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Post by jkh2007 on Feb 9, 2009 0:23:17 GMT -5
Hey whats up everyone. Been ruckin it up for some time now. But i have a few tuning quetions. Well i have an 2009 RUCKUS, right now i am about 45 down hill, 38 to 39 on the flats and 29 to 30 on the hills. I have a KN variator, right now i am running 5 gram weights but i ordered 6.5. I have a mrp exhaust, and a k and n air filter on it, took of all the intake box and just connected the filter to the tube off the carb. I have a posh racing ignition with an ngk spark cable. An ngk cable. Right now i am running 40 slow jet and 85 main with a 2 and a 1/4 turn on the mix screw. I have changed the oil three times now. I have 1200 miles on it. I am running 25 psi in my tires too. I have had a difficult time adjusting the take off. When i put in a 35 slow or a 38 slow it seems to just cut out and die untill i get up to at least 15 where enough fuel gets in to start it moving. My question is, have you guys had any trouble with this at all. With my 40 slow and 85 main it seeme to run good last night. I have read many posts and people leave in there 35 or 38 i just cant seem to figure out that concept. Finally i have tried runnng higher then an 85 main but it seems to backfire at top end when i am around 37, is this becuase its too rich? Sorry about the questions. Hope u can guide me.
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Post by chanito on Feb 9, 2009 6:44:45 GMT -5
 Before swaping slow jet, you usually adjust the idle mixture screw, as a rule of thumb, if adjusting it requires more than one turn out from the stock position, you go to the next size up. the stalling on acceleration can be cure by selecting a higher main jet (the correct solution would be a softer diaphargm spring, but we do not have one) the back fire at high rpms could be too early a time for the gas you use, try a lower octane rating gas and/or removing your CDI unit
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Post by jkh2007 on Feb 9, 2009 23:41:30 GMT -5
So let me get this straight, so i should try like an 88 main jet and lower octain. Cause right now i put in the highest possible. So is that bad? And that should help with the stalling at low speeds.Also, i always thought that that was too high for the main jet! Thanks a bunch Chianto! U rock ;D
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Post by jkh2007 on Feb 9, 2009 23:48:12 GMT -5
???Also with the slow jett i tried to up the mix more then one turn and it seemed to just die on me. Maybe i should try a higher main like 88 and a slow jet of 35. Whatdo u think? |
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Post by Kami no Chiizu on Feb 10, 2009 0:07:31 GMT -5
So let me get this straight, so i should try like an 88 main jet and lower octain. Cause right now i put in the highest possible. So is that bad? And that should help with the stalling at low speeds.Also, i always thought that that was too high for the main jet! Thanks a bunch Chianto! U rock ;D If you run higher than regular octane, your scooter will run like crap. |
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Post by seansean on Feb 10, 2009 1:19:02 GMT -5
With your setup, and what I've read from others with similar, I'd try a 38 and MUCH lower main jet. I know someone who is having success with a 35/75 or 78 setup and filter directly on the carb. Also, you will get more push out of 89 octane or similar from a CLEAN gas station if you are running stock motor. The main is for top speed and low end stumble is more likely caused by slow jet AND/OR air/fuel mix in my own expierience, but Chanito is a tuning god so um - yeah. On a side note, you might like 5.5 or 6g weights more for the KN. It will give you more top speed and still be pretty quick off the line and up the hills. All kinda depends on your weight.
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Post by STILL CONFUSED on Feb 10, 2009 11:19:59 GMT -5
I have tried running the filter on the carb and what i got was a 70 main jet and a 35 slow. The Ruck ran like crap, really it did. Right now i went from a 40 slow to a 85 main. What i may try is dumping my gas in my tank and switcing it to 85 instead of 89 and try running a higher main like 88 and going back to the stock slow jet. To see what happens with that. I also ordered a new spark plug and i am going to check the gap and see if that fixes the pop and high end. If u guys have any other suggestions that would be great!
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Post by seansean on Feb 10, 2009 15:42:50 GMT -5
It's not gonna be the gas, I'm pretty sure. Something is off with your jetting and your air/fuel screw. Be scientific about it and get a jet kit. If you are going to do aftermarket filters then you need to learn how to tune, and there is no better time than now. If it idles with a 35 slow jet, then try adjusting the screw in or out to affect the idle. You basically want the screw to be set where you have the highest idle. Once you iron out the kinks in the slow setup, figure out your top speed. Start testing jets until you get the fastest top speed jet. Don't use random combos of slow and main jets, just take your time and be SCIENTIFIC yo!
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Post by chanito on Feb 10, 2009 19:31:21 GMT -5
 You need to read the thread about the stock carburetor, and then follow some simple rules. First is a bad idea to install the filter right on the carb "on a CV carb" The carb needs still air because the way it works, once you open the throttle you allow engine vacuum to reach the diaphragm, which raises the needle and allow more gas, if you have the filter right at the opening of the carb, there is not enough volume of still air and the air rashes thru the filter and creates pulses right under the diaphragm, creating a weird working carb, so make some king of intake pipe to add filtered air volume, to prevent this from happening. Second worry about the idle mixture, before even trying any jetting once it is done then go on to the main jet 
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Post by seansean on Feb 10, 2009 20:39:35 GMT -5
Ooops! Shows how much I've learned about CV carbs and how they work. I've got a PC20 so it's been a while since I've worked on the stocker. Chanito Rocks!
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Post by jkh2007 on Feb 10, 2009 23:13:25 GMT -5
Yeah i figured out about the filter a long time ago. I am now running the stock tube with the filter on it. So i got that. As for the main when i tried an 88 and a 90 the main popped a lot it felt like it was getting to much fuel at the top end. So as i tuned it down to an 85 it worked out really good. However when was doing the set up as a 85 main and a 35 slow, it would cut out and die in the beginning from 0 to 5 mph then it would be ok after 10 and accelerate out. As i went up the slow jetts from a 38 then to a 40 where i am at now. That seemed to be the trick. But what i would like to know is the 40 slow jett to rich for the ruckus or no. Trust me i have been working on this for five months and its been trial and error but i have been learning a bunch
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Post by jkh2007 on Feb 10, 2009 23:20:39 GMT -5
Another question for heavier riders what do u guys reccomend for roller weights? Like 6 to 7 or is the stock 6 gram weight the best
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Post by seansean on Feb 11, 2009 1:00:05 GMT -5
The roller weights depend on what variator and the weight of the rider. I'd say for both KN and Polini you could use anywhere between 5-6g weights, but I'm not sure about the stock variator. It all depends on how much top speed you want to give up. 5.5 is pretty ideal for not losing too much top speed but getting it to rev up quickly and still climb hills.
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Post by jkh2007 on Feb 11, 2009 11:03:23 GMT -5
Yeah i have a kn so i will stick with the 6
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