various weed whacker designs and how they adapt for bikes

I think it would be great if other people put their opinions of their whackers or chainsaws in this thread so that we can make it a desitnation thread for people to check out when they are considering a whacker/chainsaw for a friction drive or other bike purpose.

So I managed to snag 7 used adn junky weed whackers for $15 earlier this past week. None of them will fit my needs to use for a bike but I figured I'd report on how the makes work in terms of use for a bike. Each company sticks with a similar design for all their whackers, so learning from these could be useful.
I picked ups the following:
2 Echo
2 Eager Beavers/Mccullough
1 poulan
2 Craftsman

So far I've only taken the larger of the Mcculloghs apart but here's what I can tell so far:

Eager Beaver/ Mcculough III-SL
Great Walbro carb- fantastic. It uses a standard cable for the throttle, so you could use derailleur cable for it, no more mushing together cables to force a fit.
The carb also has a long throw and a sturdy spring. The long throw means more variations in speed.

The clutch is tiny and the drum is thin and crap, won't last for long and won't stand up to a friction drive.

The housing for the drum is aluminum powder coated, very nice, the casing could be easily kept and cut to allow a spindle to poke out.

The connection for the clutch is short- no elongated shaft like on the ryobi and craftsman. But it is workable. I do not know what size nor thread it is.

The width of this whacker is also pretty narrow, much narrower than my ryobi. The gas tank is easily detachable leaving plenty of attachment points.

This brings me to the final thing about the Eager beaver that I like- the pull start is on the rear side. Meaning that no matter the friction drive set up one could keep the pull start. Something that I like very much.

I think that if you can find a Mcculough or Eager Beaver in the 30cc range it would make a fantastic friction drive. The set up is very good, lots of places to drill and connect, the set ups is very very sturdy, most of the case is made of powder coated cast aluminum. Its small and comes with a carb that will be very easy to adapt.

I'll get some pics of this engine tomorrow.

second on the hit parade are the echos.
I'm not stripping these down too far, they run and I plan on repairing them both and selling one and keeping the other for yard work.

Echo SRM-200BE Straight Shaft

The echo has the same pull start on the opposite side from the drive shaft, so that no matter the set up it can be kept.

The engine is also sturdily built, weighing more than the other whackers though it's the same CC. I dare say that it weighs more than the 31cc ryobi by a pound or so.

Everything on this whacker is cast aluminum, including the case for the pull start. It is also powder coated with echo orange.

The whole whacker is roundish and small, it is very small, engine itself doesn't weigh much.

The guts of it look a lot like the mcculough- short shaft for the clutch very very small clutch bell which looks a little tougher than the mcculough. I didn't look at the shaft that extends out of it though.

It's a very small squat motor. I would also deem one of these in a 30cc or higher great for bikes.


On of the first whackers I ever used was an echo, my Dad still runs that same echo on the farm 20 years later. when well maintained they run well for a long time. That suggests ot me that they would also take a lot of abuse.

deacon said:

I always wondered about the Mac WW. I never saw a mack with a rear pull start but I haven't look at one in years. I have to give it a second look.

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The Other Mac is a much newer model and a little different than the older and much more high end mac I put the pics up of. I'll get some pics of that tomorrow and report what it looks like in terms of making a friction drive or bike out of.

So far if I had my choice I'd probably go with the echo or high end mac in terms of sturdiness and being able to keep the pull start.

poulan twist and edge

I call this one the green monstrosity. Everything about this heap screams cheap. Based on what I see on this one I'd never buy a poulan other than for dirt cheap prices. I suppose that they come in a higher end models and this one is probably the lowest of the low model.

Everything is plastic on this thing. EVERYTHING.

There is no clutch.

The drive shaft on the fly wheel looks sturdy enough, but would need to be removed to put a spindle on.

The pull start would not be able to be saved without heavy modification or the creation of a special drive shaft

The case and the set up is big, bulky and clunky. The handle is molded plastic.

The engine is heavy and while it is 25cc it looks larger. I was spoiled taking apart the echo and mac...

The muffler is held on with springs. It is also caged with plastic that is attached to the rear of the engine, that must be kept on for the engine to run... Getting at it to clean it would be a beast.

Air filter is loose, even after tightening it.

The carb on this is walbro but it is very cheap. It has only a low end screw for adjustment. Also the end piece would have to be attached tot eh throttle cable, There is very little throw on this carb and it's essentially an idle and wWOT carb.

Though the engine seems very large it's flatish, probably the most narrow of the engines I've looked at today. This would easily fit in frame.

Verdict. I'd only use one of these if I got it dirt cheap. I'm not even sure I'd want to use this cheap heap to clear weeds in my yard.

I learn something every time I rip into one of these babies. Deacon- you've ripped apart a few whackers- What was your favorite?

Nest on the hit parade is the larger of the two Craftsman.

Now my first friction drive was made from a 32cc craftsman. This one is slightly smaller and from the same era as that one. Craftsman WW are made by Poulan. Some of them, like my first were of pretty good quality. This one... Well, it's of decent quality especially when compared to the poulan I dissected earlier.

No notes on this one from the guy I bought it from but here are mine:

LOts of plastic, The engine is fully encased in plastic. The late 80's styling had the gas tank molded into the case.

Pull start stinks.
No clutch. (my larger Craftsman WW had a very nice clutch.)

The short drive shaft will need to be removed to be of any use. The shaft itself is heavier than newer models and a die could be used to give it some threads.

The carb is Walbro, without a primer, only one line into the carb.
Carb is seated onto the engine through the plastic case. Without heavy modification the case is needed for this engine to run.

Muffler is held on with springs, but muffler comes apart for cleaning the insides. It is inside the case covered in plastic.

Plastic is held to the engine through a series of bolts. These are all easily removed.

The craftsman uses an Allen bolt for almost everything.

The full plastic case causes some issues. Namely the unburnt oil collects in the case and builds up a black gummy mess, which I'm sure smokes like he!! every time the thing is fired up. Additionally stuff sticks in it, like grass, seed and in the case of this one cat hair. This was one disgusting weed whacker.

I couldn't get it clean and I'm sure I can't find parts for it so... I'm taking it apart to "play" with.

A few note from my first Craftman build... They are a pain in the butt to work with.the plastic case must be heavily cut and chopped for it to be used as a friction drive. Even still the thing is heavy. Though you may not care too much about weight when riding a motorized bike it is heavier than a newer WW. What can I say I got it for free.

So I fully removed this engine from the case. I needed part of the case so that the engine is sealed and the carb has a place to live. I used my trusty dremel and cut the part from the case that I needed then cleaned it up and reattached it and the carb to the engine. I sprayed the whole engine down with WD40 and gave it a good scrub. A quick spritz of carb cleaner cleaned the last of the mess off. It's not perfect and it doesn't shine but it looks a lot better than it did. This engine was run with a very rich mix in it and put away wet and dirty. I don't understand people that don't care for their power equipment. It's expensive so why not care for it a bit? I wish I'd gotten a few pics of what this thing looked like before cleaning, it was freaking gross.

One the engine is out of the case it has a lot more going for it than before- it's small, lightweight, that one line in carb means it'll only need one line going to it from whatever gas tank one decides to use. There are also multiple attachment points where the case had attached. These could be drilled out easily and larger bolts put through them or tapped.

I'll get some pics tomorrow its too dark to get them now.

A Craftsman build would not be an easy one but not a totally bad one. Lots of plastic to contend with and if you don't want that plastic then you are going to need to be adept with a dremel.

deacon said:

Im going to have to buy a dremel tool. I think I have about everything else. I bought an angle grinder as part of my welding things and find that I use it a lot more than I thought I would.

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Everyone should have a dremel. Home Cheapo is having a sale on them for the holiday season. One of them was $60 and the other $80 and they had a set of almost every attachment for $30. IF you are going to do it now would be a great time to get a good deal.

The best bit for cutting the plastic FAST is the rotary tool bit- cuts in any direction and fast. Then there are a couple of smaller diamond bits for shaping and a drum sander for smoothing.

My dremel is my most used tool.