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Recentering the jets?

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Doug said:
As mentioned by Piman, all this has to be done with the jet tube up and flush with the bridge. If there is a tiny (and I mean tiny) bit of binding when the jet tube is all the way up, remember that the running position (2+ full turns down) will have clearance... and it's probably centered well enough.
Click to expand...

I agree completely. It's just the circumstance of not being there to SEE what's happening and knowing the "anvil" will either work easily or something else is wrong, IYSWIM.
 
I bought all those tools.....Waste of $ for me......

The eye is capable of discerning 1/1000"

Better than what I got with the tool.

When you tighten the nut it puts side load on the alignment device so when it's removed the needle moves.

If you want mine....PM me.
I'll send it free & pay for the shipping also in order to be rid of it.

(That is, unless I threw it over the hill in the same general direction as the Lucas control box & flasher relay)
 
I made some of those centering tools in a lathe. I made them a bit longer than what kit B has, and it has helped me and those I've given them to. Doug is correct in marking the bell position. If you can get the piston to "plunk" nicely with the bell (chamber) screws just slightly loose, the problem is the chamber. Try rotating it. Heck, try straightening the screw ears. Don't tighten 1 screw all the way first. Tighten them evenly and snug, not over tighten.

Peter
 
Oh, so that's what that funny little cylindrical thingy in the kit is for! Dang, you guys, where'd I be without you?

Anyway, I just did two carbs this morning, centered the jets without the special tool, took maybe two minutes each. Doug has it exactly right; you need to sneak up on the adjustment. Tighten the nut a smidgeon, lift and drop the piston to recenter if necessary, tighten a smidgeon more, and so on. It's not unlike many things you do in bicycle work, like adjusting the preload on wheel bearings. Probably similar things in many other kinds of machine-maintenance operations.
 
my issue is that you can 'sneak up' but ultimately, the bearing is wanting to seat at a specific (wrong) position /bcforum/images/%%GRAEMLIN_URL%%/wink.gif


What is the 'Anvil' tool I've seen mentioned twice so far? Is there a photo of it?
 
I will try again.

Remove the choke lever, remove the nut just above it, remove the spring. to do this pull the jet down and remove from the carb.

Remove the piston from the dashpot.

Put jet tube back into the carb body.

Now you are ready to center the jet.

Loosen the alum nut on the bottom of the carb body till the needle falls into the jet, all the way down.

Now, tighten the nut 1/8th turn and wiggle the jet from the bottom, where the choke lever attaches till the needle is again free and all the way down.

Do this again and again till the alum nut is tight and the large piston still falls to the bottom from about 1/4 inch up with a thunk.

Pull the seat out the bottom carefully add the nut and the spring and push gently back up into the carb and screw in.

Reattach choke lever and adjust carb.
 
Luke_Healey said:
my issue is that you can 'sneak up' but ultimately, the bearing is wanting to seat at a specific (wrong) position /bcforum/images/%%GRAEMLIN_URL%%/wink.gif


What is the 'Anvil' tool I've seen mentioned twice so far? Is there a photo of it?
Click to expand...

In "kit B" there's a small centering tool and it can be referred to as an 'anvil'. Same thingie as the other photo only shorter. The longer one has advantage in that it won't allow the jet sleeve to squirm around as much. Down-side is the jet needs to be removed. The short one was designed to be used with the jet in-situ. Jack's method works as well as any, it just takes longer (usually).
 
Even though I ordered the kit, I think I got it.

I ended up screwing the mixture nut up as high as it would go and using the sleeve of the jet tight against the needle, while pushing down on the piston to center things. I tightened the jet bearing nut and then backed off of the mixture nut 12 flats.

I'm getting the satisfying 'clunk' now at least. The car doesn't run any better, but I'm chasing that again after lunch.
 
Hello Luke,

glad you got there, but forgive me for pointing out that is exactly what I advised earlier (Post three of this thread)

Alec
 
Hehe, we were all working on it. Now he knows how to do it he can show others as well.

Of course it is now too rich by a lot but a good place to start.

Useing the small pins that lift the piston, or raise the piston with a thin screw driver just a bit 1/32 inch, lean a carb about half a flat at a time then lift it a bit and see what it does.

If speed increases too rich.

If speed drops too lean.

If raises slightly then stabilizes is just right.

You doing the easy part now.
 
I got my Gunson color-tune in the mail at noon, so everything is supposedly tuned to that specification. We will proceed from here.

I did try the method that ended up working for me beforehand, but could not get things to center. The key was forcing the piston down while I was doing it I think.. I didn't have the damper cap on at the time either.
 
Which is exactly why I prevously asked if you were following the book procedures. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif
Jeff
 
Bet Luke knows how to do it now. Always good to learn the hard way as we all did, stays with you.
 
Just to add my 2¢ -

From *hard* experience I learned that centering the jets is much easier if the jet and needle aren't bent.

Ask me how I know ....

Tom
 
Jack, you mentioned lifting the piston only 1/32 of an inch to test the mixture... is that enough? I have been using the lifting pin and pressing it all the way in. Am I raising the piston too much?
 
Tony, 1/32" is correct. You just want to barely "tickle" the piston. Pushing it up too much changes things drastically, as you are enriching the mixture quite a bit. Remember, the throttle plates are closed when doing this.
Jeff
 
So by pushing it up all the way I am incorrectly judging my mixture? No wonder I could never seem to get the mixture rich enough according to the lift test. I will try again tomorrow.
 
Hello Luke,

another bit of advice, get as many colour tune plugs as you have carburettors, that way you don't have to keep swapping from front to back cylinders to set the mixture.

Alec
 
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