20 replies to this topic

[Tyler]

Hey guys

I've been having serious trouble with my bike's running in the cold. It seems to be flooding, and does not get to warm operation temperature, unless sat idling in traffic for about 5 minutes without moving. And even then, it doesn't idle properly.

I would like to look into fitting fuel injection to my bike. My old man's 900 is great in any weather/ at all altitudes, and has excellent fuel economy. I just want a simple system that would run off a throttle position sensor, and rev meter (crank position sensor), and a simple ecu to control injectors and spark.

Anybody done any research on this, or know how feasable it is? Or how I could sort my horrible fuelling, and sort my economy out?

Thanks
Tyler

[tdm850rider]

Clean the carbs and check your thermostat first.
Much cheaper than building an FI system from scratch.

[catsbum]

Here's my favourite question coming up.................


Where are you?

[wicklamulla]

Here's my favourite question coming up.................
Where are you?

Tony !

[bcristian]

I was thinking about something like this too - fuel injection (if properly done) really kicks carb butt. Not only because it can be built to self-adjust to any temperature/humidity/altitude conditions, but also because it is so much more controllable and it can be set up any way you like. There is nothing stopping you from say going the Suzuki GSXR 1000 K8 model and put an "engine mode" switch that toggles between sport mode and fuel economy mode.
Then I usually wake up. (sorry, no offense intended)
The electronics involved is not exactly rocket science, there are loads of really cheap programmable microprocessors out there, more than capable of doing real time engine management for a 2-cylinder, 12k RPM max engine, and it only takes a few thousand lines of code to do it.
The mechanical part is another matter - I don't think it's even possible to build a DIY FI system. Nor would it be feasible in fact, since it would be much cheaper to just buy the parts from a breakers. I'm not exactly up-to-date on the prices here, but I would venture a guess that it would be several hundred quid for the lot (FI fuel pump, throttle bodies, TPS sensors, etc).
Now for the really difficult part: you would need loads of time with some rather expensive electronics equipment (such as a digital oscilloscope) and a dyno, plus a means of changing/controlling the composition, pressure and temperature of the intake air. I guess that unless you own (or have unlimited access to) an engine tuning shop, for the money you would spend on this you could easily buy a few (FI) bikes.

[tdmuser]

Here's my favourite question coming up.................
Where are you?

oh dear


looks like your going for the carpe most usefull poster of 2008 comp......598 posts,,, 570 saying "where are you" ,,, dont think thats gonna win it

[robelst]

fuel injection (if properly done) really kicks carb butt

That's not my experience; cold-starts and high speed fueling may be better but even modern FIs can be jerky and snatchy, and sometimes respond rather temperamental on half-hearted twists of the throttle. Carbs may be less accurate in theory but still can't be beaten when it comes to smoothness.
And these are engine-specifically developed factory systems, it's unlikely to improve on that by sticking on some FI-bits that a breaker has lying around

Why not just fix the cause of the problem rather than dismissing the concept of carburettors altogether?

Edited by robelst, 12 January 2008 - 10:56 am.

[duibhce Kaelann]

That's not my experience;

nor is it the experience of those having had a blast on both the 950 (carbed and very smooth) and the 990 (injected yand very twitchy) KTM adventure. Not sure the difference isn't just due to a lousy FI setup by KTM but the difference is quite astonishing.

[dandywarhol]

Logically, if the engine was ok when it was new then overhaul the parts that are worn and it will be as good as new again - why mess about with an unknown????

[tdm850rider]

Logically, if the engine was ok when it was new then overhaul the parts that are worn and it will be as good as new again - why mess about with an unknown????

Agreed, you could wind up with a 500 pound paperweight.

[bcristian]

Wow, let me clarify: what I meant is that the FI would be a really cool mod, one I would really love to work on if I could (but since it takes about 35k USD worth of equipment to boot, it's never gonna happen).
Now, I know that there have been (and still are) some really crappy FI systems on several motorcycles, particularly on their first versions - Honda Varadero, KTM 950/990 Adventure to name some well-known screw-ups. On the other hand, if you are not bound by the same time and mass-production economy issues as a big company, you can always come with a (much) better tuning, if you put enough work into it. Think about how many engine tuning shops there are, and they improve on the factory thing - even if none are anywhere near the factory budget.

[Landy]

Can it be done? 99 times out of 100 the answers is yes but how much time, money and effort do you want to put into it! Especially as Mr Yamaha has already don it for you. Buy a 900 why don't you its a better bike any way (now enrolling in witness protection scheme)!

[TonyDevil]

yes it can be done (looking at doing it on my XTZ850), BUT and its a big BUTT
......unless you are an electronics guru leave it well alone on a mk1/3VD
the 900 FI system can be pretty much bolted onto the mk2 4TX engine (as shown by the tutorial on the TRX site)
http://trx850.motoma...opic.php?t=2022
but because of the wide variety of parts required the cost of the 900 parts is more than the value of the 850 bike
basically its a full electrics transplant, you also need some of the sender sensor thingys out the engine
apparently the 3VD engine doesnt have the case holes/mods (but i dont have all the details on this)

if you really want to do this to a 4TX buy a crashed damaged 900 and rip its guts out

if you are prepared to wait a little (could be 12months away) there is possibly going to be a DIY kit produced by raidxtreme (see superten xtz site for info)
http://supertenere.proboards20.com/

Buy a 900 why don't you its a better bike any way (now enrolling in witness protection scheme)!

not sure i agree on the better bit, but i agree with the rest, if u want a fuel injected TDM, buy a 900
a decent 2nd hand bike is under £3k
or you can pick at cat C up for under a grand, plastics & the like will cost you another few hundred

[bcristian]

As far as money is concerned, it would be completely insane to even consider this thing, TonyDevil put it better than me - the parts cost more than the whole 850.
Yet, if it somehow I would stumble upon a treasure chest in front of my door tomorrow morning (mind you that it would take a very big chest, as over here the state would steal the better part of it right away and tax the rest), anyway, if that would happen, I would start building all kinds of crazy (and utterly impractical) stuff like this the next day.
A DIY FI system is particularly appealing to me, since it involves two things I love: motorcycles and programming. The latter being my full-time job, and I still remember when I started learning it, on a communist Z80-clone 8 bit processor, writing programs by hand directly into the memory (remember POKE/PEEK, anyone?).

[tdm850rider]

I remember writing programs in ExBASIC and saving them on a cassette recorder....

[SteveGlover]

I remember writing programs in ExBASIC and saving them on a cassette recorder....

Luxury. I remember writing programs in FORTRAN directly onto IBM punched cards. What fun we had when we dropped the stack of cards and had to sort them out.

[Doc]

Luxury. I remember writing programs in FORTRAN directly onto IBM punched cards. What fun we had when we dropped the stack of cards and had to sort them out.

We had a card punch at school, wrote the programs in 'CESIL', and posted the cards to an office in Croydon where they had a mainframe with a card reader. After waiting excitedly, about a week later, the results were posted back on a stripey sheet of paper...."Syntax error, line 20"

I guess computers have moved on a fair bit really.

[bcristian]

Oh, I am so glad I missed out on the card punchers. I was too young at the time, and only properly qualified people were allowed to use the behemoths.

[tdm850rider]

I forgot about the punchcards.... all that 'clackety-clack', the compuer room kept so freakin cold...
and 1 card out of sequence.... error error

[JBX]

I forgot about the punchcards.... all that 'clackety-clack', the compuer room kept so freakin cold...
and 1 card out of sequence.... error error

I guess it was before the war.

The Civil War I mean...