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B175 carb problem tickler?
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Munroist
Northern Ireland
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July 2, 2020 - 7:27 pm
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hi folks

havent been on here in a long time. B175 626/17 carb

restored bike sitting in garage for long time and only getting round to sorting out carb in last few days.

since restoration carb was always running very rich. Anyway, found out that the new needle that replaced original one was wrong.

now right needle and starting and running much better except. After starting a wee while petrol pouring out of tickler.

is it the float that is sticking, because the tickler is working ok.

any ideas would be much appreciated.

Munroistfingers-crossed

1970 BSA Bantam D175, D14/4, B175 or Supreme - call it what you like!!!

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Blue Heeler
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July 2, 2020 - 7:50 pm
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Either the fuel shut-off valve is shot or the float has a hole/is cracked....or a bit of grit/gunge between valve and seat. Typical problem from being stood. 

** Please log in to view ** ...(possibly this one, you`ll have to double-check)

** Please log in to view **....(If you want to go the whole hog. 4-stroke carb fitted to the B175 isn`t it? My D14 is different)

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Munroist
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July 2, 2020 - 8:11 pm
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Blue Heeler

thanks. Will check. I assume you mean the float needle. Was new stay up float etc also put in new float needle. Can still put in original float etc as I still have them and the problem never arose before.

Would air leak between float chamber and carb body be a possibility?

cheers

Munroistold

1970 BSA Bantam D175, D14/4, B175 or Supreme - call it what you like!!!

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Blue Heeler
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July 2, 2020 - 8:19 pm
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That`s it Munroist, I`m an Aussie and traveled around a bit, use various terminology. 

An air leak between float-bowl and carb body shouldn`t cause carb to flood because the float will still be doing its job pushing the  needle valve shut and cutting off fuel.

Maybe bit of grit between needle valve & its seat. Did you check the seat before fitting new needle valve? What type is the one you removed?

Often another strip-down, clean and reassembly does the trick...with new stuff playing up.

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Munroist
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July 2, 2020 - 8:32 pm
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Hi.

the original one was the normal one that used to be white plastic but now a its yellow with age, the same for the needle. Float doesn't leak or anything it's still ok. 

I will check float seat 2moro and maybe put in originals. 

You tend to think that the repair/stay up float etc kit would be right. And then you find it comes with the wrong needle. Didn't check at the time, just assumed. Dismantled carb the other day, double checked everything. Wrong needle!!!!!

Now right needle in 1st slot and not 2nd as suggested ie lowest position/minimum fuel. Now much better. Except leak at tickler.

will get there ...........

Munroistclap

1970 BSA Bantam D175, D14/4, B175 or Supreme - call it what you like!!!

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Munroist
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July 4, 2020 - 5:12 pm
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To Blue Heeler

Think I might have success.

Stripped carb for the Nth time. Meticulously cleaned, checked all bits were right as original. Found that the float bowl gasket surface was not 100% flat. Managed to squeeze in 1.5 thou feeler gage at one point when assembled. So duly emeried on flat surface. So perfect now.

Took out replacement stay up float and needle and put in original which is still OK. 

Annoyed that I hadn't check the replacement needle with the original one. Now double checked and new correct needle fitted.

Started her up and no problems with carb this time. Not pissing out fuel from tickler as was doing.

So think carb Ok now.

Still getting wet plug though!

Double checked timing with disc, checked points, looked at spark plug and thought....... If its not firing every time or week spark then it won't be burning fuel correctly. Is that the cause of wet plug?

Checked plug spark. Not great, oily, carbon, Yellow spark. Thinks.... Get new spark plug.

Bingo. Now ran 6 miles (rain forecast so not going too far). Checked plug on return. Dry plug!!!!!

Looks like new plug was needed. 

So fingers crossed have got bike back running something like it was years ago. Managed 55MPH and had some puff left. But not chancing my arm yet.

Fine tune carb in coming days. fingers-crossed

Wife says "I see it's running now, good time to sell" old-lady

Hmmmmm!!!!!

Cheers old

1970 BSA Bantam D175, D14/4, B175 or Supreme - call it what you like!!!

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