EFI Throttle body mods

Has anyone had a throttle body modification done on their 2011 or 2010 YZ 450? I'm not talking about reprogramming, but an actual physical modification? I am looking for information on this modification and who performs them. We have a new GYTR head and Vance and Hines pipe combination we want to try, and we would like to get the butterfly at least modified to provide a smother laminar air flow at initial opening. We also feel that the butterfly valve doesn't completely open at full throttle, but the shop doesn't have the sophisticated hardware/software to calibrate the TPS and the programming. :thumbsup:

There is a company that makes slide style throttle bodies for suzuki, kawi and honda, but not yet yammy as they are new (according to the magazine article).

Pretty cool stuff though, basically instead of using a butterfly valve like the stock models do, this custom throttle body used a flat slide, like those found in carbs for the previous years.

I don't remember the price, but it looked very very promising IMO.

I don't think your going to gain more than a horsepower given that you have all the other flow mods done to the engine by going to something like this, but it would help.

The only other mod out there is the injectioneering 0 throttle mod, where when you twist the throttle even only a degree the engine seems to lurch in terms of power. Injectioneering corrects this if you send out your throttle body to them.

If you're wondering about boring out the throttle body and adding a larger butterfly for increased airflow, I have heard no one that does this. Your probably on your own for this one...

Simon smart body is the name of the company that manufactures the throttle body with a slide.

here is an older post with info on what company is doing throttle body mods. Their web site only shows honda, but in reading post and magazine article they also do the yamaha.try calling them


web site link http://www.injectioneering.com/about_us.htm

After reading your post with the link, I think I will pass on this company. We are looking for what they do, I just would like another company to do the work.

Despite all of the bad press floating around, I was completely satisfied with the work, and turnaround time I received from Injectioneering. The mods they performed worked as advertised, and made me happy with my new motorcycle.

With regard to the "bad press" Injectioneering received early on, I think it's fair to point out that from all the posts I've seen that mention any problems, what apparently happened was that they were hit with an unexpectedly high demand for the modification and were simply overwhelmed by it. Since the company existed prior to the 2010 model year, it's safe to assume that they had an established capacity that matched their customer's demands fairly well, and it seems that this was upset by the simple number of requests for their work on these throttle bodies.

It's also reasonable to assume, as new as the model is, that the mod was, at least at first, still in something of a prototypical stage, and not 100% smoothed out for a rapid turn around.

An important point is to look at what the complaints were, too. Not one that I remember seeing had to do with the quality of their work or the effectiveness of the modification, only the amount of time it took to get it there and back, and of the confusion on the part of their staff as to where in the process a given throttle body was, or inaccurate delivery date promises. Read for yourselves, but bear those things in mind.

I sent an email to Injectioneering requesting pricing information and a rough timeframe.

My bike is just too darn twitchy, so hopefully this injectioneering mod pans out.

Also planning to get a throttle cam from G2 to slow the response at low throttle (or something similar).


Simon smart body.They are like night and day.


Simon smart body.They are like night and day.

The shop and I are building it for someone to race the east nationals. What is the number.

Ill send it over to you.Whos riding the bike?Steve roman?

The shop and I are building it for someone to race the east nationals. What is the number.

Click me

Hopefully you're got more money than the average guy - $900! WOW!!

Bahahaha!! Love the clicky!

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