Leaky Carbs

jposig · May 11, 2023

1958 R/50. I've been riding this bike for well over 30 years after inheriting it from the original owner. Has always run great and start on the first or second kick.

I went to ride it one day, tickled it like I've always done, and fuel started leaking out of the side main jet and the 2 little vent holes in the carb body below the slide on the air box side.

Knowing everything was original, and at the recommendation of members here, I sent them to Charlie/BING. He went through them completely and replaced/upgraded all of the parts. I installed the
carbs and they still leaked with my usual tickling method.

I called Charlie and he said send them back, which I did. He took me on right away, reset the float heights, bench tested and sent them back to me. Installed carbs, same thing, called him and he said he has no clue.

While he had the carbs the first time, I drained the tank which is still super clean from the factory sealant in it, and replaced the petcock assembly with a factory unit. When I got the carbs back, I installed my usual 93 non ethanol fuel.

I'm going to call Charlie again, but curious if anyone here has had this issue and what the fix is. Though totally different animals, 3 seconds is the time to tickle the carbs on my Norton.
For the helluva it, it took 10.5 seconds for fuel to come out the tickler on the left side carb, and 13.6 seconds for fuel to come out of the right side carb.

I'm now wondering if my issue is being caused by keeping the ticklers down too long after the rebuild and with the new and upgraded parts.

Any input greatly appreciated.

Thank you,
Jim

20774 · May 11, 2023

Jim -

Are you saying you're holding the ticklers down over 10 seconds on each carb and they finally flooded? I would expected much sooner, but there is no reason to hold them down that long...hopefully you were just doing a test. I agree with the Norton scheme, maybe 2-3 seconds at most.

The tickling/starting technique is something that each owner has to figure out with their machine...they seem to have a mind of their own! After 30 years, I suspect you know it well. When cold, I also do the 2-3 seconds tickle, then with throttle closed, kick the engine over maybe 5-6 times. Then I crack open the throttle a small amount, bring the kick start around to the beginning of a compression stroke, and then push it firmly through. Usually starts right up.

With the work that Bing has done, the carbs should be good. If the floats are working, once you let up on the tickler, the fuel flow should stop. If they aren't, could be some dirt is on the seat. But you cleaned the tank. On my R69S, I have two clear plastic filters on the lines to each carb as a check against grit.

Let us know what Charlie says.

kbasa · May 11, 2023

jposig said:
1958 R/50. I've been riding this bike for well over 30 years after inheriting it from the original owner. Has always run great and start on the first or second kick.

I went to ride it one day, tickled it like I've always done, and fuel started leaking out of the side main jet and the 2 little vent holes in the carb body below the slide on the air box side.

Knowing everything was original, and at the recommendation of members here, I sent them to Charlie/BING. He went through them completely and replaced/upgraded all of the parts. I installed the
carbs and they still leaked with my usual tickling method.

I called Charlie and he said send them back, which I did. He took me on right away, reset the float heights, bench tested and sent them back to me. Installed carbs, same thing, called him and he said he has no clue.

While he had the carbs the first time, I drained the tank which is still super clean from the factory sealant in it, and replaced the petcock assembly with a factory unit. When I got the carbs back, I installed my usual 93 non ethanol fuel.

I'm going to call Charlie again, but curious if anyone here has had this issue and what the fix is. Though totally different animals, 3 seconds is the time to tickle the carbs on my Norton.
For the helluva it, it took 10.5 seconds for fuel to come out the tickler on the left side carb, and 13.6 seconds for fuel to come out of the right side carb.

I'm now wondering if my issue is being caused by keeping the ticklers down too long after the rebuild and with the new and upgraded parts.

Any input greatly appreciated.

Thank you,
Jim

On my R60, I just push them down a couple times for about a second each until fuel dribbles out of the tickler. I generally don't use any choke at all, and it starts right up.

20774 · May 11, 2023

IMO fuel coming out of the ticklers is way too much. I think this might be a hold over from some very old motorcycles. The idea is to fill the float bowl back to normal values or so. Then by kicking with the throttle closed, you pull gas fumes into the combustion chamber. Once that's done, that mixture should light off provided the bike's in good tune. If you tickle too much, there is the danger that fuel will flow through the carb throat into the intake valve and create hydro lock in the cylinder...that can bend a conrod. They don't need to be "flooded"!

jposig · May 12, 2023

20774 said:
IMO fuel coming out of the ticklers is way too much. I think this might be a hold over from some very old motorcycles. The idea is to fill the float bowl back to normal values or so. Then by kicking with the throttle closed, you pull gas fumes into the combustion chamber. Once that's done, that mixture should light off provided the bike's in good tune. If you tickle too much, there is the danger that fuel will flow through the carb throat into the intake valve and create hydro lock in the cylinder...that can bend a conrod. They don't need to be "flooded"!

I totally agree with you about "old school" thinking in everything, and I've been riding and racing bikes since the late '60's. Just because my method worked for 30 years doesn't mean that I shouldn't modify my methods now especially with all of the new updated parts in the carbs.

I just spoke with Charlie and explained everything as I had put in my thread here. He said he has the same bike/carbs as I do and stated he barely touches the ticklers at all. There really isn't a generally accepted spec on these carbs like there is with the Norton rule.

I know that each individual bike regardless of marque' has a unique starting technique that the rider needs to develop, and that's what I'm. going to do now.

I'm draining the oil and will kick it over a lot to attempt to get as much of the fuel out of the motor as possible while draining and clearing the carbs which have been sitting for days. Then I'll install fresh oil and plugs and start with 1 second tickling, try to start, then 2 seconds, try to start, etc....

Will post results when I've got it running again.

Many thanks to all of you for your time with responses.

Jim

kbasa · May 12, 2023

I give each of mine a pair of like one second pokes. A little fuel comes out of the left one, none on the right. I'll kick it through lightly to get to TDC, then give it a decent kick. Sometimes, first kick, usually second kick and it starts.

20774 · May 12, 2023

Neither of my carbs leak after tickling...I usually push them for a count of 2 or 3. Bikes starts pretty quickly. I still contend that physical leaking of the carbs when tickling is not correct. Vech's procedure for starting was "NO TICKLING". Petcocks on for a count of 5, then off. No tickling, no throttle. Kick start the bike. Then petcock open, light throttle. My bike never started that way!! Guess there's various ways of starting them. YMMV!

jposig · Oct 7, 2023

jposig said:
1958 R/50. I've been riding this bike for well over 30 years after inheriting it from the original owner. Has always run great and start on the first or second kick.

I went to ride it one day, tickled it like I've always done, and fuel started leaking out of the side main jet and the 2 little vent holes in the carb body below the slide on the air box side.

Knowing everything was original, and at the recommendation of members here, I sent them to Charlie/BING. He went through them completely and replaced/upgraded all of the parts. I installed the
carbs and they still leaked with my usual tickling method.

I called Charlie and he said send them back, which I did. He took me on right away, reset the float heights, bench tested and sent them back to me. Installed carbs, same thing, called him and he said he has no clue.

While he had the carbs the first time, I drained the tank which is still super clean from the factory sealant in it, and replaced the petcock assembly with a factory unit. When I got the carbs back, I installed my usual 93 non ethanol fuel.

I'm going to call Charlie again, but curious if anyone here has had this issue and what the fix is. Though totally different animals, 3 seconds is the time to tickle the carbs on my Norton.
For the helluva it, it took 10.5 seconds for fuel to come out the tickler on the left side carb, and 13.6 seconds for fuel to come out of the right side carb.

I'm now wondering if my issue is being caused by keeping the ticklers down too long after the rebuild and with the new and upgraded parts.

Any input greatly appreciated.

Thank you,
Jim

I finally finished my Norton and am now back on my BMW with the carbs on the bench still trying to fix my initial issue of flooding the motor even with a tiny tickle. I called Charlie again and asked if he tested the ticklers on the bench. He was pretty hazy on this so I'm not convinced he did. I emailed him a request for a parts diagram that might show any and all internal passages and never heard back. I sent another email today expressing that I was surprised
that he has not at least called me to see if I've made any progress since he has stated he's never seen this before or if he's come up with an idea, as it's now up to me to fix them after spending $ 645.42 with zero results. As noted, I'm a BMW car expert with over 50 years of experience.
If anyone has a clue, or if there is someone in my area, 27343, I'd appreciate any and all advice. I'm also happy to pay someone to come to my shop on my Farm.

Thank you.

52184 · Oct 7, 2023

I’m a bit confused on your original post. If you are holding the ticklers more than a second or two and fuel overflows then stops, that’s normal. All the tickler is doing is depressing the floats to slightly overfill the bowl and enriched the starting mixture.

But if you’re tickling for a second or two then seeing fuel continue to flow out of the carbs after releasing the ticklers, that’s not right and would seem to indicate that either the float, the tickler rod, or both are getting hung up. Possibly the tickler rod clip is interfering with the float, or the float is hanging on its pivot.

Note also that if the carb was redone by Bing, it’s likely the float needle seat was refaced and, of course, a new float needle installed. Your carbs may be flowing fuel more freely after the rebuild and only need tickling as per the original usage of 1-2 seconds tickling.

Best,
DeVern

20774 · Oct 7, 2023

Without rereading the above, I'll offer some thoughts:

- have you tried starting the engine without tickling? Just turn on the petcocks, let the bowls fill, then kick the engine throttle closed 4-5 times. Then open the throttle some amount, ignition on, try and start the bike.

As for leaking, there can only be a few things that explain that:

- when you push on the tickler, the button doesn't return to the up position and keeps pushing on the float. That's what tickling is all about...holding the float down to allow fuel to flow into the carb bowl.

- releasing the tickler, the float must be able to come up and have the tip of the rod to seal against the seat. If the rod isn't sealing for some reason, then it will continue to leak.

- the float must not be compromised...the older brass floats would crack and gas got inside and they didn't float.

- the float must be positioned on the rod correctly. The two thin wires across the top of the float must snap into the groove in the rod.

- the rod moves up and down while the ends ride in small holes or bosses in the carb body. If any corrosion builds up in those holes, then the rod can't move freely and can stick in the up or down position.

I might have missed something, but those are the only reasons that the carb will leak.

jposig · Oct 8, 2023

20774 said:
Without rereading the above, I'll offer some thoughts:

- have you tried starting the engine without tickling? Just turn on the petcocks, let the bowls fill, then kick the engine throttle closed 4-5 times. Then open the throttle some amount, ignition on, try and start the bike.

As for leaking, there can only be a few things that explain that:

- when you push on the tickler, the button doesn't return to the up position and keeps pushing on the float. That's what tickling is all about...holding the float down to allow fuel to flow into the carb bowl.

- releasing the tickler, the float must be able to come up and have the tip of the rod to seal against the seat. If the rod isn't sealing for some reason, then it will continue to leak.

- the float must not be compromised...the older brass floats would crack and gas got inside and they didn't float.

- the float must be positioned on the rod correctly. The two thin wires across the top of the float must snap into the groove in the rod.

- the rod moves up and down while the ends ride in small holes or bosses in the carb body. If any corrosion builds up in those holes, then the rod can't move freely and can stick in the up or down position.

I might have missed something, but those are the only reasons that the carb will leak.

A sincere Thank You to those of you who spent your time with some excellent suggestions. My original floats weren't cracked or fuel filled, neither are the new ones. The ticklers don't stick. I made sure the floats were positioned so the ticklers would not interfere with the wires on top of the floats.

The carbs are uber clean, zero corrosion. Floats go up and down fine with the tops of the fuel bowls off.

I think that's a good idea about trying to start the bike without the ticklers, but what I think I'll do first is leave the spark plugs out and see if fuel floods into the cylinders without using the ticklers after kicking it over a few times.

What baffles me is somehow this issue started prior to the parts replacements, and that's what I need to figure out.

Thanks again and I'll report back after I've followed through with your suggestions.

Jim

pglaves · Oct 8, 2023

The sealing is done by the needle and seat. If the seat is damaged even a new needle won't seal unless the seat is replaced. I am not sure from reading what has happened here.

Leaky Carbs

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