AWD Limited Slip Cbr500R build

[Deadbeef]

Hello all,

I have drawn up plans in cad 3d mocked up with a crf250r engine for an idea of placement for this kart shown below before I found that CBR500R engines are cheaper and have 6 speed trannys with all the goods of fuel injection and a gauge cluster that can be reprogrammed for the correct Mph and even can have an after market gear indicator added.

Parts I have so far on hand are from a suzuki eiger 400 4x4 below.

cv shafts left and right twice over

3 front differentials to be used for front rear and center diffs

left and right steering knuckles.

As for the engine being a six speed 45 hp twin cylinder engine found on ebay for 600 or less minus some parts that can be bought as well on the cheap comparative to a equally powerful engine.

This build will be all completed by myself with the help of a friend for some fabrication.

power will be from the drive sprocket via a custom enclosure into housing a #520 28 or 22 tooth sprocket down to a 10 tooth then converted into the custom housing for the center differential out to both rear and front diffs with a 10 tooth pinion driving a 36 tooth ring gear then out via Cv axles to 11 inch slicks.

pic linked below is of parts mocked for the custom gear/transfer center diff case to be cnc milled. 22, 28, and 36 tooth drive sprockets pictured for mock up to be determined at final build of frame with 90% parts installed for weight on a scale to be a deciding factor for what size sprocket off the engine.


there are some kinks to work out of this build as we go such as placement of parts and sizes of things for a nice compact kart that will push the limit of what my wallet can afford.

Gear ratios to tire diameter / rpm to mph through the gears from the cbr500r engine are as linked below with gearing charts for the said sprockets.

https://imgur.com/a/cirP7Ma
I know there will be speed / power loss in the drive train and with the weight of this kart to be yet determined.

Any feed back is welcome and if this some how doesn't make sense to you feel free to ask or just explain why I am an idiot and this thing won't move 1"

p.s. any and all errors in spelling and calculations are my own fault thank you.

 

[mckutzy]

Hello and welcome...

I can't quite see the pics...

Here's the link on how..
http://www.diygokarts.com/vb/showthread.php?t=737

 

[Deadbeef]

Hello and welcome...

I can't quite see the pics...

Here's the link on how..
http://www.diygokarts.com/vb/showthread.php?t=737

well I did that and it shows them on my end

Here is the Imgur link https://imgur.com/a/cirP7Ma

 

[mckutzy]

Ahh I see now...

So what are you using for a chassis to start???

 

[Deadbeef]

Fabing it from scratch out of 1 or 1.25 inch steel tube stock once I have the engine on hand.

 

[mckutzy]

Well your setting the bar pretty high... Why not start with a donor buggy and go with that...

Going to need a good equipped machine shop, how you going to weld this frame??

 

[Deadbeef]

We make custom bobcat hydraulic brush cutters and other custom fab equipment.

---------- Post added at 10:51 PM ---------- Previous post was at 10:33 PM ----------

Also I have yet to see an awd kart with front engine and 3 limited slip diffs. Let alone a plan in 3d or gearing data.

Subscribe to the thread and wait for the YouTube series to hit.....

 

[landuse]

Interesting concept. I look forward to seeing what you come up with

 

[itsid]

Not a fan of the rotated engine tbh..
and while I get that you need the output shaft pointing that way..

shift-connect will likely be a pain to route (rod worse than cable and cable still messy)
and while it is a watercooled engine you still run the rear cylinder hotter than the front one,
which is never a good thing under load and the higher the load the bigger the difference..

Also keep in mind that you will suffer severely from gear train power loss,
so dial in on the 'slower' side of things to keep the torque up first.
[reason is fairly simple.. if a larger gear fits, a smaller is likely to fit as well.. to go faster.
if you do not go fast due to losses you might have a harder time fitting a bigger gear in a smaller housing ]

Promising indeed.. I'd rotate the engine back, fix the newly designed housing to accept the 90° input
and maybe assume the engine to have no more than maybe 30horses (and the lower torque that comes with it)
so that it's snappier than what the excel sheet suggests

'sid

 

[Deadbeef]

Sid,

I understand your concerns on the mounting of the engine for cooling purpouses.

The CBR500R engine has the water pump inlet and outlet on the sprocket side of the engine.
I intend to mount the radiator in the front of the kart with the fan running all the time as to keep the fluid that is pumping at its coldest.

as for the power out put being mounted this way it links the engine to the center drive shaft just like how the bike is set up except the shaft is in "front" of the engine.

 

[itsid]

Don't misunderstand my concern..
I'm not really afraid the engine would overheat.. that's fairly uncommon with engines that size
(okay, my bike runs hot in an instant as soon as it's not moving or not moving fast enough.. but that's a different topic)
Anyways, the problem is, that you will have a temperature differential between the two cylinders of the engine

One being better cooled than the other
one being not only the first to see the fresh coolant but also the one that's seeing some additional airflow.

I can't tell what temp difference will be possible for an engine like that,
but if you look at some V twins and the issues they have with the rear cylinder overheating
(no matter if air or water cooled) you might understand what I'm trying to make you aware of.

I see no issue with the single cylinder 250 frankly,
but an inline twin like the 500 might not be too happy
with it being mounted sideways.

You could fab an air shroud to help airflow a bit (or shield the engine from airflow entirely)
but frankly... I can't see a reason for that if rotating the engine would solve all issues.
(not to forget about the shifting linkages...)

Sure.. it also looks wrong and I'm biased because of that alone you might say,
and you won't be wrong I guess.. but there's a reason why Honda installed their engines "properly faced forward"
on their FL Series karts (Odyssey) no matter if single cylinder 250 or twin 400

A ten-ten jackshaft is rather pointless ratio-wise,
But I get the idea behind it..
If you want to have less hassle redesigning you setup
replace that with a beefy 1:1 RAGB perhaps.

I'd also have the engine over or in front of the axle rather than behind it,
but that's just personal preference..
as long as you consider all weights and the resulting balance of the final vehicle
you'd be good either way.

Once you have the engine, mock up a crude wooden chassis with wheels and put it in it's place.
you'll see what I mean immediately

'sid

 

[Deadbeef]

I do see you bring up some valid concerns! This is exactly why I am here in open forum.
Thank you for your input.

For the cooling factor you bring up points I have not encountered before.

We are planning on doing a pneumatic shifting system as we have a friend that has it on his drag car.

That Right angle gear box would probably weigh the same as my custom enclosure to get the gear ratios correct.

I do think there may be further clearing up when I get home from work and can re sketch a better detail of how the 22:10:10:36 jackshaft thingamajing from engine to diffs would work.

mounting the engine balanced over the front axle with is another beast that is a placement thing cause of the height of the engine and its oil pan shape being odd.

again I will clean up some of the drawings and add more details for a better look of what I am describing.

Thanks again!

 

[itsid]

please do..
front engine.. yeah I misread your drawing..
mainly because on a small size vehicle like we're talking about
leg room is a precious thing, and clogging it with an engine is fairly uncommon.
(also mid engines nevermind)
So somehow the steering column got a backrest indicator for me.
Ah well...

pneumatic shifting is a cool idea.. dialing in the solenoids for a motorcycle engine IDK... doesn't sound like too much fun to me really..
and certainly overkill for a project where shifting times are not of an issue,
especially since it can be replaced by a simple shifting lever and a tierod (once the engine is facing forward)

But if your friend has one and knows how to set one up properly,
I'd be interested to see it being done.
(and with that I'm kindly asking for a detailed de-pict&script-ion I'm afraid )
and between the two of us... overkill can be fun so yeah go for it

I'd still say you want a lifesize real world mock up once you have the engine,
since frankly now realising that's a front engine you drew...
your toes will be dangerously close to a red hot exhaust pipe

Oh..
I just realised
with a differential (uhm say most common ones)
being essentially fancy right angle gearboxes with two outputs..
the center diffs INput will be parallel with the axles,
as would be the PTO of the engine with it facing forward... *headscratch*

Yes.. yes I need another sketch or two.. I do have questions now

'sid

 

[Deadbeef]

Well time being a factor drawing 10 week old baby in the house, here is a view with details saying what output goes where.

Overall Kart length is 65 inches for the frame. Plenty of room to cram a seat and engine in there.
That is why I am building from scratch, can always stretch or shrink as needed once all parts are on hand.

 

[itsid]

Essentially a peerless 100 so to speak...

Have you looked into 4x4 ATV drivetrains yet?
I bet there's a ton of nifty ideas you can get inspired by

'sid

 

[Deadbeef]

Sid,

I have 3 atv differentials and cv shafts plus steering knuckles

See pisc off diff below

 

[Deadbeef]

Progress has been slow, I have more parts and more of a concrete idea as to how this thing will be constructed.

I also will be using a Kawasaki Ninja 650R engine, 71 HP says the specs, I know that will not be 71 to the wheels at all...... being HP lost through the gearing and drive train to all 4 wheels......

I will Post pics Tomorrow with parts laid out before frame construction begins!

 

[Kartorbust]

Still though, regardless of how much is lost do to just the inherent nature of all things mechanical, it'll still have more than enough power. Parts gathering sucks, but needs to be done.

 

[Deadbeef]

parts gather is a part of the game yes. Rome was not built in a day.

Probably gonna end up north of $2000 spent on this thing......

 

[Deadbeef]

Here is the front and rear pre any modifications except some work to the center and front differentials.

Not all parts at laid out for a better visual with less pics.