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 Post subject: in over my head
PostPosted: June 29, 2021, 7:48 pm 
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So I recently bought an old Kei car and the engine it came with was not going to cut it in the USA so I decided to do what every insane person would do I bought a Hayabusa engine and slowly started collecting parts for the build. Now that I am able to finally get started on it I have no idea how I am going to possibly fit everything in the engine bay. My first problem was finding a way to adopt the Miata suspension components I bought for it the solution was found when I came across kineticvehicles.com. Then there is the crazy offset of the output of the Hayabusa but I think the prop shaft used in MK Indy locost may work. But now I am driving myself crazy trying to find a way to fit a steering rack.


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 Post subject: Re: in over my head
PostPosted: August 29, 2021, 9:14 pm 
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Hi there and welcome. Jack from Kinetic is great.

You need a driveshaft adapter and then you can pick a driveshaft that will handle the hp and is about the right length. A shop can swap the ends to match your diff and the driveshaft adapter on the engine side.

Might I suggest you mock up the suspension, steering and engine with cardboard? That will make it easier to test things out.

Which kei car do you have? Pictures?


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 Post subject: Re: in over my head
PostPosted: October 15, 2021, 12:25 pm 
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Location: Mineral, VA
gto7419 wrote:
Pictures?


I second the motion...

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BMW 2002 donor, M10 motor, 4 spd trans, IRS, tube chassis.
viewtopic.php?f=35&t=20787


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 Post subject: Re: in over my head
PostPosted: December 18, 2021, 7:59 am 
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Sorry for the slow reply guys life got in the way and haven't had time to work on it here is a photo of a test fit.
Image


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 Post subject: Re: in over my head
PostPosted: December 18, 2021, 2:10 pm 
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Need more pics if you want us to try to offer solutions. We can also draw solutions on your pics using ms paint if the words don't make it clear.

Maybe miata spindles are not the best choice. Fwd strut type spindles with high rear steering arms may suit you better.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: in over my head
PostPosted: December 19, 2021, 1:01 am 
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Miatav8,MstrASE,A&P,F wrote:
Need more pics if you want us to try to offer solutions. We can also draw solutions on your pics using ms paint if the words don't make it clear.

Maybe miata spindles are not the best choice. Fwd strut type spindles with high rear steering arms may suit you better.

Sorry, I tried to upload more photos but the site kept giving me an error. Hopefully, it shows now let me know if you want a specific side.
Image

Image

Image

Image

Image


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 Post subject: Re: in over my head
PostPosted: December 19, 2021, 9:12 am 
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Good pics.

This would be difficult and a lot of work (in an attempt to get every aspect right) for an experienced fabricator. A locost without all the constraints would be much easier.

Sell the busa and use a Honda pc800 shaft drive or to a lesser extent, other Honda shaft drive which have a wider cylinder angle (like the early magnas) and plan on a diff change also whatever BEC you decide to use. You will still have a lot of fabrication including the prop shaft design which is critical to get right if you want it to last.

If you really want a busa bec, sell the kei and build a locost or buy something old that isn’t a kei.

The offset output is normal for most bikes.

For a low forward rack position (with an engine that will fit), the frame needs to kick up forward of the strut tower to put the crossmember right behind the roll pan just below the grill opening like a bumper.

If you want to stay busa, consider building a full length frame of 11ga 2x2 or 3 using the miata bits set to the right wheel base, then cut away as needed to lower the unibody on as much as practical so the inner fender can be cut out completely where the head and exhaust need to go. Flare the fenders for the new track width and miata sized wheels and tires.

Buggy racks are available for RHD or you can flip an oem fwd rear steer LHD rack for use as front steer. You need a rack wide enough that the inner pivots are the same width as the miata rack or use a center tapped rack where the center of the rack moves back and forth, not the ends. A plate would be bolted on with the inner pivots drilled to whatever width is needed.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: in over my head
PostPosted: December 19, 2021, 12:59 pm 
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Yea it is definitely not an easy project, selling the Kei car is a no go this car is very special to me. There were several things that came up when trying to solve the prop shaft output angle one of them being making myself a transfer case for the output. The only other engine that came to mind that wasn't a motorcycle engine is the k6a but part for it in the USA aren't that common, that is why I ultimately went with the Hayabusa. I did look at possibly having the engine go in the back but from the back of the seat to the centerline of the rear wheelarch there is only 22 inches.


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 Post subject: Re: in over my head
PostPosted: December 19, 2021, 3:20 pm 
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I wish you had asked us here. Zero pressure to take our advice.

You can find older wrecked salvage bikes cheap (auction generally adds about $600 in fees to price):
https://www.ridesafely.com/en/salvage-c ... 9&rcppg=10

Bike dealers often know of wrecks for sale. Doesn't hurt to call around.

Just about any 400cc or larger bike motor will be more powerful than an antique kei, though you still have not told us what model it is.

I agree. A 520 chain offset, oil bath drop box with a tensioner shoe would solve that and provide a little more header room. Straight cut gear to gear would be noisy. However, if you raise the car an inch or two with the full frame, the clearance will improve. The original shaft is too small of an OD for the length to prevent whipping so you will need extra room. Also the miata diff flange may not be centered. I think it is toward the right side a 1/2 inch but it has been a long time since I checked. Plan on a 2.5-3 inch od shaft.

Look at a honda shadow 750 for being a shorter distance from the front of the head to the sprocket for sideways mounting plus the exhaust is on the side so it would exit forward instead of into the strut tower.

Look at a honda shadow 1100 for shaft drive and plenty of torque. The standard and cruiser bikes in a milder state of tune are better for installation in a car; less likely to surge at part throttle or need cush drives.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: in over my head
PostPosted: December 20, 2021, 5:59 am 
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Joined: June 29, 2021, 7:16 pm
Posts: 19
Advice of any kind is always appreciated. Is there by any chance any page that has dimensions listed for the pc800 engine?
The model is a Mazda porter, as for the original driveshaft I have no intention to use it is just there to test fitment, honestly, I would be worried using it on a 50hp engine on a Hayabusa I think it would crap itself.
Here is a quick photo showing how the Hayabusa would fit in the bed of the engine.
Image
Other engines I briefly looked into are fjr1300, r1, CBR1000.


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 Post subject: Re: in over my head
PostPosted: December 20, 2021, 8:38 am 
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I would not want to butcher the kei anymore than necessary.
The shaft drives have higher output shafts/lower hanging sumps than the sprocket drives.
Consider the 750 shadow is generally cheaper than a vtx or pc800 and much more common for finding future parts or replacement engines, plus cooling should be easier with less displacement.

Looks like the older sprocket 750 is the best fit for ground, tunnel to driveshaft, and strut tower clearance. Should be cheaper too and plenty of power for a kei though the miata diff ratio is numerically too high for highway speed versus cruise rpm but you could work out the bugs with that choice then upgrade later with a diff conversion.


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_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: in over my head
PostPosted: December 20, 2021, 10:16 am 
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viewtopic.php?f=36&t=19397&p=253047&hilit=magna+midget#p253047

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: in over my head
PostPosted: December 21, 2021, 9:56 am 
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Joined: June 29, 2021, 7:16 pm
Posts: 19
When the weather clears up I will lift the Hayabusa out of the car and take photos of the engine bay with dimensions. I have never seen those honda engines you mention in person so my perception of their size could be completely off. My closest comparison would be a Honda VF750 which I have seen a couple of in person. I will say the 1100 shadow does have my attention.


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 Post subject: Re: in over my head
PostPosted: December 21, 2021, 10:06 am 
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I know what you mean. Find a bike shop where they sell under consignment. Bring tape measure. I'd tell them I'm trying to pick a bike to use in a KEI car from Japan. Act like you are interested in buying (you know, reverse salesmanship).

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: in over my head
PostPosted: December 22, 2021, 12:44 pm 
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Joined: June 29, 2021, 7:16 pm
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Finally got a break in the weather and had time to take this quick measurement.
Image

Image


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