I want to know if anyone has attempted to swap carbs for injection on a VFR or another four cylinder bike or would know where to start. I know the first question will be why on earth would you do that, the main reason is simply for fun, to see if it is possible. Secondly is to try and make these old bikes more compatible with modern fuels such as those containing ethanol (which i beleive eats the rubber bits of carbs please correct me if that is a false statement) and it should give the ability to tune fueling using a new on-board computer instead of taking the carbs off to get at the jets.

Well, you can start here: http://projectcbr250rri.blogspot.co.uk/

See you at the turn of the century...

Ciao,

thankyou :)

It is possible but it takes alot of work.. you can count on your fingers the ones that have successfully done it

looking at other attempts, like the one on the link above, i agree with that. I guess a vfr would take a few years to do maybe i could look at the newer vfr parts like fuel pumps etc and see if they can be grafted on only problem is they are for much bigger capacity engines.

are there generator upgrades for nc21 /24 engines already? i ask because it would likely be needed for all the extra power sucking parts.

Vfr400KM wrote:are there generator upgrades for nc21 /24 engines already? i ask because it would likely be needed for all the extra power sucking parts.

The generator is the least of your concern.

The stock 350watt generator is capabable of running a fuel injected setup.

There are 2 main reasons that only a small amount of people have fuel injected VFRs.

1. It requires a lot of knowledge and skills in a variety of areas with specialised machining equipment AND / OR an awful lot of financial investment. The more you have to sub things out the higher the cost.

2. The stock VFR can be set-up to run really well on the standard CVKs.

If you were even considering fuel injection on a vfr400 here are a few of the steps you'd need to undertake (in no particular order)

Install a fuel pump / return in the tank - requires cutting the tank and welding in a new assembly to hold the fuel pump.

make custom throttle bodies for the vfr.. these could be as simple (not really but as it goes..) as remodling the original carb throttle bodies (destroying them as carbs in the process... not a great way to do it but i've seen it done.. or have some made by a throttle body maker... if you really have all the equipement you could even make your own.

install a camshaft position sensor and modifiy the cam-shaft if need be to provide a cam timing signal.

get a custom ecu wired in to run everything and set it up as needed.

optional depending on ecu and setup would be to install tps, map, lambda sensors.

i've toyed with the idea in the past but I have access to a serious machining shop (they cut gears etc for Honda motors) and can fabricate a lot of the stuff myself but the time / money / effort required to get something set-up really isnt worth it for the majority of people.

Mike Norman builds 460cc class race bikes and uses FI to get every last ounce of power out of his race-bikes but some of those cost upwards of 20,000 dollars in parts to get running.

I don't mean to sound like a buzzkill but it is an awful lot of specialised work that if you cant do yourself is going to inflate the cost exponentially, especially when you need parts re-made as they are not quite right.

The vfrs are fine with ethanol anyway... you can buy a set of viton carb kits from littekblair and replace the fuel hoses with modern rubber and you shouldnt have any issues running ethanol based fuel unless you try to go crazy and use something like e90 etc..

It is a lot of money and a lot of work, but i can say it works great.


Michael

Taking a small high-revving motorcycle engine from carb to fuel injection is a complex task, and you have the additional task of packaging all the fuel injection items within the area of a tightly-faired motorcycle.

If you want to see a current, ongoing project with a NC30, look here: https://blog.familjenjonsson.org/blog/2 ... 1-of-many/

The owner's last post to this NC30FI build-blog was 11 May of 2017.

I don't know the current state of this project, don't know if the bike gets ridden much at all, the owner has recently turned his attention to an airplane project.

mruehl34 wrote:It is a lot of money and a lot of work, but i can say it works great.


Michael

If its done properly no reason to believe it wouldn't.

You as well as Mike run FI correct?

There are a couple of local guys here that also have FI converted NC30's, I didn't get chance to check it out but I believe he had what looked like a lambda sensor in the exhast too, shame I didn't get to ask if it was actually connected and used in the system or just there for help with diagnosis (wide-band).

I couldn't personally justify the conversion for a street bike due to the time and cost but if they are no object then there is no reason anybody with the right contacts and knowledge couldn't convert a bike.