XJ750 D - EFI

http://dave_jack.tripod.com/id27.htm

I saw this mentioned in another post. I was completely unaware of this model until then...perhaps I need to get out more! Has anyone seen one outside of Japan?. I quite like the beast... 8)

 

There was one on the UK ebay recently. There is also a member from OZ with one. Both were special imports. The 750 D was only available to the japan market.

Ghost

 

How come that Atari is so awesome? I want mine to tell me fuel consumption and all that stuff. Plus it looks cooler than my fish finder. I'd even take one in Japanese if I can find it, as I know a bit and can learn at least enough to read my instruments km and liters is a bummer though.

Edit: "ahno...nihongo wa dekimasen...chyotto dake...tottemo muzakashi desu" (>_<)

 

KM and Liters is the "right" way You USA guys just HAD to be different didn't you lol

 

I seem to recall we got our units of measurement from the same mother country you did initially...

Reminds me of a bit this one comedian told. He'd gone to Canada, not realizing the speed signs were in KPH. "So, I see this sign that says 'Speed Limit 110'. I thought, YES!!!" (floors it) "A little later, I see another sign that says 'School Zone Ahead/Slow to 80'. Well, gee, that's the *least* I could do, man..."

 

Ya, that's true. Then we smartened up and realized how stupid imperial units are

 

(SIGH) I miss imperial units, it still does not feel like summer when it's a scorching 42 degrees (celcius) outside! Give me the high 90's any day!

 

Not to mention the elegance of "miles per gallon" vs. "liters per 100km" which is how I usually see economy reported in other lands. I can't wrap my head around that.

 

Easy, how many liters do you expend to travel 100kms? I do think it's less logical than km/Ltr, but to each their own.

I do pretty good with metric, but mileage is something I didn't even try. Didn't use vehicles in Israel, and didn't stay in Mexico long enough to be forced to calculate. (Eh, what's 2000 miles, eh? It actually would have been nice to know.)

 

Uh, no shit fintip, I know what it means I just meant that it doesn't have any intuitive meaning to me. If somebody says "Oh, my bike burns 2 liters to go 100 km" I have no immediate sense it that's good or bad or what, without getting out a calculator.

 

2L/100Km roughly eqates to approx 80-90 MPG. No wonder it is hard to comprehend.

Rough Equivalents:
3.3 Liters per gallon
0.62 miles per Km

Very Rough guesstimates
3L/100K = 60-70 mpg
4L/100K = 45-50 mpg
5L/100K = 30-35 mpg

Hope that helps Mike

Ghost

 

Not impressed by it's performance numbers but I do want to take my bike EFI

 

Well, you're a little off there ghost. Gallon = 3.785 liters. Again, not the point, as fintip said, mpg just seems more logical.

 

Hey Ghost
Not sure where you got your calculations for gallons = litres, but I found this site that shows a different equation.
Not disagreeing, just fot gits and shiggles.
Just change the -20 where it says start to 1.

*EDIT* Beat to the finish :roll:

http://www.metric-conversions.org/volum ... .htm?val=1

 

Only because you grew up with those units. Once you start having to do any serious math, metric units are far more logical. Everything is base 10; most people have 10 fingers; easy peasy. There's a reason why groups of 5 and 10 are the easiest for elementary students to learn. There's also a reason why Imperial and SAE units are such a difficult mess; they are a remnant of the medieval guild system, which kept regular folk from competing with tradesmen.

 

I remember riding through the U.S. years ago on my X with kilometres and miles per on the speedo. It certainly was a journey of mental arithmatic. When I'd fill up I'd reset the trip meter, and knew (depending on my riding) how many kilometres I could go on a tank full, including reserve. So as I'm riding along the thru-way (sp) I'd see how many K's left till I ran out, then look for a service centre sign that said how many miles until the next gas. Now using the speedo I would convert my remaining fuel into K's left and convert that to miles that the sign said so that I knew I had enough to go past it or pull in.
Really added some excitement to the trip, until I found out how useful a can of gas strapped to the back seat helped.
Does this make any sense? It's late, I'm tired and have to get up early. :cry: :cry:

 

nope, still missing the point. I get the decimal nature of metric, I've done quite a bit of college level physics and engineering work, all in metric. My point is more about how you don't travel in blocks of 100km, so who gives a crap about how much fuel that takes? KM per liter would be fine. "Oh, I just put 12 liters in my tank, how far can I go? Well, let's see, uh, if it takes 3.7 liters to go, uh..."

Edit: and I gotta say, I don't know why everybody always feels the need to explain how the metric system works, they do teach it in the states, you know. Also, I don't know why people are having such a hard time understanding that liters per 100km seems like an unnecessarily awkward calculation.

 

For the record, my bike gets about 352 furlongs to the gallon. (3,520 chains) :lol: Oh and BTW its litres not liters!

 

"My car gets 40 rods to the hogshead, and that's the way I like it!" --Grandpa Simpson

"litres" (snort) now you're just talking crazy.

 

And just to make it even more like guesswork is it more correct to use Imperial Gallons or those newfangled US gallons.

 

I think we should use the metric system as well, it is a bit easier, but whatever. On the flip side, to make things a little easier for the SAE folks, if you see a speed limit in KM, simply multiply by 6 and drop the last number. i.e. 50kph x 6 = 30mph (last number dropped).

 

Instead of measuring how many litres it takes, which is weird, it is easier for us to think in terms of distance you can go. 100km feels arbitrary, some random distance... A single gallon, or litre, whatever, makes more sense mentally to use.

 

UK Gallons should ALWAYS be used.. this is why i hate mpg.. is it in UK or US, the car companies never tell you.

L/100 is an easier way to calculate efficiency, than K/Litre.

Ex:

say you know your efficiency is 47mpg, that's 6L/100 or 16.6K/Litre

How much gas do you use to travel 300km?
You know right away real quick that it takes 18L
300/16.6 is a pain to calculate out.
mpg you have to convert then calc, pain in the arse.

It's just easier for us that use Km and Litres, to use L/100. mpg means nothing to me except I know 50 is good for our bikes, i'd have to convert my L/100 to know if it's running right. Or just know the L/100 for good economy.

I guess it comes down to the base10 system, L/100K is a base 10 measurement.

How many gallons does it take to go 100miles? @47 mpg, you have to divide 100/47 which equals 2.18 (rounded) 2.18 isn't a nice number to look at

Ok i'm rambling now lol

 

After only 2 posts on topic, this has become a 2 page discussion thread on fuel economy and the different ways to express it. I for one would like to here more about this model XJ750 D - EFI as I didn't even know it existed. EFI on these XJ's is/would be a sweet enhancement. Now knowing that Yamaha produced one of the the same engine design as that which I own and did so with EFI multiport fuel induction, I am highly intrigued.

I want to know more. Are there any design differences between say the head on the 82 XJ750 and the 84 XJ750? If not, then it would be much easier using parts off of a factory bike than engineering a setup. For instance, I have been looking at Jenvey for throttle bodies, and was going to start building an MPI rack that would "bolt up" right into the original intake boots, and then of course add the crank trigger and other needed modification. This route would be considerable more costly.

I will start researching this model more, and perhaps it might be more cost effective to acquire a parts bike and have it shipped to the US, than building a setup from scratch.

 

It would be nice to know what company manufactured those throttle bodies and if they are still available from said manufacturer. Might have to order from Japan, but it could all be worth it.
BTW, it's hard to wrap my head around Litres or Tyres, Just looks wrong. :lol:
Britain, Australia,Canada and USA, country's separated by a common language. :wink:

 

I agree. But I have been browsing around all morning, and there just doesn't seem to be a whole lot of data out there on this model. I have found some more pics, and from what I have seen, I am not real impressed with the set up of the factory fuel injection rack.