Husqvarna 55 build: Anyone done a timing advance or have any port timing #'s?

[muddstopper]

Here is a great thread on porting, http://www.arboristsite.com/community/threads/porting-101.108900/. There are several other good links to other threads hidden in some of the replies. I spend most of a full day just reading all of them. I still dont know crap, but think I have gotten a general ideal as how to port my 55.

 

[thefarmboy21]

Finally got around to porting the jug and checking everything again. I must've not got the right reading on the transfers in the beginning because the number changed several degrees and I didn't even touch them.....in any case, here's the new numbers:

Exhaust: 105
Transfers: 124
Intake: 75
Squish: .020

Didn't get as much out of the intake as I thought that I was going to, but I'm going to leave it anyway. Now I just have to finish cleaning it up and re-assemble everything. Then order some plastic Chinese parts I guess.

Anyone know who carries Hutzl/Farmertec parts besides eBay? I'd really rather not wait 30+ days for them to come from China.

 

[Nitris223]

HLSUPPLY and Northwoods saw may carry some of the plastic from China.

 

[ML12]

I'm putting together a 50 with a 55 (Huztl) top end. I turned the base down so that with a gasket I would be at 0.020" squish.


I did some mild port work, mostly widening out the intake and exhaust, didn't change any timing numbers, and I also opened up the muffler with 3/4" tube, turned the baffle plate into swiss cheese and welded the original louvers shut.


^ The intake

^The muffler.

I figured this would be a good saw to try my hand on port modification as the parts are dirt cheap. It definitely needs the decompression valve, and I plan on advancing the timing slightly, probably 1/3 of a keyway.

 

[thefarmboy21]

I shaved my flywheel key (integrated) last night. Got about 5-6 degrees. Yours will have an actual key....probably easier to just buy a slightly thinner key. You had it running yet?

I'm putting together a 50 with a 55 (Huztl) top end. I turned the base down so that with a gasket I would be at 0.020" squish.
View attachment 561275

I did some mild port work, mostly widening out the intake and exhaust, didn't change any timing numbers, and I also opened up the muffler with 3/4" tube, turned the baffle plate into swiss cheese and welded the original louvers shut.

View attachment 561276
^ The intake
View attachment 561277
^The muffler.

I figured this would be a good saw to try my hand on port modification as the parts are dirt cheap. It definitely needs the decompression valve, and I plan on advancing the timing slightly, probably 1/3 of a keyway.

sa

 

[ML12]

No, I'm still waiting on a carb kit among other things, that and enough free time to get out to the shop to finish it. Maybe this weekend.

 

[b fish]

No, I'm still waiting on a carb kit among other things, that and enough free time to get out to the shop to finish it. Maybe this weekend.

Keep us updated! I am getting ready to do a couple open port 55's. They are fun little saws! And parts are all Over the place. Can't get enough 55/51 Husqvarna's !!! I have one stock closed port. It Runs like a Raped Ape! Wish I had more top ends like that!

 

[ML12]

Update: I got it all running great and made a few cuts with it but then the oiler decided to disintegrate the plastic gear came out in about 15 pieces. So now I have it apart again waiting for a new oil pump. Should be here next week.

When it was running it seemed quite strong, it definitely needs more tuning as I think it is still a bit on the rich side, didn't quite have the higher rpms that I was expecting, but I think that has more to do with not raising the exhaust or transfers any when I machined the cylinder base. I really don't have anything else in my line up of saws to compare it to, and I got it in a non-running state so I have no idea what kind of gains I made.

I think if I get bored in the future I will put the bigger 55 carburetor and air filter on it, that should also help and it would get rid of the stupid choke set up. I also think the timing could be advanced further as it doesn't kick at all yet. I might even mess around with gasket thicknesses to drop the squish further, Brad S suggested that the lower limit is 0.016" on another thread, and mine is right around 0.021"

Its a nice little saw, just wish that I could have kept the chain brake on it, the decompression valve interfered with the brake flag so the chain brake had to go as starting it without the decomp would likely wreck the starter in short order.