Engine size/power

[Diesel Dave]

Mike Siebert did something similar with an off the shelf frame kit:

http://www.youtube.com/watch?v=YAy8DrojAuQ

[alexanderfoti]

Ohhh, where would one get one of those in the uk?

[Bugsy_malone 666]

Mike Siebert did something similar with an off the shelf frame kit:

http://www.youtube.com/watch?v=YAy8DrojAuQ

I watched that and then this was one the links:

http://www.youtube.com/watch?v=PbwnI_SU ... re=related lol! from one extreme size to the other

I did start looking into the CVT scooter transmissions, I figured it might be possible to strip the engine and replace the crank with just a straight bar, and have a gear where the conrod was! then drive change out the engine to a small transmission bar to go sideways to connect with another chain system for to the flywheel. Just an idea like

Maybe I could build a hybrid bike with diesel electric power, think I'd need a bigger bike mind to fit it all in!

Was just looking at other bikes and thinking I'm sure a bike I used to have wasnt all that powerfull, a kawasaki KE100. I remember it as a great bike, one which cost me loads and used to break down regular! Turns out in good form they are a massive 11hp @7500RPM! capable of 62mph (although I dont think mine ever went that fast!) and that was just 99cc. I guess that was a fairly light bike compared to my Z250, however apart from a lighter (and somewhat tiny) frame the engine was worlds apart in weight. a little aircooled 2 stroke weighing nothing vs a 4stroke twin weighing a few tons. I think the 165F is a bit heavier than the current unit.

So KE100:



Z250:



Thats not my one but mines like that.


And what I want is something a bit like this:



only with a diesel lump, to be classed as a kind of survival bike!

[Rhynri]

Sexy bike, that last one. what is it?

[Bugsy_malone 666]

Sexy bike, that last one. what is it?

Its a modified kawasaki Z250, eg its the same frame and wheels as the 2nd one(well essentially theres about 3 different models of Z250 including a single and a couple of twin engines) down but highly modified, I like it!

[Rhynri]

Sexy bike, that last one. what is it?

Its a modified kawasaki Z250, eg its the same frame and wheels as the 2nd one(well essentially theres about 3 different models of Z250 including a single and a couple of twin engines) down but highly modified, I like it!

I just love the look. The big beefy wheels. It'd look good just about anywhere.

[Bugsy_malone 666]

Ok well I set my expert of a g/f to work on solving some maths for bikes and engine size etc.

At the moment shes putting an Excel spreadsheet together in such a way that it would be possible to calculate how much hp you'd need to go how fast 'in theory'.

We did some real guestimation on figures which will be different per bike/person, and it still needs some work as there is a theory that if you have X amount of drag and the frontal area of a bike is X amount, with X amount of HP you'll do X amount of mph.

Anyway we did a bit of guessing, based approx on my weight/the bike and what sort of drag the whole thing has, then guessed a frontal area of bike + rider, then put in the HP.

with 2HP - 37.7mph
with 3HP - 43mph <--------------My 165F engine
with 5HP - 51mph <-------------Yanmar L48
with 7HP - 57mph <-------------Yanmar L70
with 10HP - 64.5mph <------------Yanmar L100
with 20HP - 81.2mph <-----------Kubota 500cc Twin (approx)
with 30HP - 93mph
with 54hp - 113mph <----------- N/A 1600cc Vw golf diesel

so these are guess work figures but I would say based on some of what I have read on peoples performance, pretty close. This is based on no wind or hills lol! obviously we havent taken into account gearing or anything and theres still number crunching to be done, but I think it serves as a good guide. The bad part is my engine will do an estimated 43mph on the flat with no wind!

[coachgeo]

...
so these are guess work figures but I would say based on some of what I have read on peoples performance, pretty close.....

Actually from what my memory recalls from write ups in here and elsewhere your about 10-15mph off. For example the 10hp on average (some better some worse) are pushing it at 55mph and engines is more happy at 45-50mph.

[alexanderfoti]

I was looking at my manual and have noticed that the 186f in mine (according to the manual) puts out 9.5bhp max, and 8.5 bhp continuous and that's a 406cc l100 clone.

Does your calculations include drivetrain losses (up to 25% on cvts!) and rolling resistance of tyres?

As above, the numbers do seem a bit optimistic.

[Bugsy_malone 666]

Well we are still working on this. It doesnt include drive train loss at all as I think theres probably a few to many variables involved in doing so.

as for rolling resistance at the moment we just have a drag factor, its a combination of wind resistance/tyre resistance/ bike weight/rider weight etc, as a result its a bit of a guess at the moment to make some numbers work.

We are still in the process of working out a way to make the drag section of our spread sheet work so you can put figures in for things you know, like rider weight and bike weight to adjust the drag factor, as for transmission loss I have no idea where to start with that one yet.

I think maybe being optimistic if you said the speed was 10% out would probably make sense, but if my g/f can be bothered to do some more maths and fluid dynamics to get a better drag factor I might be onto something.

At the moment the thing we have is done in such a way you can apply it to bikes/cars/trains/etc.

I thought a good first effort though

[alexanderfoti]

Defo a good first effort! I would be interested to see the spreadsheet if possible when you are done, would be good for future bike builds

with regards to drivetrain loses, I would first decide what gearbox you are going to use, i think 20-25% for cvt is a good number. I expect the Enfield gearbox with grease is also 25%. The ablion(villiers) box I am using is probably closer to 15-20% as its oil filled.

[Sphere]

Are you sure that Kubota twin 500 is actually diesel? 20 hp seems a bit rich.