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Old 07-19-2011, 07:03 AM
The Berry The Berry is offline
Motorized Bicycle Newbie
Join Date: Jul 2011
Location: Los Angeles, CA
Posts: 9
Question Just Wanna See If I'm On The Right Track Here

Hey everyone. I'm new to the forum and to the hobby of motorbiking. I got my first motorbike last month in June. Right now, I'm in the middle of tuning my carb, and as the post title suggests, I want some input to know if I'm going in the right direction with my tune up.

On specs, the bike is a RAW 66cc (or 80cc), 2 stroke engine. The bike frame is an 18'', steel, beach cruiser frame. Originally, the bike had all stock parts when I bought it. It ran good, always started on the first try, and even hauled my 165lbs butt up some hills with ease despite having a broken, gutted up air filter, (all that remained was the top half of the plastic stock cover with that black, little air-cleaner mesh. I could literally lift the mesh and look into the carb if I wanted to), and a ripping spark-plug boot. The previous owner ran a 32:1 fuel/oil mix using premium gas.

Since getting the bike, I've gotten rid of that broken air filter and replaced it with a SBP standard air filter, replaced the damaged spark-plug boot with a high performance one from SBP, swapped out the stock throttle and the bikes original break lever with a throttle/double break cable lever combo from, and continued the 32:1 fuel/oil mix, though I use regular, 87 octane with synthetic 2 stroke oil. With the current mods, the bike ran a little better. It had a little more power at WOT, and I could get it going at a slightly slower speed from a complete stop then at first.

It all ran good, but then I noticed it was drinking more gas then when I first bought it. Recently when I went on a ride with a full tank to see how things were going, I came back with a little below 1/4 of a half gallon tank after traveling about 8 and a half miles. On another instance, I rode 2 miles from a gas station with a full tank, filled to the cap. When I got home, about 2 in a half inches of that was gone. I figured it might be running too rich.

Then after checking the spark-plug, which turned out to be black, somewhat wet, and oily, I saw that I needed to adjust the carb needle, so I took a look at that. My brass needle has 5 notches, and had the e-clip on the middle notch, so I moved it to the very top notch to lean out my mixture. I ran my bike for awhile, then checked the plug again when it cooled. Since it was a chocolate-brown color, I figured that carb setup would be best, but now my bike seems to idle a little bit higher, with the engine maybe running a little, tiny bit hotter then before the carb adjustment.

This particular idle speed in itself is nothing that is crazy high, (not like I have it at WOT with the clutch in,) but at this particular idle speed, the bike vibrates a little more then usual, and is a little louder.

Noticing that, I tried to adjust the idle down some with the bike running, but that didn't do much of anything too noticeable. When I messed with the throttle cable's tension and loosened it some, I got it to run at the same idle like before the mod and the carb adjustment. However, the bike dies after about 7 or so seconds of running at that idle speed unless I keep revving it up.

So my question is, is it normal to have a little higher idle that is louder, and more vibrant with a leaner mix?

The bike rides fine, even acquiring a little more top speed and power than before at WOT, the spark plug is chocolaty-brown and fine so far and the bike's gas usage is unnoticeable like before between rides, but it's just the current idle it is set on.

If anything I guess I could set the e-clip to the notch that it below the top notch to see how that works out.

(I probably would not have made it this far with mods, throttle adjustments, and carb adjustments without reading this forum, so thank you all for all the helpful info.)
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