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Post by dev150cc on Aug 2, 2014 16:16:35 GMT -5
Ok, I've got the exhaust mods in place (made a baffle) and now on to carb tuning. This thread is just for my own reference, but I'd enjoy company if you want to play along, offer advice, etc. This bike originally came with a 102 main jet. Way too lean, so I put in a 115 and have been driving that for a hundred miles or so. Definitely an improvement, but I feel like it's still not quite there, and the plug was still not giving me a decent tan. The holy grail I'm looking for is that coffee colored insulator tip. Today I swapped the 115 for a 125 and it ran like poo. Boggy and wouldn't get up to speed over about 2 miles around the neighborhood. I'm not surprised by this, but I wanted to find out how much was too much. 125 is too big. The insulator tip of the plug has the black soot you can see in the pic, but only on one side, and not too heavy. It reminds me off fireplace soot. The other side of the core is white. The black soot is dry, not wet. I did adjust the air/fuel mix screw to where it ran best. Here's the plug:  The shop I went to didn't have any 122's, but I have a 120. I'll drop that in there with a new plug and see how the plug reads. I'm betting it gets me closer to a healthy coffee color. More to come... |
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Post by dev150cc on Aug 7, 2014 0:16:09 GMT -5
Well, I tried the 120 for three miles and it really ran boggy like the 125 did. I put the 115 back in and it's happy again. It'll stay. I dabbled with the fuel mix and it seem happiest right about the 2.5 out point. Moving on...
Variator weights. I may try some 11's to replace the 12's, just to see if there is a marginal difference. And then may opt for sliders instead of rollers. may even try 12 rollers.
I bought all sort of LED lights lately for front and back. I'll tackle that after performance is optimized.
I checked the battery out after I killed it dead by leaving they key on. It's the original form when it was sold in 4/2013. It survived my accident, and me killing it, and charged up fine. It's holding about 12.78 volts. Also gave me a chance to check my charging voltage while running - right at 14.03 volts.
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Post by JerryScript on Aug 7, 2014 0:31:54 GMT -5
When you were swapping out jets, did you attempt to adjust the needle when using any of them? The 120 may have been correct, only needing the needle lowered (clip raised). Remember, adjusting the a/f mixture at idle doesn't mean you have the proper mix at half-to-full throttle, that requires proper needle adjustment.
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Post by dev150cc on Aug 7, 2014 1:39:27 GMT -5
Hey there. It was idling fine, a little low, but not by much. It would just bog at 1/2 to full throttle. Ok up to that point.
But no, I didn't mess with the needle.
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Post by JerryScript on Aug 8, 2014 1:05:50 GMT -5
The needle comes into play at about 1/4 throttle or sooner (depending on many factors), and if not set properly will show symptoms anywhere between 1/4 to full throttle. With the 115 main jet in, try raising the needle. If it has a movable clip, put it lower one notch at a time. If it doesn't have a clip, you can add a thin washer at a time. Raising the needle by lowering the clip allows it to begin to come out sooner and end up higher, allowing more fuel to flow through the main jet. This, or using the 120 main jet and lowering the needle (raising the clip) could help you hit the sweet smooth acceleration, and find that coffee color. Just keep in mind that a coffee color is not as important as smooth responsive acceleration, so long as your color is not white (white can mean lean which is dangerous to the engine).
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Post by dev150cc on Aug 8, 2014 17:42:34 GMT -5
At lower speeds, the 120 (even the 125 to some extent) was fine. I just couldn't get beyond medium speeds (say > 35mph) without it just bogging and choking. So the main jet will stay at 115. Overall, I think it's pretty happiest there.
Now.... you got me thinking the other day. I'll see if I can raise the needle a notch to see if I can make the mids just a bit more responsive. Not that it's bad, but if I can finer tune that, then I may not even go to the next lighter rollers.
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Post by dev150cc on Aug 8, 2014 23:55:39 GMT -5
Jerry, you were right - raising the needle one notch gave me a tad more smooth power in the midrange (with the 115 main jet). Makes me wonder what it would be like changing the main somewhere between a 115 and 120 (do they make a 117.5?)
Anyhow, I'm pretty pleased and will order the next lighter sized rollers to test variator tweaks further now.
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Post by JerryScript on Aug 9, 2014 0:22:00 GMT -5
Glad to hear it helped! I usually continue to raise or lower the clip till it makes things worse, then go back a notch. If I make it all the way to the top, I know I need a smaller main jet, if I make it all the way to the bottom, I know I need a larger main jet.
Different jet manufacturers make various sizes, I know Keihin makes a 118 , I believe Mikuni makes a 117.5
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Post by dev150cc on Aug 9, 2014 0:57:54 GMT -5
Ok, that helps me understand what I experienced. I adjusted multiple times on a long ride. It was in the 3rd/middle notch stock. So I raised it one notch. Ok, no problem. Then for comparison, I went the other way and lowered it one notch from middle - definitely a little lean. Returned it to middle just to cleanse the pallet. then finally raised it again one notch to see if it was my imagination. Seems just right.
I have a tach I ordered (my bike doesn't have one). I really need to put it on and see what kind of rpm's I'm running. Just ordered some 11g rollers (I have 12g's on there presently).
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Post by alleyoop on Aug 9, 2014 1:02:27 GMT -5
Ok, that helps me understand what I experienced. I adjusted multiple times on a long ride. It was in the 3rd/middle notch stock. So I raised it one notch. Ok, no problem. Then for comparison, I went the other way and lowered it one notch from middle - definitely a little lean. Returned it to middle just to cleanse the pallet. then finally raised it again one notch to see if it was my imagination. Seems just right. I have a tach I ordered (my bike doesn't have one). I really need to put it on and see what kind of rpm's I'm running. Just ordered some 11g rollers (I have 12g's on there presently). If you lowered the clip from the middle 1 notch that is raising the needle and that would richen it NOT lean it out. Raising the needle richens it(moving the clip DOWN) Lowering the needle leans it(moving the clip UP). Alleyoop |
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Post by dev150cc on Aug 9, 2014 1:11:33 GMT -5
You're right - I used bad verbage there. I was referring to raising the needle by *lowering* the clip. I should have called that out more clearly.
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Post by JerryScript on Aug 10, 2014 20:29:50 GMT -5
I personally wouldn't mess with the weights until I had the tach installed. You can do weights by feel, and end up with a pretty good setup, but you'll never know if it could be better without a tach (or a whole lot of experimentation).
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..BAD TO THE BONE..