New Guy With a Couple O&R Questions

[O&RBike 47]

Howdy all. Helping my son build a small (BMX) 20" bicycle that uses a 1HP O&R engine as a power assist. The idea will be to pedal it up to approx. 10 MPH and then let the motor propel the bike to (hopefully)20 MPH if geared properly.  Not sure if it work but it will be an interesting exercise for his mechanical engineering project.

 

I am new to these engines and have a few questions . It has a  1/2" sleeve with an internal taper that mounts to the crank pto. It looks to be  maybe a 10-24 grade 5 fastener holding it on...doesn't  instill a lot of confidence. Is there a torque spec for this screw..? Can I swap it out for a grade 8 socket head cap screw? 

 

Regarding the strange doughnut shaped exhaust manifold...can I loosen the cylinder head/barrel assembly just a little and rotate that exhaust to point in the direction I want it to and then snug it back down again? Do I need to change the gasket or seal once I break it loose? Is there a torque recommendation for this or just make it "tight"...?

 

Thanks in advance.

 

Gerry

[Wallfish 698]

Hi Gerry,

You can swap that bolt/screw to whatever you want.

Yes the head will unscrew and you can rotate the exhaust manifold and tighten back down. I don't know a torque setting but haven't had any trouble just getting them tight. Sometimes the gasket tears and will need to be replaced if it does.

They make a gearing system for a bike application and it was called "Chicken Power". You can find some pictures if you scroll through the posts here. Friction drive on the tire but it sounds like this one is going to  be a custom setup.

[O&RBike 47]

Thanks Wallfish. Yes I have seen the "Chicken Power" engines in the past but never owned one or knew much about them. I saw a crazy articulated scooter called an Eel Wheel too.

 

This one will be clutch and chain driven. I will try and post some pics as we progress....or maybe not if it doesn't work lol.

 

The screw that holds the pto shaft on feels like it is an interference fit on the thread..perhaps to keep it from backing out ? Any recommendations on the torque here or just use my best judgement ? Don't want to snap it off.

 

Thanks again.

Edited August 8, 2015 by O&RBike

[Ian 2,417]

Hi Gerry, welcome to MOM. Have fun and make yourself at home..

That sounds like an interesting project, I look forward to seeing your progress

[Wallfish 698]

Use your best judgement for torque on that screw.

I assume you are going to use a jack shaft to get your correct ratios.

[O&RBike 47]

Thanks again, yes we're using a jack shaft setup with a final drive ratio expected to be about 18:1.

 

Ran the motor for the first time today.We're running some 16:1 (castor + 120 octane) mix we had already made up for a West Bend 580.Thought it might foul the plug but it seems to like it...runs good.

 

We did notice one odd problem. The recoil operates fine unless the motor is running, then instead of winding the rope back in it actually it wants to feed it back out. The starter pawls or whatever is in there must not be retracting fully. 

Edited August 9, 2015 by O&RBike

[Wallfish 698]

The pawls should have small flat springs which close them for starting and then the centrifugal force of the flywheel spinning when it starts should force them out to stay disengaged. Sounds like you may have something binding them up in there.

 

I use normal air cooled 2 stroke oil mixed at 32:1

[O&RBike 47]

We'll pull the recoil cover off today and take a look. Is that synthetic 2-stroke you're using..? .seems that's all the stores have now.

Regular 87 octane gas?

It's hard to find non-ethanol fuel around here I hope it doesn't destroy the carb diaphragm.

[Wallfish 698]

I use regular 87 octane and have no available stations that sell non ethanol gasoline. I only use my engines for display and don't really work them so it doesn't really matter to me. Yes the ethanol will eventually turn the diaphragm into cardboard so if you plan to use the engine I'd suggest paying the money for a can of Trufuel. They sell ethanol free fuel in expensive cans at mower shops and Home Depot.

 

The original specs of the engines suggest using 30w oil but oil technology has changed so much over the years. Yes, i use synthetic oil

 

Let me know if you need any pics of the pawls if it isn't apparent what is binding them up

[O&RBike 47]

One of the pawls was sticking...we removed them both, bent the springs up a little to add tension and put it back together with a few drops of oil on the pivot points.. Seems to work good now.

Lot of end play in that half of the crank..!! Looks like .100 or more. If I'm guessing right the little brass eyelet in the center of the recoil cover acts as a thrust bearing to control this which is why you need to add a drop of oil every so often. What a strange little motor.

We loosened up the cylinder and rotated the exhaust manifold where we needed it to be...seemed to go alright I don't think we damaged any of the gaskets.

There was once or twice while we were running it over the course of the day where the motor appeared to "run away"  ...that is the the throttle was in the idle position but the engine seemed to be accelerating. Maybe it was my imagination or I was breathing too much 2-stroke exhaust. :-/

Thanks for all the help so far...I'm sure I will need more.

 

-G

[O&RBike 47]

Curious what you guys are using for throttle cable setups on these. I'm trying to rig up a mini bike type twist throttle and looking for ideas. It doesn't seem possible that it will spring back to idle unless there is some kind of return spring in the handlebar throttle itself as the spring at the butterfly is so light.

 

What does a stock throttle  cable look like ?

 

Thanks

[Wallfish 698]

The O&R throttle setup on these carbs are a little different for hooking up a throttle cable in the sense that the cable does not pull the butterfly open, but it needs to push the butterfly closed to get to the idle position.

Most twist throttles will have a return spring built into them.

 

here's a pic of an O&R throttle. Not sure where to get the small conduit but maybe a bicycle shop will have it.

Where about in Jersey are you? Grew up in the Cherry Hill area across the bridges from Philly.

 

[expeatfarmer 591]

I came across a method of removing Ethanol from fuel using water there is a kit available but basically it is a matter of adding water to the fuel which then is absorbed by the ethanol and separates out then with a steady hand you pour off the petrol and leave the ethanol. No smoking /naked flames etc. if you try it.

[expeatfarmer 591]

link is www.ethanil.co.uk

[Wallfish 698]

Not sure why this posted in this thread but removing the ethanol also lowers the octane. Best to start with high octane fuel and add an octane booster BUT, make sure you research the booster because most are made with some form of alcohol, so adding it back into the fuel doesn't make any sense. You will need to find a petroleum based octane booster. I know Lucas makes one but I'm sure there are others.

Funny, I just did some research into this exact thing a couple days ago. I sent some questions into a site which explains most of this but didn't have anything concerning the removal of ethanol with water to use the fuel. Hopefully they will answer back

[O&RBike 47]

here's a pic of an O&R throttle. Not sure where to get the small conduit but maybe a bicycle shop will have it.

Where about in Jersey are you? Grew up in the Cherry Hill area across the bridges from Philly.

 

OR throttle.jpg

 

 

 

 

 I am in Cranford...pretty much in the center of the state. 

How hard is it to find an original throttle...do they come up for sale on this forum or Ebay? Should I be searching under Ohlsson & Rice or Orline? 

Edited August 15, 2015 by O&RBike

[Wallfish 698]

Have only seen 2 show up for sale but that doesn't mean I missed some. They come mostly from Chicken Power engines. The one in the pic came from an Orline hedge trimmer.

You can try sending a PM to member Webhead and see if he has one for sale.

As a last resort, I can probably sell the one in the pic even though I need it for a Chicken Power. I'll never use it to mount on a bicycle but I like to keep my engine stuff complete. I'll let it go if I have to because I'll probably come across another one before you do. It will need a longer conduit and cable for use on a bicycle.

[O&RBike 47]

As a last resort, I can probably sell the one in the pic even though I need it for a Chicken Power. I'll never use it to mount on a bicycle but I like to keep my engine stuff complete. I'll let it go if I have to because I'll probably come across another one before you do. It will need a longer conduit and cable for use on a bicycle.

 

 

 

 

'That would be most awesome if you are willing to part with it just name a price. I usually take forever to finish a project and it doesn't bother me to look for weeks or months for a part but this one is for my kid and you know how kids are he is all amped up to get it done so he can ride it around school.

 

I'll take a look around first.

Edited August 15, 2015 by O&RBike

[O&RBike 47]

Ok O&R gurus.....Every once in a while the engine will not want to idle down even though the throttle is fully returned and the governor/butterfly is closed it begins running at a high speed.....  I'm not sure how its even possible since the butterfly is shutting off the air supply and venturi effect. Its like the engine is running away.

Then it will stop and idle normally again ?? Do these carbs have an actual idle circuit in them. Is there some way the fuel could be circumventing and feeding through the high speed circuit ? 

[Wallfish 698]

Something could be causing a lean condition which does cause that to happen. ( such as: running out of gas, dirt in carb, clogged screen in tank, pinched fuel line, you get the idea)

Also be sure the governor arm is secure to the carb and not bent or rubbing anything.

Be sure the butterfly is closing and not binding when the cable is moved to idle position. The cable can sometimes slip off and not push it closed

There are not separate circuits for idle and high speed

[O&RBike 47]

OK thanks....I'll check out the possibility of a lean condition.