Project 100 (custom enclosed Honda C90 targets 100 mph vmax and 100 km/L FE)

[Frank Lee]

Maybe the Super Cub 50s back in the day were causing problems?

I'd like to know why the entire world except for us gets to have Super Cub 50s.

[Curtis in Texas]

Although my subscription to this build is late, I've been following it from day one.
Being kind of a new guy here I thought I'd best catch up and learn the Members and thought processes before jumping in and adding any comments.


I like the body style of the recliner you've designed. I'm partial to weather protected bikes versus open air cockpits. No offence Craig! I've burned up your server for several years following your experiments!!!! I'm a big fan of KLR's!

Having owned several of the air cooled 90 cc Hondas I can tell you that keeping that little wonder cool will be your biggest challenge. Obviously, but here's a suggestion!
You might consider welding a sleeve around the cylinder and water cooling it with a radiator and electric water driven pump. Some Buds and I converted a Honda 125 cc engine from air cooled to water cooled successfully back in the late 70's for S&G's.

Sadly since the head was not water cooled and it eventually melted. But we were using it as a trail bike, not a road bike.

Just throwing out an option.

Curtis

[cvetter]

Visionary: You have calculated that 100mph can be achieved with 11.5hp and you believe your aircooled Honda is up to the job. Who am I to discourage you? I wish you could ride with us from Las Vegas to Barstow next month so we could see if your numbers and heat dissipation works in real USA riding.

I am not even sure that my 17 hp Helix will be able to stay with the traffic. The hills are long. The traffic is in a hurry to get home to Los Angeles and not afraid to drive beyond the posted speed limit. It could be 100 degrees. The winds might be awful.

But it represents REAL conditions. This is why I consider this to be a Test Ride.

Craig

[Frank Lee]

I don't worry too much about traffic- they usually have the option of passing and if they do that it's fine by me.

[SwamiSalami]

What a neat project. Looking forward to updates!

[visionary]

Update 007
Progress has been slower than I would have liked because my full-time workload has been quite pressing. There have been a few changes worth noting and I have made progress on related matters.
Firstly the changes – the intermediate drive shaft has been fixed and this allows the geometry of the rear suspension to be completed. I am using a “monoshock” from a Honda (it’s the same Fireblade unit I used on my original prototype) but its mounted horizontally beneath the seat. This compact installation should be quite strong, but my principle reason for using this design is to keep all the mechanical components within the central “B” unit. This allows the front and rear sections to be quickly removed should redesign be necessary.

Image – top shot of shaft & shock


In response to points raised by Curtis
The ideal cooling solution would be liquid cooling, I agree, but I’m already some way along with the project and I prefer to finish “as is” rather than delay. I’m a firm believer in the concept of “a fast failure” – where its often more beneficial to get something working promptly, so that a full re-design can include lessons learned.
Here is how I hope to control engine temperature on this first air-cooled prototype.
The image (below) shows how the cool (high pressure) air enters through a duct below the pedal area. It expands and slows before circulating around the cylinder head and barrel. I will use an electric fan to direct this cool air onto the cylinder more directly. Then the heated air is ducted through the side bodywork before exiting via vents (placed at low pressure zones just behind the leading edges of the side panels). Thus the natural pressure differential between front and sides drives the circulation.
Additionally I hope to liberate some of the warm air due for exit, and use it to heat the cabin.

[Curtis in Texas]

Forgive my questions, but isn't this little Honda Engine 6 volt unit? Maybe the newer ones have been changed to 12 volt, but every one of the little Honda 90's I've had were 6 volt.
Here in the US we have gotten away from the 6 volt systems on most of our motorcycles and so, I'm thinking finding a high speed electric fan would be difficult for us. But, you being in England, may have a unit that will keep the little engine cool.
You're going to need to move a LOT of air to keep it cool inside the box. I'm pulling for you really, but I see it's going to be a challenge.

I'm probably one of the few guys here in the US that still has a working 6 volt only battery charger!!!

When I look at your frame, the 400 Burgman engine come to mind as a perfect alternative to the little Honda. But, I'm from the bigger motor, work less, type engine guy. I use to have a catalog of the Piaggio Family of scooter and bike engines. They would have one that would fit your needs exactly.
Too bad they aren't certified for US Emissions.

Eventually I want to build a Streamliner like yours and would love to use your body design on mine. I like an enclosed body for weather protection. But I want to use a diesel power plant so I can run a belt drive air conditioner. Mainly because I live in Texas and it does get hot here.
Plus it a long drive across our State. So being able to hold a max speed is important.

I've built a lot of bikes and still have a shop full of project bikes.
Almost ready to start my Diesel Tiger build. I have all the parts, just need time.

Interesting rear suspension. Is that a linked unit?

[visionary]

Reply to Curtis
Your questions and comments are always welcome!
The donor C90 is a 1987 12V model – most European versions have been 12V since mid 80’s.
As for fan size and volume of air, this is a pure guess. Anyone able to accurately calculate the cfm flow through a complex duct system, relate that to pressure differential across intake and exit vents, factor in heat exchange rates, etc – that person gets my admiration, I couldn’t do it. But what I can do is observe other similar systems and make an educated comparison. I only have 11.5hp target, and heat output is directly proportional to power. Racecar (no fans) sidepods cool total heat production through water and oil radiators, with entry apertures of 400x100 per side, so scaled down from 800hp I think this should work – but I might be wrong, testing will show which. If it needs more airflow there is an option to increase exit vent size with “gills” in the lower body sides, but with a drag penalty.

I’m with you on the engine power! A surplus of power makes for a more enjoyable driving experience but in this new world (gas prices) I’m not sure that’s a luxury I can afford. The frame would adapt to many current engine options as long as they have (near)horizontal cylinder configuration.

When its finished, you or anyone else would be welcome to use the body design for your own versions. I will mould the final outer panels in fibreglass and will be happy to sell them, but there’s a long way to go yet. My aim is to finish it for spring, but to test the “raw” un-bodied mechanicals just after Christmas.

I’ll post more detailed images of the rear suspension next time
Thanks for your interest
Pete

[Curtis in Texas]

Cool reply!
I was not aware that they changed over to the more practical 12 volt systems on that engine.
Good thing to know!
You might look at a row of 12 volt computer cooling fans for cooling.
They draw less power than a bigger electric radiator fan. And some are high volume fans.
I've used the little squirrel and box fans for many of my projects.

Ex: I built a motorcycle helmet forced venting filtered cooling system by mounting a small 12 volt squirrel cage blower to the back of my Helmet and plumbing it to the front to blow onto my face. It was filtered because of my allergies were rampant and I loved riding, but hated the sneezing and watery eyes. The plumbing from the fan to the front of the helmet was flattened out pvc tubing I heated with a salamander heater and squashes against the helmet for a blending form fitting look.
It plugged into the bikes battery and the cord was bundled with the communication cables. It worked well and I still drag it out for high ragweed pollen count days. I was able to make it unobtrusive and naturally balanced.

Maybe a row of small 3" box fans can be fit in the intake and ducted onto the engine. By using multiple fans you can control the amount of air flow volume.
Just remember to factor your engine heat exits in the low pressure areas of the bodywork and you'll need less forced fans when moving.

Marketing the body work would be a nice way to recoup your development cost. Or at least to offset it. I'd be a customer! I could certainly see a market for that design for the home experimenter like myself. Although what I envision mine would need a longer bodywork than what you're building. I'm a frame/ engine builder guy and body work is not my strong point, but stretching it a little is not beyond my skill set. Your body might work just fine if I placed the engine between my knees like the Quasar. Which is a possibility, especially if I can get one of Fred Hayes Diesel KLR motors! His engine just begs to be used in an aerodynamic bike! So many possibilities!
(EDIT: I see Fred has developed and Competed in Craig's Ohio Challenge with a very slick Diesel Streamliner this Summer. Way to go! Fred!)

I do like the way Craig did his aerodynamics testing and refinements with floppy plastic sheeting. Quick clean and easy to fine tune. Not to mention very light weight. I had to grin when I heard he was using milk carton material for generation 2. I really hate working with itchy fiberglass and resin. All that sanding!!! Yuck!
But, being as Craig is an Industry Professional and Garage Mechanic like the rest of us I would expect nothing less than the most practical method for testing an idea.

Ya'll have a good day!

Gotta get out in the shop! Customers are waiting on their bikes!

[visionary]

Update 008
This update covers one of my biggest hurdles in the frame construction process, the relocation of the carburettor to fit within the engine compartment. I’ve chosen to show the stages of fabrication before completion to illustrate the challenge and possible solutions.

Here is how the engine currently fits in relation to the seat and frame. The carb must fit below the frame bars and allow for a filter to be fitted. The incoming (cold) air comes from below the footbox section and the intake port is located on the top of the cylinder head.


The new port will be constructed from TIG welded sections of aluminium and a short section of original casting.

I’ve already made my “tube” by turning out the centre of some suitable aluminium bar stock, and then cutting short angled sections with which to “lobster back” the gentle curves between carb and head.

So the goal is to fabricate a new inlet port, locating the carburettor low down, facing forward into the incoming airflow. This is necessary to keep the carb position away from the drivers legs and outside the compartment for noise and safety reasons.

There are some obvious problems with this solution – the longer tract length and the vertical distance. The inlet tract will be approximately 200mm longer than original. This will have an effect upon throttle response and the engine torque curve, but I hope that the effects will not be severe. The vertical section should also have a negative effect, but its not clear how large this will be, mainly because this type of system is rarely employed. The effect on driveability will probably be masked by all the other changes to the vehicle making it difficult to evaluate. These problems are temporary in any event, eventually the system will be redesigned to allow fuel injection as part of the “stage two” power upgrade.