carb rejjeting

[Random13]

Hello,

Where can I buy 125 carb rejetting kit ?

as per some of my previous posts I am having a real issue with my engine rev where it seems to hold back as almost brake is applied at somepoint through the rev range .

I have taken the crab apart few times, checked air filter and cleaned although my filter is 2 years or 15k miles old but have washed it and re oiled it using k&n filter . it is not k&n filter but normal crappy ones

Many thanks

[c_dug]

Poor Crab!

Have you changed anything that would mean it needed a bigger jet? I'm thinking a new exhaust. If not and it is all standard I would suggest you are barking up the wrong tree.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Random13]

no I think it has not been setup correctly from the beginning

it is a sym cheap taiwanise bike which is sort of like honda cg 125

this is a link to my discussion which did not get far so thinking of re jetting as it is becoming really annoying

[c_dug]

My Haynes manual says quite wisely:

"Keep in mind that many so-called carburettor problems are really not carburettor problems at all, but mechanical problems within the engine, or ignition system malfunctions. Try to establish for certain that the carburettors are in need of maintenance before beginning a major overhaul."

I think it has a point. I would say it is unlikely that is has the wrong jet in it, and unless you know what you are doing it is quite possible to make things worse fiddling with a carb.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[temeluchus]

Check the air filter and take a look at the plug.

If the air filter is filthy, replace.

if the plug is black but the air filter is clean, check the choke is returning when you shut it off.

if the plug is brown or white, air filter is clear and choke seems to be working properly, drain the float bowl as it may be water in the fuel.

good luck,
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Some shite cruiser. Now with guns and FREEDOM!

[Intruder_Andy]

If it not revving/holding back on revs, this would indicate (to me anyway) to much air getting in to the fuel mix creating a lean condition in which the bike won't rev due to excess air.

I can see why you'd think about rejetting, but as stated previously unless you've gone for sporty air filters and/or straight thru/race exhaust/end can, a rejet simply isnt worth the hassle.

You say you've taken apart the carbs, have you cleaned them thoroughly, checked diaphragms for splits, used compressed air to clear jets/passages?

Simply not doing up an air hose tightly enough can cause similar problems.

This issue usually occurs when reseating the carbs on the intake rubbers. Check if these are damaged/split and that carbs are seated properly.

Check plug(s) to confirm if engine running lean or rich (lean = white plugs, rich = wet plugs).

Did you/have you fiddled with mixture screw on carb at all?

Andy