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Honda S1000: How To Install A Motorcycle Engine In A Car

by Matt Brown

 

It is well established that: Small Car + Big Engine = Hot Rod. The bigger the engine and the smaller the recipient vehicle, the hotter the rod. Putting a 1.8 liter in your Honda CRX? Mild hot rod. Putting a Space Shuttle SRB in your Peel P50? The hottest of rods. Installing a motorcycle engine in a car seems to be a violation of this rule. I hope you will agree with me after reading this article: it is anything but.

 

 
Solid Rocket Boosted Peel P50: The hot rod asymptote.

Motorcycle engines have a few advantages that help bring the hot rod equation into balance: they are lightweight, they have integrated sequential transmissions, they are inexpensive, and many go well past 10,000 RPMs. What they lack in power, they make up for in power density; you can get 200 horsepower in a tiny package weighing 130 pounds, and that is with the transmission.

Sure, you can upgrade pistons and connecting rods and throw on turbochargers to squeeze out more power, but the approach to this project was: simple is good. I know, that sounds insane; we’re going to take an engine that was designed for an entirely different type of vehicle, and stick it into a car made half a century ago, but somehow we’re going to try to keep it simple.

With that in mind, the first step is to find a car that will still be fun with 150-200 horsepower. Fortunately, that’s pretty much any car that weighs less than a ton. Unfortunately, that’s not a lot of cars. Many Japanese cars from the mid-1980’s and earlier, older MG’s and Triumphs, even some later cars with liberal weight reduction could be done. There have been a few Miata motorcycle engine swaps, including the documented-on-MotoIQ Miatabusa project. This project is a fascinating read, though since simplicity was a goal here, heavy engine modifications and things like a custom CNC transmission adapter plate and output shaft were out of the question. I live in one of those emissions testing states, so for something like this, life is easier with an older, emissions exempt vehicle.

The perfect car for this? A 1964 Honda S600. It’s small and light, and it was Honda’s first mass-market car, so it has a story to it. Also, it still jives with the aforementioned Hot Rod Equation, as this car originally came with a 606cc engine, and the donor engine is a 1 liter that has over three times the power. Also, it’s cheap! Especially if you start with one that has, uh, seen better days.

 

For a project of this magnitude, on top of basic tools, some specialty tools were needed, like:
  • A welder 

That’s about it, actually. If you’re playing along, you’ll need some way to cut out sheet metal for brackets and such, so if you don’t have a waterjet in your garage, you might want a vertical bandsaw, a drill (possibly drill press), and grinder too.

To keep things simple, many of the motorcycle parts were carried over. This was done to avoid complicated hurdles that could cause the project to end up on eBay with 8000 other “my loss is your gain,” or “impending divorce,” or “bankruptcy blowout sale,” half-finished projects. Since the plan was to carry over the ECU and motorcycle transmission, the to-do list boiled down to:
  • Install the engine in the car, and

  • Connect the motorcycle output to the driveline 

Super simple! Kind of. Actually, those steps have several sub-steps, some of which have sub-sub steps, so it looks more like this: 
  • Install the engine in the car

    • Run fuel lines to and from your engine

      • Replace fuel pump

      • New fuel tank?

    • Weld up a custom header

      • Attach exhaust to header

      • (Probably just build all new exhaust)

    • New intake?

    • Attach gas pedal to throttle body

    • Attach motorcycle clutch MC to car clutch pedal

    • Attach shifter

    • Mount new gauges, or adapt engine to old gauges

    • Plumb the engine to the radiator

  • Connect the motorcycle output to the driveline

    • Attach the output shaft to the driveshaft

    • Adjust driveshaft length appropriately

    • Possibly add two piece driveshaft to account for offset

    • Possibly replace driveshaft, diff, half-shafts, and hubs to account for increased power

    • Add a driveshaft loop

    • Also, while we’re at it, upgrade the brakes, probably


Okay, that’s not so bad, that’s a doable list of things, right? Most of these things should exist in the knowledge base of a serious gearhead, so if you haven't done some of this stuff in the past, now is a perfect time to add it to your repertoire. 

Cool, so here we are with our to-do list. All we need to do now is explain each item it a reasonable amount of detail. Let’s start at the beginning.

 

Install the engine in the car

Hopefully, before you’ve reached this point, you’ve removed all the stuff you plan on replacing, like the old engine and transmission. That’s actually the first step, so let’s start there.

 

Remove all the stuff you plan on replacing or not using

Empty engine bay = blank canvas.

Remove the old engine, transmission, driveshaft, you probably don’t need a heater or air conditioner or any of those vents or tubes, possibly the entire dashboard, spare tire and jack, old heavy 12v, anything that looks emissions related, maybe even the windshield wipers; the lighter the better. If you’re planning on daily driving this thing, you might want to be a little more conservative with your weight reduction, you crazy badass.

Okay, stuff removed, back to step one:

 

Install the engine in the car

Oddly, there are no off-the-shelf motor mount kits for installing a 2007 CBR1000RR engine in a 1964 Honda car. Thankfully, building your own mounts is easier than it sounds; the only hard part is figuring out the reaction forces and placing the engine mounts in the appropriate locations. Stick a floor jack under the car where the engine will go, lower the engine onto the floor jack with an engine hoist, and adjust the height and location with the jack. An engine hoist is not required here, you can hang the engine from the middle of a ~6ft 4x4 wooden post (or a couple steel tubes you have lying around) and have a friend help you drop it in. Once on the jack, you may need to prop the engine up with some wood blocks to keep it from falling forward.

 

Like, 90% finished.

The engine location should be chosen with some concern for weight balance, but also of concern is minimizing the output angle of the driveshaft and efficient mounting to the frame. A higher angle will put more (non-torque) forces into the engine and the differential and may cause failure in a place you don’t want to have fail. You also want to place the engine as close to the frame as you can so you can have shorter, more efficient mounts. Keep in mind the items you may not have installed yet, like headers, intake, oil filter, etc… You don’t want to get it all mounted in and then realize you can’t change your oil without pulling the engine.

 

Once you have the engine in roughly the position you want it, it’s time to add mounts between it and the frame. The engine is hard mounted to the frame, no rubber mounts; keep it simple.
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Comments
8695Beaters
8695Beaterslink
Tuesday, November 28, 2017 6:58 AM
About 2 months ago, a CBR1000 Caterham kit car showed up on the local Craigslist. It was fairly nicely done, but definitely needed some help. The builder used a Merkur rear axle with a final drive completely unsuited to the bike gearing. It also had no rollbar and the wiring harness was an awful spaghetti nightmare. There were a few other minor things that needed to be done right, but for the most part it was a cleanly built home-brew toy.

Major tip on these cars (either building or buying): don't skimp on the wiring. Do it right the first time.

Also, be careful with clutch dumps. The original owner of the car sold it when his wife tried to do a big smokey burnout. The clutch exploded so spectacularly it seized up the engine. Someone else bought the car, rebuilt the bottom end, but got bored before they finished fixing the other problems.

Since I don't own a welder, I needed to find someone who could swap the Merkur rear end for a spare Nissan R200 I had sitting around (an R200 which already had an LSD and for which many drift-spec gear ratios are available). Before I could find a good fab shop, the car sold. I was about a day away from buying it anyway. I did get to ride in the thing. It was wildly fun. I have a lot of regret over not buying that car. I also realize if I had, it would absolutely be my grave.
SM_Clay72
SM_Clay72link
Tuesday, November 28, 2017 9:22 AM
I love it. With a welder and a brain most things can be adapted or modified to solve a problem.
Mike Kojima
Mike Kojimalink
Tuesday, November 28, 2017 12:42 PM
In Europe, there are a lot of motorcycle based hillclimb cars.
spdracerut
spdracerutlink
Tuesday, November 28, 2017 6:25 PM
Great build! Looks like a fun car. Gotta love the sequential. I always wanted to do a boosted liter bike engine in an Exige.
Dan DeRosia
Dan DeRosialink
Wednesday, November 29, 2017 6:09 AM
Well that is a damn cool build. Really interested to see what is going to be done for the reversing gear.

I keep wishing I was smaller so I could race some of the motorcycle engined sports racers that are popular in SCCA. Oh well.
libertymkiii
libertymkiiilink
Wednesday, November 29, 2017 7:47 AM
I have built 2 GSX-R powered Yamaha Banshee 4 wheeler(s) so these builds are very interesting to me. It is lots of fun to build and fabricate.

I think this idea is perfect for something for fun but not for competition.

For anyone considering building one of these as a track car/ race car id say it needs to be fully custom tube chassis. I considered such a build on a MR2 spyder (2100 lbs oem curb weight) after looking around I could see that the lack of torque on a estimated 1500 lb car just would work.

Here is an example of an MR-S with a 1300cc hyabusa turbo swap. Just cannot hang with the other cars https://www.youtube.com/watch?v=Pkkr4QyJ5oU

On my MR2 spyder I went with the Honda K20 swap which had much more potential and fewer weak points.
engineered
engineeredlink
Friday, December 01, 2017 7:24 AM
nice build!
Blue-Civic-Hybrid
Blue-Civic-Hybridlink
Tuesday, December 05, 2017 5:39 PM
This just made my brain explode.
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