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Discussion Starter #1
I was running a stock 114 jet for quite some time and latley i couldnt idle and thered be a miss when i squeez the throttle or give it a little blip to go over something. The spark plug was all black. blacker than midnight..so that told us that it was rich. i had a friend clean out the carb and we put in a 118 jet and a new plug. Seemed to have a little more low end but at wide open throttle there'd be a nasty miss and stumble like it wasnt getting enough fuel. We putted around the hood, then pulled the plug...she was greyish which is lean and not getting enough fuel.



How is that running lean when we went from a 114 to a 118 jet? for 2,000 ft elevation in the colder weather what can you recommend to run for jets? I was thinking of ordering a few more jets in the 120s to see if that helps. ANy other screws or anything on the carb i need to adjust too? Its a cali carb .
 

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I was running a stock 114 jet for quite some time and latley i couldnt idle and thered be a miss when i squeez the throttle or give it a little blip to go over something. The spark plug was all black. blacker than midnight..so that told us that it was rich. i had a friend clean out the carb and we put in a 118 jet and a new plug. Seemed to have a little more low end but at wide open throttle there'd be a nasty miss and stumble like it wasnt getting enough fuel. We putted around the hood, then pulled the plug...she was greyish which is lean and not getting enough fuel.



How is that running lean when we went from a 114 to a 118 jet? for 2,000 ft elevation in the colder weather what can you recommend to run for jets? I was thinking of ordering a few more jets in the 120s to see if that helps. ANy other screws or anything on the carb i need to adjust too? Its a cali carb .
Me thinks you and your friend don't know much about carbs. First, is the gas fresh and clean?



Next, do a complete engine tune and service, following the instructions in the manual, to eliminate any other potential problems.



Still not running right, next step would be looking through the carb, because it's cheaper than electrical problems. Completely disassemble the carb, then carefully clean and inspect each piece for damage or wear. Replace worn and damaged parts. Reassemble carb making double-dawg sure every piece in the parts explosion is used. Adjust float height as directed. This is critical. Install the #118 jet. Visit a hardware or hobby store for a single flat washer to slide up the needle shaft to raise the needle. Set the pilot screw about 2.5 turns out. If the carb had problems, and you did the carb work properly, these settings will be so close to perfect you probably will not want to ever touch them again, unless you ride way up in the mountains or something.
 

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Clean the carburetor completely; lots of links for proper carb cleaning on the forum. It's easy and don't try to cut corners like I did the first two times I cleaned the carburetor! Blow carb cleaner, air and a wire to make sure every orifice is clean; do not mess with the jetting until the bike runs correctly or you are just trying to fix a non existent jetting problem. Of course if you are riding in some extreme altitude areas maybe jetting could be an issue; but you have to start with a clean carburetor first. Just my .02 as I was going to change my jetting when I thought my carburetor was clean and it was not; cleaned carb and all my problems went away.
 

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Eddy, you're right about making sure the carb is clean and working as designed, but wrong about the jetting. Stock TWs in North America are jetted too lean to make the EPA happy, and tend to run best at extreme altitude. If not at high altitude, best jetting can be 1 to 3 sizes bigger on the main than stock, depending on the exact market, year, and geography.
 

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Discussion Starter #7
From reading all these posts on carbs..i think a 118 is too lean for 1,000 ft and colder winter riding..should i experiment with a 125 or 128?
 

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i agree with qwerty about shims for the neddle. i run a #130 main jet with two .020 shims. and i have very good throttle through all five gears at an alt of 300-400 feet. if you start to run into too rich issues you could use that as an excuss to buy an exhaust, lol. i know when i put on my exhaust it ran real darn lean.
 

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Main jet won't affect starting and will have minimal effect on cold-naturedness or off-idle throttle response. The pilot circuit has the most effect on cold starts, the needle height has come into play on throttle response when cold.
 
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