daveh
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Posts: 417
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Post by daveh on Mar 23, 2023 11:39:02 GMT
In process of sorting out a few finishing jobs to get bike ready for road soon I hope. Tank had a fill of fuel for fist time and after I had left tap on a while I was getting a leak from carb. Not happened before when running of small fuel supply. Took the carbs off to check float height and float needle sealing. Float height OK, but found one of the float needles was damaged as shown in picture. The small sprung spigot was solid and when I pushed to get it to move it jammed down in position. Anyone seen this before. Strange thing is it is on the side that was not leaking.  |
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Post by alfie on Mar 23, 2023 22:55:58 GMT
In process of sorting out a few finishing jobs to get bike ready for road soon I hope. Tank had a fill of fuel for fist time and after I had left tap on a while I was getting a leak from carb. Not happened before when running of small fuel supply. Took the carbs off to check float height and float needle sealing. Float height OK, but found one of the float needles was damaged as shown in picture. The small sprung spigot was solid and when I pushed to get it to move it jammed down in position. Anyone seen this before. Strange thing is it is on the side that was not leaking. yes quite common, caused by gunky old fuel residue. the plunger acts as a shock absorber to maintain fuel level when traveling over rough ground it stops the floats bouncing around. the conical tip looks like there is a wear ridge present. i would replace both valves |
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daveh
Full Member
Posts: 417
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Post by daveh on Mar 24, 2023 7:49:35 GMT
In process of sorting out a few finishing jobs to get bike ready for road soon I hope. Tank had a fill of fuel for fist time and after I had left tap on a while I was getting a leak from carb. Not happened before when running of small fuel supply. Took the carbs off to check float height and float needle sealing. Float height OK, but found one of the float needles was damaged as shown in picture. The small sprung spigot was solid and when I pushed to get it to move it jammed down in position. Anyone seen this before. Strange thing is it is on the side that was not leaking. yes quite common, caused by gunky old fuel residue. the plunger acts as a shock absorber to maintain fuel level when traveling over rough ground it stops the floats bouncing around. the conical tip looks like there is a wear ridge present. i would replace both valves Yes that confirms what I was thinking. Carbs were badly gunked up when I cleaned them up last year, but obviously this part not easy to clean out inside. New ones already ordered and hopefully arrive today or tomorrow. I wondered why there was a sprung plunger. Makes sense! Thanks. |
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Post by alfie on Mar 24, 2023 8:05:09 GMT
You'll need to clean the seats with polish and cotton buds too
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daveh
Full Member
Posts: 417
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Post by daveh on Mar 24, 2023 13:59:30 GMT
Yes, I had previously done the seats when I overhauled the carbs, but did not see the issue with the needles. I'm sure they were working OK, so maybe the crud in the hole moved about and jammed it. These arrived today so hopefully fixes the issue.  Will have to re-set the float heights.  |
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Post by Graeme on Mar 25, 2023 18:42:50 GMT
They are funny little buggers.
I rebuilt a set of carbs and thought they looked fine...so I didnt change them.
And then!
A screw driver head tap on the side of the carb normally fixes the drip of fuel.
Lesson learned.
Gee.
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ian
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Isle of Man
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Post by ian on Mar 25, 2023 21:01:29 GMT
I had my worst problem with these little blighters on one of the Peaks meets. The day we were due to leave Buxton for Liverpool Turned the fuel on only for it to start flowing out the overflow tube  . I got pretty good at turning the fuel off as we stopped at junctions, traffic lights etc, then back on again as we set off. Biggest worry was riding onto the ferry & parking up. I thought the bike would get chucked off it started pissing out petrol all over the deck, so just left the tap off hoping there was enough fuel left in the carbs to get me on & into position. Luckily. there was. |
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daveh
Full Member
Posts: 417
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Post by daveh on Mar 25, 2023 22:36:00 GMT
Got the new ones in and back on the bike. All running OK now. Also seems to be ticking over much better. Could have been making it run too rich?
Yes tried the screw driver tapping, but the one that was stuck in was too far gone.
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Will have to re-set the float heights.
. I got pretty good at turning the fuel off as we stopped at junctions, traffic lights etc, then back on again as we set off. Biggest worry was riding onto the ferry & parking up. I thought the bike would get chucked off it started pissing out petrol all over the deck, so just left the tap off hoping there was enough fuel left in the carbs to get me on & into position. Luckily. there was.