There are two plastic pipes coming off of it, not connected to anything, one was once a clear pipe and cut at an angle, other one is black. Bike was ever so slightly lumpy and a small loss of power was noticed...checked plug, air filter, etc., Are these pipes supposed to be connected to anything? This bike was bought recently, looked like it had never had an oil change or any basic maintenance. 22k on the clock This bike is a T reg
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Re: Just taken carb off of a Yamaha sr125
Offhand, I would suspect the clear tube to be overflow while the black (smaller and connected at the bottom of the bowl near a bleeder screw) would be drain hose for removing stale or contaminated fuel inside the carb's bowl. As long as their is no suction on any of the tubes with the engine running, you should be OK. Should there be suction felt at the free end, then it should be connected somewhere and most likely would be to the fuel valve/petcock or must be plugged.
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Look at the 3 main points... Is it getting air? Is it getting fuel? Is it getting spark?
Check the plug gaps and see what colour the spark plugs are (The colour will tell you if it running rich or lean). Also check for spark (and its colour) by check holding the plug against the head (be careful).
Check to see if the filter is blocked up (replace as they are cheap), also check for leaks from the airbox to the carb, run the engine and spray wd40 on the rubbers, if the engine changes speed there is a leak (new rubbers)
As for fuel, change the filter (always good). Then look for fuel flow through the pipes to the carb (unhook pipe from the carb and put it in a jar, open tap.... Then check the fuel pump, see if there are any loose connections, also when you turn the ignition on do you hear the pump?
There is a adjustment knob to change the idle speed, there are also fuel air screws in the carb themselves, if they are not plugged (american market plug them with brass caps) then they should be white plastic knobs behind the airfilter box on the carb... Turn these full in and then 2 turns out!
Also change the oil, old oil in these bikes (especially in winter) tends to effect running and cutting out may be a symptom.
from memory a fuel line( runs to a fitting on carbs which feeds all carbs with a common tube) a vacumn line to opperate the fuel tap(slightly larger diameter comes off the manifold) a tank breather line
G'day. We don't get your bike here in Australia but if the pipes your talking about are clear or semi-clear then they will be overflow pipes in case the bike falls over.- these are often the vent for the fuel bowl too. Then they don't connect to anything. You usually rout them down & to the back of the carby & they slot down the back of the engine-commonly between the engine & swingarm pivot.
with black plugs it might be that there is no back pressure because of the cut off pipes. It also could be valve guides leaking oil into the cylinders.It is most likely that the carbs are not tuned to the opened exhaust
When you say new carb kit what exactly do you mean as this problem sounds more like a fuel problem rather than electrical although I would bypass the engine kill switch just to be sure and also the side stand cut out switch, have you cleaned out the pilot jets and air bleed pipes (do not poke anything into the holes just blow them out).
Does the vehicle tickover ok and only cut out when riden?
There are two lines coming out of the fuel petcock (shut-off valve). The small diameter one is a vacum line that connects to the top of the rubber intake located between the carb and the engine head. you should notice that all four intakes have a vacum port in this location and they should all be capped excet one - usually #2.
The second line of the fuel petcock is the larger diameter one, and is the fuel line. Make sure you install an in-line filter if it has been lost. The fuel line connects to the carb on a pipe that feeds all four carbs. The pipe is located on the lower portion of the carb, down by the float bowls. There will be a connection port between #2 and #3 (right in the middle of the carb assembly). It will be difficult to see when everything is assembled and even more dificult to reach.
I have been working on my carb today,the pipe from the bottom of the carb should just run down by the bottom of the swinging arm,there should be another pipe from the pipe on the left side of the carb just above the fuel intake which also runs down to the swinging arm and connect to nothing.