Echo CST_610 EVL twin cylinder chainsaw

[mikenlapaz]

Echo CST-610 EVL Twin cylinder chainsaw

Item number: 160200813701

Got carried away and bid on this. I rethought my position, too many project and not enough time. There are several threads on converting these on RCUniwerse.

112 puts you in the lead. Put this classic opposed twin in the air. Ralph Cunningham has converted one of these before and they have been used as base for another well known twin of a few years ago.

[rcign]

The crank and one cylinder are/were used by D&B, BME, and Spehar twins......One cylinder has the spark plug at a funny angle, about 25 degrees down, so D&B and Keith used the other cylinder on both sides..The odd cylinder can be rotated 180 if the locator pins are changed, but the spark plug still looks funny...The stock carb manifold has the carb parallel to the cylinders, so most conversions make a new vertical carb insulator block, some use Homelite 4 petal reeds like in the Fox twins... .They run about like a G62, but very smooth.....Last one I bid on went for $275 to someone else....
Keith makes some of his twins with bigger bore cylinders, using bronze bushings in the pistons to match the wrist pins to the crank..I think the BMEs over 95ccs use proprietary cranks and rods....

[mikenlapaz]

Ralph, when I saw it and bid I was thinking, "I wonder if I should just have it sent directly to Ralph and have it done converted correctly" Then rethought overall position.

[rcign]

E Bay being what it is, after 3 days someone will end up paying over $300 for it.....

[KrisW]

	Quote: Originally Posted by rcign
	The crank and one cylinder are/were used by D&B, BME, and Spehar twins......One cylinder has the spark plug at a funny angle, about 25 degrees down, so D&B and Keith used the other cylinder on both sides..The odd cylinder can be rotated 180 if the locator pins are changed, but the spark plug still looks funny...The stock carb manifold has the carb parallel to the cylinders, so most conversions make a new vertical carb insulator block, some use Homelite 4 petal reeds like in the Fox twins... .They run about like a G62, but very smooth.....Last one I bid on went for $275 to someone else.... Keith makes some of his twins with bigger bore cylinders, using bronze bushings in the pistons to match the wrist pins to the crank..I think the BMEs over 95ccs use proprietary cranks and rods....

Actually, when BME went to the long-nose 5.8, with 3 bearings, is when BME started using the proprietary crankshafts, then the 102 soon followed with the longer stroke crankshafts soone thereafter, but the Echo twin crank is a good starting point if a person is interested. This was the old "BME-61" that they marketed, and was one of surprisingly strong twins, for it's displacement. Usually a Twin makes about 85-90% of the power of a comparably sized single, but the 61 kind of defied that norm, and was a very stout engine for it's time (about 7-8 years ago now)

[rcign]

BME twin I had here had 5.8 machined into the plugs in the piston port holes in the cylinders..Blue anodized case, bronze bushing in the pistons, Echo twin crank and rods....SDC80 carb, Homelite reeds...

[KrisW]

	Quote: Originally Posted by rcign
	BME twin I had here had 5.8 machined into the plugs in the piston port holes in the cylinders..Blue anodized case, bronze bushing in the pistons, Echo twin crank and rods....SDC80 carb, Homelite reeds...

Don't forget the short crank shaft with extension. When keith started using the longer crankcase and third bearing it became the "100". Still the same engine but with a better crankshaft, redone rods so the pins matched the pistons, and of course the "100" caps on the ports.

[rcign]

Haven't seen the insides of any BMEs except this 5.8 and a few 50s....The cylinders on the 50s looked to have different (wider) transfer ports than the 5.8 twin....Seems like the twin would be better with the 50 cylinders ?

[KrisW]

	Quote: Originally Posted by rcign
	Haven't seen the insides of any BMEs except this 5.8 and a few 50s....The cylinders on the 50s looked to have different (wider) transfer ports than the 5.8 twin....Seems like the twin would be better with the 50 cylinders ?

Unfortunately, the 50 has a proprietary shortblock design, and the separated cylinder 50's are the ones Keith used on the 5.8/100. I have two of them right here on the shelf. The single cyinder "50" has 49 molded on the cylinder, and the 5.8/102 has "50" molded into the cylinder. Definitely different designs, as the single cylinder 50 hs a HUGE exhaust port compared tot he 5.8/102 jug, as well as much larger transfer ports.