990 FI to Carb conversion

[rgmax]

After my Moab trip earlier this year I concluded I had to fix my 990’s clichy FI response or move on.


I had tried the usual solutions, latest KTM map, G2 throttle tube, remove secondary butterflies with only minimal success. The FI small throttle opening response was still very jerky and inconsistent. It was tolerable on the street, but off road was annoying as hell.


The possible fixes were;


1) PowerCommander

From the threads I’ve read on ADVRider and Superduke.net this has its own issues and hasn’t been proven to solve the throttle response issue.



2) TuneBoy

Pretty much the same as PowerCommander with the additional problem of finding someone who knows enough to tune it. The cost of the software plus Dyno time makes this even less attractive than the PowerCommander.


3) 950 Carbs

That was the path I decided to pursue.

A set of 950 carbs, main wiring harness and ECU came up for sale in the ADV Flea Market at a price less than the cost of a PowerCommander.


The additional parts needed to complete the conversion are;


950 timing wheel
950 clutch master cylinder cover and choke lever
Fuel pump, I used a Mikuni DF52-136 vacuum pump
Fuel pressure regulator
Fuel hose, clamps, vacuum hose, tie wraps, etc….



I wanted to keep the ABS system so I used the stock 990 wiring harness. The 990 ECU has two plugs, one of which matches the 950 ECU. I reassigned the wiring on the harness plug to match the 950 ECU pinout. A few other minor wiring mods were necessary to make the neutral switch interlock and temp sensor work. Some parts were scavenged from the 950 harness. Everything works just like factory except for the sidestand interlock.


I’ve been riding the bike on the street for the past two weeks and did a short 25 mile (40 K) off road ride today from 200-5700ft (60-1740m) elevation.


It’s a completely different bike. To say it’s night and day better would be a huge understatement. I never imagined it could work this well. The throttle response is super smooth.


Total cost for the conversion was about $550.

[ADVJake]

welcome to the 990 carb club
good work adapting the 990 harness, i didnt know where to get bits for that plug so i just got the 950 harness.

[roundtripping]

After almost leaving myself a little present in my underwear this weekend due to a gravel vrOOOOM that was supposed to be a smooth little vroom I gotta admit this is looking more and more attractive to me as well....

[rgmax]

Originally Posted by ADVJake

welcome to the 990 carb club
good work adapting the 990 harness, i didnt know where to get bits for that plug so i just got the 950 harness.

Using the 990 harness made the conversion pretty easy actually. A 950 harness isn't really required, the few parts I used off it can be sourced from KTM or easternbeaver.com.

Most of the work involved reviewing the 990/950 wiring diagrams and coming up with a workable pin reasignment for the ECU plug. (I'll post a table)

[zugy]

I have been wondering about this on the new 690 KTM. I got used to using the clutch more often on my 990 but never thought of carbs on this one. Is it as responsive and powerful as the FI? I like to hit the gas hard ya know... sometimes.

Ultimately both performance and mileage, either desired is possible I hope. Is this happening?

Ziga Diga!

[rgmax]

Originally Posted by zugy

I have been wondering about this on the new 690 KTM. I got used to using the clutch more often on my 990 but never thought of carbs on this one. Is it as responsive and powerful as the FI? I like to hit the gas hard ya know... sometimes.

Ultimately both performance and mileage, either desired is possible I hope. Is this happening?

Ziga Diga!

Funny you mention the clutch thing, off road I noticed I hardly ever touch it now. Gear selection is also less important, I also can use a gear higher or lower than before.

The bike pulls stronger/smoother from low RPMs and makes it much easier to climb over rough terrain. I can't express how much better off road it is now, in comparison it was total crap before.

Power seems the same. I have only filled up twice, mileage seems about the same also.

[Evil 1]

Luddites.....

[MortimerSickle]

Originally Posted by rgmax

The additional parts needed to complete the conversion are;


950 timing wheel
950 clutch master cylinder cover and choke lever
Fuel pump, I used a Mikuni DF52-136 vacuum pump
Fuel pressure regulator
Fuel hose, clamps, vacuum hose, tie wraps, etc….

I am about to put a 990 in my early '04 950 Adventure. I had wondered about compatibility, but your list looks like I should already have every thing I need.

Could it really be as easy as just changing the timing wheel, and bolting the motor in? I hope, I hope, I hope.

I saw in another thread that a guy doing this was having a time trying to get his jetting right, but he had Super Duke cams, so maybe that is the problem. Have you had any jetting issues?

[chipwich]

Playing devil's advocate...wouldn't it be much less hassle to upgrade to an '09 or '10 Adventure?

[rgmax]

Originally Posted by MortimerSickle

I am about to put a 990 in my early '04 950 Adventure. I had wondered about compatibility, but your list looks like I should already have every thing I need.

Could it really be as easy as just changing the timing wheel, and bolting the motor in? I hope, I hope, I hope.

I saw in another thread that a guy doing this was having a time trying to get his jetting right, but he had Super Duke cams, so maybe that is the problem. Have you had any jetting issues?

It should be as simple as changing the timing wheel. Its not too difficult. You will need a clutch hub holder tool. I used the one from MotionPro.

I raised the needles one notch and set the fuel screws at 2 turns. Typical changes for a 950. Ran excellent. At least up to 7-8K. I haven't done any full throttle/max rpm runs.

Just this weekend I installed a Jetkit/Prefilter from Head2Wind. It sharpened up the throttle response a little. I haven't had time to test it further.

I don't think the small displacement difference between between a 950 and 990 is enough to require major jetting changes. 942cc vs 999cc or about 6%.

YMMV

[marin ktm]

Are they any better?

[rgmax]

Originally Posted by chipwich

Playing devil's advocate...wouldn't it be much less hassle to upgrade to an '09 or '10 Adventure?

I actually briefly considered a 09-10 model but from what I have read here and in most bike magazines the FI still has issues. Happy yours is working for you.

Doing the conversion actually wasn't much of a hassle compared to riding it the way it was....

[MortimerSickle]

Originally Posted by rgmax

It should be as simple as changing the timing wheel. Its not too difficult. You will need a clutch hub holder tool. I used the one from MotionPro.

I raised the needles one notch and set the fuel screws at 2 turns. Typical changes for a 950. Ran excellent. At least up to 7-8K. I haven't done any full throttle/max rpm runs.

Just this weekend I installed a Jetkit/Prefilter from Head2Wind. It sharpened up the throttle response a little. I haven't had time to test it further.

I don't think the small displacement difference between between a 950 and 990 is enough to require major jetting changes. 942cc vs 999cc or about 6%.

YMMV

Just what I wanted to hear.

Thanks.

[MortimerSickle]

Originally Posted by chipwich

Playing devil's advocate...wouldn't it be much less hassle to upgrade to an '09 or '10 Adventure?

If you are referring to my project, my old engine went south. I couldn't find a 950 replacement, so I am forced to accept a larger engine.

[chipwich]

Originally Posted by rgmax

I actually briefly considered a 09-10 model but from what I have read here and in most bike magazines the FI still has issues. Happy yours is working for you.

Doing the conversion actually wasn't much of a hassle compared to riding it the way it was....

I haven't owned or ridden a pre '09 FI bike, so can't compare. My 09 runs perfectly though, and really wouldn't to go back to carbs having spent my whole ridding life doing the jet juggle. For a more empirical point of view you might want to PM inmate JKlotz, who owns an '07 and has ridden mine. He seemed to think that they have solved the fueling problems.

No complaints with mine on or off road.