ltr efi on a 250r

[trx450r1989]

Has anyone tried to hook up an ltr efi to the 250r yet

[8686]

I haven't tried the LTR EFI yet, but one of my 250R's has a Pontiac Grand Prix EFI on it. Works pretty good, especially since no one has ever been able to get a 250R to run good with a carb on it.

[rustyATV]

Originally posted by 8686
Works pretty good, especially since no one has ever been able to get a 250R to run good with a carb on it.

:huh

[trx450r1989]

or has anyone tried to run an fcr carb on the 250r. the fcr seems to be the best carb out there.

[8686]

Originally posted by rustyATV
:huh

I was just kidding, amigo. :huh

[cdrookie]

lol!!

as for ltr efi.... WHY????????????????????
you're wanting to take the electrical system(complete system) and FI components from a 450cc 4 stroke machine and put them on a 250 2 stroke... you actually think that would work? and what would be the benefit?

FCR carbs are great
for 4 strokes

there's absolutely nothing wrong with the pwk's. simple, cheap, and effective.

[rustyATV]

Originally posted by 8686
I was just kidding, amigo. :huh

Oh, ok! I was about to say "Speak for yourself!" :p

As for this EFI thing, someone correct me if I'm wrong, but the LTR system is a point injector where, for a two stroke, you might want to use an older throttle body injector, like what came in domestic cars in the late 80's to early 90's

The difference is a point injector "pulses" full on or off, varying fuel delivery by varying the length of the pulse. A throttle body injector was designed to be a drop in replacement for a carburetor and which was designed to spray continuously, and varied the quantity it sprayed.

Digital tuning is always more accurate than analog tuning, especially when it automatically compensates for mixture changes.

[rustyATV]

http://en.wikipedia.org/wiki/Gasoline_direct_injection#In_two-stroke_engines

[jcs003]

the retrofitting of a modern 2 stroke efi isnt out of the realm of possibility. the issue is; im not sure they use reed type intakes.

i stand corrected. here is one that uses a reed type intake with EFI:

http://www.motocrossactionmag.com/Main/News/REVERSE-CYLINDER-EFI-TWOSTROKE-OSSA-IS-BACK-With-A-3802.aspx

[rustyATV]

I've been trying to find a cutaway of Evinrude's direct injection system, and see how they handle lubrication.

[jcs003]

ktm has done it.

http://www.motocrossactionmag.com/Main/News/REVERSE-CYLINDER-EFI-TWOSTROKE-OSSA-IS-BACK-With-A-3802.aspx

this a a confusing article:

http://www.motocrossactionmag.com/Main/News/REVERSE-CYLINDER-EFI-TWOSTROKE-OSSA-IS-BACK-With-A-3802.aspx

[jcs003]

this is along the lines of a retrofit kit that has potential on our engines.

http://engineeringtv.com/video/Direct-Fuel-Injection-Solution

envirofit direct injection retro-fit kit:

http://engineeringtv.com/video/Direct-Fuel-Injection-Solution

[markk]

WHY WHY WHY---- A carb can be just as effective as fuel injection- just as long as you what what your doing with the carb.--- I dont understand why you would want to take a classic machine like a trx250r and try and rig up an ugly fuel injection system on it-

Just my 2cents- I dont think that ATVs need to keep up with automobile industry. If they start gettin any worse its gona start costing us a thousand dollars or more to just throw a pipe on a quad and have all the Electronics hook up on it.

I bet anyone out there with a 2005 or newer vehicle cant count all their sensors on their vehicle with all there hands and toes. And every sensor makes somothing work correctly!!!

[jcs003]

first benefit is that a direct injection has the benefits of a small and big carb. no tuning. longer engine life. more power with lower compression.

bottom line is the increase in torque is well worth it.

[fearlessfred]

Originally posted by jcs003
first benefit is that a direct injection has the benefits of a small and big carb. no tuning. longer engine life. more power with lower compression.

bottom line is the increase in torque is well worth it. alltho i love e.f.i. (i have been running e,f,i, since 2002) i would have to disagree with you on that statment. a correctly tuned carb will make as much horsepower as efi the engine life would be no different and the thing about compression,i have never heard that before . i do admit that the throttle responce of the bottom is better and if u modify the bike u still have to tune them

[jcs003]

Originally posted by fearlessfred
alltho i love e.f.i. (i have been running e,f,i, since 2002) i would have to disagree with you on that statment. a correctly tuned carb will make as much horsepower as efi the engine life would be no different and the thing about compression,i have never heard that before . i do admit that the throttle responce of the bottom is better and if u modify the bike u still have to tune them

you have been running EFI, on a 250r??

if a carb worked so well it wouldnt be phasing out. dyno testing has proven over and over that EFI is a definite performance enhancer on any engine. EFI makes an engine more efficient.

also engine life is increased due to better atomization, at any rpm. a more efficient fuel burn lowers combustion chamber temperatures. this in turn increases piston/ring wear.

[8686]

Originally posted by jcs003
first benefit is that a direct injection has the benefits of a small and big carb. no tuning. longer engine life. more power with lower compression.

bottom line is the increase in torque is well worth it.

Sillyness.

If efi is so much better then why are some racers at the top level converting LTR450's to run a carb?

[jcs003]

Originally posted by 8686
Sillyness.

If efi is so much better then why are some racers at the top level converting LTR450's to run a carb?

"sillyness" be more specific. you tell me why they are converting back to a carb set-up...

it is common knowledge that EFI is better.

they sure as hell dont let carbs go heads up against EFI in drag racing. car or bike.

[fearlessfred]

Originally posted by jcs003
you have been running EFI, on a 250r??

if a carb worked so well it wouldnt be phasing out. dyno testing has proven over and over that EFI is a definite performance enhancer on any engine. EFI makes an engine more efficient.

also engine life is increased due to better atomization, at any rpm. a more efficient fuel burn lowers combustion chamber temperatures. this in turn increases piston/ring wear. no not on a 250r, on a cannondale,and ltr 450 ( factory set up) i would like to see a dyno test that shows peak horsepower gains for the efi .the tests i have seen ,show slight gains right off idle dont get me wrong,i personaly like efi,but i dont think it is nessary to have good perfomance and long engine life, it may be nessary for emission control. that is why the ltr has two maps from the factory

[jcs003]

Originally posted by fearlessfred
no not on a 250r, on a cannondale,and ltr 450 ( factory set up) i would like to see a dyno test that shows peak horsepower gains for the efi .the tests i have seen ,show slight gains right off idle dont get me wrong,i personaly like efi,but i dont think it is nessary to have good perfomance and long engine life, it may be nessary for emission control. that is why the ltr has two maps from the factory

even MFI(mechanical fuel injection) is a performance adder. corvettes had this technology and many other sport/hi-performance auto makers followed.

the performance gains and cleaner emission coorelate. direct injection is even cleaner and produce more power. example: cadillac used a 3.6L V6 in their1st generation CTS that produced 255hp. which was a very clean high mileage engine. in the 2nd gen they used the same base engine with direct injection that produced 304hp with better emission ratings.

[jcs003]

here is a short article that explains the benefits:

http://hemrickperformance.com/Carb.aspx

it also talks about the problems of having all the additional components.

all the articles were many pages.

[fearlessfred]

Originally posted by jcs003
even MFI(mechanical fuel injection) is a performance adder. corvettes had this technology and many other sport/hi-performance auto makers followed.

the performance gains and cleaner emission coorelate. direct injection is even cleaner and produce more power. example: cadillac used a 3.6L V6 in their1st generation CTS that produced 255hp. which was a very clean high mileage engine. in the 2nd gen they used the same base engine with direct injection that produced 304hp with better emission ratings. the old corvette fi was primative and was mostly used on the drag strip ,not daily driving and was an option plenty of them got converted back to carbs ,on horsepower tv they converted a ls1 to carb and the horse power was the same

[jcs003]

Originally posted by fearlessfred
the old corvette fi was primative and was mostly used on the drag strip ,not daily driving and was an option plenty of them got converted back to carbs ,on horsepower tv they converted a ls1 to carb and the horse power was the same

no offense, but, horsepower tv is glorified advertisement.

the vette FI was the precurser to EFI and DFI. of course it primitive. circa 1957...

[fearlessfred]

right on,u win

[derby]

Originally posted by fearlessfred
right on,u win


John Stallworth used to build EFI systems for banshee's and 250r's. I have seen them run. Kevin Gigot works with EFI on 2-strokes. So it can be done. I remember John telling me he could set up an EFI system for around 3 grand. You also had to ship him the entire motor for setup.

http://www.bigboremotors.com/engine-building.html

[troybilt]

Originally posted by derby
John Stallworth used to build EFI systems for banshee's and 250r's. I have seen them run. Kevin Gigot works with EFI on 2-strokes. So it can be done. I remember John telling me he could set up an EFI system for around 3 grand. You also had to ship him the entire motor for setup.

http://www.bigboremotors.com/engine-building.html

Yep, I was going to mention this myself. They've been building efi for snowmobiles and banshees for years... i.e. on snowmobiles before efi was standard. I've still got the DW magazine with the test... I'll read up on that again.

Gigots are close personal friends of my college roommate. I've talked to them before when I was building a duner banshee back in college. The Gigot family is from Garden City, Ks, where my buddy runs on of the largest feedlots in the Midwest, and the Gigots have a large farm out there. I'll try and find out more information, I don't even know if they still are building these setups anymore.

[jcs003]

Originally posted by derby
John Stallworth used to build EFI systems for banshee's and 250r's. I have seen them run. Kevin Gigot works with EFI on 2-strokes. So it can be done. I remember John telling me he could set up an EFI system for around 3 grand. You also had to ship him the entire motor for setup.

http://www.bigboremotors.com/engine-building.html

good stuff. thanks. it would be nice to get more info on the 250r set-up.

i am aware of EFI conversion kits for street bikes. i wonder if one for a smaller bore street bike(or snowmobile) can be fitted.

[8686]

Originally posted by jcs003
no offense, but, horsepower tv is glorified advertisement.

the vette FI was the precurser to EFI and DFI. of course it primitive. circa 1957...

Not trying to be rude, but everything you're saying has you sounding like an LTR450 rider that got lost in the wrong forum.

[jcs003]

Originally posted by 8686
Not trying to be rude, but everything you're saying has you sounding like an LTR450 rider that got lost in the wrong forum.

no sorry. i ride an 86 trx250r and a 400ex/250r hybrid.

i have previously owned: kx60, yamaha warrior, yamaha banshee, 400ex and 250r respectively.

[rustyATV]

Originally posted by markk
WHY WHY WHY----

It might be just me, but I've noticed that people in this forum are stubbornly resistant to the idea of change. Why is that?


Originally posted by markk
A carb can be just as effective as fuel injection- just as long as you what what your doing with the carb.---

An analog system can be effective, but will never be as accurate as a digital system, especially as conditions, such as air temperature, humidity, and the cleanliness of the air filter, change.


Originally posted by markk
I dont understand why you would want to take a classic machine like a trx250r and try and rig up an ugly fuel injection system on it-

Do you also take issue with aftermarket frames, arms, shocks, plastic, cylinders, axles and wheels? Because if you don't, then your rejecting an EFI system, which would likely be invisible to most people, is irrational.


Originally posted by 8686
Sillyness.

If efi is so much better then why are some racers at the top level converting LTR450's to run a carb?

The fuel injection on early LTRs was very problematic and prone to failure. I have a feeling that it was Suzuki's testbed for the RMZ450's fuel injection. All of the top dirt bikes are now fuel injected, I believe

Bottom line is fuel injection is a selling point because it's one less thing that people have to mess with. I'm someone who's willing to put in the time to jet a carb right, but I've met only one other person who will do the same. When I try to explain even the basic principles, most people resist emphatically. The result is a lot of poorly jetted bikes and quads.

[fearlessfred]

you made some good points ,the last part about most people not knowing or wanting to know how to jet correctly is very true, i have been tuning all my friends carbs since 1985, and they will still ask me to read there plugs ,but most of us ride our ltrs more than our 250rs now . when it comes to jetting i think most people dont trust themselves not to hurt there motors