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YBR 125 Wont start


KimB
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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?

Hmm that's a good point, I've never had to adjust any float hieghts, could you explain what the best way to go about doing it is.

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you usually invert the carb and measure from the gasket surface to the top of the float at the pint where the tang just touches the float needle, and set it to spec by bending the tang either way untill it measures right...you'll need to know the specified height

heres a picture (not your bike)

Floatheight.jpg

100_0752.jpg

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And what about the idle screw if it has a flat spot worn into it it will be realy PITA to adjust the height of the slide,you can sand it round again if it does have aflat spot wont be perfect but it will work.

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Good Morning everyone.

So first thing I checked was float height which was around 6mm lower than it should have been, so I adjusted that. Put it all back together and it literally started straight away. Only one real issue now which is the revs still don't drop quickly as you can see in the new video, it's running without the choke now.

http://youtu.be/Z0oZO2U5JFA

The other thing is, surly the with the choke on the bike should tickover higher ? I have to keep revving it with the choke on otherwise the tickover is too low ?

Thanks again for all of your help I never thought I would get it working.

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Thats great Kim, now turn the mixture screw 1/2 turn to richen the mixture, If the screw is on the filter side of the carb that'll be 1/2 turn clockwise I expect, dont worry about the choke idle speed you wont use choke for long, besides you may have richened it some with your earlier drilling antics

is 12:48 still morning in Herts then ? ;)

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The other thing is, surly the with the choke on the bike should tickover higher ?

Only when engine is cold" when warm, it will flood engine, is a engine needs choke to run ,it is too lean, [ too mutch air,]

i think you have an air leak,, :eusa_think:

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Do you have an AIr Cut off valve and a Coasting Enricher?

Coasting Enricher - this is on the side of the carb, it may contain a diaphragm which could have a hole in it.

AIr Cut off valve - this connects to the carb manifold, the engine head and the airbox via rubber air pipes. Check for pipe damage or if they are loose.

I don't think that either aare serviceable items.

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That was one the best vids i've seen BH clear and easy to follow. So Kim give it go and report back with what you get,I think you just need to fine tune the carb now and all should be right.

Ps please put up your avitar nice to have a pretty face to see now and then.

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Thats great Kim, now turn the mixture screw 1/2 turn to richen the mixture, If the screw is on the filter side of the carb that'll be 1/2 turn clockwise I expect, dont worry about the choke idle speed you wont use choke for long, besides you may have richened it some with your earlier drilling antics

is 12:48 still morning in Herts then ? ;)

Okay, I will have a look, the mixture screw is underneath the carb.

I wrote the message forgot to post it before 12 then went and did some work and realized later I hadn't sent it.

Only when engine is cold" when warm, it will flood engine, is a engine needs choke to run ,it is too lean, [ too mutch air,]

i think you have an air leak,, :eusa_think:

Good point :)

Do you have an AIr Cut off valve and a Coasting Enricher?

Coasting Enricher - this is on the side of the carb, it may contain a diaphragm which could have a hole in it.

AIr Cut off valve - this connects to the carb manifold, the engine head and the airbox via rubber air pipes. Check for pipe damage or if they are loose.

I don't think that either aare serviceable items.

I know which items you mean but what exactly do they both do ?

I will check for leaks and see if the diaphragm is okay.

Hes a video with the basic settup. idle -mixture air screw etc.

Ill have a watch before adjusting tomorrow, I've been awake since 8am yesterday, not functioning correctly at the moment haha

That was one the best vids i've seen BH clear and easy to follow. So Kim give it go and report back with what you get,I think you just need to fine tune the carb now and all should be right.

Ps please put up your avitar nice to have a pretty face to see now and then.

I'll look first thing tomorrow morning :).

Okay don't want to scare anybody though!

One final query, the indicators don't flash they just stay on constant, I looked at the relay and took the cover off it, it doesn't pull the contact back and forth so i'm guessing it needs a new relay ?

Thanks again everyon, So happy its almost done.

Kim

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Hi again everyone.

I had a look yesterday and again today, minus the bike not ticking over on the choke it seems to run once warm. It has a little bit of hesitation when rev'd hard and fast but I will sort that. Just need to sort the indicator issue, then I can get it in for an mot :)

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Well at first they were staying on and not flashing, there was a front left indicator bulb out though, as I went to replace the bulb it worked again flashing only on the left side and not on the right now ? It seems to flash slightly slower than what I feel it should.

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