Fuel injection project for a Honda NX 250.

What if any parts are out there to make a Honda NX 250 fuel injected? I was trying to think of a bike that would have fuel injection that parts could be used on the Honda NX 250. The CX 650 turbo has two 336.5 cc cylinders and its a turbo, so the injectors are likely too big. I figure a 1000 cc 4 cylinder would be about right, but are there any exotic fuel injected dirt bikes out there? I also want to find some way of installing a catalytic exhaust muffler or something. Just looking to make a Honda NX 250 really clean. Its already very good on gas to start with, being a liquid cooled, dohc 4 valve single. Anyhow, I am not looking for your opinion on how valid my idea is. I am just looking to see if it could be possible to macgyver fuel injection onto a Honda NX250.

thanx in advance for any feedback,

:thumbsup:

do a internet search for "megasquirt".

That would be a cool project. I once thought about trying to hook up a throttle body off an RC51 to my CRF450R. But, then I started looking at the specs on the RC and I saw that just one throttle body had a bore of 54mm! That's huge! My CRF only has a bore of 40mm!! Multi cylinder street bikes are all about top end horsepower and they use some huge bores to get the best intake flow at high RPMs. I'm thinking a better bet is a smaller V-Twin like a Suzuki SV650.

The inline 4 throttle bodies are no good because usually two or all four throttle bodies are one solid piece of metal. The V-Twin bodies are usually separate.

A 2006 Honda Ricon ATV happens to use a 40mm throttle body too. I may have to poke around there some more. Not too sure about any other ATVs that are fuel injected.

The only other trick would be to get the body to actually fit to the cylinder and airbox. Maybe you could just keep looking till you found a throttle body that fit directly to the air box, and then you might have to get a custom rubber adapter made to get it to fit the intake on the head.

Hey Burned, what do you do to get the FCR to fit a DR-Z? Does it just fit? Or are you getting any special adapters?

Like Burned says, the electronics can be handled by MegaSquirt. Though it's designed for multi cylinder engines, and there's probably way more stuff you need there than for a single, it should work. It's a little large too.

If you want a real education in fuel injection, this would be a killer project (you can't get simpler than a single cylinder motorcycle engine). But if you're looking for a quick easy solution, go buy a new bike.

Chris.

I would simply keep researching until I found something doable. Lower emissions, more responsive, possibly a little more torque and power on tap, and better cold starting/warm up etc. As is, the one I test rode today seemed pretty limited in the exhaust smell, so its already efficient even with carb. That DOHC 4 valve liquid engine gets good gas mileage, probably a bit better overall than the SOHC RFVC air-cooled XR/L engines.

I guess to do fuel-injection, you need a MAP/MAF sensor and an O2 sensor, an ECU and all kinds of other K-rap-ola. Mega Squirt sounds like they have enough stuff.If it was possible to get together, it would be sweet. Then if I could find some way of getting a catalytic muffler on there without choking the exhaust, and open up the air just a little with a K & N air-filter if available, then that would do it. 91 to 94 octane gas and a neat smooth very low emissions dual sport :thumbsup:

Hey Burned, what do you do to get the FCR to fit a DR-Z? Does it just fit? Or are you getting any special adapters?

depends on how you go about it.

the off road drz's already have the fcr.

for S/SM you use the offroad manifold and a sudco air boot adapter.

I guess to do fuel-injection, you need a MAP/MAF sensor and an O2 sensor, an ECU and all kinds of other K-rap-ola. Mega Squirt sounds like they have enough stuff.If it was possible to get together, it would be sweet. Then if I could find some way of getting a catalytic muffler on there without choking the exhaust, and open up the air just a little with a K & N air-filter if available, then that would do it. 91 to 94 octane gas and a neat smooth very low emissions dual sport :thumbsup:

Most fuel injected bikes I've looked at (pretty much Honda and Yamaha sport bike service manuals) don't have an O2 sensor. They run in an open loop mode continuously and use pre-programmed fuel maps. They do come with a MAP sensor, atmospheric pressure sensor, throttle position sensor, intake air temperature sensor, and engine coolant temperature sensor. You'd also have to figure out a fuel pump. Most sport bike fuel pumps are pretty big and fill a large hole in the bottom of the tank (very car like actually).

If you really want to learn some more about EFI on bikes, look around on the internet and you can easily find a copy of a Yamaha R6 service manual. It would be a good read to see all the different parts that make up that bike's fuel system.

One more option is to hold out a few years and get an EFI system off a 250 MX bike. I think the writing is on the wall and 450 and 250 MX bikes will soon be equipped with EFI right out of the factory.

Chris.

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