Tuning my 2006 big bore Ruckus --- journal

[turbowagon]

Hey all,

I'm going to use this thread as a journal for the tuning process of my big bore ruckus. Hopefully it will be useful to others who install Chanito's piston. (and also w/ your feedback I hope to achieve a good tune myself)

I have a Veypor VR2, so I will be plotting performance curves here after each new tuning step, so we'll have a quantitative measurement of each change.

Here are my performance mods:

- 41mm overbore piston
- Battlescooter H.O. cam
- Polini variator
- modified stock airbox for more flow

---------------------------------------------------------

Initial tune:

85 main jet
40 pilot jet
Idle Mix Screw untouched

This was the initial configuration I used when I started up my Ruckus for the first time after the big bore.

Overall impressions:

Decent idle, jerky under partial throttle, steady acceleration under full throttle until about 30 MPH, crappy top end 30 MPH+

I went for two 30 minute rides with this tune, once with temperatures around 60°F, the other time with the temperature around 45°F. Both had similar crappy top ends, the part-throttle jerkiness seemed maybe a little less on the colder day.


Performance curves:

Unavailable, as I had not installed the Veypor yet


-----------------------------------------------------------

First pilot screw adjustment

Yesterday I installed the Veypor, and in the process pulled the spark plug.

The plug was black and covered in carbon deposits, so I assume I've been running rich:



Then I adjusted the idle mixture according to the service manual 2006+ directions. I started by letting the Ruckus idle for about 10-15 minutes to warm up to operating temperature. I then adjusted the throttle screw until the engine was running at 1600 RPM. The next step was to adjust the idle mixture until the RPMs are at their highest. The strange thing is, I got the highest RPM (about 2000), with the idle mixture screw turned all the way in! Is that normal? Does that mean my pilot jet is way off or something is wrong with the carb?

Once I get the speed sensor of the Veypor installed, I'll go for a ride to log some baseline curves, but do you guys have any suggestions for my next jetting? Maybe 38/82 and then readjust the idle mix?

[Dandy Dan]

First...I think you've made some smart performance choices...you haven't dropped a slew of money on mods that make insignificant improvements like fancy ignition coils and CDI's but rather you've just addressed the 4 biggest areas (displacement, valves, intake and gearing) which are definately the right areas to start with. Furthermore, the Veypor will be super helpful and I applaud your systematic approach...taking your time and doing it right is the way to go.

Regarding your idle mix and slow jet tuning...it sounds like you are doing a great job with the idle mix tuning....I haven't done mine personally but I have dabbled a bit and I suspect my 42 slow jet is giving me a rather rich idle so your 40 SJ with the screw turned it makes sense. As for the slow jet, the 40 is a nice way to go...I found with a 38 you can get a stumble off the line when you crack the throttle but going up to a 42 can suck at idle. Obviously it's different for everyone but I think your 40 slow jet is good enough to leave for now until you have the main jet sorted out and then you can fiddle with this and re-do the idle mix screw if necessary. Changing your main jet does have a small effect on the idle and slow jet because the MJ isn't 100% sealed at idle I believe so I'd leave these adjustments until the MJ is dialed. Chanito is right that the MJ is really the first thing you should dial in.

Currently, my Ruckus which has the same mods as your engine plus the Yosh, an aftermarket coil and the K&N intake, is jetted at 42/82 which I find to be pretty solid across the board but too rich (I believe) at idle.

Now about your current jetting...it's too bad that you don't have Veypor benchmark graph for your stock Ruckus as that would be cool to compare your Ruckus too. Anyways, about your black plug...yes that plug is black and a sign of running rich but one thing that always amazes me is how quick plugs change colour...I've had a plug go for being that black to white like snow in a 30 second ride. The point is, plugs change colour very quickly and so you can't get an accurate reading if you just go for a ride and then putt up your driveway, let it idle for 10 seconds and then shut it off. If you want an accurate plug chop it needs to be just that, a plug chop....drive a full throttle at your top speed for atleast a couple hundred meters and then hit the kill switch and brake to a stop. If you have a hard time doing this by your house just take your spark plug socket with you and do it on the side of the road. I just thought I'd mention this so that you aren't tuning with bad plug readings because once I had a rich idle but was totally lean up top and I thought I was rich up top because I didn't realize how fast the plug changed colour so after a run I'd let it idle for a 30 seconds or so and then pull it and it would be all black and sooty but if I had done a proper plug chop it would have been white.

Anyways, for your next jetting setting I'd say stick with the 40 slow jet...that has nothing to do with your lack of top end. For the main jet, I'd say go down to a 82 and then go for a nice run to get the engine warmed up and then do a proper plug chop and report back. Good luck

[turbowagon]

Thanks Dan for the detailed response, especially your comments about the spark plugs changing "color" quickly. I wondered about that myself, but wasn't sure. And with the idle mix adjustment way off, I was definitely running rich at idle, so that could be falsifying the readings.

Even though I suspect the next step will be an 82 main jet, I'm going to keep the 85 until I can get some baseline curves.

[Dandy Dan]

Good idea....it sucks to try a jet out but not really give it a fair shot and then later end up wondering if you should re-try it.

What's holding you back from installing the speed sensor for the Veypor? I installed mine in just a few minutes by routing the wire back and then using quick set JB weld (epoxy) to secure the magnet and sensor. I just encased the wire about an inch back from the sensor in a blob of JB weld and it was hard enough to ride in maybe 30 min.

[Dandy Dan]

So what's your scoots name? You may wanna add that to the thread title.

[turbowagon]

Thanks for the pic. That's the same spot I chose to mount the sensor. I just didn't have the J-B weld yet, so I'm going to pick some up from the hardware store and mount it tonight.

And my scooter's tentative name is "Libby"

[Dandy Dan]

Okay...make sure you get the quick set stuff...I've never used the regular stuff but I don't see why you'd wanna wait longer than you have to since the quick stuff is great.

[chanito]

Maybe, because the regular stuff is like ten times stronger In some aplications you must have the regular epoxy, because it can take heat and once it is set it can be machine like metal
Anyway, my two cents, the fact that you need to screw the mixture in so much means the slow jet is WAY BIG, get the next size down, so at least you are in the ball park, then concentrate on the main jet

[turbowagon]

Thanks, Chanito. That was my intuition about the slow jet. The other possibility I thought of is that the engine wasn't fully warmed up and the Starting Enrichment Valve (?) was maybe richening the mixture. I'll readjust the idle screw after I go for my next ride to be sure.

I got the Veypor installed fully, and should get some baseline curves this weekend. The weather is perfect. Can't wait to go for a nice ride. I'll post up my results on Monday.

[Dandy Dan]

Sounds like you're well on your way to getting this dialed....even the results of a poorly performing jetting setup are very valuable because they tell you what doesn't work and what to try next.

The SE valve should be closed after 1-2 min of idle so I doubt that was messing up your idle...if it idles fine now I'd leave it until you've got the main jet dialed because it's a lot of hassle for nothing if you have to re-do it again in a few days.

[turbowagon]

Dan,

Any suggestions for what kind of data logging to do w/ the Veypor that will help the tuning process?

I was planning to do a bunch of full-throttle runs on a long straight, and maybe also some part-throttle runs as well. Any other ideas?

[sanjuro62pt1]

turbowagon said:

Dan,

Any suggestions for what kind of data logging to do w/ the Veypor that will help the tuning process?

I was planning to do a bunch of full-throttle runs on a long straight, and maybe also some part-throttle runs as well. Any other ideas?

I would suggest doing 1/4 timed runs. You can glean performance comparison numbers like:

[Dandy Dan]

Yeah 1/4 mile runs are probably the best way to go...that's what I use. The graphs of speed vs. time are really informative and from those you can figure out your 0-20mph, 0-30mph times etc and see visually where your power is kicking in and dropping off.

[Dandy Dan]

turbowagon said:

The strange thing is, I got the highest RPM (about 2000), with the idle mixture screw turned all the way in! Is that normal? Does that mean my pilot jet is way off or something is wrong with the carb?

Turbowagon, I finally got around to messing with my idle mix screw the weekend and I got the same results as you. I was running a 42/82 setup and I couldn't get it to idle properly so I dropped down to a 40/82 and I got the best (highest RPM) idle with the idle mix screw turned all the way in, just like you.

Perhaps this isn't a totally correct way to think of it but the way I think of the idle mix screw is that it's essentially a fine tuning adjustment for the slow jet. So if your slow jet is way off, it doesn't matter what you do with the idle mix screw, it's not going to idle well.

I didn't spend a lot of time messing with the idle but the idle seemed pretty reliable with a 40 SJ and the IMS turned all the way in. It seems likely that the true, best idle is somewhere in the 38 slow jet range though so I'll likely give that a shot sometime. With a 38 SJ you shouldn't need to turn the IM screw in all the way so you can really perfect the mix.

[turbowagon]

Well, no performance curves today, since the wheel rotation sensor on my Veypor stopped working. It's mounted in the perfect position with the magnet passing just millimeters from the sensor. I tried flipping the magnet over too. It was working great and then after I swapped out the jets, no speed readout. Unless I somehow messed up the configuration. Any ideas?

Back to the tuning. Looks like I was rich on the bottom end and lean on the top end with my 40 / 85 setup. I initially thought I was rich across the board and swapped jets to 38 / 82. The top end completely went to crap, so I went to a 38 / 85, and picked up some performance. I'm still lacking, though, so I think I'll try an 88 main jet next. (I need to order the 88 / 90 / 92 jets from battlescooter).

[turbowagon]

I forgot to mention, that with the 38 / 85 setting, I still needed to turn the idle adjustment screw all the way in, so maybe I'll need to go back to the stock 35 slow jet???

[Dandy Dan]

You can also get those 88/90/92 jets from your local Honda dealer which is probably cheaper (about $5 each) and faster.

Quite a few guys (chanito, IHAR?) are running the stock slow jet so maybe it is the way to go. Thanks for the info....I'll play with this sometime.

[Kami no Chiizu]

Happy birthday, Turbo, hope the girl is doin' good.

[turbowagon]

Thanks Kami!

My dealer didn't have any jets in stock, so I ordered the 88, 90, and 92. They should be in by Friday. I can't wait to get my Ruckus up to its potential.

- Joe

[Dandy Dan]

Whenever I got into my Honda dealer and order some freak Ruckus part they always wanna check if they have it in stock...they usually don't have a Ruckus in stock let alone a fuel line check valve or something but they always check and come back empty handed. I guess the jets are a bit more common since other Honda's probably use em too.

FYI, I finished another Rucksters BB engine tuning last night and settled on 40/90 with the stock variator (4mph faster up top than the Malossi) and 6g rollers.