My Cox Minibike

A Cox motorbike! This is going to be an interesting build.

I like the detail on the model already.

This is really cool! Great detail, looks like it's going to be fully functional.

Welcome to the forum!

Keep us posted!

Welcome to the forum. You have quite a unique project in progress. Looks like you have the skills to bring it to completion. The cox engine may be small part of the project. I did not keep any of the information on them but at the last Hobby Show I went to there was a group that specialized in miniature engines and cars. The guy had on display a fully functional drag race car ( rail ) with a small v8 engine. The whole thing was only 3 1/2 ft long, but sounded real nasty when started up!  So, I'm sure there are people out there who can fabricate spoke wheels with disc brakes/calipers ....you'll just have to find them!  
Keep us posted on your progress!

I perused quickly thorough this thread this morning before leaving for work. I really love the frame and front-end! Is this being modeled with a particular full-scale bike in mind.. maybe one you've owned or would like to own?

It looks like you have some room to make decisions on the back-end.. to maybe fit your primary-drive on the output-shaft side.. and final-drive on the opposite side.. sort of like a torque-converter/snow-mobile drive. This might help to balance the bike and give you more options with the final-drive ratio. You'd need to prepare the frame for a pair of bearings to support a cross-shaft. I'll bet you've already though about that.

The centrifugal clutch that Cribbs (Ron) spoke of.. would be an item to seek/source. Try searching Cox/Jerobee engine-drive parts on eBay.. and see if you can find anything. One of our members "overlord" (Lieven.. from France) has recent experience with the Jerobee clutch set-up.. and its' associated parts.. dis/re-assembly.. tuning etc. on a scale-model Corvette that he has, with a similar Cox .049 reed-valve engine. I'm sure he will find your project fascinating!

Please keep us up to date with your progress!

Welcome to the Forum !! I seen this early yesterday didn't know what to think of it BUT, it is VERY COOL ! Looks like who ever made some of the parts you show knew what they were doing . Don't see that you post a location but that will probably help in locating a CNC person to help with the manufacture of needed parts ? I bet Jessie James of West Coast Choppers would bee a candidate for making some hi dollar parts Just Kidding hope your project finds what it needs >> What are your intentions for it when completed ?

wow that is a nice project
welcome btw

hod did you get/make that water colling head
and also that radiator

Excited at the feedback!!  
The main points are to enjoy making it and the challenges that come with it, and looking at it when its complete! I'm a long way i think from settling, and as i tend to get deep into my little projects i build to my hearts content, so i can see myself building a box/display.
I myself ride a Yamaha MT-03 (14 model), though i've taken inspiration from this pretty new breed of motorcycles, which seem to cross all boundaries and mix and match styles from whatever goes. They say there was a category created just for the Yamaha MT-03 for example - The Motosport Motard. I love the creativity in the unique bikes i'm seeing over the web though!  Big fan of the retro racer kinda look, and also love the practicality of an adventure bike. Huge Steampunk fan too, so there will be a bit of brass, leather, and maybe a little wood? I think i've chosen a green for the seat?

I was searching for a Venom GPV-1 for parts when i learnt that they've been discontinued, though i was able to get a chain and a ZH Racing wheel adapter for GPV-1 & HOR, along with the Hot Racing Alloy rear swing arm, which i just might work for the look i want. The rest i also just ordered are transmission for the Kyosho HOR. Yeah running the chain from the opposite side "to balance" might be it.
Not totally sure how i will make it electric start and squeeze a magneto in there? At the moment i'm trialing bits i find around the web and in transit i have a geared high torque little motor which could suffice for the starter if the rpm isn't as sad as the other i trialed. Because i know these little Cox engines need a good fast kick to fire up. Originally i hoped to combine the magneto with the starter motor, though i doubt that's going to work, so i might fit it (whatever it is?) behind the engine main gear? No that's where i was putting the start motor drive... hm...

I made the air intake by chopping into a Zotac GTX560 graphics card, the engine cooler from a boat engine water cooler, with a filed down  heatsink. It fit so well i nearly cried! The tank took me about four days all together, and a mounting method and paint for it is not done. Rear swing arm fixture i chopped off a 450 helicopter blade balancer. A few things are but place holders for now just for the purpose of seeing how something else will work and therefore something else may need changing.

You speak of a magneto, but are you sure you don't mean generator? A magneto is for providing ignition spark, which this doesen't need due to having a glow plug & not a spark plug.

That's what i mean. Thanks for the correction.

Why not use the starter as an alternator
I do it with my diesel generator
PS diesel would make this project even cooler
But ignore that I am a diesel head

Diesel is definitely something i could think about, but i'm not sure if i'll need to make some special mix of fuel for that, not that i'll be running it often, but the goal is to have it functioning and if diesel lowers the revs closer to a more normal bikes idle..
Good point, then there is converting AC to DC for lighting and recharging. The smallest converter/regulator i could find is still pretty big, so i might have to design my own circuit, which is something i can do, but the circuit components on the other hand.. Small enough to fit under the tank?

If the starter is used as alternator you always have a DC system
And as regulator
Look at boost/Buck converters
They come in small packages

Wow thanks, surprised how small that 20x20x5mm module is, and much more compact than that other thing i was looking at.
The concave i made in the rear of the tank happens to be just on 20mm wide, so i think with a touch of the Dremel it will fit perfect

roddie wrote:I perused quickly thorough this thread this morning before leaving for work. I really love the frame and front-end! Is this being modeled with a particular full-scale bike in mind.. maybe one you've owned or would like to own?

It looks like you have some room to make decisions on the back-end.. to maybe fit your primary-drive on the output-shaft side.. and final-drive on the opposite side.. sort of like a torque-converter/snow-mobile drive. This might help to balance the bike and give you more options with the final-drive ratio. You'd need to prepare the frame for a pair of bearings to support a cross-shaft. I'll bet you've already though about that.

The centrifugal clutch that Cribbs (Ron) spoke of.. would be an item to seek/source. Try searching Cox/Jerobee engine-drive parts on eBay.. and see if you can find anything. One of our members "overlord" (Lieven.. from France) has recent experience with the Jerobee clutch set-up.. and its' associated parts.. dis/re-assembly.. tuning etc. on a scale-model Corvette that he has, with a similar Cox .049 reed-valve engine. I'm sure he will find your project fascinating!

Please keep us up to date with your progress!

Thanks to your post i had a search around for cox parts which may be useful, including the Cox - Jerobee-drive parts, which i couldn't fine, though i did find this Cox Queen Bee .074, which i purchased from ebay USA for $160 without blinking. This was the throttle control and muffler unit i was admiring some 7 weeks ago, and didn't expect to find one!
While i don't think the throttle control unit will fit the .049. Nit that i want to modify my model at this point because i am happy with it; though, i hope to use this on another bike model possibly. This shaft looks too long on this engine anyhow, so it would work well as i want to make the next shaft driven.

I need to find or make or find a clutch for this bike! I was hoping to have it controlled as on a real bike, but short on the precision machinery at this point. Maybe a tension system like i think this is, would work?

A little progress.

My Cox Bike wrote:
I need to find or make or find a clutch for this bike! I was hoping to have it controlled as on a real bike, but short on the precision machinery at this point. Maybe a tension system like i think this is, would work?

That "looks like" an idler.. but it's actually a band-brake that actuates when the throttle is closed. It's linked to the throttle-servo and wraps-around a groove in the clutch-bell set-up. Try searching Cox GTP Nissan/Maples throttle.. just to see what comes up. I'm not sure if the "Jerobee" models used the same clutch-system.. but I'd bet on it.

How will your cooling-system work? It looks real good.. with all that plumbing and all.. but what will you use to pump the coolant through it? The boat-modelers use a water-jacket that delivers fresh-cool water around the head, via a pick-up tube placed behind the prop for circulation. The associated plumbing carries the fresh-water in-around the head.. and expels it. A closed-system might not provide enough cooling.

Cox Hobbies used "heat-sink heads" on many of there non-aero powered models to help keep the engine cool. They look similar to the one in the above photo.. except they are totally-flat. You might be able to forego the liquid-system completely.. if it will fit within the bike-frame's perimeter.

Here's a photo of the Cox part#8477 heat-sink, designed for their "Sandblaster" model.. and used on many others.



Mounting-options are a linear 360 degrees around the glow-head. It measures 1-11/16"L x 1-1/16"W..  with the furthest point from the center of the head being 1-1/8".

I think you'll need to find a compromise between an exhaust-throttle sleeve.. and that box-header design that you currently have. An .049 exhaust-throttle sleeve will only fit an .049 cylinder that's been "milled" for it. They're usually obtained in pairs. Boxing the header could still be done.. but the sleeve would need to move within the stationary box. It may be better to keep it simple.. with reliable exhaust-throttle/open-header and air-cooled heat-sink head. You could then concentrate more on the centrifugal-clutch drive.

There are other reed-valve engine throttle-systems.. but they wouldn't lend themselves well to your 90 degree engine-layout for this bike. Those can be discussed when you build a shaft-drive bike!

Thanks for the very useful information. Gotta   here right now, but hope to get into soon.

Mean while, can anyone help me out and vote on my engine for COX-ENGINE-OF-THE-MONTH?

https://www.coxengineforum.com/t10174-vote-on-the-next-cox-engine-of-the-month-october-2016#128644


I just want to point out out that i have not modified the engine, apart from cutting some plastic, but i've only added to it, and not only do every one of those additions
serve a purpose, but it adds to the whole appearance.

And most of all, knowing that there's a little cox deep inside, is the best part.    

Here's a little story of a tear-down and assembly of my Jerobee car engine (or that's what I think it is). Maybe you've seen it already, but in any case it shows the centrifugal clutch assembly among other things.

https://www.coxengineforum.com/t10059-mystery-motor-from-an-unknown-vehicle

Hi Coxbike, welcome to the forum!! That's a nice project and I admire your courage to start and continue building such a machine.

Flywheel- clutch assemblies are rather large compared to the engine. The Jerobee uses a steel (partnr 1090) or aluminium (670) flywheel with 2 composite flyweights. The flyweights made by Jerobee, Cox and MRP are the same. The flywheel is bolted with a clutch shaft to the tapered end of a "car crankshaft" made by Cox. The crankshaft has a bigger diameter than the normal ones and they also need a different crankcase. Ex Model Engines sells those components:

http://www.exmodelengines.com/cox-.049-car-engine-crankshaft.html

http://www.exmodelengines.com/cox-.049-car-engine-crankcase-refurbished.html













The clutch on the Cox Nissan is of the same design:



The Cox Gassers has a different design. The aluminium flywheel is a lot thinner and bolts onto a standard Cox drive washer. The clutch has 3 flyweights. Those parts are almost impossible to find though.











On a Bee engine, exhaust throttle is normally used. If you want to use a carb, you can switch to a Tee Dee as on this bike. I don't know if you saw this already. It's on RC Groups:



http://www.rcgroups.com/forums/showpost.php?p=18061316&postcount=97

Hope this helps.

Lieven

That's nice but I think My Cox Bike 's is better , it has BRAKES and handle bars !!  You should hook up with this guy My Cox Bike (since I don't know your name and that's OK !! Rock and Roll !!