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- Performance Modifications & Enhancements ( https://www.xt660.com/forumdisplay.php?f=52)

- - Throttle response ( https://www.xt660.com/showthread.php?t=22945)

Throttle response

I have a more general question regarding the xt660 that also includes other bikes.

I have had several bikes and one thing that I like in a bike is throttle response and I think that is what is missing from the xt to be a fun bike.

For example the KTM 640 that I owned a couple of years ago had a CV carburettor. The throttle response on that bike was the same as for the xt660. I test rode a friends KTM 625 that was equipped with the exact same engine but had a Keihin flatslide carb. The difference was huge so I got myself a Keihin that transformed the bike totally.

The same I have also done with two of my old Ducatis, 900 supersport (CV) and Ducati 750 supersport (CV). I replaced the CV carbs with flatslides. Huge diffrence!

I would like to have the same throttle response on my XT660 but keep it injected. What can be done? I know that the new KTM EXC bikes have injection and they have the throttle response that I am after. So it can be done with injection but the question is how?

Has anyone tried for example another injection system on the xt660? e.g megasquirt or even put a Flatslide on ?

Would you describe the difference in riding / throttle response?
Have you considered a Power Commander with custom fueling map?

Anyway, you got my attention at "megasquirt".

what xt have you got? x, r or z?

I think what your really talking more is not response but free revving under load, as the xt motors spin up freely when not loaded but on a standard engine, in gear under load it takes a while to rev the engine trough the range. I think you will be looking at the basics of air filter replacement, fuel mods (either kevs or PC's) and exhausts. each will help the engine take in more air, make more of a bang and allow the fuel to exit the engine better

"but on a standard engine, in gear under load it takes a while to rev the engine trough the range"

im not to far away from standard but i go from changing gear to limiter pretty quick tbh it do sent take awhile on mine untill about 70 mph its change gear hit limiter change gear hit limiter its not like it take time to climb

Maxwell12345: Yes you are on the spot, it is the free revving under load that is damn slow on the XT660.

If any of you have ridden a KTM with flatslide, be a 625 / 660 or a XC or EXC you know what I am after. I know the XC and EXC are competiton bikes that cannot be compared but I know what a huge diffrence the change of carb did to my KTM 640 and the ducatis. I think that the free revving of the XT660 is like a CV carb model, sluggish and with lack of "temperament".

My bike is a Xt660X -2004 with DNA stage 2, snorkel removed, KEV mod but standard exhaust (I like it silent..).
I have considerd a Powercommander but I do not think that it will accomplish what I am after.

Or it could be that simple it is just lacking power? I am used to stronger bikes.

But I also feel the same diffrence on cars, some are with more temperament and throttle reponse. Compare a standard Alfa romeo to a Volvo, both can have the same horsepower and tourqe but it is delivered diffrent.
I would say that the XT is a volvo and the KTM is the Alfa Romeo.

Would you describe what you are after as:
* more elastic engine (more useable from down below 3000rpm than stock)
* faster throttle response (faster delivery of power to the wheel)
* better take performance
* different "feeling / feedback" to the rider
* different torque pattern (eg. more low-end torque vs more high-end extension)
* more HP to the wheel

?

Its the crap fuel injection:rip[2]:.A big carb far better.:newspaper:

Quote:

Originally Posted by Kurbens (Post 203114)

i never realized how much restriction the stock exhaust is till i fitted mine for winter (bike came with akros) and god the lack of power and lack of engine braking and the time it took to rev was so poor i couldn't believe the difference it made it sluggish on accelration and decelration

The KTM's are a lighter built motor with a lot less
internal mass to accelerate... The XT can be made to
rev out more freely..but It's not a KTM and will
never be one...

The biggest gains from these motor are from the intake side, you try & run fast with a big sock rolled up in your mouth.:Itching_KFKKYE:

You can compare a KTM big bore short stroke quick revving motor to a long stoke motor, the shorter stroke will always rev quicker if both bikes are standard, but there is some thing you can do to a XT, if you had to ride Kriss007 XT it would smash any KTM 690 by a long way with 76 rear wheel HP.