rear engine 4 wheel steer tube buggy

[tuff zook]

im thinking of building a rear engine 4 wheel steer tube buggy
i going to use a fzr1000 road bike engine mounted in the rear chain driven to a dummy shaft that pokes into a suzuki sierra 5 speed and then to a suzuki sierra transfer case with 6.5/1 reduction gears and from there out to 2 hilux front diffs and it will be all hydro steer with cutting brakes on rear to help with the front digs
i would be still running the standard fzr gear box and clutch so the reduction is wild and the motor makes 145hp
so the reduction starts motor rpm divide it by first in the bike box and divide that by first in the car box and then divide that by 6.5 in the crawler gears in the transfer and then divide that by diff ratios i have worked it all out once and it comes to about 298 percent reduction so 2000rpm divide 298 = 6.71 rpm at the wheels and you can leave the car box in first and be able to have the quick gear changes of the bike box
and it will have 25 gears in low range 25 gears in high range and 5 reverses plus high and low and by having the gear box and transfer in backwards 2x4 is really front digs and a tailshaft disconnect in the front will give me rear wheel drive
and im looking at running a set of 38-12.5-15 maxxis creepys on beadlock rims

motor specs
Engine Type Liquid cooled 4-stroke, DOHC,
forward inclined parallel 4-cylinder
Displacement 1002 cc
Bore & stroke 75.5 x 56.0 mm
Compression ratio 12:1
Maximum power (DIN) 145 hp/10000r/min
Maximum torque (DIN) 10.9 kg-m/8500r/min
Starting System Electric
Carburation BDST38/4 MIKUNI
Lubrication Wet sump
Transmission type Constant mesh 5-speed
Primary reduction ratio 68/41(1 .659)
Secondary reduction ratio 47/17(2.765)
Clutch type Wet, multiple-disc
Gear ratio ist 36/14(2.571)
Gear ratio 2nd 32/18(1 .778)
Gear ratio 3rd 29/21(1.381)
Gear ratio 4th 27/23(1.174)
Gear ratio Sth 28/27(1.037)
Oilpump type Trochoid
Ignition System T.C.I. Digital
Generator A.C. generator
Battery 12 V 14 AH

ok i found all the ratios
1st in the bike box is 2.571:1
1st in the zook box is 3.652:1
transfer gears are 6.5:1
and diffs are 4.88:1
=298:1
and thats workin the chain drive from motor to gear box as a 1:1 ratio
if i wont it to crawl more i can play with diffent size sprockets
so really the crawl ratio can be endless


so please let me no what you think

cheers
shane

[DUDELUX]

Sounds like some wild plans.

[UhhOhh]

Sounds good but at what RPM does the fzr engine make it's power? Jap 4cyl sportsbike engines of that vintage ride like a 2 stroke which may not be ideal for what you want to do.

[tuff zook]

i really dont think it will worry it to much due to the amount of reduction because even in 1st,1st,low it would be going so slow that you could drive it a 5000rpm it wouldn't worry it anyway

[gudge]

5000rpm? What about 15000rpm?

[tuff zook]

yeah it wont do 15000rpm but it will sound awesome on limiter at 13500rpm lol
it would be priceless when your on limiter and ppl would be like wow they flyin and then your just crawl around the corner

[RED60]

yeah it wont do 15000rpm but it will sound awesome on limiter at 13500rpm lol
it would be priceless when your on limiter and ppl would be like wow they flyin and then your just crawl around the corner

While it may seem like you'll be going extra slow, do your numbers again on here... include all ratios..... on the limiter, I don't think you'll be crawling all that slow...... just an opposite point of view...

[tuff zook]

red60
i just edited my post so just read agian

cheers
shane

[DamTriton]

Gear ratio ist 36/14(2.571)
Gear ratio 2nd 32/18(1 .778)
Gear ratio 3rd 29/21(1.381)
Gear ratio 4th 27/23(1.174)
Gear ratio Sth 28/27(1.037)

Gear spread is only 2.48:1 Most vehicle gearboxes have a 1st of around the 3.5:1 ratio and a 5th around 0.8:1 giving a gear spread of about 4-4.5:1

Upshot of this means you will be locked into the one speed range. (equivalent gear spread in a vehicle would be locked into 1st-3rd gears or 3rd-5th.

The gearing gap between Tcase high and low range with this narrow gear spread would mean there will be some intermediate speeds that are simply not attainable, ie beyond revving her tits off in Tcase low or stalling out in high, remembering the motorbike engines are not built for torque. Note also that you would not have the option of changing your Tcase gear High <-> Low once moving so you are pretty much stuck with your selection.

[tuff zook]

damkia
yes it does have a 1st gear ratio of 2.751:1 but thats in the bike box but you have 1st to 5th in the bike box and 1st to 5th in the zook box so you shouldn't need to shift from low to high on the run anyway
and if you no anything about suzuki crawler gears you can't really shift on the fly anyway because the gap between high and low is to big anyway it just a thing you have to get use to

and i no the bike motor doesnt have much torque but 1st n the bike box is 2.571:1 and 1st in the zook box is 3.652:1 and the transfer gears have a reducted high range of 1.5:1 over the standard 1.2:1 and the diff gears are 4.88:1 so it should still have enuf reduction to take off in high anyway and i hope to get the whole thing to weight about 600kg-700kg on a guess so i really think the bike motor and the gearing is the least of my problems

[DamTriton]

damkia
yes it does have a 1st gear ratio of 2.751:1 but thats in the bike box but you have 1st to 5th in the bike box and 1st to 5th in the zook box so you shouldn't need to shift from low to high on the run anyway
and if you no anything about suzuki crawler gears you can't really shift on the fly anyway because the gap between high and low is to big anyway it just a thing you have to get use to

and i no the bike motor doesnt have much torque but 1st n the bike box is 2.571:1 and 1st in the zook box is 3.652:1 and the transfer gears have a reducted high range of 1.5:1 over the standard 1.2:1 and the diff gears are 4.88:1 so it should still have enuf reduction to take off in high anyway and i hope to get the whole thing to weight about 600kg-700kg on a guess so i really think the bike motor and the gearing is the least of my problems

Yeah sorry about that, didn't see the bit about using BOTH gearboxes and then the Tcase...

Carry on....

[RED60]

yeah it wont do 15000rpm but it will sound awesome on limiter at 13500rpm lol
it would be priceless when your on limiter and ppl would be like wow they flyin and then your just crawl around the corner

While it may seem like you'll be going extra slow, do your numbers again on here... include all ratios..... on the limiter, I don't think you'll be crawling all that slow...... just an opposite point of view...

You've left out the bikes primary reduction in your calcs... 1.659... so essentially you will have around 500:1 reduction.. about 12 metres/minute ground speed at 2000rpm or abt 50m/m at the motors torque peak... hope it all works out if you go ahead...

[stilivn]

Mate is the bike box gonna hold up to the 38's.

[tuff zook]

Mate is the bike box gonna hold up to the 38's.

yeah it will cause theres not going to be shit all load on it with the amount of reduction im going to have and besides its a crawler not a race car

[Tuff Events]

Mate is the bike box gonna hold up to the 38's.

yeah it will cause theres not going to be shit all load on it with the amount of reduction im going to have and besides its a crawler not a race car

Remember that load will always transfer to the weakest link, no matter what you have after it! The internal components of the bike box are not designed to be fully loaded & unloaded constantly which is what crawling will create. My guess is that shafts will detonate. I do like the sound of what you have in mind, but can only see ongoing issues with the use of the bike setup. Best of luck with your build whichever way you go.

Pete

[rockcrawler31]

Really? guys are using motorcycle engines day in and day out in buggies that are on and off the throttle all day long. Getting jumped with WOT and flat shifted, and god knows what else. Not to mention that my bike gets clutchless shifted every upshift when i ride at the track and i can't imagine that being a softly softly caressing action.

[tuff zook]

Really? guys are using motorcycle engines day in and day out in buggies that are on and off the throttle all day long. Getting jumped with WOT and flat shifted, and god knows what else. Not to mention that my bike gets clutchless shifted every upshift when i ride at the track and i can't imagine that being a softly softly caressing action.

yeah thats what i was thinking "rockcrawler31" the bike box is a lot stronger than people think

[4X4 shorty]

May have missed it but what are you going to do about reverse??

Good luck with it tho

[turps]

May have missed it but what are you going to do about reverse??

Good luck with it tho

Drive train goes-
Bike engine - Bike gear box - Zuk gearbox - zuk transfer case - diffs.

So that zuk gearbox will take care of reverse.

[4_low]

Are you going to do a build thread would love to see this thing get built?

[coilylux]

Really? guys are using motorcycle engines day in and day out in buggies that are on and off the throttle all day long. Getting jumped with WOT and flat shifted, and god knows what else. Not to mention that my bike gets clutchless shifted every upshift when i ride at the track and i can't imagine that being a softly softly caressing action.

yeah thats what i was thinking "rockcrawler31" the bike box is a lot stronger than people think

maybe so but the bike only weigh's 200kg with the rider at best....

the buggy will weigh at least 600kg, theres an extra 400kg of mass, let alone the amount of torque / reduction going through everything......

am with Pete, cool idea and very different, but i dont think the hassels of reliability will be worth it

[Wendle]

the buggy will weigh at least 600kg, theres an extra 400kg of mass, let alone the amount of torque / reduction going through everything......

Probably be lucky to come in under 1000kg. The only weight saving over a conventional small buggy drivetrain is replacing a 4-banger with the bike engine and box. If you save 50kg you'll burn half of that back up again in bracketry to hold all these objects where they need to be and keep your chain running where it should. Rear steer adds a lot of weight as well.

If my metric conversion is right (it may not be) your motor makes 78.8 ft/lb of torque.
Even with all your reduction, if that figure is correct, it's gonna feel pretty feeble to drive in rocks.
You'll burn some of that torque off running 1 or 2 steering pumps for your front/rear steering too, the bike motor was never designed to do that. Probably still have enough torque left over to tear that Suzuki t/case in half though

Sounds like a cool project, I like the theory behind it, I'm just not sure there is anything to gain over using a high performance 4-banger (SR-20 etc) ??

[80's_delirious]

May have missed it but what are you going to do about reverse??

Good luck with it tho

Drive train goes-
Bike engine - Bike gear box - sprocket and chain (further reduction in gearing Zuk gearbox - zuk transfer case - diffs.

So that zuk gearbox will take care of reverse.

I may have missed it, but if you are linking bike transmission to
zook gearbox with sprockets and chain, you will have potential for a further reduction in final gearing

[Tiny]

May have missed it but what are you going to do about reverse??

Good luck with it tho

Drive train goes-
Bike engine - Bike gear box - sprocket and chain (further reduction in gearing Zuk gearbox - zuk transfer case - diffs.

So that zuk gearbox will take care of reverse.

I may have missed it, but if you are linking bike transmission to
zook gearbox with sprockets and chain, you will have potential for a further reduction in final gearing

Not if he uses same sized sprockets both sides...

[DamTriton]

May have missed it but what are you going to do about reverse??

Good luck with it tho

Drive train goes-
Bike engine - Bike gear box - sprocket and chain (further reduction in gearing Zuk gearbox - zuk transfer case - diffs.

So that zuk gearbox will take care of reverse.

I may have missed it, but if you are linking bike transmission to
zook gearbox with sprockets and chain, you will have potential for a further reduction in final gearing

Guessing around the 800-900:1 in "low everything" with a ~4:1 chain. An 1800rpm idle would give 2 rpm of the tyre...not to mention at full torque of the engine 10.9kg.m = ~110Nm x the ~30:1 gearing up to the tcase is about 3000Nm through an alloy case tcase before you've put it in low ratio, not to mention the stresses further down the track in the chassis, axles and driveshafts. Just got to hope you don't lock your wheels in a crack in the rock

I see carnage on a grand scale....

Could you lose the motorbike gearbox and use a small shaft to the zook gearbox? Saves some weight and length.

[redzook]

been done a fair bit there is a couple of build threads on pirate
i think this vid is when he had a gsxr750
http://www.youtube.com/watch?v=LLcgf-q- ... re=related" onclick="window.open(this.href);return false;

[mud guts]

been done a fair bit there is a couple of build threads on pirate
i think this vid is when he had a gsxr750
http://www.youtube.com/watch?v=LLcgf-q- ... re=related" onclick="window.open(this.href);return false;

That thing sounds pretty cool trying to climb Backdoor

[jrh86]

Its a sweet idea I really dont think engine load will be a.issue as some others have sugested as they have used large capacity motorcycle engines 4 years in dune buggys and they use turbo charged gsxr 1300 motors in smart cars and mini mokes look on you tube
On another note as ppl have suggested I think the little zuk mite explode but im sure once the u have issuse with it mite rethink og going to land rover transfer
And with the engine have maybe running throu a set up simulir to a atv quad so that the belt will slip a bit when put under extreme load rather than breaking the drive line just a thought

[MightyMouse]

Perhaps a shear pin or torque limiting clutch might be a good idea... that's assuming that you can set it before the point of damaging something ......

[chimpboy]

Sounds like a fun thing to experiment with anyway. Worst case I guess you dump a 4cyl car engine in later if it doesn't work as planned.

Simplified in my head, you would probably leave the bike box in 1st all the time (or you could, hypothetically), and it's 2.5:1 gearing roughly. So basically when it is at 5000 rpm the vehicle will go at the speed of a four banger at 2000rpm. At 11500 rpm redline of the FZR you're going the equivalent of a 4 cyl at 4600 rpm. In other words the effective output from the bike motor is not far off a Sierra's.

To me that sounds pretty reasonable and driveable however like others I am not sure the overall power that you would want is there. Also personally I would hate the noise of it but I know that is just me, a lot of people love the sound of a high revving bike engine.

Random thought: would you not want to make one of the transmissions an automatic? That to me would make the whole shebang a lot more versatile and driveable.

Are those engines water-cooled or air-cooled?

Anyway good luck, we all love to see a project that's outside the box!