Modified Intake Airbox for more POWWWWAAA!

[scooterchu]

Hi Everyone,

First day on the Kymco forums, but not new to forums in general (I'm usually in car forums) anyways...

I picked up my Like200i a couple weeks ago and it's been a blast. I've always wondered if there was any cheap DIY tinkering I could do to it.


(Sorry if it's a repost)
Today as I was inspecting my air filter, I noticed the airbox top inlet neck (the neck after you remove the flexible intake tubing) is REALLY tiny. just about 1 cm in diameter and the airbox top outlet also flattens into a tiny rectangle about 1cm x 10 cm.

Upon further inspection; it looks like the factory designed an additional reducer plug to go INTO the neck. It kind of looks like a hollow plug. and it's glued in there pretty good!

Anyways, because that plug is oval, I put a small wrench head in and turned the wrench 90 degrees (so the edge of the head catches the narrow side of the plug) and yanked that plug out! Now the inlet is almost 1" (inch) wide and the throttle response is better. Lost a little bit of off the line torque, but the top end is MUCH MUCH stronger; maybe gained a few mph! I'd definitely recommend you to take a look when you inspect the filter next time.

I'm certain that it will lean out the mixture by a few tenths on the upper end so I'm wondering if they made any aftermarket computers that can control air/fuel mixture; but it should be a fairly safe mod!

The reason why I assume it was in there was to help noise restriction as removing that plug and cutting the airbox flow guard thing made valve noise slightly more audible.

[Lucasan]

Love to see some pics of that you feel like posting...

[JOB]

I removed the plug after reading your post and the high speed results were great. I picked up 2-3 MPH to a consistant 60+ MPH. I also changed out the air inlet hose that comes out of the airbox to round hose that is not tappered. I will let you know how it affects my mileage. JOB in New Mexico.

[axy]

I suggest to everybody to study a bit how injections works.

[MotoRandy123]

Well generally speaking if you go from a 1" tube to a 1 1/2" tube going into the air-box
the scoot will accelerate a little quicker. The mix should still be OK as long as you only
mod going into the air-box. I've done this on my Yager and it definitely feels more
responsive. The restriction is there for noise most probably.

[JOB]

Axy, I may be wrong but I thought that the primary benefit to Electronic Fuel Injection is the ability to compensate for fuel octane, temperature, altitude and air density on the fly. We haven't changed the air box volume or routing we have just made the airflow more efficient, if slightly less quiet. Let me know if I am wrong. I always save all original equipment parts for re-installation late.

[axy]

Axy, I may be wrong but I thought that the primary benefit to Electronic Fuel Injection is the ability to compensate for fuel octane, temperature, altitude and air density on the fly. We haven't changed the air box volume or routing we have just made the airflow more efficient, if slightly less quiet. Let me know if I am wrong. I always save all original equipment parts for re-installation late.

If it does all what you described above, it will also compensate for bigger airflow caused by removal of restriction.

"Altitude", "air density" and "bigger airflow caused by removal of restriction" all come to a single thing: "more or less airflow in a given time unit".

[kriden]

Great post.  Thx for listing.  I just did the mod this afternoon and it did make a slight difference.  I hate any kind of restrictions and this plug had to go.  I still question the fact that the scoot "hits a wall" right at 60 MPH.  I feel certain there is some sort of mapping governor in the cpu.  Still investigating.  But over all, still VERY happy with this scoot going into my third season.  It just has so many plus points.  Have a great season and be safe everyone.

[MotoRandy123]

I agree with you about "the wall". I think on smaller scoots they run out of power so hit a wall
but on the Yager it has plenty then stops. I think it runs out of variator so the revs rise to max
and that is the limitation. If you could get taller gears you might raise "the wall"...

[91cavgt]

I agree with you about "the wall". I think on smaller scoots they run out of power so hit a wall
but on the Yager it has plenty then stops. I think it runs out of variator so the revs rise to max
and that is the limitation. If you could get taller gears you might raise "the wall"...

I agree.  I did this mod and did get to 60 mph faster, and gained a couple MPH when there is a tailwind, but otherwise still have about the same top speed.  I too was wondering if tuning the CVT to get a bit taller gearing would help, or if the exhaust is a restriction at high rpms.  I was looking for an aftermarket exhaust for my Like to make it louder and MAYBE gain a bit more top speed but have found nothing.  Would an exhaust designed for another scoot fit the Like if one were to add an oxygen sensor bung? 

[tclhb]

It's probably there to increase air velocity at low rpm. My guess like the original post said is you will lose some low rpm performance.
It's kind of odd, but motorcycle manufacturers will even put restriction in the exhaust for low end, and then a valve opens up for higher rpm. I don't understand how that gives you better low end performance, but it does. My 2001 CBR 929 had that, and so does the Honda VFR.

[big blue]

Hi all, I also removed the restrictor plug and it did give a bit more seat of the pants acceleration. I did not see an increase in top end.  It seems that about 60mph is about tops. I have spoken to a shop that does a lot of mods on CVT scoots and he told me that a variator change could give a few more mph. When time comes for a new belt I might consider a Dr Pulley or Malossi performance variator.
  Len

[kriden]

Thanks for all the follow-ups everyone.  This is a great forum for sure.  I had an Aprilia SR50R and that little 50cc rocked.  The only reason I got it was for the fuel injection and over the top 2-stoke.  But it sucked until breakin was over.  It had a mandated 35MPH limit (something about Euro regs).  35 MPH?  Can you image?  I know that is also a USA reg for 50cc, but you can die from that.  I think we all agree, you need that little something, something when that idiot on his cell cuts you off and you need to get out of a jam ASAP.  I had heard the SR50 was grossly hindered and it turned out it had two main restrictions that they put in. One was a spacer in the front variator that limited how far down the belt would go and the second was a rev limiter in the CPU.  The shop literally hooked up a first gen Game By to a connecter behind the front left turn signal and put the scoot in "Shop Mod" or something.  OMG, that thing was 100% fire breather after that.  I added an Arrow tuned exhaust and was hitting 55-62 (on level ground in the right conditions) no prob.  Of course it lacked torque as it was only a 50cc, but it had NO issues moving around town and pulling in stop and go traffic.  It loved 40-45MPH.  An amazing scoot for sure.  Local dealer lost their Aprilia license and since the engine was pretty advanced, I decided to sell it.  It was my fav until the Like 200.  My point is, I am sure we will find something to get the Like to 65 minus the "tail-wind".  Variator weights are probably the easiest to try first etc. But it has so many good points that I am not gonna worry too much or throw too much $ at this.  It is very cool that we are all on the same page and will keep each other updated etc on out findings.  I do have a post to make about when I changed the belt on Saturday.  I will post that shortly.  But for this, I will keep looking into that Holy Grail of 5 extra mph and keep everyone updated.  There was a post out their somewhere about a possible limiter in the cpu.  I hope to get more info about that when I can get to my dealer next time.  Take care. 

[91cavgt]

I was bored today so I took my Like apart and took some pics of the restrictor, and how to remove it. 

After taking the air box lid off and remove the inlet accordian, here is what you see;




So take the wrench in the tool kit and stick it into the air inlet like this;




After inserting the wrench, then turn it sideways like this;



Then grab ahold of both the air box lid with one hand and the wrench with the other hand and pull the wrench out like this;



As you can see, the insert will come out, but it won't be easy.  Once the insert is out, now you can compare the 2 openings and determine for yourself if doing this is worth it or not.  Here is the side by side picture for comparison;




If there has been a loss in low end power, it is not noticeable to me. 

[de dee]

    just something to think about,.  scooter is designed to go 35 to 45 miles per hour and you fix it to go 60 mph. but have you fixed it to stop it at 60 mph, the brakes are very important too,.