Have your balls dropped (smart carb)

dirtrebel said:

I guess I'm not sure on that, I feel like it (hitrate mix) saved me when I was running super lean. I will try the straight leaded race and 91 50/50 and then a tank of the concentrate mix back to back and see if I can tell.

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The octane booster is also really good for keeping moisture out of the fuel..

dirtrebel said:

It is possible, but I doubt it because I have gotten to know the difference in a rich bog and lean bog. I will keep u posted. Maybe Randy will chime in because I asked him about the probe placement at least 3 times on the phone, he said impossible to read too hot. good luck to ya have fun braaapin' and tunin'.

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You want the probe to be placed at the "flame tip". That is the hottest point of the flame. You want to know that number. The flame tip varies from engine to engine and pipe to pipe. In general, a straight header pipe like on a sled, the flame tip is approximately 5 1/2 to 6 inches from the piston skirt. With our bike pipes having a 90 degree bend at around 3 inches the flame tip is a little shorter. I place the probe at approximately 4 to 4 1/2 inches and am getting good results. EGT and plug color closely match.

mtn-doo said:

You want the probe to be placed at the "flame tip". That is the hottest point of the flame. You want to know that number. The flame tip varies from engine to engine and pipe to pipe. In general, a straight header pipe like on a sled, the flame tip is approximately 5 1/2 to 6 inches from the piston skirt. With our bike pipes having a 90 degree bend at around 3 inches the flame tip is a little shorter. I place the probe at approximately 4 to 4 1/2 inches and am getting good results. EGT and plug color closely match.

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so is it possible to falsely read too hot if the probe is closer than the arrow?

No. If the probe is closer than the tip of the blue as shown in the picture, your temp will be lower. The Tip of the blue, where the arrow is, is the hottest part of the flame. Closer or farther will read a lower temp.

Of corse. Reading your plug is mandatory. It is the true evidence of your burn. Folks monitoring egt's need to understand probe placement and flame tip. Once you have compared your plug to a good egt temp, you have your number. After that, the egt is a safety alert. If you ever get lean on a ride your alarm go's off at your pre set number allerting you to chop the throttle. Without the egt alert, you wouldn't know until it's too late. If you have a sudden change for some strange reason, you can immediately see it. Excellent monitoring device.

mtn-doo said:

Of corse. Reading your plug is mandatory. It is the true evidence of your burn. Folks monitoring egt's need to understand probe placement and flame tip. Once you have compared your plug to a good egt temp, you have your number. After that, the egt is a safety alert. If you ever get lean on a ride your alarm go's off at your pre set number allerting you to chop the throttle. Without the egt alert, you wouldn't know until it's too late. If you have a sudden change for some strange reason, you can immediately see it. Excellent monitoring device.

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So just finished tuning my cr500 that is ported for racefuel... I ended up with the q07 on the 38mm and the bike idles/pulls beautiful.... 1 maybe two kick starts. The bike pulls clean and hard. the plug is a light brown..... temps are in the 130's up the trail (My bike has 4 gears and I normally am in 4th) and I am rarely getting above 150 on 1 minute hard/steep pulls.... It is being ridden starting at 7000ft up to 11000ft....

4 gears ?? Thats the coolest 500 i have ever seen up the trail. Where is ur temp probe ? What alt are u riding ?

Yep... only has 3 gears up.... thought that was strange... it's a 97 maybe it's modified?... I ride from 5000 to 11000... majority is 8000 to 10000. Temp probe only fit coming off the right radiator.. I also added temp sticks to the heater collar and radiators... to have a secondary way of checking ..

Ah is see. Your gearbox is broken. They only made a HRC 4 speed gearbox in 1988-89. And to get one it would cost you about 7000 bucks these days lol. Your temps are low because you measure at the inlet to the water pump not the outlet from the head. So your temps are prob much higher than you think.

Just an update on the smart carb setups, I finally have mine working right and here's what I did.

1. Remove the floating balls from the tipover valves, quits flooding.

2. Install the oversize needle and seat, quits running out of fuel on long pulls, that was the reason I was getting really hot after WOT for long periods of time.

3. Heat collar needs some shaping with a dremel. Where the collar meets up with the small port on top of the inside of the carb needs to be ground down flush with the port. With the collar sticking up above the port it causes a reduction of air volume and it also cause turbulence reducing the air pressure going into the float bowl. That port is what makes the smart carb work, the air velocity and density are what pressures the fuel bowl and adjusts for elevation and temperature, it needs to have free flowing air going into it. Its best to grind it smooth all the way out to the end of the collar. Not having enough air pressure into the float bowl will drop fuel flow and lean it out on the top end.

4. If you're running an intake with no velocity stack the inside edge of the collar needs to be ground down to an angle, the vertical lip causes air turbulence. I just ground down the area around that intake port and it seems to work fine, but i'll go all the way around next time I have it off.

5. Adjusting the metering rod to the proper height. The metering rod is designed to be set at 55-65 clicks. If you have it at more than 65 clicks out the rod will stay dropped down too far and will lean it out at WOT. So for example a q05 rod at 80 clicks out is going to be rough the same low throttle as a q07 rod 65 clicks out , but the midrange will be rich and the WOT is going to be about the same as a q07. It seems like to get proper WOT temps the metering rod needs to be in that 55-65 clicks which will make the bottom rich, but keep the clicker in that range and turn in the idle screw to add enough air to make it idle

Hope that all makes sense....at least the carb is fiiiiiinalllly consistent! Now i'll drop down to a q07 rod and see how it works.

mxracer299 said:

Just an update on the smart carb setups, I finally have mine working right and here's what I did.

1. Remove the floating balls from the tipover valves, quits flooding.

2. Install the oversize needle and seat, quits running out of fuel on long pulls, that was the reason I was getting really hot after WOT for long periods of time.

3. Heat collar needs some shaping with a dremel. Where the collar meets up with the small port on top of the inside of the carb needs to be ground down flush with the port. With the collar sticking up above the port it causes a reduction of air volume and it also cause turbulence reducing the air pressure going into the float bowl. That port is what makes the smart carb work, the air velocity and density are what pressures the fuel bowl and adjusts for elevation and temperature, it needs to have free flowing air going into it. Its best to grind it smooth all the way out to the end of the collar. Not having enough air pressure into the float bowl will drop fuel flow and lean it out on the top end.

4. If you're running an intake with no velocity stack the inside edge of the collar needs to be ground down to an angle, the vertical lip causes air turbulence. I just ground down the area around that intake port and it seems to work fine, but i'll go all the way around next time I have it off.

5. Adjusting the metering rod to the proper height. The metering rod is designed to be set at 55-65 clicks. If you have it at more than 65 clicks out the rod will stay dropped down too far and will lean it out at WOT. So for example a q05 rod at 80 clicks out is going to be rough the same low throttle as a q07 rod 65 clicks out , but the midrange will be rich and the WOT is going to be about the same as a q07. It seems like to get proper WOT temps the metering rod needs to be in that 55-65 clicks which will make the bottom rich, but keep the clicker in that range and turn in the idle screw to add enough air to make it idle

Hope that all makes sense....at least the carb is fiiiiiinalllly consistent! Now i'll drop down to a q07 rod and see how it works.

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Good info! I am getting some lean issues on my modded 300 in the dirt now too. Wonder if I need a 078 rod? And high flow nozzle. Cory?

Yes, you need the high flow needle and seat as well as the Q09 for dirt. Remember to not lean out your bottom end too far. Keep the rod a little higher and your mid and top will be great.

What rod are you running? I was planning on running the 076 (q07) or 078 (q09) on dirt. The q09 rod was borer line lean when I tuned my motor on dirt. You shouldn't need the oversize needle and seat, you can't hold it wide open long enough on dirt to run the fuel bowl out, maybe on sand dunes...I didn't run mine out of fuel.... BUT I was just doing techy trails, if you are running it wide open for very long you may need it.

So I have ran my 2013 ktm 300 with mobetta porting sx ecu from 3000 ft to 8000 ft so far using a 38mm smarty billet... q9 rod on dirt ... running it at 40 to 50 degrees in the desert tapped out at 70 I might be thinking it is running rich. I have about 90 miles on the carb so far and bought it used... now I do mix my gas up to about 98 octane with race leaded 110. I have leaned it out about 60 clicks from full rich... it's amazing to me the difference between the same bikes... now don't get me wrong it runs great but it is running a tad rich.. I could not imagine having a richer rod ...
Now I will say this... I had a hell of a time starting it... to the point I could not... it was flooded so maybe I have the float problem... but this was at the start... and once started never happened again.. I will watch this... it is either the floats or I have been riding the cr500 all winter and have become so accustomed to pulling the gas on starting that I got into a bad habit for the 300 without thinking.. we will see... I just have to remember to not touch the gas when starting at all... then it starts perfect everyone when cold... seems stupid but when you get in a certain habit it is sometimes hard to break

Mine use to run out of fuel all the time until i got the newer needle and seat. I had to run the float level very high on my 500 so it didn't run out of fuel. My rollovers stuck a handful of times. They were the newest generation. I can still remember when the bike actually fired and it was like a fire hose out the tail pipe of raw fuel LOL

My bike was a bear to start cold. Took forever ! I thought it was just my setup but i have friends that have some youtube video with the same results on their bikes. Another reason i switched back to 1-2 kick cold starts !

In my last post i was talking about the rollover balls. Caused grief. Old and new. Also my floats had to be adjusted so my Millar TWIRP wouldnt run out of fuel which it did for a while until i adjusted to 13mm i believe even with the new needle and seat.

Tuning for EGT is a novel idea and fill your boots by all means. Ive heard things like u dont have to jet the Smarty yada yada yada. From my experience with the Smarty i had to constantly play with needles and adjustments to get it to run. It never started period. It never idled at any altitude. I hear guys say it stays spot on at all alts and temps. At the beginning of the day id have one setting and by the end of the day id be 8 clicks different. I dont buy it period.

When i ran the 76 rod it would eat fuel like crazy. It was the only rod i could run to keep deto at 3/4 throttle away. I ended up with the 80 needle which was so lean but it was the only way it would start and run somewhat. I ran fuel builder in premium to make it happy. Others i have talked to had to do the same thing.

The bike was a vibration machine. I cracked a pipe, and every bolt came loose when i initially started with that carb. I couldnt even hold on to the bars. My hands ended up being so numb from riding the Smarty. My current setup not the same animal.

I have since moved on to the Pulse intake. It is above and beyond my last experience in every respect. It starts, its been two weeks since i fired it and it started in 3 kicks. It idles, fire it up and i can take my hand off the throttle. It pulls hard. Tuning has been super easy with the airscrew in its baseline. I have not loosened the carb clamps once this season and had to remove the carb or twist it to adjust the knob on the top. The Pulse is so smooth at idle. Smooth everywhere. The vibration is much less it still amazes me day in and day out.

The 500 is not for everyone. Take my post for what its worth. For some guys the Smarty works. For me not so much. I have to say the support APT and Corey gave me was excellent. He is a passionate individual and he even helped me on Sundays to figure my issues out. I thank APT and Corey for all their hard work, unfortunately the Smarty has moved onto greener pastures !

I like the looks of the pulse! May I ask you a good place to purchase it?

My 330 on a near zero morning, left outside all night, covered in frost.... Touch the button and it purrs... Doesn't get much better than that. I have set the bike up and been on the road doing demo's and company rides and haven't even taken the carb jacket off. I just fill it with gas and ride 2 to 3 days a week. Caramel brown plug, 1260 egt's. All altitudes, all locations. Gotta love modern technology. I spent my life with dripping spaghetti hoses and pwk carbs and jet's. Those old carbs did start the cold motor well. We just tipped them over until we had fuel running out of every hose in the carb then start kicking! lol
Fond memories for sure!