I was going to add some info here on my brain child idea I had about a carb swap to an LTR450. First off why a carb swap at all? if you could try to make as much of the variable the same between the 2, F.I. would perform better for a few reasons. it is less susceptible to changes in weather and elevation. once dial in for your setup it will work well in a much larger range of ambient conditions. 2nd, the angle at which you can mount a FI set up is greater, with carbs, you a limited by the angle the floats are. since LTR's have a down port head similar to a sport bike, typical carbs will not work unless you make a manifold the levels the carb at the expense of chocking the intake port bc you are adding a kink in the intake track. therefore all of the carb swaps up to this point that I could find were all using FCR carbs that came from either a crf 450 dirt bike or from a yfz or yz 450. the make bore is 44mm, but to add all the extra goodies to the carb plus the labor was >$500 plus the price of the carb. on the plus side, carbs are easier to fix in the middle of the desert and dont require a super clean work area and do not require a laptop to make adjustments, not a big deal to me when the atv is at my house but out at the dunes, if something acts up I am most likely done riding. so to me the carb is more reliable. since the ltr has a head similar to a sport bike, I started to look at what that crowd does to increase their performance. I found that the Hayabusa crowd will swap in down draft lectron carbs that can be mounted at a very steep angle so that the motor can still benefit from a down port design of the head. this is done when they have exceeded the flow capacity of the the stock TBs that cant be bored out any larger. so that gave me the idea of running one Hayabusa carb on my LTR suzuki quadracer to my knowledge and according to lectron, no one has attempted this idea. probably since the LTR is the only 4 poke atv with that type of head design and not many people competitively drag race LTRs in the first place.
One of the pics compares a dummy 44mm lectron to a 45mm bored stock LTR tb. the other pics show a 46mm lectron that I am running with other add on to better help with my set up, larger fuel bowl, different floats, adjustable power jet. also, the carb was shorten about 0.500" inchs the engine side and the front lower lip of the bowl was shaven down a bit. I gained about 8 hp to the wheel with the swap over the bored tb before my head gasket popped last time on the Dyno. their were a few obstacles that I had to overcome to get the idea to work that I will cover once I get the pics uploaded to the computer.