Stihl ms 460/660 Hybrid. 469e

[Powerstroke Cowboy]

Bruce and I did some things with me porting oem jugs, and him sending them to China to be copied. I got to see firsthand that the Chinese are 100% capable of doing very nice work. The prototype cylinders they sent us back for the 661 were absolutely beautiful. They ran almost as well as oem jugs that I ported.

Then, after giving them the green light....they sent Bruce 100 units of the most fughed up looking crap I'd ever seen.

Yep....they are capable. No....they are not honest, and will fugh over anyone for a buck.

The moral of the story? You have no idea what you are going to get when you buy this garbage.

That's sad, real sad. But as a general rule that's how they seem to operate.

 

[Powerstroke Cowboy]

Nate,

A dab of Al filler here. 2 spots on each side. Can hand grind at the end. I have 4047-supposed to be same alloy as slugs. 4043 would work. Quick dab and done. Shouldn’t anneal the piston.

View attachment 412137

I don’t think you need to worry about the lowers too much unless they are truly shrouded. You have some leeway because you have case/jug volume mismatch there. I’d even them out, use slug 2 with the welding, and shorten blowdown-especially because you’ll be lowering case pressure with any lower mods.

Edit. You can just do 2 dabs on the exhaust sides of the ring groove. You’re short circuiting case pressure out of it now.

That's exactly what I ment when I said weld the end of the ring gaps in post #207.

You explained it way better than me!

 

[NateSaw]

That's exactly what I ment when I said weld the end of the ring gaps in post #207.

You explained it way better than me!

Seems I need to try it! I wasn't blowing you off brother. I think I need to do a tad more port work, then seat the cabers in... From here on, I plan to run the saw alot between changes. I wondering though, if the first change should be to bite the bullet and mod my riser to accept the wj....

 

[Powerstroke Cowboy]

Seems I need to try it! I wasn't blowing you off brother. I think I need to do a tad more port work, then seat the cabers in... From here on, I plan to run the saw alot between changes. I wondering though, if the first change should be to bite the bullet and mod my riser to accept the wj....

I didn't feel like I was being blown off. There's only so much time in a day to mod things. If one always jumping around trying something new, you never get anywhere.

 

[NateSaw]

Great thread, I love seeing the effort and modifications necessary for these types of builds. You’ve done a lot of work keeping everything clean and as proper as it can be! Takes serious time.

I’d be getting more air through that HD, numbers are fairly close to what I would start at. Seems to be running decent.

Typically if you’re willing to do this much work I’d look at adapter a crank with a longer stroke before cylinder swaps personally!

Thanks Ethan. I'm pondering the wj mounting conundrum. I'm studying an hd50a vs an am wj as we speak. I need the short atomizer from a wj to try boring the HD series. On the choke side they measure the same. It'll be all about the venturi. The am wj's atomizer measures 0.213" on diameter, and the oem HD is 0.215". I'm kinda hoping the 2thou difference is am vs oem. If I had a wj atomizer that would measure the 215thou, it'd press into the HD and fit the bored venturi.

 

[NateSaw]

Anyone have a wj atomizer they could measure out? I'm tempted to buy a full wj rebuild kit w/ atomizer. I'd like to confirm if they are 0.0215" in diameter first.

 

[Rich Fife]

Anyone have a wj atomizer they could measure out? I'm tempted to buy a full wj rebuild kit w/ atomizer. I'd like to confirm if they are 0.0215" in diameter first.

I might have a spare in the carb/piston box. I'll go out and check.

 

[NateSaw]

I might have a spare in the carb/piston box. I'll go out and check.

Thanks!

 

[Rich Fife]

I have a WJ67B and a WJ140A

 

[NateSaw]

I have a WJ67B and a WJ140A

Idk if it matters or not. I have a duke's am wj. I'm torn between boring an HD, and making another riser to accept the wj series.
As you can see, things get tight and accuracy will be critical. I need a fuggin mill. This print isn't finished. I'll have to make fasteners that recess into counterbores to hold the riser to shortened stock studs. The fasteners will be bottom tapped barrels with slots in a flat top. They'd need to bottom in the counterbores flush with the riser to allow the intake boot a plane to compress against. The I'd have to tap the riser for studs at a 20.5* angle to mount the wj. There WILL be intrusion between counter bores and threaded holes without perfect accuracy.

 

[bogieboy]

Bruce and I did some things with me porting oem jugs, and him sending them to China to be copied. I got to see firsthand that the Chinese are 100% capable of doing very nice work. The prototype cylinders they sent us back for the 661 were absolutely beautiful. They ran almost as well as oem jugs that I ported.

Then, after giving them the green light....they sent Bruce 100 units of the most fughed up looking crap I'd ever seen.

Yep....they are capable. No....they are not honest, and will fugh over anyone for a buck.

The moral of the story? You have no idea what you are going to get when you buy this garbage.

With a bit of cleanup, the one i got from HL wasnt too bad LOL especially considering the clearance price on the 661 jugs... probably gonna pick up a second one to play around with here soon... see what gains i can make over the first one...LOL

 

[Rich Fife]

Without popping out the nozzle there is no way for me to get an accurate measurement... with digital calipers on the very edge of the bore I was getting .215 sooooo idk. I'm not gonna pop out the nozzle on a perfectly good 660 or 661 carb... lol

 

[NateSaw]

Without popping out the nozzle there is no way for me to get an accurate measurement... with digital calipers on the very edge of the bore I was getting .215 sooooo idk. I'm not gonna pop out the nozzle on a perfectly good 660 or 661 carb... lol

Don't do that on my account. Someone probably has one loose rattling around a carb parts organizer!

 

[NateSaw]

With a bit of cleanup, the one i got from HL wasnt too bad LOL especially considering the clearance price on the 661 jugs... probably gonna pick up a second one to play around with here soon... see what gains i can make over the first one...LOL

Is there an mmws 661 jug?

 

[Dolkitafreak]

Thanks Ethan. I'm pondering the wj mounting conundrum. I'm studying an hd50a vs an am wj as we speak. I need the short atomizer from a wj to try boring the HD series. On the choke side they measure the same. It'll be all about the venturi. The am wj's atomizer measures 0.213" on diameter, and the oem HD is 0.215". I'm kinda hoping the 2thou difference is am vs oem. If I had a wj atomizer that would measure the 215thou, it'd press into the HD and fit the bored venturi.

Remove nozzle, bore, reinstall!

 

[Mastermind]

Nate, I'd recommend boring the throttle bore out to fit a bigger throttle plate rather than boring out the venturi. If you leave the throttle bore size stock, and then bore the venturi, you will lose some of the pressure differential that creates the low pressure signal, then the carb will actually draw less fuel. A trick from back in the day was to use the choke plate, in place of the throttle plate, then bore the carb to fit. On the choke side, bore it over the same percentage it was compared to the throttle bore. Make a new choke plate....

Then increase the venturi in a D shape as not to cut into the fuel delivery passage from the pump side.

 

[Loony661]

Is there an mmws 661 jug?

Yes, I bought one from HL. Couldn’t pass it up - it was $15… We’ll see how it times out if I find a saw to put it on.

 

[Ketchup]

If you leave the throttle bore size stock, and then bore the venturi, you will lose some of the pressure differential that creates the low pressure signal, then the carb will actually draw less fuel.

This.

Sometimes there is no need to change the venturi at all. Just the bigger throttle bore makes a real change. More fuel.

Other times changing only the venturi will buy more air and less fuel. It depends what you need.
And where your idle jets are located.

On yours, I wonder if just going back to the original jet size would make a better top end. Many people
over carb a saw and just make it harder to find the good tune. You gained roughly 7cc, is that enough to matter?

It’s a rabbit hole. It can create a lot of idle and throttle up issues when you start boring the carb. Jet, bore, venturi all change your ratios. I spent as much time fighting the carb on one hybrid than the whole rest of the build.

 

[NateSaw]

Remove nozzle, bore, reinstall!

I like the sound of that WAY better than making another riser.

 

[NateSaw]

Nate, I'd recommend boring the throttle bore out to fit a bigger throttle plate rather than boring out the venturi. If you leave the throttle bore size stock, and then bore the venturi, you will lose some of the pressure differential that creates the low pressure signal, then the carb will actually draw less fuel. A trick from back in the day was to use the choke plate, in place of the throttle plate, then bore the carb to fit. On the choke side, bore it over the same percentage it was compared to the throttle bore. Make a new choke plate....

Then increase the venturi in a D shape as not to cut into the fuel delivery passage from the pump side.

Oh no doubt Randy! I had/have every intent on boring the throat to accept the wj butterfly... I wanted to emulate that carb in the hd body down to 1/2 a thou... Interestingly, the choke side on both carbs is the same. Idk if that's cause I'm measuring a duke's wj though...