There is a great write-up for the YZF tank swap and R6 tail conversion that has been around for quite a while and had been the only real reference online for this swap. This is a common method for converting but I will try to build on it and add some details and alternatives that I’ve learned of during my custom build.
YZF Tank and R6 Tail Swap Write-Up
The stock FZR gas tank consists of a steel tank, mounted between the frame rails with a plastic tank cover mounted on top of it. This design is weak and dated looking. The FZR also has an airbox in front of the reservoir and under the tank cover containing the air filter. The stock tank is perfectly fine for the bike and most riders, and the design remained unchanged during the course of the FZR’s production. The stock tank and cover quickly becomes limiting and problematic, though, when someone decides to customize their bike beyond stock configuration.
The YZF600r (not YZF-R6!!) tank is a steel tank with the tank and shell made as one piece. This adds durability and also updates the style and appearance of the bike with more modern angular lines and also allows the opportunity to wire a low fuel LED using the sensor built into the YZF tank. This tank has a slightly higher fuel capacity, so it increases total miles per tank, but increases weight and alters the COG slightly.
Tail Swaps
The FZR600 was first produced in 1989 and its appearance and design varied very little over the course of its production until 1999. When the FZR debuted it was cutting edge, but was quickly outpaced by a rapidly changing industry and market and it shows its “retro” roots, especially in its bulky tail section. Many riders are pleased with the rest of the bike’s appearance, but most want to change to a tail section from a newer bike to give their FZR a more modern look. These tail swaps have been done using parts from numerous types of bikes with varying amounts of difficulty and success, but the most common is the R6 tail. Depending on the desired use of the tail, swapping the tail section out can vary greatly in method, but one common problem with all R6 tail swaps onto a stock FZR is seat to tank fitment.
The FZR600 seat is shaped much differently than later sportbikes. It has a raised portion in the front that rests in a recess in the stock tank cover. When changing to a R6 tail the R6 seat must be used as well since the FZR seat will not fit properly on the R6 tail. Since the R6 seat does not have a raised section in the front and is generally flat, it leaves a gaping hole in the back of your tank. While this does not harm anything per se, it is an eyesore. By converting the tank to a YZF600 tank, which has a solid shell, the R6 seat mates up perfectly and matches the curve of the tank as well.
With so many options and methods for tail swaps, I’ll leave that for another topic but for the sake of the writeup we’ll assume the bike already has another tail on it at this point.
Finding a Tank
Any year YZF600 tank will work for this swap, but the best years are 96-07. The original tanks are not quite as sleek looking, but will still work. My tank is from a 99 YZF600. Ebay is a good option for buying a tank since they are fairly common, or you can occasionally buy one off a board member. Tanks can vary greatly in cost depending on condition and shipping costs. $100-$200 seems to be common. The tank fits the FZR frame well, but is not a completely bolt on upgrade. Used tanks may need servicing before they are suitable for install. Excessive rust inside and particles need to be cleaned out and the petcock may need a new seal and replacing the fuel filter is probably a good idea as well. Be sure to get a cap and key with the tank or separately. The FZR cap will not work on the new tank.
Removing the Stock Tank
The stock tank must be removed before the new one can be installed. The less fuel in it the better since it will make it lighter and easier to handle. Drain the fuel out or turn the petcock to off and disconnect the fuel line. Be ready to catch any dripping gas. Remove the seat and unbolt the bolts holding the tank cover to the frame and remove the screws securing the front of the tank cover to the mirror stay. The mirror stay/tank cover mount needs to be removed from the frame as well. This bracket can be modified to use as the new mount, but if it is to be reused, the support arms for the mirrors need to be cut off. The tank is mounted to the frame by a small crossmember between the frame rails and to the seat bracket. Unbolt this tube and remove the tank. This bracket will not be reused and will not fit with the new tank. You can remove the mounting bracket for the crossmember from the frame at this time, but it is not necessary.
Mounting the YZF Tank
The YZF tank mounts to the frame differently than the FZR’s tank cover does both front and back. I will contribute what I know about ways to mount the tank and hopefully others who have swapped tanks can offer their tips and tricks here too. It is possible to modify the FZRs front mount which requires no additional cost, just labor. The write-up listed earlier shows how to modify and reuse stock FZR hardware as well as how the tank needs to be trimmed to fit properly.
When I purchased my bike, it had FZR1000 fairings modified to fit and had a FZR1000 tank mounted up. The FZR1000 tank is also a single piece steel tank like the YZF and has similar mounting dimensions. The FZR1000 tank is not a good option for a swap on the FZR600. It is much wider and the controls will hit at full turn. But the front tank mount for the FZR1000 is a perfect fit for the YZF tank.
An example of reusing the stock front mount
This bracket screws directly to existing holes in the FZR600 frame and match the bracket on the YZF tank making the front mount completely bolt on provided you can source one of these brackets. They are available to order from the dealership. I am using a long pin with a retaining clip instead of a bolt and nut for easy removal of the tank for service or tuning, but a long bolt and nut would work just fine. I found that modifying the bracket bolted to the tank that I could get a better fit along the FZR frame. I trimmed about ¼” off the lower end of the bracket so that it did not contact the frame, and elongated the bolt hole about 1/8” forward with a dremel tool. This allowed the tank to move forward slightly and narrow the gap between the rim of the tank and the frame. To help mask some of this gap as well as protect against vibration, and dirt to an extent, I took some bulk rubber vacuum tubing from the auto parts store and slit it with a razor blade. I then filled it with light silicone and ran it along the lower lip of the tank. This pic shows the gap before modifying the mount. Its more than ¼” gap and doesn’t sit flush at the bottom angle of the subframe. Trimming the mount slightly greatly improves the fit.
The rear mount can be fabricated from the stock FZR bracket as seen in the earlier write-up or the FZR1000 or YZF600 mounts can be modified to fit as well. Some sort of mount needs to be made and a rubber grommet/cover included to reduce vibration and to securely hold the rear of the tank. I cut and rebent it myself to fit the frame and then reinforced it as best I could. Or its possible to fabricate a completely new bracket with very basic tools and a few important components. I had originally planned on riveting it to the frame, or just bolting it down.
I ended up going a different direction with my project at this point and had to come up with a one off solution for mounting to my R1 subframe instead of the stock subframe like in these pictures. So hopefully others who have done this swap and used a different method for the rear mount than in the original write up will add them here.
Fuel Pump
The FZR has its fuel pump mounted to a bracket on the tank reservoir itself. The YZF tank does not have a bracket for this. One can be fabricated to reuse the FZR pump or a different model of fuel pump can be used. For a while I had what I think was a FZR1000 pump that bolted directly to the underside of the rear tank mount I already had. It was a much larger pump and I have since made a bracket to use the FZR fuel pump.
Airbox
The stock FZR airbox will not fit under the YZF tank shell unmodified. Some people have trimmed it and reshaped it using various methods and mediums. I did not have an airbox so I never bothered with this step.
The alternative to modifying the airbox is to switch to pod filters. Pod filters are individual filters for each carb(or sometimes one filter for 2 carbs) and allow for complete removal of the airbox. Switching to pod filters can increase the power and performance of the bike but can also make tuning difficult and inconsistent, but when tuned properly can greatly increase performance. Using pod filters makes modifying the airbox unnecessary since it will no longer be used at all, but using pods may require tuning modifications for correct performance. An example of a modified airbox is in the original write-up. If the airbox is removed, it’s a good idea to put a filter on the transmission breather tube. There is a vent tube that goes from a nipple on the top of the engine case to the airbox to allow filtered air to vent the engine. When the airbox is removed, dirt and other nastiness can get into the engine. One option to remedy this is to purchase a small K&N style filter from the auto parts store and attach it to the end of the tube. The filter can be secured to the frame with a zip tie. There is not enough room to slip the filter directly onto the breather tube. It will contact the bottom of the tank. Leaving this vent uncovered and open is not recommended.
Low Fuel LED
The YZF tank has a low fuel sensor built in from the factory. It can be wired to a LED somewhere else on the bike to notify the rider when fuel reaches a very low point. This is useful to have since the YZF tank does not have a reserve selection like the FZR tank does. With the YZF tank, once you’re out of gas, you’re stuck. With the FZR tank, turning the petcock knob will allow a few more miles of travel. My personal setup is different since I am using a custom aftermarket gauge setup, but here is a wiring diagram. Wiring up a LED is a pretty simple process with the diagram.
If anyone else has used different methods, please share them.
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