Re-assembly of Husqvarna 50 (51/55) need timing and muff mod advice

[Chris-PA]

I dont think thats the case. The solder is .061. I have thinner .028 stuff but its too thin to get a reading

I use two strands of the thinner stuff twisted together - it's a bit softer that way.

 

[sweidish445]

I use two strands of the thinner stuff twisted together - it's a bit softer that way.

Glad you questioned me.. i just remeasured squish with two thin strands, as well as with the thick stuff again. While both read the same, i came up with .029 at pistons edge this time. About 1/8" from the edge is measuring the .035 i came up with earlier. I see your point though! I did a 350-346 conversion and it was so difficult to compress the thicker solder i went and got the thin stuff.

 

[birdcolonel]

Here are my timing numbers I've came up with, best I can tell with a flashlight. All numbers are with no base gasket, haven't checked the squish yet, but I will as soon as I get a chance. Didn't have the right size solder.

Intake:
Open 71 deg before TDC
Close 71 deg after TDC
142 deg duration -- OPEN for 142 degrees

Exhaust:
Open 75 deg after TDC
Close 75 deg before TDC
150 deg duration -- OPEN for 210 degrees/CLOSED for 150 degrees

Ports:
Open 56 deg before BDC
Close 56 deg after BDC
112 deg duration -- OPEN for 112 degrees

Do these look right?

Unless I'm missing something, on your exhaust number, 150 degrees is closed.

 

[sweidish445]

My initial exhaust open/close was around 110°. I heightened the exhaust a little so that number is a few degrees different now.. just need to heighten transfers a bit and ill be in business!

 

[sweidish445]

One year later, and this saw is finally running. From what I know, it sat dead for over 3 years. I ended up with the moderately ported closed port jug, Lil red barn piston, no base gasket, and mm. Over the last year I've picked away at this build little by little between a million other projects. I ground down carb shafts and screws, matched all transitions and gaskets from air filter to the muffler. Also ground case at the transfers to match the wider transfers on the jug. The stock bucking spike had me feeling bland also so I modified a 372 dog and made another chain catch like the one I built for my 372 with dual spikes.
Today I decided to advance timing at the flywheel also. Tuned pretty rich but it made about a dozen cookies so far and it's running awesome!
I picked up a few different rims to play with. I started with the .325 7 pin. Have a .325 8pin as well as a 3/8 8 pin. I intend to grab a 3/8 7pin however as I feel this may be the best setup.
I'm just glad I can start looking at another project without feeling guilty that this one isn't finished!

 

[thefarmboy21]

Let me know what rim/chain combo works out best.

I need to order the rest of the parts for my 55. How many degrees did you advance your timing?

 

[sweidish445]

At flywheel I filed about 1/4 width of key. Used piston stop and marked flywheel. Filed till I had about 5mm advance at flywheels edge. I believe ex. Was raised almost 8° transfers 2° and intake lowered 5°. These weren't the exact numbers I was aiming for since I used a different piston than originally planned.
Ive run a 55 rancher which comes with the 3/8 7pin rim stock. Without porting or m.m. it cut very well. I don't intend on this saw being my goto saw, which is why I want to experiment. I just want a quick cutter, no work horse.. with my saw and the .325 7pin, 18" semi chisel, the saw wont bog, runs strong as an ox in the cut. For the record, cutting rock hard seasoned oak. I'll let you know what I come up with and hopefully get some video..

 

[thefarmboy21]

At flywheel I filed about 1/4 width of key. Used piston stop and marked flywheel. Filed till I had about 5mm advance at flywheels edge. I believe ex. Was raised almost 8° transfers 2° and intake lowered 5°. These weren't the exact numbers I was aiming for since I used a different piston than originally planned.
Ive run a 55 rancher which comes with the 3/8 7pin rim stock. Without porting or m.m. it cut very well. I don't intend on this saw being my goto saw, which is why I want to experiment. I just want a quick cutter, no work horse.. with my saw and the .325 7pin, 18" semi chisel, the saw wont bog, runs strong as an ox in the cut. For the record, cutting rock hard seasoned oak. I'll let you know what I come up with and hopefully get some video..

Mine is just a 55 Rancher (built a 50 a year or two ago) I have the numbers written down somewhere, but I did some mild work to it. It was originally the 3/8 7-pin. The 50 was .325 chain 7-pin I believe. I just want this one to cut really fast, it won't be a felling saw most likely. If I keep it, it'll just be to toy with, shownoff to my buddies and cut campfire wood. Either gonna build a gnarly modded muffler for it, or try my hand a building a pipe.

 

[sweidish445]

18" .325 7pin rim

 

[sweidish445]

8pin rim... not much different?

 

[sweidish445]

I threw on a 3/8 7pin rim, and a 16" 3/8 LP oregon chain a few nights ago and I'd say it cuts best with this setup.. need to get me a 3/8 8pin and probably a 60dl chain. The 59dl just barely fit.. I did get a video, but my ass is in the way the whole time. I'll spare you guys..

 

[thefarmboy21]

I threw on a 3/8 7pin rim, and a 16" 3/8 LP oregon chain a few nights ago and I'd say it cuts best with this setup.. need to get me a 3/8 8pin and probably a 60dl chain. The 59dl just barely fit.. I did get a video, but my ass is in the way the whole time. I'll spare you guys..

But would you expect that since it cuts better with 16" 3/8 than an 18" .325, that it would likely cut the fastest with 16" .325?

 

[thefarmboy21]

Does that thing have much of a muff mod? Sounds quiet. Definitely idling on the fast side....im a hot rodder, so I like them to idle as low as possible lol.

 

[sweidish445]

I was going to inquire about that. It's idling low as possible at idle screw. Can't I make a lil dimple or notch in the carb venturi to richen mix of idle? How do we fix this? I don't mind where it's idling so much, but would like it a tad slower.. the muffler I just removed the inner baffle and open the exit port. Didn't modify deflector tho, so it's nothing wild. I matched everything from carb to muffler and even ground my carb screws and shafts down a bit. Spools up strong!

 

[sweidish445]

I was going to inquire about that. It's idling low as possible at idle screw. Can't I make a lil dimple or notch in the carb venturi to richen mix of idle? How do we fix this? I don't mind where it's idling so much, but would like it a tad slower.. the muffler I just removed the inner baffle and open the exit port. Didn't modify deflector tho, so it's nothing wild. I matched everything from carb to muffler and even ground my carb screws and shafts down a bit. Spools up strong!

Wait, that made no sense. Lol

 

[motor head]

Has any one tried a non windowed piston in these semi closed port cylinders?

 

[sweidish445]

I used the jonsered 590 630 piston from lil red barn I think.. had windows..