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YBR 125 Wont start


KimB
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Yip" this feeds the choke jet. :yeah: not the brass pipe in centre, the hole on bowl edge, a pipe [on carb body] drops in there, blast it clean thru, And picture of choke lever is correct for off , when lever lifts it opens choke jet. by means of plunger it connected to.

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Yip" this feeds the choke jet. :yeah: not the brass pipe in centre, the hole on bowl edge, a pipe [on carb body] drops in there, blast it clean thru, And picture of choke lever is correct for off , when lever lifts it opens choke jet. by means of plunger it connected to.

That's right, well hopefully that's the cause of the issue, i tried to blow it through already with no luck, i measured using a 1mm drill how far down it goes and it only went down in between the first and second step in the first photo. I hand spun the drill bit a couple times and nothing came out, not sure whats stuck in there.

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It will be crude, i am 100% shure this is the problem" :yeah: A drill my be too big. thin wire. ultra sonic would shift it, poke in from the low hole too. this needs to be clear , as fuel passes thu low hole, fills to float level. choke pipe feeds off here, ,,,

While blasting [carb or brake cleaner] spray up feed pipe too, while choke lever in open position :yeah:

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It will be crude, i am 100% shure this is the problem" :yeah: A drill my be too big. thin wire. ultra sonic would shift it, poke in from the low hole too. this needs to be clear , as fuel passes thu low hole, fills to float level. choke pipe feeds off here, ,,,

While blasting [carb or brake cleaner] spray up feed pipe too, while choke lever in open position :yeah:

Well I really hope so, I did notice it last carb clean but wasn't sure if there was something meant to be down there because i tried the 1mm drill trick, i have some .6 and .8 welding wire, hopefully that will go through. I will strip and go over the choke system again :). Fingers crossed.

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Hi again,

Okay I unblocked it, Unfortunately I couldn't unblock it with a piece of .6 welding wire, a bit of a body but i had to drill it with a 1.1mm drill, as soon as i got past the two upper steps on the side of the float bowl it was unblocked.

Now it seems to run fun with the choke on the revs drop right down (choke on being the lever lifted up) but as soon as its lowered it raises from 1k revs to about 5k ? Sometimes it slowly drops but it seems to sit there.

The slide doesn't move at all when it goes from 1k - 5k rpm but I just noticed there is a spring allowing the needle to raise and lower on its own slightly ?

Thanks for all your help so far

Kim

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Did you try and adjust the slide height once warm via the idle adjustment screw[the large1 on the oppsit side of the picture above]?

If so did the idle drop at all when turning the screw out?

If not then I would think the seals in the choke plunger are shot and not sealing it closed.

I still cant wrap my head around this though makes no sence how turning the choke off would increas the rpms,even if the seal were shot it would still drop rpms,,unless you have the slide set so high that even full choke can't kill it and once the choke is turned off it is running at the right mix and the slide is too high to let it idle. :shrug:

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,,unless you have the slide set so high

:yeah: " all the adjusting to compensate lack of idle, And check your throttle cable . if this is tight , no amount of screw adjustment will help. . back off cable to drop slide . back off idle screw , and start again to find idle,, :thumb:

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The slide is on the tickover screw so not the cable, and I set the tickover with the choke on at 1k rpm. But with it off when it shot up to 5k I lowered it only slightly and it starts to drop itself, The drop in rpm wasnt an instant drop it was more of a lower slowly then drop fast all of a sudden. Maybe I will video it and put a video up and see what happens. Let me try that.

I will go do it now.

Kim

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Here is a short video, starting with choke on a couple revs to show it drop then choke of and it raises on its own. Then again with choke on at the last couple seconds

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Crikey thats a heck of a high idle, more than I was expecting!

BTW have you checked the cylinder head bolts are'nt loose and did you check the carb pilot jet is not plugged?

I know, It's so bizarre.

Nope Pilot Jet isn't plugged, It seems to start from cold now though which is great, I will know tomorrow if the starting is sorted from cold, i will also check the cylinder head bolts too but i'm positive I torqued them.

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Yes I did, I have another vid where I lowered the tickover during the video and you can see when i adjust the revs only a tiny bit it almost drops it all the way down to 1k ish. It's very hard to explain and capture what happens but im trying my best to explain, in that video I fitted a brand new choke plunger assembly to see if that would make a difference but it didnt.

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Well" you"ve fixed the choke, cause its starting without spray, take of the air filtre pipe[ rear of carb, feel slide with finger, as you open and close throttle, [few times bike off. ] i think you"ve got sticking slide, start it with pipe off , see what happens , head torch an asset here.

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The slide is on the tickover screw so not the cable, and I set the tickover with the choke on at 1k rpm. But with it off when it shot up to 5k I lowered it only slightly and it starts to drop itself, The drop in rpm wasnt an instant drop it was more of a lower slowly then drop fast all of a sudden. Maybe I will video it and put a video up and see what happens. Let me try that.

I will go do it now.

Kim

Ok you set the idle wrong then if you set it with the choke on,,Idle shoud be set with the choke off so I was right you have the slde up way to high.

Start bike,,warm up turn choke off and lower the slide to obtain idle speed.This also may requier adjustment to the air/pilot screw

edit also check the idle screw is it round or does it have a flat spot worn into it?

Re edit as blackhat said you need to loosen the cable to alow the slide to drop when adjusting the idle so loosen the cable and re adjust after idle is finnaly set.your pluged choke circuit is why your bike wouldn't start before.Now it will if you set it all correct.

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Ok you set the idle wrong then if you set it with the choke on,,Idle shoud be set with the choke off so I was right you have the slde up way to high.

Start bike,,warm up turn choke off and lower the slide to obtain idle speed.

Thats a good point, you set the idle speed with a warm engine and no choke

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Probably needs rejetting and or adjusting because it splitters and bogs when I got to rev without choke on.

You shure that Pilot jet was out and cleaned. :eusa_think:

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what about float height, is that right?

If the fuel level is drastically low the pilot jet will be uncovered, oh it'll start allright with choke but when the choke is shut off it'll just suck air through the pilot and raise the rpm's accordingly?

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