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Carb, rich or lean?

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    Hey Gang,

   I have a friend ( believe it or not ) that just bought a 10 year old carbed bike.   He is wondering how to check the carb for lean or rich.  I have been out of that game for awhile and only remember to A. Whack the throttle and see if it bogs down or B. Check the plug for that nice light gray color.   Please bring us up to date with the latest techniques on carb set-up.

    Thank You   :)

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I still use this...

 

spark plugs.jpg

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4T?

Bog on a 4T is usually a problem with the accelerator pump.  Plug check is a good place to start though.  You can certainly tune the fuel/screw and idle by whacking the throttle with bike in neutral.  

Buying a JD kit was good for the RFS bikes.  

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Buying anything used I recommend pulling the card and cleaning it.  Then you know what you have and go from there.   A JD jet kit makes things really easy and it works great.

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                Yes 4T.   Thanks gents

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Your friend in my opinion has a  bike that the previous owner set up real rich on the pilot jet. Mabey also has a rich clip position, and mabey a high float level. Also the fuel screw may be damaged or turned out to far. This also leads to excessive fuel compsumption. Symptoms include hard starting when hot and a rich feeling at off of idle. This bike may haul ass but needs to be inspected for correct carb jets and specs.

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I will step out from behind the curtain - haha.  You guys are cracking me up with this mysterious friend, :) but sure is good to have friends like you all.   Thanks.  I will take the next steps as directed... on my new to me 10 year old bike, as those are all good starting points that should be considered when buying a used bike! Cheers. 

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You could always take it into a local shop to get dialed in too, depends on how many wrenches you want to spin.  I "think" it's around $150 at a place like C&D ?

Either way, it be nice to treat it with a fresh carb clean / rebuild

 

 

More importantly, Congrats on the bike.  Per our discussion, I think it's just what you wanted.

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FYI,

all good info posted.. however a 10 year old bike, and to start by chasing jetting is not the best trouble shooting method.

Yes probably a good idea to yank the carb and clean it all up, with new parts if needed after a good inspection, for example the lifecycle of the accel pump diaphragm come to mind, freshen up  (JD recommended kit is a great baseline and you get new jets with it along with the Accel pump leak jet setting mod) and get that baseline set up with new fresh parts.

Important as well,  is to base lining the entire engine ie: valve setting, Comp test, no air leaks, cables good, clean up ignition (open ignition cover and clean up stator and "flywheel" of magnetic debris etc., clean connections, fresh plug, verify cap and plug wire, clean grounding, torque fasteners, etc etc  .

My point is the machine needs to be solidly baselined, before chasing one item, especially jet setting.  Good luck these bikes are fairly bullet proof, just don't chase your tail.

And yes Thomas is always a good call. The Dr. can do.

 

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Who is "Thomas in Alpine" ?

 

The only Alpine-y moto folks I know of are Allan / Allen? Fox Engine Works, and the wizard, "Mr Olive Oil In Your Forks" guru, Suspension 101

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Thomas is the only one I let work on my bikes. Good, fast , and affordable.

We joke that he's dirt bike rain man 

PM me for his number. 

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good points here . there is a nozzle that the acceleator pump has to squirt thru , that can get clogged as well .that part isnt found in a carb rebuild kit and must be cleaned, youll know if its that because when you blip the throttle it coughs or stumbles.

if the carb is rich on the main ,motor  will stumble with a load, or pulling a hill in a higher gear.

if rich at idle , may notice smell from exaust , or using choke has little affect

Normally clean carb, put carb kit in ,reset needles and jets to factory spec.

Rain man can fix bikes!! ive let him fix about ten varios bikes and he has a 100 percent fix rate with me, not to mention most fair price, and fastest turn around time.

EDIT  If the carb is flooding partially , that will cause a rich condition if the float valve dirty or sticky , an indicatior of that is high crankcase oil level,or poor pefrormance,

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Also, check your air cleaner. If that's clean, then pull the side cover off the air cleaner and see if it runs better or worse. 

Something I learned from this site. ??

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