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- How to use an American-made BDX wiring harness on your 150cc Chinese engine - August 16, 2018
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Update July 25, 2015: This a reboot of our popular article from 2013, which was downloaded 100,251 times. Thank you to everyone who continues to find this information helpful!
This article isn’t meant to cover installation practices, but is more of a heads-up for hang ups and issues you should expect during and after a GY6 swap into your Ruckus. This article also won’t be talking specifically about the BDX swap kit, but covers general issues you may experience with any GY6 swap whether doing it yourself or purchasing a packaged kit.
What to expect during installation
Installation should take anywhere from 1 to 5 hours, but may take more depending on your experience and level of mechanical skill. I’m a doctor, not a mechanic! We frequently get asked questions from guys interested in swapping who don’t really have much mechanical experience. These guys are typically in search of a 150cc swap kit which will involve the least amount of head scratching and will run smoothly right after installation. While most packaged kits are straight forward to install (to varying degrees), the truth is, there will always be some tuning and tweaking after installation to get everything working correctly. Swapping for the novice in many situations is going to involve minor install gremlins that have to be worked out after the swap is complete.The main thing is sticking with it and asking questions along the way. We’re happy to answer installation and calibration questions for our customers, and we also believe there is no such thing as a dumb question, so by all means ask away. The expectation for the novice going into any swap should be that it’s going to be a learning experience and that extra time should be anticipated. Going into a swap with the right expectations and a healthy level of patience can be the difference between having a properly installed engine setup that purrs at idle, or a hack job that can barely be started. Take your time and ask questions!
What to expect for reliability
There are some reliability issues across the board with swaps that should be known.
Expect some bogging and hesitation issues (with vacuum fuel pumps)
The majority of GY6 swaps (including our kit) use the common Mikuni fuel pump, which is driven by vacuum pulses that the engine generates while running. They work well to get fuel to the carburetor, too well actually. The vacuum operated fuel pumps seem to frequently be too powerful for original and aftermarket GY6 carburetors, forcing extra fuel past the internal valve. This extra fuel then gets forced into the intake tract, which is then sucked into the engine. This impacts fuel economy and causes the bike to run rough and erratic at low speeds, often killing the engine when coming to a stop. We’ve setup a return line on our dyno to demonstrate how much extra fuel is being pumped by a Mikuni pump paired to a GY6. What you’re seeing is the extra fuel constantly exiting the float overflow tube of the carburetor and flowing back through our return line on its way to the tank. If you’re able to fabricate a return line to your fuel tank, this works well and solves the over-fueling issues. But this isn’t a reasonable solution for most swappers. We’ve experimented with restrictions in the line and other methods, with varying levels of success. The most elegant and effective method we’ve found of getting around this issue is to keep it simple and stick with the original Ruckus electronic fuel pump. The stock electronic pump seems to be best suited for this job, avoiding over-fueling issues with the help of the stock ECU or an external pump controller. Currently, only harnesses which use the original Ruckus ECU are able to use the stock fuel pump – but the ECU is big and bulky so most harness makers opt to remove it from the system. Our harness doesn’t use the stock ECU (removed for a clean install and to avoid clutter), but we are developing a special stand-alone controller which will drive the stock pump and also allow you to adjust pump output.
Expect charging issues with 8-pole Stators
GY6 engines usually come with 6-pole or 8-pole stators which typically don’t output enough power at idle to charge the battery while running the headlights. This is a minor inconvenience most of the time, but can lead to a dead battery and huge headaches under the wrong conditions. The simple answer to this is to upgrade to an 11-pole stator, but this isn’t totally necessary.A side note, if you have severe battery charging issues (while riding), this isn’t normal and there is a fault in the system. Contact the maker of your harness and try to get an answer as to what’s going on.
Expect less longevity than the original Honda 50
But also expect less expensive replacement parts! In this way the cost of maintenance equals out, especially if you consider all the extra power of the GY6 150cc. Factors that affect reliability: Air-cooled Cylinder Design This is an area where the original Ruckus engine really outclasses the GY6. The GY6 is air cooled (versus the liquid cooled stock engine), which means that the GY6 is generally less forgiving to less-than-excellent maintenance habits and won’t last as long as the 50cc Ruckus engine if not well taken care of. On the other side of this coin, GY6 parts are generally far less expensive than the 50cc parts and easy to get from dozens of vendors online. Our best advice is to practice preventative maintenance – frequent and timely oil changes and routine air filter checks. Electrical System Wire quality, internal wire connection methods, and fuse protection play major roles in how long your electrical system will last before popping a connection loose or frying something. Unfortunately, there aren’t really any established resources out there that compare the quality of wiring practices between harness brands. Warranty Coverage varies between vendors who offer warranty against defects. Be sure to check with the seller for warranty details. The BDX warranty:
- Engine & Power train: 2 years/10,000 miles
- Electrical System: 5 years/20,000 miles
- Engine Mount: Lifetime
What to expect on Maintenance
Oil Change Intervals (1000 miles per change)
The Ruckus service manual specifies an initial oil change after the first 600 miles, and then changing the oil routinely every 2500miles. With the GY6, we recommend an initial oil change after the first 100 miles, with subsequent changes every 1000 miles.Recommended engine oil type is 10w40 of a reputable brand. Synthetic is not necessary, but should not be used at all until after the break-in period. Final gear oil should be replaced every 2500 miles.
The GY6 vibrates. A lot. This will cause nuts and bolts to come loose if not properly torqued. Things like aftermarket mufflers may also repetitively loosen over time if not properly supported. A dab of red Loc-tite 272 works very well for larger fasteners, while blue Loc-tite is better for smaller fasteners. One of the most important fasteners of the swap is the rear axle nut, which secures your rear wheel to the engine. We offer a vibration resistant locking nut.
Expect way more speed and power
We’ve talked mostly about the downsides of GY6 swapping, so closing this article with the positive aspects of swapping seems appropriate.
- 55 – 60mph top speed The numbers speak for themselves. With double the horsepower rating, you can match and maintain traffic speeds, even up decently sized hills.
- Big time acceleration boost Again, this goes without need for much explanation. Expect a lot more torque for stop and go traffic. Roughly speaking, the GY6 will accelerate a Ruckus from 0 to 30mph about the same as the original engine reaches 0-15mph.
Bottom line: Swap it yourself!
We advise against having a local mechanic shop attempt to install your swap. Small engine shops aren’t familiar with the Ruckus and can end up having just as many questions as you would, but they’ll be charging you per the hour to learn the same information that you can get at no charge. If you feel totally over your head for the install, it is best to seek out one of the many shops that deal specifically with Ruckus installs. Many can be found on the forums. However, we highly recommend using the swap as an opportunity to learn and get yourself familiar with the workings of your swapped Ruckus.
Need help with your Swapped Ruckus?
We get a lot of calls and direct messages from Ruckus owners that have non-BDX swap kits (sold by other vendors) that are looking here for technical advice. We’re happy to lend a hand, but be aware of the following:
Visitors asking for advice please note: In order to quickly help troubleshoot your problem, confirmation is needed from you at each step that you understand any directions offered and that you have followed them completely.
Please provide relevant details of your results, so that one of our Techs or Engineers can figure out the next troubleshooting steps for you. Help us to help you. Thank you.