86cc hybrid stroker big bore ms361

[Clarkc9743]

Just like the thread suggests I got bored over the winter and created a 86cc 361 abomination. The specs are a echo 590 crank. 066 cylinder, the clutch I had to bore out, run a tap and turn down the diameter of a echo cs 670 clutch. Will have more pics tomorrow evening with more details. I have to pull it apart and epoxy the intake and I'd like a little more compression as well and maybe some finger ports.
Yes I'm aware the sap wood is spongy but I'm thoroughly pleased with something I didn't even know if it would work or not.

 

[Clarkc9743]

This evening I tore it down for some epoxy it was spitting back terrible and almost seemed overly rich most of the time at idle. This filter kind of confirms it. Has about a tank of run time.
Next we have the clutch area, nothing to special but it was a absolute nightmare to hand tap the threads in this to suit the echo crank. It actually chipped at the edges from the induction hardening not threading.
Had to make a spacer out of 1/16 steel for the bar to keep the chain out of the clutch. Along with a small spacer to keep the oil pump gear down.
Next we have the flywheel side, I didn't take a pic but I used a 1/8 end mill and marked roughly where I wanted the new key to be and cut. The tapor isn't the same but it's kinda close, enough so the flywheel will kinda bite on the tapor some. So the key keeps it from spinning. I used some 1mm brass to space out the cover because it was to close to the flywheel and would jam.

 

[Clarkc9743]

Next we have the massive amount of grinding everywhere obviously had to drill and tap spots for the av mount and top cover had to weld for the av mount.
Next we have what it looks like when you use a trashed cylinder and didn't know you didn't get all the aluminum transfer out. Didn't ruin the piston but definitely can feel the marks. Will definitely need new rings.

 

[Clarkc9743]

Last we have the carburetor setup which is just a 044 style carb with a 5/16 spacer and the hole in the plastic cut out to fit with a 066 boot because it was the straightest. For the choke lever I used bits of air line jb welded on the original lever and it works good looks terrible though.Carb studs are also 046 the 361 were way to short.

Throttle linkageis a 046 but shortened a bit.
Next is the muffler Wich was attached with a aluminum spacer block cut at I think a 12* angle on one side to get the muffler where it should be
Last the general numbers were 86 123 and 99.5 I cut .030 out of the chamber originally and I think around .300 off the base. The echo crank has a pretty long rod along with the deck height of the cases makes this barely workout. I have cut an additional 20 from the chamber, will raise the transfers to 120 and the intake will be 79-80. But that is tomorrows project. I'm just pleased it ran at all. Chassis is a holzfforma 361 with skf/bao bearings and the 590 crank/066 cylinder. I didn't spend much time porting because I didn't know it would be any good but will report back in a few days once it's back together and can get another short video. I will get a weight measurement when it is full of fluids but I think with 25" lightweight bar and chain it was around 16.75 lbs. Wich in my opinion is very respectful.

 

[Powerstroke Cowboy]

WOW! Now this is a frankinsaw!

I'm looking forward to seeing what you can get out of this thing! Good job Sir!

 

[Clarkc9743]

I am very green when it comes to porting. Very basic work I understand the concepts and such but haven't got to put it into practice yet. I feel like it's lacking case volume from the size of engine. That and this cylinder even after removing aluminum is pretty bad shape so I don't care if it ruins it. I think I will try my hand at some finger ports just for fun since it ran decent before with way to much intake.

 

[Powerstroke Cowboy]

Get the intake timing where it needs to be and you might be surprised. You are losing fuel and air back out the carb, that adds up to less air and fuel to feed the engine. Less case compression will make the air through the transfers, sluggish. Slower reving and less throttle response.

If you do finger porting keep in mind the location of the ring pins.

@Ketchup how about this for a hybrid 361?