Hi, my wife has a xr125 which she is using to get her confidence up before going for her big bike license.

2 weeks back I was informed that the bike was going like a dog.....it would start but was behaving peculiarly when accelerating - it appeared the choke was on.
A week later it appears that the bike is behaving in a similar fashion (x1000), but the choke isnt on this time.

- The bike starts fine.
- The bike revs fine in neutral.
- In gear, the bike will not accelerate beyond a dawdle before wanting to stall, followed by stalling if you deccelerate immediately - it has the same feel as driving with the choke on but exaggerated.

Any advice would be appreciated, Id like to try fix this myself so may ask plenty more questions.

Thanks

Gotta check fuel flow - disconnect pipe from tap - and run into a jar to see is flowing nice for at least 10 secs +, & check filler cap breather hole by undoing cap whilst draining fuel into jar (does it flow quicker with cap off?) .

If OK - drain carb and check for shite

Is air filter clear ????

Take plug out & check colour (post photo if not sure wot you're looking at.

Awesome, sorry for delayed replying.

I will give this a go this evening, wanting to pick up some carb cleaner and a new plug.

The exhaust is blowing a bit and has gotten a bit worse - could this be the problem ?

A leaking exhaust will effect the running - but probably only marginally

Pigford......I think I need help.

1. I disconnected fuel line between tap and carb, fuel flowed well.
2. Opened petrol tank cap and fuel flow did not alter - no blockages.
3. Carb...well, that is now in my kitchen. Removed Float chamber and there appears to be some (tiny amount) fine black powdery stuff at the bottom. I have drained this.
4. Air filter...looks a mess to me (as attached). Was planning to get a new one tomorrow and fit. Is it ok to use clean engine oil on the filter ?
5. Spark plug....another mess...as attached (Black, powdery, gungy..not wet).
6. I didnt check compression, but replaced the plug and shocked myself while testing....wow, the current can jump to earth itself.



A few question to questions....
1. Can one use a general degreaser to clean the carb, in addition to carb cleaner ? (how would one clean a carb?) - I read one can boil a carb in lemon juice (dont laugh). Why should one not use water to clean a carb, assuming it is dry before refitting ?
2. How do I remove the throttle valve slider from the bike ? - Do I need to take the entire throttle cable off ?
3. I notice on the choke there are 3 settings...the butterfly is full open, partially open...and closed ??
4. The obvious question....what next to get the bike run ?

PLENTY more questions to come.....hope that is ok.

Im going to nose around a bit and check of the jets are clear....

Thanks for the help.

Attached Thumbnails

 

 

That plug is BLACK.. Althogh , with a filter that old and clogged, im not surprised lol..

It could also be that black from the choke sticking or you're burning oil. Checked the level ??

Anyway, while the carb is in pieces, make sure the float bowl valve doesnt have a fine filter hiding under it. These often get wet.

It's a shame you took the carb off before checking the fuel flows from the carb drain freely too.

Anyway. Dont use degreaser on your carb. It leaves a residue. You can use petrol, or carb/parts/brake cleaner.

Blow out ALL the jets while your in there.

Take the top of the carb off and check there are no holes in the diaphram. Thats how you get the slider out too. BE VERY CAREFUL not to lose any parts and be very systematic taking it apart. Keep things in order.

The choke has three settings. Its nothing complicated or fragile. You will be able to see it open and close now the carb is off.

__________________
Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

haha yeah......the seller prob though I was a sucker (which I may have been......but this can be my motorcycle-101 class ....all good. Hopefully the only real expense will be to fix exhaust holes (fingers crossed!)

OK.....
- I havent checked the oil level as yet....will do during daylight hrs. The bike doesnt leave smoke trails behind it..tbh I will need to be more observant though, my wife has been riding this one so I have been out the loop until this issue.

- Float bowl jet ?...Im flummoxed. Is this the Primary (Needle) jet, Primary Pilot jet, Pilot screw...or something with the overflow ? - I didnt see any filter hiding around any of these....what do you mean "These often get wet" ? - water ??

- Carb drain.....I took the carb off the bike and then initially emptied using the carb drain before just pouring out the float chamber. The drain appeared ok. Why do you ask ?

- Thanks for the degreaser warning....I was about to soak in "muc-off", the label makes it sound good for all jobs . Anyways.....filled a tub with petrol and got cleaning. Also used some Brake/ Clutch cleaner.

- Blasted a shot of cleaner through the jets.....took a peak though em and they clean as a whistle. Tightened all the jets back in place. Only the Pilot screw was 1.75 full turns off tight (as before I dismantled) - sound correct ?

- Diaphram....I unscrewed the top of the slider and took the slider out. I saw a spring but no diaphram....does the 125cc have one ? The slider is still attached to the bike which is why I asked if it is possible to remove this without disconnecting the entire throttle cable. Do I need to clean the slider ?

- At the risk of asking the obvious....having the choke fully closed, is this for the same reason as having a petrol tap....to switch off when not in use ? ...or once one has flooded the carb ?

Thanks for the help.....

[quote=Trichelia;297944]haha yeah......the seller prob though I was a sucker (which I may have been......but this can be my motorcycle-101 class ....all good. Hopefully the only real expense will be to fix exhaust holes (fingers crossed!)

OK.....
- I havent checked the oil level as yet....will do during daylight hrs. The bike doesnt leave smoke trails behind it..tbh I will need to be more observant though, my wife has been riding this one so I have been out the loop until this issue.

- Float bowl jet ?...Im flummoxed. Is this the Primary (Needle) jet, Primary Pilot jet, Pilot screw...or something with the overflow ? - I didnt see any filter hiding around any of these....what do you mean "These often get wet" ? - water ??

Sorry, I meant float VALVE.... Its what opens and closes when the float bowl is full so the carb doesnt flood. Sometimes there is a fine mesh filter under it which is easily gummed up. These filters can also hide under the main jets etc. You really need to take the jets out of the carb. Check it properly.

- Carb drain.....I took the carb off the bike and then initially emptied using the carb drain before just pouring out the float chamber. The drain appeared ok. Why do you ask ?

See above. If this is clogged or not working properly, the carb wont have sufficient fuel to run when you open the throttle.

- Thanks for the degreaser warning....I was about to soak in "muc-off", the label makes it sound good for all jobs . Anyways.....filled a tub with petrol and got cleaning. Also used some Brake/ Clutch cleaner.

- Blasted a shot of cleaner through the jets.....took a peak though em and they clean as a whistle. Tightened all the jets back in place. Only the Pilot screw was 1.75 full turns off tight (as before I dismantled) - sound correct ?

If the bike idled ok with it at 1.75, leave it alone !

- Diaphram....I unscrewed the top of the slider and took the slider out. I saw a spring but no diaphram....does the 125cc have one ? The slider is still attached to the bike which is why I asked if it is possible to remove this without disconnecting the entire throttle cable. Do I need to clean the slider ?

Im really not sure if it has one. I don't know the bike first hand..

- At the risk of asking the obvious....having the choke fully closed, is this for the same reason as having a petrol tap....to switch off when not in use ? ...or once one has flooded the carb ?

Nope.. The choke when fully on will close off the air supply to the engine.. This makes the air/ful mix much richer (more petrol), which is what a cold engine likes.

If you look into the carb, the butterfly in there just restricts air flow depending on its setting.

__________________
Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

That looks like a paper air filter. You're not supposed to oil those, just use them as they are. Oiling a paper filter will clog up the pores in the paper, restricting the air flow and causing the problems you've mentioned.

Only use oil if the filter is made of foam. The holes are much larger so the walls can be coated in oil and still allow air to pass through.

Thanks guys…..
I left home this morning with the carb in a Tupperware in the kitchen and the house smelling of petrol…wifes loving me !!


Backofbeyond….Air filter makes sense, thanks before I create my next problem J

I presume the float valve is under the float pin or there about….I didn’t seen any filters, Ill take a closer look. If I find one Ill give it a clean and Ill blast a shot of cleaner through the value anyway.

Found this site – looks like there may not be a filter.
http://www.google.co.uk/imgres?imgurl=http://www.dansmc.com/carbs/japanese_carbs/suzy_re5_carb.jpg&imgrefurl=http://www.dansmc.com/carbs/japanese_carbs/carb_pics.htm&usg=__vYxHYn_Xyr7XOV7XJmyNl65HUHU=&h =555&w=750&sz=55&hl=en&start=20&tbnid=junylZL4_PQT cM:&tbnh=104&tbnw=141&prev=/images%3Fq%3Dmotorcycle%2Bcarburetor%26um%3D1%26hl %3Den%26sa%3DN%26tbs%3Disch:1&um=1&itbs=1


Im still not too sure whether the slider and pin should still be attached to the throttle cable on the bike or I should remove this along with the carb ??

We’ll, short of checking for this elusive Float valve filter, I think the carb is almost ready to be reattached – and the pilot screw (air/ fuel mix?) and throttle adjustment screw (idling?) tweeked if necessary.


A few silly questions…..
- Within the lead to the spark plug (not sure what its called), is there no + and – cable ?- is that why I got a shock when testing the plug…..the power cable being the positive and bike being the negative ? Does one just touch the plug to the bike to prevent the earthing taking place though me ?

- How tight to torque the spark plug without torque wrench ? – Is there a rule of thumb on this ? I thought I heard finger tight and then half a turn tighter, something like that. (else I can grab a socket on the way home to fit my torque wrench)

- Should one torque set the carb bolts on the float bowl ?


Ill buy an air filter this afternoon and fit it this evening, I have replaced the plug, cleaned the carb, checked the petrol tank breather pipe for blockages, the carb breather pipe, the fuel line from tank to carb using On and Reserve settings, cleaned the petcock filter......Assuming there the bike is still kaput….what next ? - burn it

Thanks

Unless you really need to remove the needle and piston for some reason, i'd leave it on the cable and just give it a bit of a clean with carb cleaner and a cloth (carefully).
I serviced a customer's XT 125 like yours a couple of months ago and as far as i remember the only fuel filter fitted is in the fuel tap, there isn't one behind the float valve. You'd need to drain the fuel tank and remove the tap body to get to the filter but as you've already found the flow to be OK then i'd say this isn't your problem...anyway it seems you have a very RICH mixture problem and blocked fuel filter would cause the opposite.
If you're happy that the carb is nice and clean, refit it and the air filter and see how things are. A good rule of thumb when fixing problems is to do ONE THING at a time so when the problem goes away you'll know exactly what the hell was laughing at you!
Check the air intake snorkel into the airbox hasn't been blocked with something, it's under the seat. Another customer's bike had similar over-rich running a couple of years ago and the cause was a rag that he kept under the seat which had been sucked into the intake!
Another cause could also be the exhaust baffles coming loose and blocking the system up.....sometimes you can check this by taking off the exhaust system and shaking it to see if it rattles.

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Just going for a short ride on my bike....

The metal of the engine is the return path for the spark. Bear in mind that in order to complete the circuit the electricity has to jump across the gap at the end of the plug. That requires loads of volts, just like . Electricity is lazy though and if an easier option presents itself that doesn't involve jumping it'll take it. That would be through you if you're holding the wire or the cap - even if the plug is earthed against the engine. You can avoid the taser experience if you close the plug gap down to nothing but that tends to knock the performance of the bike down a bit :confused1:

How tight to torque the plug? Finger tight plus half a turn? Sometimes!

Let's assume you're putting in a new plug. Screw it into the hole and tighten it gently until the threads bottom. Easiest way to do this bit is to use a socket but turn it with your fingers. At this point you need to tighten it up so put the ratchet or whatever on the socket and turn it. New plugs have a crushable washer fitted and that's where the half turn bit comes in. They will screw down about a further half turn before they go solid.

A used plug ( = any plug that's been tightened once) has already crushed the washer down and needs very little actual turning, just tightening. If you try to force a used plug the extra half turn you'll damage something - probably the threads in the cylinder head and that's an expensive fix. If you've got a torque wrench that's a good start. Look up NGK's (or whatever make of plug you've used) web site to give you a tightening figure but in rough terms it's just a bit tighter than the force needed to crush the sealing washer in a new plug.

Right then - after all that good advice - now just whack it all together & see if it runs OK

Hope this is now sorted, the easiest thing to do to check a sick engine is take the filter out and see how it runs, if it runs ok you've got a blocked filter if it runs worse its running weak-fuelling/carb. Then check plug/s; dark=rich, pale=weak, they should be a "biscuit" colour (I always go for cardboard box brown). Its good you now know the innards of your carb. cleaning it out can't hurt and sorting leaking exhaust should help smooth running.
A friend had a CG 125 and the choke was travelling beyond off to being partially on over centre(does that make sense?) causing the bike to hold back.
P.S. always get someone else to hold the HT lead

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And another thought.....If the airfilter's in that state it could be well worth your while doing an oil and filter change, check brakes, chain and sprocket etc. etc. Its good to do a full service on a bike that's new to you, then you have peace of mind that everything is as it should be and good to go many more miles

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Anything can happen in the next half hour