1962 650ss Build

My 650SS for some unknown reason was fitted with 932 carbs by some previous owner. With 320 main jets.
Sadly it is still under restoration so I can't tell if it's the right size of main jets.
 
Anything to report after the test ride? Any unexpected monster power wheelies? ;)

Did you tune out the black smoke you saw when blipping the throttle? Or did I misunderstand what you meant?
 
Schwany said:
Anything to report after the test ride? Any unexpected monster power wheelies? ;)

Did you tune out the black smoke you saw when blipping the throttle? Or did I misunderstand what you meant?
Click to expand...
Did not even get it out of the garage today, had a hell of a time getting it to hold idle. Made some more adjustments including removing screens from the velocity stacks, returning the needle to the center position, and re balancing the throttle stops. Subsequently flooded the engine trying to get it started.

Tonight going to give it another go.
 
seanalex said:
Did not even get it out of the garage today, had a hell of a time getting it to hold idle. Made some more adjustments including removing screens from the velocity stacks, returning the needle to the center position, and re balancing the throttle stops. Subsequently flooded the engine trying to get it started.

Tonight going to give it another go.
Click to expand...
That’s a bummer !

Patience. You’ll get there. We’ve all been where you are at some point.
 
Fully confirmed that I have a flooding issue. Float height is dead on the pip. I have a feeling that its coming through the Jet Block on the left hand carb.

Yesterday in the morning I had set the throttle valves fully open to allow the fuel to dry up. By the early evening it had all evaporated and the vacuum tube was dry, it previously had about a teaspoon of fuel drip down into it.

Brought the bike onto compression, did not tickle the carb, first kick it had a few revolutions. Second kick it fired right up. Ran well for about 90 seconds, then got that heavy too much fuel feeling, and died. Within a few moments, a small amount of fuel was returning to the balance tube. I had put the original brass float in when I last had it apart, but am thinking of switching to the black plastic for the next assembly, just to rule out the float having a pin hole leak.

I've taken apart the carbs to look at the jet blocks, and to switch them from carb to carb to see if one fits tighter than the other. It seems they do, and makes sense that those parts would wear together over time. Is there any better solution to the shitty paper washer that sits under the jet block between it and the carb body? Is it insane to put any type of fuel gasket sealer on the jet block?

I've also read on an older post here that a slightly loose, or not all the way home, pilot jet can cause this leak into the inlet tract. Before disassembly I did notice that each pilot jet had a tiny bit more that they could have been screwed home. I just didn't want to overdo it. Plan is now to run the carbs and jets through the ultrasonic today, and blow out all the holes with air. Whilst I had it apart, I also Lapped in the chopped float bowl cover for a tighter fit.


This isn't driving me as nuts as I thought it would. I've been through issues like this with the Triton, and just need to work through the combinations of problems. Many Thanks to all of you on the forum for the ideas and the support. Off to the store now to buy some more cleaner for the ultrasonic. Hope to reassemble by this afternoon, and give it another go tonight.
 
Hi, I fitted new Monoblocs to my 650SS (1963 Chopped r/h) and had a bit of trouble with rich running at idle and low speeds, finally got around to checking the float level and found it to be 3mm high :D, time was of the essence, so removed the gasket from the old original left-hand carby, it was as hard as hell but when pushed you have to do what you need to, and changed it over, rechecked float level and it was bang on, bike ran better then ever.
Interesting thing was after one days ride I forgot to turn the fuel off, expecting a sump full of petrol in the morning, I found the the opposite it actually did not flood the engine, I still have memories of Atlases and 650SS filling the crankcase within a very short time back in the day.
I have not had any issues with high speed runs, there is more than enough fuel flowing through the tap/lines and carburetors of my bike, I don't think you need to be running methanol needle and seats, they only give other problems, when racing Methanol delivery is critical you can run without main jets and they will still keep going, speedway bikes though need lots of flow because they are full throttle 95% of the time, but all you are going to do is a blast down the road for as long as you can without being arrested.
If it has not already been mentioned check your petrol cap, make sure it breathing correctly, this is a killer and I have seen so many old bikes having problems and they always say I have checked it and it is not the problem, I have removed the cap and told them to ride without it and low and behold no problems.
Burgs
 
seanalex said:
Fully confirmed that I have a flooding issue. Float height is dead on the pip. I have a feeling that its coming through the Jet Block on the left hand carb.

Yesterday in the morning I had set the throttle valves fully open to allow the fuel to dry up. By the early evening it had all evaporated and the vacuum tube was dry, it previously had about a teaspoon of fuel drip down into it.

Brought the bike onto compression, did not tickle the carb, first kick it had a few revolutions. Second kick it fired right up. Ran well for about 90 seconds, then got that heavy too much fuel feeling, and died. Within a few moments, a small amount of fuel was returning to the balance tube. I had put the original brass float in when I last had it apart, but am thinking of switching to the black plastic for the next assembly, just to rule out the float having a pin hole leak.

I've taken apart the carbs to look at the jet blocks, and to switch them from carb to carb to see if one fits tighter than the other. It seems they do, and makes sense that those parts would wear together over time. Is there any better solution to the shitty paper washer that sits under the jet block between it and the carb body? Is it insane to put any type of fuel gasket sealer on the jet block?

I've also read on an older post here that a slightly loose, or not all the way home, pilot jet can cause this leak into the inlet tract. Before disassembly I did notice that each pilot jet had a tiny bit more that they could have been screwed home. I just didn't want to overdo it. Plan is now to run the carbs and jets through the ultrasonic today, and blow out all the holes with air. Whilst I had it apart, I also Lapped in the chopped float bowl cover for a tighter fit.


This isn't driving me as nuts as I thought it would. I've been through issues like this with the Triton, and just need to work through the combinations of problems. Many Thanks to all of you on the forum for the ideas and the support. Off to the store now to buy some more cleaner for the ultrasonic. Hope to reassemble by this afternoon, and give it another go tonight.
Click to expand...
If the float has a leak you will hear gas in it if you shake it near your ear. But if I recall your tested fuel level was correct which would be unlikely with a leaky float.
 
seanalex said:
Fully confirmed that I have a flooding issue. Float height is dead on the pip. I have a feeling that its coming through the Jet Block on the left hand carb.

Yesterday in the morning I had set the throttle valves fully open to allow the fuel to dry up. By the early evening it had all evaporated and the vacuum tube was dry, it previously had about a teaspoon of fuel drip down into it.

I've taken apart the carbs to look at the jet blocks, and to switch them from carb to carb to see if one fits tighter than the other. It seems they do, and makes sense that those parts would wear together over time. Is there any better solution to the shitty paper washer that sits under the jet block between it and the carb body? Is it insane to put any type of fuel gasket sealer on the jet block?
Click to expand...

I had an issue where I was running on one cylinder. I spent a lot of time checking ignition until I satisfied myself that there was no ignition problem. Then, thinking a super rich mixture will not ignite, I went after the carbs. After taking the Monoblocs apart twice without spotting anything amiss, on the third disassembly, I spotted that the paper washer between the jet block and carb body was a bit worn. Replaced both gaskets with new from Burlen, fired up and engine ran fine.
I still have not figured why a leaky jet block gasket can flood an engine or cause a super rich mixture but it does.
I would not use any type of sealer on those gaskets.

Slick
 
tomorrow should be the first day/evening back to running this bike. Carbs are reassembled, with all new washers and rubbers, and mounted well. Have not turned on the gas yet.

fingers crossed.
 
Fast Eddie said:
Still with the alcohol needles and seats ?
Click to expand...
If the needle and seat are working properly, and the float height set right, they should not be a factor in seanalex's problem.
Drilling out a seat to fit a larger needle is a recipe for flooding, however.

Slick
 
I am just thinking, as a person who has a general distrust of ‘coincidence’ when it comes to problem solving, that the fact he has worked in the area of float seats and needles… and now has a flooding issue… could be connected somehow, and it’s where I’d be looking most closely right now…
 
So everything is back together. No visible fuel leaks. Also doesn’t look to be dumping fuel into the manifold balance tube.

Fired up well. Would still not hold an idle. But with the throttle cracked it sounded strong.

After about a min time it struggles to keep that running speed. Eventually got to a place where it would stall.

Then does not want to restart unless left for a while. So still flooding I’m supposing. But not sure where to address this. Needle float seat has been raised with a shim as well.

If the float needle was the issue and causing it to flood it would be coming out of the tickler correct?

My guess it it’s coming past the jet block or something to do with the pilot jet.
 
Have you tried it without the shim? Float won’t go high enough to seal the needle to seat.

Does the small post that the float hangs on have the small spacer in place?

Have you tried it without the float bowl extension? The inside of the extension
casting pushes against spacer binding the float.

The first and last question are what have caused me flooding issues in the past.

I remember at least one issue or another causing fuel out the tickler.
 
Last edited:
kernel65 said:
Have you tried it without the shim? Float won’t go high enough to seal the needle to seat.

Does the small post that the float hangs on have the small spacer in place?

Have you tried it without the float bowl extension? The inside of the extension
casting pushes against spacer binding the float.

The first and last question are what have caused me flooding issues in the past.

I remember at least one issue or another causing fuel out the tickler.
Click to expand...
These are all really great points, and just tried all of this now. Float bowl Spacer is good and fine. Float bowl has good movement. Removed the shim. And put on the original bowl cover. Still flooding.

One thing that I did notice was that I had felt washers on both sides of the jet holder. Re-looking at the drawings I reassembled with just one on each banjo fitting. With the washer being on the top of the fitting where it fits into the bottom of the carb. I noticed that when taking the float cover off I could see the threads of the jet holder still at the bottom of the jet block. So I was hoping that was where the leak was coming from. Re-assembled properly, and still leaking.

There is still fuel dripping into the balance pipe. Also quite a few fuel leaks coming from the bottom of the jet holder, and a few small drips from the float bowl covers. How tight should the jet holder be screwed into the body of the carb? Is there any torque setting for it or anything?

I read in another post somewhere that someone set their carbs in a vice, and then hooked up a fuel line to see where the leak was coming from. I'm going to try this tonight or tomorrow.
 
seanalex said:
These are all really great points, and just tried all of this now. Float bowl Spacer is good and fine. Float bowl has good movement. Removed the shim. And put on the original bowl cover. Still flooding.

One thing that I did notice was that I had felt washers on both sides of the jet holder. Re-looking at the drawings I reassembled with just one on each banjo fitting. With the washer being on the top of the fitting where it fits into the bottom of the carb. I noticed that when taking the float cover off I could see the threads of the jet holder still at the bottom of the jet block. So I was hoping that was where the leak was coming from. Re-assembled properly, and still leaking.

There is still fuel dripping into the balance pipe. Also quite a few fuel leaks coming from the bottom of the jet holder, and a few small drips from the float bowl covers. How tight should the jet holder be screwed into the body of the carb? Is there any torque setting for it or anything?

I read in another post somewhere that someone set their carbs in a vice, and then hooked up a fuel line to see where the leak was coming from. I'm going to try this tonight or tomorrow.
Click to expand...
Definitely time to mount the carb in the vice / on the bench and get close up to see where the f *ck this is leaking from.
 

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