Chainsaw masacre

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Now I know some of you deal with chainsaws now and then. Some of you surely deal with weed whackers so try to follow along and then HELP ME PLEASE..

I bought this chainsaw that was supposed to be a factory rebuild. I got a really good deal on it because it had parts missing. Didn't matter I wanted it for the motor I worked around everything else but now I screwed the pooch.

I tried to straighten what I thought was a bent throttle lever. I broke the brass rod that made the whole thing work.

Follow this if you can cause I am having a hard time following myself and I'm looking at it.

The engine has two intakes. One is for the fuel air mix from the carb but a second one is for pure air to the cylinder as it throttles up. Since I broke the carb and since the motor is 33cc I decided to try a more or less new carb from a 31cc weedeater.

So I put some tape over the pure air intake thinking it was kind of a ram turbo charger kind of thing for when you ratchet up the throttle to cut with the chain.

I put the weed eater carb on and gave it a try. I got it to start on full choke something it should not have done. I got it to respond to the throttle on 1/2 choke. It wanted to die on no choke.

It was also idling way too fast. Right or wrong I tried to adjust the carb. Those carbs have a high end and low end adjustment. I was working on the low end and the idle screw as well. Then of course the engine died. It wouldn't restart on any choke setting. Still wont

I sat down to think before I went on. I right or wrong decided that air was getting past the tape I put over the direct air vent into the cylinder. So of course I found a cap that more or less fit and I put it on with some blue gasket seal hoping to cut out the air.

Now it wont start at all. So here are the questions Lawn care gurus and chainsaw wielders.

What is the factory setting for the 2 carb adjusting screws. It ran at factory settings last I need to go back there and try again when the motor has rested lol.

Is it possible that there needs to be a small amount of air through the direct vent to get the fuel air mix right. If so I can start drilling holes in the cap by starting small and moving up. I can always take it off and start over I have plenty of the caps. I'm just not sure that it needs that. It seems that the motor should run from the carb alone since it runs a weed whacker of almost the same size and it did run it earlier. Still it might need more air.

It might also be that I have other air leaks or the cap isn't sealing well enough.

I need the factory setting for the carb adjustment screws. The carb is for a ryobi 31cc weed eater. I can't find the factory settings. Thanks guys
 
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stude13

New Member
May 28, 2008
404
0
0
north bend wa.
hi dec; it would seem if it ran with some choke it needs more gas to start. start the needles at 3 1/2. try a tool rental mech. good luck mitch
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
237
63
up north now
The air intake is for the COOLING FAN. Don't run the engine without the COOLING FAN air duct working. You will burn it up.

If I remember right, the screws on those carbs turn IN for richer, OUT for leaner. Get a baseline setting (1 1/2 turns from all the way in) and go from there.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
It was the kill switch I forgot I had turned it on. Duh ...

The second intake kills the engine if I open it up. The carb had a swing that only allowed it to open when the engine was running on high. It goes directly into the cylinder that I am sure of. The cooling fan is ducted differently. I can replace the shroud on this one and I will before I run it.

The 31cc carb seems to work fine today since I turned the kill switch off. I will have to make an air filter for it but it seems to be just fine. I'm really surprised. Thanks for all the help and the information.

Three and a half turns seems to be right for the low end adjustment. I had the carb mounted screwy is why the thing was giving me such a fit. I had to cut some of the round choke plate to make the carb's throttle control work right but it didn't seem to hurt anything. Since it's running and takes gas I'm going to leave well enough alone.

Thanks guys as always the help is greatly appreciated.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
I must not have explained the air intake thing correctly cause my son in law and I were brainstorming yesterday and it is the choke mechanism. The bike starts with that air vent closed, then after it starts at idle when you open the throttle, it pour pure air into the engine to lean out the mixture of gas/air. It took us a while to figure it out but that's what it does. It just leans out the mixture like turning off the choke automatically. Actually it is the automatic choke mechanism. I have no idea what will happen when I put a load on it without the massive air intake being open. It might just be like running at 1/2 throttle.

I still need to devise some kind of very small air filter for the 'new' carb. I'm thinking bottle cap with a small amount of oil soaked cloth one layer. Lots of holes in the cap,
 
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deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
I need to get back to work on the chainsaw bike. I think after the front end 31cc is running I will try to finish the chainsaw bike. I got the motor to work with the 31cc carb so all is read to ride to be honest. Probably something else I needed to do but I don't remember. The joys of getting old lots of work you don't have to do because you simply forget it needs doing.
 

Jemma Hawtrey

New Member
Dec 29, 2007
288
2
0
Essex, UK
Hi

If I am right then that second port is a stratification system port...

its one of the methods use to make clean burn 2-strokes and it was used on the Zenoah engine as fitted to GEBE's in the past.

Im not exactly sure how the system works but I *think* the idea is to dilute the exhaust gases and also to form an air block so the mixture in the crankcase at that point cant vent to air either way - which maybe something to do with the reason why the little Zenoah kicked so far above its weight.

Its just a suspicion. It would help if you had a manufacturer for the motor so research could be done :)

Jemma xx
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
The engine is made for poulan i have no idea who actually manufactured it. My guess would be someone in china.

I think it is the automatic choke mechanism. They call their first step setting the fast idle... At that point the massive air intake is closed. When you throttle up it gradually opens.

A chain saw is under a great deal of stress when it is cutting so it might be just to lean it out and make it more efficient. When I get back to the darn thing I will know more since I haven't ridden it with the 31cc carb yet. When I do I'll know more.

I just have tooo many projects half finished. I am going to finish the mtb front wheel drive 31cc before I do anything else. Then I think the chainsaw bike is next.

It's time to wrap us this building frenzy and move on to something else.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
So I put aside the little 25cc and went back to work on the chainsaw bike. The first thing I did was to take the engine off the bike. The mount was not very secure. Probably why I kept putting it off.

The new mount and getting new holes drilled and then getting it assembled took a lot of the day. Once I had it secured to the bike frame I tried to start it. It just would not start. I just knew I had plenty of gas. I had been pouring gas into the tank off and on as I had gas left over from other builds.

I finally took a look and it was all gone. Evaporated or leaded I have no idea which. I put on a different tank and some gas but somehow from an empty tank I managed to flood it. I pulled the plug and let it sit in the sun for an hour while I switched out some tires. I put the tire and wheel from the sissy test bike onto the big ole huffy with the chain saw. I had just bought a new rear tire for the test bike so I might as well use it on the chainsaw bike.

Then I put a clown tire on the test bike. I might try to start it after I finish the chainsaw bike.

The chainsaw bike started fine after I let it dry out. I think it might not need to be choked with that carb on. I'm not sure since I was having all the dregs of the gas trouble with it. I should know tomorrow.

I built a couple of air filters. I wound up using to peanut butter jar lids and some foam rubbler I had laying about. Actually it was one peanut butter jar lid and one dukes mayonnaise jar lid. That is what's on the chain saw.

It's two peanut butter lids on the 25cc bike. I am going to change the construction of the 25cc air filter. I think it might be choking the bike. Use the thin foam and cut more holes in the top. I had one of those donuts with just a few holes. That's tomorrow's project.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
This one hour job, (rig the controls and install a new drive wheel) took all day and Im exhausted and not sure it works yet. Im taking a break until tomorrow.
 
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deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
thanks to uncle kudzoo I have the prefect gravity clutch lever. He donated a old school shifter for me to use in a build. I decided it was too good to convert to a throttle so I hooked it up as a lever for my gravity clutch on the chainsaw bike and it seems to work perfectly. I'll add some pics as soon as it stops raining here.
 

Ilikeabikea

Active Member
Jan 27, 2008
2,323
0
36
65
Ptown, Texas
I can't wait to see it. I need to build a chainsaw bike and call it the Texas Chainsaw Massacre.:DThe town that movie was made about is just about an hour and half from where I live. Creepy huh.............................
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
I love it cause the chainsaw is what got massacred.

I never saw that movie cause I think violence for the sake of violence is obscene not sex.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
This thread is correctly named.

Did you know they arrested a man up north for shooting his lawn mower. Well they better get a cell ready for me cause I just may shoot this darned chainsaw bike.

I was going to get up start it and ride off into the midday sun.. Yeah right and pigs are gonna fly.

Instead I spend the day moving it all up to the front because I thought I needed to change the direction that the engine ran. To force the drive wheel to stay on. It still fell off.

So I put the old one back on and tried to run the bike. I got half a block and parts started to fall off. I put it away before I shoot it. If the motor didn't start I would shoot it for sure.

I haven't ridden a bike for pleasure in a couple of days. Tomorrow I ride if it hair lips the devil.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Well back at it with the chainsaw bike. I got it rigged for front wheel drive and find that it is way way to heavy. I'm going to have to reset it for the rear wheel. I might just mount the silly fatherless engine upside down. For sure I'm going to rethink it completely. My neighbor is going to weld me a drive wheel base since I can't for the life of me make the darn thing work.

I sure am glad that I didn't chop up the suicide clutch lever.

That huffy frame it's on now is a monster. I might just move it all to the sissy english bike that I converted to a coaster bike.

I did find out why I was having so much trouble with the chainsaw motor. That second air intake was sucking air from around the cap I put on it. I hope to heck it is fixed now. I am really losing patience with this thing.

The 31cc does all I wanted a second bike to do. I can replace the engine for 75bucks for a new one and just bolt it up. There is really no need to have three bikes two will do just fine. however I really do want to test that bigger engine again. I did ride the bike once and it did really well. I had an 1 1/2 inch drive wheel. I would like to do it with a 1 inch wheel before I give up on it.
 
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deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Okay I went back to work on the chainsaw bike. That thing has two speeds low and wide the devil open. Nothing in between. However I can't get around the block yet. The motor seems to be bouncing up and down on the rear wheel. I believe it is a combination of two things. I know the drive wheel is a little out of balance but I have ridden the bike before with it and it was fine.

I can't for the life of me remember why I didn't leave it the heck alone then. Anyway, I have changed the tire to another bike and this is a knobby on it and I think the has something to do with the motor moving. I also thing I don't have enough tension on the drive wheel.

The clutch lever is okay to work with more tension but the brake lever cable clutch is too hard to pull. That engine is one heavy mother.

I had a heck of a time with the gas tank today. I started with a two quart thermos bottle gas tank but it wouldn't do right with the pedals so I mounted one that is about a pint. I works better with the pedals but I found out you can not fill it all the way up cause when you pump air into the tank to pressurize it, the gas has to go somewhere. All over mostly.

I did find one useful item today though. I found a turkey baster works great to fill those little tanks on weed whackers when they aren't quite level. I think I will add that to the tip section.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Well I got the bouncy bouncy issue solved. It needed a stronger spring and a less knobby tire. I got about half a block and the throttle cable got loose from the vibrations.

After an hour of redesigning and messing with it, I had the engine flooded I think. I'm giving both of us a break for a while. It should do just fine.

Now one of you gearheads explain to me please, why a 33cc chainsaw motor has so much more torgue than the 31cc Weed Whacker motor.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
It's official... I am renaming the chainsaw bike the spruce goose. I rode it about two miles today and decided that it ain't go nothing special going for it. The engine is heavy and cumbersome. The controls are iffy because they go all the way to the rear. (I have gotten way used to the front wheel drive bike now.) So the goose goes into storage for the time being. I might resurrect it one day or I might build a museum around it.

Either way I am satisfied since I got it to run.

I am now convinced totally that the easiest bike to build and maintain is the front wheel drive 31cc weed whacker friction drive. At least it is for me. Matter of fact I'm going down to take it for a ride right now.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
I have FINALLY beat the chainsaw bike into shape. I rode it today and all the controls work perfectly. The drive wheel is the right size but not rough enough. I put sand and jb weld on it. I am going to let it cure at least two days. I also found that with the smaller drive wheel my clutch is slipping. I just realized that was part of the problem so I will have to adjust that when the jb cures.

But the bike is usable now.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Well I rode the chainsaw bike and it is a qualified success. I did my mile test track the short version because I was low and gas and forgot to till it before I left for the ride.

It does have more pull than the 25cc of course. I could climb the big hill more easily. Matter of fact it was still gaining speed as it went up.

Even more interesting, I could drag start it. I warmed it up with the pull rope but it died when I dropped it to the hand clutch. So just on a whim I kicked it a few pedals and dropped the hand choke. It started after a few feet. It also died when I turned it in the road so I did the same thing and it fired right up again.

I think the ability to start is about the clutch adjustment and the better friction wheel more than the compression. The jb weld and sand works very well. I have no idea how durable it is but it worked.