Bike motor into a car: Some pointers for conversion

[blue devil]

Coming from the bike world, I feel i know the motors pretty well. I know there is a bit of head scratching and profanity when you think of putting a motorcycle motor is a car. I hope this helps people before they encounter the problems and also clears up some of the electrical lingo. Nothing is like turning a key and having the motor fire right up for the first time. Just thought it would be nice to have one thread to tackle the problems and inform about products sold that might help us.

1. Kickstand switch: Really a simple fix here. Most bikes have a simple open close switch that is controlled by the kickstand. When the kickstand is down there switch is open, therefore it blocks current flow (100% resistance). When the kickstand is up the switch is closed and current is free to flow (0% resistance). Because you obviously don’t need a kickstand with 4 wheels (or 3 for the trike guys) you can simply fix this. What I did was cut the wires past the connector on the kickstand half. I stripped, soldered, and sealed them closed... by making the bridged connection on this side of the connector you can always reverse it easily. Another option is the replace the kickstand with a toggle switch. Keep it out in the open or hide it as a kill switch. I plan to convert to a push button start so this would serve as just one of a few kill switches.

2. Clutch switch: Like most automatic cars, motorcycles have a clutch switch. Remember that on a motorcycle the clutch is controlled by your left hand and because of this the wires will be located in that area of the harness. I wouldn’t recommend that you bridge this one. Most bikes just have a pressure sensitive switch that can easily be remounted onto your clutch setup you make for the car.

3. Exup valve (if equipped): Most of the fuel Injected (and some carbureted) bikes have an exup valve. While some hate it, it does serve a purpose. Most motorcycle exhausts are pretty much free flowing which in turn results in very low back pressure. The exup valve builds back pressure at low RPMs (~less then 6k rpm) and opens completely above this. The back pressure is used to aid in more low end torque. This is really a preferential type deal. Most are controlled by a motor with two cables (open and close). Most people will keep the exup motor connected to the harness to avoid throwing a SES light/code. Although the motor is connected, just remove the throttle type wires from it. The ECU will think its working correctly, when in reality it’s doing nothing at all. Obviously most people will fab their own exhausts and not include the butterfly feature. The alternative is to buy/build a chip to simulate the exup motor. These are not really common as most people just disconnect the cables instead of dropping the money on a chip.

4. Tilt sensor: Again this is more of a preference type deal. For a car that races this could be a good safety feature. Most bikes have this sensor in the nose area of the bike by the headlight. If you end up retaining it, make sure you mount it correctly... if you don’t mount it correctly the engine will just turn and turn and turn until your battery is dead but will not fire up. If you want to get rid of it, there are write-ups all over the internet to do it. Most of them are just three wires... bridge two and seal off the other.

5. Power Commander First off there are currently two main ones... one for the street (PCIII EX) and race (PCIII V). They are units the adjust the fuel maps of the ECU. They simply for the most part just plug right into the stock harness. They really are a mandatory modification if everything isn’t stock. With simple bike mods you will not have a smooth throttle band, instead it will be a bit choppy. This unit will give you the smoothness by providing the correct fuel ratio that the motor requires
Other piggy backs off the PCIII:
-Ignition module
-Quick shifter
More info: http://www.powercommander.com/eng_default.aspx

6. Speedo healer: Obviously your car will not have the same gearing and tire size as the stock bike. This is a plug and play unit that will correct your speedo for you.
More info: http://www.healtech-electronics.com/

7. Gear Indicator With a sequential transmission, sometimes remembering what gear you are in take shifting all the way to 6th or back down to 1st to find out. A simple fix is a digital gear indicator. Again this is pretty popular among the bike crowd and would suit a car very well
More info: http://www.riderstation.com/DG8.php

If you feel i have missed anything feel free to add it...

[Mrl3000gt]

Thanks so much for this, I'm not sure how I would have ever found these answers otherwise as I didnt even know about these issues.

[wyked]

Good info. You can find other uses for some of these circuits. I was thinking of using my kickstand circuit as a hidden kill switch.

[blue devil]

Good info. You can find other uses for some of these circuits. I was thinking of using my kickstand circuit as a hidden kill switch.

Wow amazing idea! I never even thought of that. I will definately do this now.

As for the info... Just a small contribution for how much the forum has helped me.

[chetcpo]

Stickified.

[chandler]

definately keep the tip over sensor. it mimics and inertia fuel switch.

[blue devil]

definately keep the tip over sensor. it mimics and inertia fuel switch.

I agree. Just dont forget to mount it the right way

[Hank]

Definitely good suggestions above.

To add to #7 about the Gear Indicator it might be more helpful to purchase a Gear Indicator with a Timing Retard Eliminator built in. Suzuki, Kawasaki & Triumph motorcycle (my Hayabusa included) engines have timing retard built in to limit the top speed in 6th gear. The GIPro unit eliminates the top speed limiter and it indicates the gear you are in as well. The unit basically fools the ECU into thinking you are in a different gear. It takes advantage of mapping different timing curves for different gears, but it does not effect the idle quality like earlier TRE units.

I eliminated the kick stand and tip-over sensor for my Hayabusa into kit car application because my kit included a fuel pump inertia switch behind the fuel tank.

I also recommend a sequential shift light for a motorcycle engine into kit car application. I purchased an Ecliptech unit here.

[dhempy]

4. Tilt sensor: Again this is more of a preference type deal. For a car that races this could be a good safety feature. Most bikes have this sensor in the nose area of the bike by the headlight. If you end up retaining it, make sure you mount it correctly... if you don’t mount it correctly the engine will just turn and turn and turn until your battery is dead but will not fire up. If you want to get rid of it, there are write-ups all over the internet to do it. Most of them are just three wires... bridge two and seal off the other.

Hmmm...would that work in a car, particularly a race car? Seems like it would detect a tilt around every corner.

-dave "whaddaIknow" hempy

[chandler]

keep in mind on bike you can lean the crap out of em and drag knee. i race mine at putnam in indiana and its never shut off on me while in a darn good lean.

[Blackbird]

I asked myself the same question that Dave just asked, and I'm not sure that I would leave the tilt sensor in for the very reason that you stated, Chandler.
As I understand it, when riding a bike, you lean it over to counteract the G force, therefore you change the orientation of the tilt sensor and keep it relatively vertical to the direction of the force.
In a car the sensor stays vertical and takes side load in a way that a bike isn't likely to generate.

I'd hate to have my car shutoff in the middle of a corner on a racetrack, it sounds downright dangerous.

Jerry, great idea!
Thanks for all the tips, I'm sure more will come up as more folks build BECs.

Moti

[chandler]

good call. i didnt think of that. either way inertia fuel switches from fords are about 15 bucks in a two wire setup. ive flipped my focus though and it didnt shut off. i had to reach in and turn the key off. there more of an impact switch.

[dhempy]

Yeah, I think it's the same reason swing arms on bikes don't see side loads, but trikes do. When a bike leans, it is leaning exactly enough so that the bike doesn't fall over. A car doesn't lean, so it is trying to fall over.

I vote for ditching the tilt sensor. Or mount it to the fuzzy dice.

-dave

[olrowdy_01]

Yeah, I think it's the same reason swing arms on bikes don't see side loads, but trikes do. When a bike leans, it is leaning exactly enough so that the bike doesn't fall over. A car doesn't lean, so it is trying to fall over.

I vote for ditching the tilt sensor. Or mount it to the fuzzy dice.

-dave

You can use the tilt switch by using a "mount" that allows it to swing from side to side (make sure the wires from it allow it to swing freely). That will simulate the motorcycle leaning in turns and the switch will still do it's job if you roll over. I used some tie wraps looped through each other (like a chain) to restrict it's movement to side to side.

Good info. You can find other uses for some of these circuits. I was thinking of using my kickstand circuit as a hidden kill switch.

I used my original kill switch for the ........ (ta-da) ................. *kill switch*!

[edit]Something that might help someone. I had the idea to put a momentary switch across the kill switch wires to momentarily interrupt the running of the engine for the paddle shifter. One little problem that came up ........... once you trigger the kill circuit you have to turn the key off and then back on to get the engine to run again. Oh well, it was just a thought.

[chandler]

good idea