 over that side of the Pacific Ocean.......................................................How bout you ? seeing we're mates now?

windthrown

I am currently not in a position that I can ship saws or equipment down under. Sorry. Logistics of buying real estate here and being way too busy. I have shipped lots of saw parts and other equipment to Oz, NZ, and the EU though.

I was responding to the OP in the last post, as well as yours. KISS... keep it simple stoopid. Yes yes yes. Bailey's does not ship saw parts down under? They have OEM and non OEM parts for Stihl. I never use anything but OEM parts on my Stihls. The quality is vastly inferior on most other aftermarket stuff. A big bore kit for a 660... that would result in one mean machine! I found that a DP muffler on my 066 had more than enough power for my needs.

::. ..::.. ::.:::: Braille week? "I see," said the blind man to his deaf son.

MrDiesel

Thanks JC,

I was asking a question not giving advise but by the way you have descibed removing a cylinder i can see your experience with working on saws anyway.

My reason for asking is becuase i wanted to look at other options rather than opening up the exhaust. I know a few people with severe hearing issues after working day in, day out with ported saws. Some even have to sleep with a radio on.

sharkey

You can try advancing the timing if all you want is a faster rev? You can also lighten the flywheel for the same effect but what is your exact goal?

windthrown

My muffler modified and ported saws are not that much louder than other saws. I keep the muffler openings and porting fairly tame compared to others though, with good results. I also wear ear protection when I run my saws.