Anyone with Carb tuning Experience?????

Hate to have to call James every time we need something on this forum. Anyone familiar with the fine art of tuning a carb?? I've been fucking with this carb for a week now. The Yamaha dealer told me I don't have a Ferrari, I have a Malibu. Granted I'm running a 450 but I feel I should be able to get the carb still tuned in. Tell me if I'm just anal!!!! It's okay because I'm getting pissed, and the a/f meter is a loner and I need to get it back to the King. Started out stock with air and fuel. Went with an exhaust tip and opened up air box 04 style (no snorkel) w/K&N air. Factor specs were 133 main jet; needle jet thin spacer on bottom. A/F screw?? Didn't check it before adjustments. I've dropped the main jet to a 115; switched the needle jet washers fat on the bottom, thin to the top. And have the A/F screw at 1.25 turns out. I've got a spread sheet of all the adjustment I've made through this tuning! WOT has started out at 11.7-12 stock, when I'm in full throttle I'm hitting mid-12's-13, hit rev limit it drops into low 12-11's. down hill upper 11's. Is this normal and expectable? Mid-range is the sweet spot 12.9-13.3. Idle is still a little rich12.2-12.6. I ride about 2-3k feet higher than this tune up is at(5.4K'), so it will lean out some at higher elevations. Somebody with some experience talk to me!!!

Try dropping main to 110,idle is fine anywhere from 12 to 12.5,i try to get anywhere from 12.5 to 13.2 wot,if its still rich on top end,drop another size on main jet,the first thing u need to do is get wot right then get the bottom end right with the pilot jet and air screw.

safe to be a little on the rich side , if you have warmer weather coming it could get a little leaner as temp rises, my 2 cents

i dont have an afm yet but been kind of a tuner freak since my street bike days will usually change jetting in summer and winter, call me anal, the search for performance in a sickness

Kenny G wrote:

...........when I'm in full throttle I'm hitting mid-12's-13, hit rev limit it drops into low 12-11's. down hill upper 11's. Is this normal and expectable? ........

I'm no expert in carb tuning but I do know what happens when you hit the rev limiter. When the rev limiter comes on, the CDI is killing the spark, taking several fuel ignition sparks out before sending one or two to the plug and repeats over and over. This happens to prevent the engine from revving any higher. Meanwhile, the carb is busy mixing the same amount of fuel to the same amount of air and sending it down the pipeline. Now very little of that fuel is being burned and it is going out the tailpipe very rich. Your A/F gauge is measuring this inappropriate set of conditions. In fact, it may measure inaccurately until it clears itself out (kind of like a fuel soaked spark plug).

So, disregard any A/F mixture readings while it is into the rev limiter. Just back off the pedal until it is running smoothly. That is all the faster that you are going to go anyway, and the squirrels and their friends living alongside the trail will thank you. ....???

This might not apply to the 700, as the ECU has control of the mixture as well as the spark. It depends on how sophisticated they got in limiting the RPM.

very good point steve

Thanks guys. That makes a lot of senses Steve, that is basically what I'm seeing. WOT throttle I'm seeing the upper 12's - low 13's; but when left WOT it drops into the high 11's - low 12's. I'm not going to f--k with this anymore!!! Think I'm okay with moving into the 7-8K elevation????

Kenny, Don't let it git the best of You. HAHA

How does it feel by the seat of the pants ? Is it faster and smoother than it was before ?

Also, You can put a new spark plug in it and take it for a good ride, pull the plug and see what color it is. That will tell You a lot.

Yes Larry, It is quicker from the bottom end up. And most riding is in the mid-range; so what's up with the top-end, unless your a duner?

call me today

like firefighter said hows it feel seat of pants, or you could do a plug chop and check color , give james a call see what he tells ya, your on the right track

right before it bangs off the limiter what is the air/fuel

WV Hot Rod Rhino wrote:

right before it bangs off the limiter what is the air/fuel

That is what was thrown a wrench into the confusion; I was reading wot while the peddle was smashed to the floor and then into the rev limit. I couldn't figure out why everything was going to shit, now I understand what happens when you're balancing off the rev limiter. I'm no mechanic, but I've been learning along the way. WOT upper-12 - low-13 before hitting rev-limit, then the bitch goes rich! I'll be shipping the A/F Meter back tomorrow James. Thanks for allowing me to use it. Also got the Rydon installed, looks like a great product, had to make some modification to match up with the roll cage. The carb/exhaust mods gave the ole girl a lot more get up and go out of the hole. She'll hold 38 mph on the flats and tops out at 42 on the down hill. I gained a few more mph's and a lot more quickness.

Wanted to thank all ya that gave advice and support while I schooled myself through this air/fuel, mod/adjustments. Finally got a break in the weather and ran the bike a good 6 hours, she purred like a kitten and performed very well. Thanks again, that's what makes this forum GREAT. Let-Em Buck!!!

Just a little FYI, The only color that matters on the spark plug is a Black ring around the bottom of the porcelen, 13 to 13.5 leaves a black ring approxamatly .100 high at the base of the porcelen. If you dont have a plug reader you can cut the threads off the plug and see it very clearly. Brown,Tan and any other color is just the other crap in our fuel. Unburnt fuel or runing rich only leaves black soot behind.

isn,t the color supposed to be brown down there ?

never mind didn't read that good long day at the hell hole

Stuntmanmike wrote:

Just a little FYI, The only color that matters on the spark plug is a Black ring around the bottom of the porcelen, 13 to 13.5 leaves a black ring approxamatly .100 high at the base of the porcelen. If you dont have a plug reader you can cut the threads off the plug and see it very clearly. Brown,Tan and any other color is just the other crap in our fuel. Unburnt fuel or runing rich only leaves black soot behind.

Now that is really interesting. I have never heard that before. The soot burns off closer to the tip, I presume? What I am wondering is how long does this black ring persist once it is created? What I am trying to determine is whether this ring stays around long enough that it influences the plug read on the next look-see (say,after you change the jetting and then recheck). Or, are you gauging the width of the black ring every time you check?

It will change if you put atleast 5 min on it after an adjustment.

Stuntmanmike wrote:

It will change if you put atleast 5 min on it after an adjustment.

Thanks Mike, I love learning something new every day.