rejetting

[johntm]

Is there any info yet on rejetting the carb in the Big Ruckus? As difficult as it is to get to the carb, I'm too lazy to just start experimenting.

[Dandy Dan]

Not really....we don't really have any Big Ruckus tech pioneers on this site so perhaps you'll be one for us?? If you look into it maybe you'll get promoted to a Big Ruckus Tech Wizard ;D I think the BR uses a pretty standard CV type carb so just go in there and remove the hoses and wires and then flip it over to remove the bottom and unscrew the old jet. You probably don't need to change things much so just try going up or down one size.

[johntm]

dandydan said:

Not really....

Well bummer.

OK, I'll rip into it and start tweaking.

[Dandy Dan]

Cool! Let us know how it goes ;D

[johntm]

Ok, I got started on the rejetting.

I installed a K&N air/fuel mix meter (basically an O2 sensor welded in the exhaust header) to see what my changes do.

I started with opening up the air intake. Anyone taken the blower duct off of the front of the variator package? There is a half-blocked air intake on the front of the air cleaner. I opened that up.
Next, I changed both the slow and main jets to one size bigger than stock.

Now that I have the thing back together, go ride. I can use my gloved finger to partially block the air intake, and watch the meter on the handlebar to see how rich or lean I am at different settings. Oh, and don't forget to have your handy Honda carb adjustment tool. The little D shaped pilot screw is a pain, although a tech has since let me in on the secret - a small spring pushed over the screw head hakes a handy way to adjust it without springing for the real tool.

LEAN!!!!! OK, open the pilot, since changes to it carry forward through the entire range. Still too lean. OK, partially block the intake. Better, but still sluggish.

Change both jets to two sizes over. Block the intake (with friction tape) to allow 60% open (or 20% larger than stock). Close the pilot to 3/4 turn. That works pretty well, but a bit rich. That's OK, slightly rich is better in my opinion.

I'll let you know what more I do (and this isn't ending here) and what kinda terrible things I'm doing to my fuel mileage.

[Dandy Dan]

Wow great info! How much was that K&N mix meter? I'd love to get one. It's it like a broad band sensor or is just lean or rich?

[chanito]

looking forward to some

[Phil_R]

johntm said:

Ok, I got started on the rejetting... Oh, and don't forget to have your handy Honda carb adjustment tool. The little D shaped pilot screw is a pain, although a tech has since let me in on the secret - a small spring pushed over the screw head hakes a handy way to adjust it without springing for the real tool.

First... an admission of guilt, I have the Honda tool. (#07MMA-MT3010B)

A .22 caliber "shell casing" makes a near perfect substitute tool... flat one side to match the D shape of pilot screw adjuster. Longer shell casings are better... A .223 (military 5.56mm) casing is "necked" down to .22 caliber and the rest of the casing makes a nice handle.

I use ES-322 Digital Tachometer for "optimum" idle-mix setting... about 1-3/4 turns open (stock jets, stock BR) on my Big Ruckus.

K&N Air/Fuel Ratio Monitor $157.69 @ Summit Racing Equipment

[johntm]

Here's Il Chromo. (Soon to be known as the "Big Pimpus")



PS: The K&N sensor and display is about $250. Fortunately I can use it on many bikes. It's display shows half-percent steps fron
11.5:1 air:fuel to 17:1, with 14.(shown as 14.5) as ideal.

[Dandy Dan]

Wow! That chrome looks pretty awesome ;D I'm diggin the look but you should do the front headlight frame and maybe the bars too. Is that real chrome or chrome in a can? It looks real.

[tedsmini]

If there was any "chrome in a can" that looked that good it would net a billion in profits the first 6 months ;D

[chanito]

I love the look of that big ruckus ;D ;D

[TonyFaz]

John, did you ever wrap up your rejectting tests? what were the final findings?

Thanks,
Tony in NJ 2006 BR

[Phil_R]

johntm said:

I installed a K&N air/fuel mix meter (basically an O2 sensor welded in the exhaust header) to see what my changes do.

What did you do about PAIR to prevent air entering at exhaust port and causing a false o2 reading? Block air at the head or disable the PAIR control valve...

[tfazio]

John...can you please post your final assessment on rejetting with stock exhaust and minor airbox mods....Summarize it all please.

OK on the 2006 BR with RED Contra Spring and Daytona Variator.
First Jason at BSS is incorrect in one assumption that he reflex and BR have the same rollers....the BR rollers are all 26g and the Reflex is 31 (x3) and 26?(x3) the variator is intended to have the 3 of the 31g rollers from the stock variator installed.

So I tried it with 3 26g rollers and with-out a tach felt that it was revving too high for my liking. Has anyone found a Tach trigger wire up on or near the dash cluster?

So i put all 6 rollers in, and FYI it is a "edit profanity" to re-assemble with the driven pully closed and i cant spread them by hand....anyway squeezing the belt helped but i did eventually get it...a little trial and error but over all not a big problem, the engine helped out a little too

Ok with the 6 26g rollers is is very good....the Daytona's ramps are smoother overall and three of them are cut back deeper on the top end so as to really squeeze the pully closed, so i think it works pretty well.

I ordered 6 24.3g rollers and I am going to change to them. Also aside from my off the line carb bog (thats what i call it) everything else is very good. My planned total roller weight is 145.8g i am only shaving off 10.2g from what it is now, but i think it only needs a little bit more rev between 20 and 40 and hoping this does the trick.

Anoyther FYI, my mixture screw is 2 3/4 turns out and everything else is stock and I am in NJ. Sea level for the most part.

[tedsmini]

How much did it cost to chrome the BR frame? How much? It looks chrometastic ;D ;D ;D ;D

[johntm]

tedsmini said:

How much did it cost to chrome the BR frame? How much? It looks chrometastic ;D ;D ;D ;D

You seriously don't want to know. By the time the bike is done, I could have two of 'em.

I'm almost done with the tuning. Got a Supertrapp muffler on a header pipe I knocked together. Opened the air intake wide open. Two sizes bigger on main and low-speed jets. Closed the mix screw to 3/4 turn. Looking pretty good now, just need to run it a bit and make sure.

Also, Phil R, thanks for mentioning the PAIR valve. Heck, I didn't even know about it. I assume it is a air intake into the exhaust port to make tailpipe emissions more palatable? I guess I'll just have to block off the PAIR valve intake. Where is it? Aw, heck, I'll just go look.....

[Dandy Dan]

I'm stoked to see some finished pics! Please post em when you've got er done.

The PAIR thing just adds fresh air via sort of a check valve into the exhaust so that thing continue to burn so more crap gets burned up. You could get rid of it pretty easy but you'll save a tree if you dont'!

[Phil_R]

tfazio said:

aside from my off the line carb bog (thats what i call it) everything else is very good.

Anoyther FYI, my mixture screw is 2 3/4 turns out and everything else is stock and I am in NJ. Sea level for the most part.

Try setting mixture screw @ 1-3/4 ~ 2 turns to see if that helps with your off-the-line carb bog... My BR has stock intake and exhaust, ideal idle-mix is very near 1-3/4 turns open/out on mixture screw. No off-the-line bog... overall acceleration is comparable to other 250's.

[Phil_R]

johntm said:

Also, Phil R, thanks for mentioning the PAIR valve. Heck, I didn't even know about it. I assume it is a air intake into the exhaust port to make tailpipe emissions more palatable? I guess I'll just have to block off the PAIR valve intake. Where is it? Aw, heck, I'll just go look.....

PAIR intake... simple way to temporarily (for test purpose) disable air-injection into exhaust. Open air filter housing, remove air filter... two small openings in addition to primary carb air feed opening. Opening at rear of air box is the crankcase breather and must remain open. Opening near front (close to carb opening) is the PAIR connection... temporarily close with duct tape. This will allow a true o2 reading, and is easily reversed after testing is complete.