034/044 Stroker hybrid

[Clarkc9743]

Few weeks ago I ran across a 036/044 hybrid build using just the cylinder seemed interesting but alot of work. I did like the idea alot though.

Long story short I found a 034av with plenty of good parts came with a 034 super I bought. Plan was to sell the super and build the other. I have 044 slant fin with 10mm case I got for cheap a long time ago with bad crank bearings.

I'm always trying to find the lightest thing possible with power so I did some looking and checking and this is what I found. The 044 uses the same bearings, the flywheels are the same tapor however the 044 is about .190 larger. So no using a poly wheel unfortunately. The crank (one without a piston)actually looks pretty much identical aswell just much longer stroke. The crank even fits in the 44 case as is but barely rubs.

So where I'm at now is I'm waiting on a meteor 044 10mm piston. A boring bar for my mill to clearance the cases about .060-.070 just to have plenty of room and keep volume similar as before. And various odds and ends like the carb, and a better filter setup like on the 044. But this could be pretty interesting.

I wished I had a 12mm crank just to see if it would fit because even though a big bore is frowned upon I'm sure it would have a little more potential than normal 044 setup. But regardless will be a very light weight saw to use with a 25" Stihl light bar.

 

[Fruecrue]

I made this a while back to facilitate projects like yours, maybe it’ll prove useful to you.

 

[Clarkc9743]

I may fill it out just for info and pics. The wheel appears to be same tapor but slightly different size holes may work and may have to find another flywheel

 

[Dolkitafreak]

How similar are the cylinder bolt patterns?

 

[Clarkc9743]

As far as I know just needs slotting like a 044/046 hybrid. I haven't got to that point yet. I just got my boring bar for my mill in today and plan to try it out soon.

 

[Clarkc9743]

Tried out the Amazon boring bar today seemed to do good enough for a chainsaw case.

You can see I have got just a little bit more to do down in the tapored area it is just barely rubbing.

Plenty of room now in the main case area before had about .003 of room should help loss of volume by the bigger crank too.

 

[CJ Brown]

Any progress on your project?

 

[Clarkc9743]

Fly wheel tapor appear to be same but size is slightly different I am going to bore the 034 flywheel slightly at the right tapor to match. I've just been working on other projects while it was warm about to start back on this again.

 

[Scotty Overkill]

Very cool project, I'm a big fan of the 034 series (I have.3 of them, one I ported mildly), I'm highly interested in seeing this project come into fruition.

Will the 044 cylinder clear the plastics ok?

 

[J_M____]

I built the 036/044 hybrid. So you are using the 044 crank in the 034 case? I was wondering when I was building mine if just a longer rod could be swapped to make it easier. Keep updating, I’m wondering how it works out. You can see on my build how I got the 044 carb/ choke linkage/filter to work. I Still use that saw frequently. It’s been a great runner. Good luck

 

[Clarkc9743]

Yes I'm just using a 034 case that has been bored out to roughly the clearance it was with a smaller crank, and a 044 topend too. The whole idea just for fun is to make as light of a 70cc saw as possible.

 

[Scotty Overkill]

Any updates on this build?

 

[Clarkc9743]

Finally got back on this project after several others. Port timing stock ended up at 73 120 103. I made a gasket out of 1/16 gasket material and chopped the top of the piston into a very small popup.

Then took .025 off the band and base. Might could use a shorter single ring piston to avoid machining it for clearance but I didn't feel like it.

After all the cutting and grinding I ended up with 79 121 102 and .025 for squish for now I'm going to leave it since the chamber is a D shape I would like to keep it between 185-195psi. Still need to clean up some rough edges but the main work is done.

Quite a bit of grinding on the cylinder to make it fit under the plastics also drilled a hole for a husky decomp. I'm young but lazy when it comes to starting high comp saws. Also ditched the old cracked 034 cover in favor of a 036 pro cover.

Next is to weld a tiny pad onto the cylinder to drill and tap a spot for the cylinder cover all thread and then to figure out my carb linkages with the 066 style carb I'm wanting to use.

 

[Clarkc9743]

Got back on this yesterday and finished it up. Appearantly the 044 crank has a slightly shorter pto side Wich made for this interesting contraption and cutting some off the clutch drum. I need to bore the center out so I can put a washer and snap ring on it. It is a 325 9 pin welded tona 3/8 7 if I was to run 3/8 I would pretty much have to run a 8 pin and weld that to a 7 still needs a little machined off to be inline with the bar. Also had to shave down the oil pump worm gear so the clutch wouldn't hit it.
Not pretty but it starts and kinda runs. I need to 3d print a choke lever and tune it. I ended up using a dukes brand 044 carb and it seams to be pretty darn rich at 1 turn out on each but it starts and revs. Used a cut up 044 filter housing and adapter. I drilled the cylinder for a decomp but I really need to make a flat spot for the washer to seal because I don't think it's doing much sealing currently. Still waiting on a lot of little parts before I go and use it. Would like to clean up the rusty old muffler and paint it but it works for now. Should be able to cut something soon. Only took me almost a full year to get it together. Weighs in at exactly 13 lbs empty. So same weight as a 462 just worse anti vibe.

 

[drf256]

Interesting project. The 044 drum is same size as the 360 drum, just shallower. You just need the larger drum bearing.

The 360 crank does have a longer PTO side crank than the 044.

I like how you solved the depth problem.

 

[Clarkc9743]

Currently having fuel feed issues along with not having a choke lever yet makes starting pretty much pointless. Pretty sure the fuel line is kinked need to shorten the elbow on the carb and use a different impulse line it is stretched pretty tight. Next would be the flywheel side seal I might have bothered installing. More small set backs without much time to work on it.

 

[Clarkc9743]

Well after lots of delays and breaking my collar bone I finished it today. I had boogered up the flywheel side seal when installing. After probably 20 minutes of various run time and a few cuts compression ended up at 205. I have not made a working choke but I discovered it doesn't need one of you tip it on its side for a short while. Then pull the cord afew times lightly with the decomp in. It has the husky decomp so it's super easy. After that it will fire pretty easily.

It seemed decent without timing advance but kinda boggy. I filed some off the key and that fixed that, I may try for 1/2 the key I have more keys if I ruin it.

This thing is super lightweight too. I have weighed it partially filled with fluids and a 3/8 20" tsumara premium light bar vs my 261 with a 261 325 sugi light bar that is almost empty on both fluids. And then my 462 with a 20" 3/8 also mostly empty on fluids. The 034 does not have dogs on it yet but it's close enough to say it's the same or close to the 261. When both are filled.

I will try to get a video in a few days when it isn't raining a flood.

 

[drf256]

Did you check the position of the keyway in both cranks? Even though they use the same coils, the cases are different and the timing could be off.

 

[Clarkc9743]

I have not, Wich is why I think it needs a bit more advance yet. It was enough to run before and runs much better now. But only about what a ported saw runs like with no timing advance. I'm going to look at my 046 and check with a degree wheel between it and this abomination.

I would almost Garuntee there is a 4-6* difference between them though. Not only are the cases different but the flywheel's are different diameter because I was wanting to use a poly flywheel but couldn't due to the size difference. Plus it would make sense why it was so lazy at first.

 

[Jake Dykstra]

Assuming you put a 44jug on the 34 how did you make up the 2mm less stroke? Where did timing numbers end up?