RE: Echo BME twin
 

so that means that keith has the crankase back in order?

RE: Echo BME twin
 

I don't know Keiths plans.
I simply ordered 2 more blocks
and will have my first one done soon.

RE: Echo BME twin
 

I don't think he has any plans on making this engine again. When I bought my two cases from him I understood that they were new old stock and there were something like 40 of them available. When they are gone that would be it. Besides, the market for engines and planes is tending bigger. Wouldn't surprise me to see the 50cc class go away as the singles get bigger and lighter.

RE: Echo BME twin
 

Guys I need a couple of Reed valve assemblys.

Does any one have them?

How abour pieces to them?

Ralph

RE: Echo BME twin
 

Guys I'm so close yet so far away.
The belt broke on the Harbor Freight lathe.

I'm down to needing a Prop Hub and making some gaskets.

For some reason the piston squish is less than .015.
The piston almost hits. I need a thick base gasket for clearance.

RE: Echo BME twin
 

You could use 2 stock gaskets if you need to rather than one thick one.

RE: Echo BME twin
 

The stock base gaskets are pretty thin, I wouldn't gain much.
I was planning on using permatex. Now I have a .010 gasket
and that will probally compress to just over .005.

I'll assemble it and use clay to check final clearances.

RE: Echo BME twin
 

Ralph, did you find reed valve assemblies? I need two as well.

I use 1/8" diameter rosin core solder to check my deck height. Just bend a 90 degree angle in the solder, and insert it into the plug hole so that it touches the cylinder wall. Then turn the engine over a couple of times to flatten the solder. Then pull the solder out and measure your deck height. (Piston to head clearance.)

AV8TOR

RE: Echo BME twin
 

I have a couple reeds lined up, but the deal is far from done.
I should find out this week sometime. If I come up with some extras I'll give you a heads up.

The solder idea sounds pretty good. We used clay to see if the valves were close to hitting the piston.
But there are no valves to worry about here.

I noticed you have 2 different prop hubs for your twin, which do you like best?

I'm having the one with set screws made. But it's not to late to change if I do it soon.

RE: Echo BME twin
 

Yeah, I use clay on the hot rod V/8 engines I do, but the solder is easier with these little guys.

Actually it's the same prop hub; it just wasn't finished in the first photos. I added the set screws later.

Let me know if you find another two reed assemblies and I'll buy them.

Take care,
AV8TOR

RE: Echo BME twin
 

av8tor: Did you add the 2 set screws because of the left-hand thread setup? Thanks Capt,n

RE: Echo BME twin
 

Hi,

No, I just added them because I have one someone else made for my Poulan 42cc that is done that way and I liked the look of it and thought it was a good idea. I modified the crank for a right hand thread stud like the series of pictures I did for you in the other Echo thread.

AV8TOR

RE: Echo BME twin
 

What threw me off is one uses a bolt and the other must use a stud.

So the Bolt or Stud threads into the crankshaft.

I ended up with a hedge trimmer crankshaft.
The prop hub will thread onto the shaft and be locked down with a set screw. There is a flat spot on the
shaft already that drives the cutter.

And the prop bolt will simply thread into the fat end of the prop hub.

Well my prop hub has been put off a few days. I may have it by the weekend.

RE: Echo BME twin
 

Yeah, in those photos, it just had the normal prop bolt. But I later made a hub that uses a stud all the way through, and as you noticed, the set screws. The prop just fits onto the stud with a nut. Later I will use a hub nut if I don't use a spinner....

AV8TOR

RE: Echo BME twin
 

Well it looks like my connection on carburetors just fell through.
What carb. are you using and where can I get one reasonable?

If it's not one thing it's two.

RE: Echo BME twin
 

I'm using a 13.5mm carb. I'll get you the number tomorrow if you like. It's just one I had in my box of carbs. E-bay seems to be the best deal on carbs according to the guys here in the forum.

AV8TOR

RE: Echo BME twin
 

Once I found out that these engines are sub-7000rpm engines My thought went to
wondering why the big ports?

The 2100 series engines, 21cc, turn 9500 to 11000rpm according to Echo.
So why the fuss about large ports?

Also the carb size. I know there are people out there that can figure the CFM.
the stock carb flows now and how much the twin will flow.
It may run pretty good with a stock carb, but maybe not.

I have the parts now to build a stroker engine. I'm going to use the 25cc engine's crank which has a 2mm longer stroke
and the 21cc pistons which is 1.8mm smaller than the 23.6 cylinder. So it will still be a 21cc engine, times 2.

My hope is for an engine that will be more effecent because of the smaller ports and great low end and mid range because of the smaller ports and the longer stroke.

In theroy this should be the perfect all around engine.

I just need to get that stupid prop hub made so I can test it.

I'm just wondering what you guys think.

RE: Echo BME twin
 

I'm going the other way... I am going to build another one with all the mods like my 23.6cc stroker engine. I'm going to use 25cc crankshafts and ported 23.6cc cylinders and see how it works out.

AV8TOR

RE: Echo BME twin
 

I think I know a guy that has Big Tiger 10-10 fuel about 35 miles away. I may run over and pick some up soon. Ralphbf.... where can you get a new belt "FAST" for a Harbor Freight Lathe? It seems just like Grissly, and a couple other brands of lathes. Mine is a #44859 8x12. I got to get a spare belt . If you cut in slower speeds....maybe a stretch-abe vacume cleaner belt will get you buy!!!! Capt,n:D

RE: Echo BME twin
 

"where can you get a new belt "FAST" for a Harbor Freight Lathe?"

The parts manual shows 2 belts for your lathe: a simple V-belt and a cogged timing belt. You might try McMaster-Carr. It has 2L and 3L v-belts. If it's the cogged belt that you need, McMaster has some, but the correct dimensions may be harder to find. John

RE: Echo BME twin
 

The belt is on order. 7 to 10 days starting 2 days ago.

It's not my lathe so I don't know what it takes.
Jack said he picked up a cogged belt that should work as long as he takes it easy.

Thanks Guys

RE: Echo BME twin
 

AV8TOR, that is exactly what my plans were before I talked to Keith.

This will be very interesting to see how each engine performes.

I don't understand the 7000rpm barrier, I just accepted it for some reason.

RE: Echo BME twin
 

It's going to be a bit before I get around to doing the next one. Too many projects. But I have the crankshafts, etc. One of these days...

AV8TOR

RE: Echo BME twin
 

I should have mine finished in 7 to 10 days, if the cranks and rods are good.


Ralph

RE: Echo BME twin
 

I'm still waiting on my prop hub.

But my friend tried to start his today.

I noticed a run out between the prop hub and the case.

Picture is not good but the crank has .012 run out.

It looks like the shaft is bent from the front bearing out.

The problem with used free stuff is that it is used and some times abused.

Luckly all we will loose is our time.
In 4 echo dealers we have came up with about 35 engines.

We will be inspecting a little closer from now on.