Webers

My 1915 was in a fine state of tune until yesterday. Took the car to a shop for help with my clutch. While I wasn't there the helpful mechanic took it upon himself to adjust my carbs. Now the motor is chuffing and spitting like it used to. I went back and had him tweak the mixture but it's still not running smoothly like it was. Is there an easy standard for getting all four mixture screws just right? Do you turn to peak RPM, or peak RPM and a little more, or?

Rich:
Read this article that Larry Jowdy wrote:

http://www.spyderclub.com/phpbb2/viewtopic.php?t=8818

Very easy way to get your carbs talking to each other.

...or go to the Knowledge section tab on the right and read article 211 by Gordon Nichols.

I have purchased and am trying to learn how to use a Uni-Syn. First problem is that no matter how far I reduce the opening I can only get the red float about 2/3 up to the first line at idle speed on either carb. Second issue is putting the unit over the front stack on the right carb or the rear stack on the left chokes the engine down to barely idling. Is each throttle supposed to be sychronized in each carb, or are they set up as primaries and secondaries? In any case, does it matter which stack to measure airflow through? The tech article makes this process seem so simple, but I am having nothing but difficulty. I'm not accustomed to being quite this incompetent.

You don't need the red float to go to the top. The position of the float is ONLY a reference point. Put the Uni-syn on any carb barrel.
Adjust the center piece of the Uni-syn so the carb runs normally (not choked) Note the position of the float. Move the Uni-syn to the other carb without thouching the center piece of the Uni-syn and the float should be at the same posiion. If it isn't then adjust the idle screw on the end of that carb to match the float position that showed up on the first carb. (BAsically, all you're doing is raising or lowering the idle of that carb to match the other carb. or in other words, you're adjusting the air flow between the carb's so each carb pulls the same amount of air.)



But,,,,,,before you do that, get the engine to operating temp's and at idle, start with the air mixture screw on the #1 cylinder barrel.

Turn it in slowly until the engine stumbles. Then, very slowly, turn it out until the RPM's raise and then start to drop. Re-adjust the screw to reach maximum RPM's. Then do the same with the #2, #3 and #4 barrels. Once this is done, check each barrel on one of the carb's. both should be drawing the same amount of air. If not, re-adjust the mixture screw on the barrel that's pulling less air but do this very carefully and don't move the screw too much.
Get them as close as possible.


OK, so now it's time to balance your carb's attached to each cylinder head. Start by removing one linkage arm (makes no difference which you remove) then do the the Uni-syn thing as explained in the first paragraph..

Once the carbs are balanced between the heads re-attach the linkage and you may have to adjust it a bit as you're outcome here is to make sure that both carb's open at the same time and, at idle, one carb isn't opening a bit more than the other.

Rich,
Larry gives very good instructions. But the unisyn sucks! Spend a couple extra bucks and get a synchrometer (snail): http://www2.cip1.com/ProductDetails.asp?ProductCode=ACC-C10-7125
They're much easier to read and you can adjust the airflow by rotating the sleeve. You won't have any choking issues.

This may be worse than I thought. Pulling the plug wires off #3 and #4 results in no discernable RPM drop. Similarly, I can put my hands over both right side venturis and get little if any RPM drop. Odd thing is that the engine doesn't sound or behave like it's only firing on two cylinders. Putting the Uni-syn on either of the left venturis either drops the idle, if the airflow is screwed down,or the float doesn't rise if the airflow is opened more. The thing only has about 3500 miles since new. What do I check next?

Terry, I would have mentioned that the Uni-syn sucked but actually the carb barrels suck and the uni-syn just sits there and smiles.

Actually, since that's what he Rich has, I thought it would be nice to let him know how it works.

RIch,,, Start by turning up the idle screws on each carb. Put the Uni-syn on one carb and start by having the center hole plate on the Uni-syn wide open. Slowly close the center Uni-syn plate and the float starts to move.

If it doesn't move, try turing up the idle again.

Let me know what happens Also, if you want, I can call you tomorrow and talk you throug the steps

Larry, you're right. It's important to discuss the fundamentals without throwing things off-topic. I'm sorry about that. It's just that I could never get my unisyn to work properly and I was lucky enough to get a snail from Warren at the first Morro Bay shindig.
Rich,
When was the last time you adjusted the valves?
If they're too tight it would affect carb adjustment.

Only about 1100 miles since the valves were adjusted, and they were set at a relatively loose .004.
Here's the sequence of events leading up to my problem(s). The carbs were perfect. I was dinking with my clutch cable and finally decided to flatbed the car to a guy with a lift. After he got the clutch cable re-attached and adjusted,in my absence, he started the car and says it belched a ton of black smoke. He took it upon himself to mess with the carbs. The only explanation I could come up with for the smoke was my having jacked one side of the car way up and perhaps gas spilled into the manifold where it sat until he started it. Anyway, the car was poofing and chuffing like it did when I first got it off the transporter from Carey. Not horrible, just not as smooth as I know it can be. I went back and he played with the idle mixture and the idle screws. Slight improvement only. This is where I started farting around with it. The mixture setting doesn't seem like rocket science, but since I still couldn't get things right I assumed an imbalance between the carbs. Using the Uni-syn I either get the float to move up to the first line but the idle slows, or if I have it adjusted so the idle isn't affected then the float doesn't float. And why does the choking effect of the Uni-syn vary between front and rear stack?

And it just got worse. After deciding I'd had enough for one day, and to wait for more replies, I started the car to move it to the other side of the garage. Pulled the shifter into reverse and GRAUNCH the car leapt back and died. No clutch.I crawled under long enough to determine the pedal and the throwout arm are still communicating. WTF?

Firstly...maybe a new mechanic is in order.
What was wrong with the clutch in the first place?
Just may need adjusted further.

As for the carbs, I'd start over.
Turn each mixture screw in till it LIGHTLY seats.
Don't force 'em shut. Then back each screw out 1 1/2 turns.
Check and/or replace the plugs especially on 3&4.
If it starts and sounds sorta right, let it warm up real good. Blipp the throttle along the way. If you can maintain idle at around 1000 rpm, you should have better luck with the Uni-Syn. Do try to get a snail gauge, though...much easier to use. My Uni-Syn is an ornament on my pegboard.
Good Luck!

My .02

~WB

nice engine

I have raised the flag of surrender. Having the car flatbedded to an aircooled expert on Wednesday.

Rich--bummer--at least you have an aircooled expert to help.

I haven't read anything good about Webers in a very long time. Haven't they stopped making them at the "standard" location and gone to Spain or someplace? Maybe your Webbers are the good ones?

I have Solex/Kadrons fronm Scat and they are simple single barrel units ---I have never had a bit of trouble out of them.

Rich--I hope you get your engine straightened out--I understand how frustrating it can be when somethinf to do with your Speedster isn't working correctly!---Jack

Rich, I guess I'm lucky to have a good Weber guy locally who's taught me quite a bit. Once I got mine dialed in, the only issue is keeping them clean. Then you learn to love them - or replace them with fuel injection ($$).

Actually the carbs were working great until the idiot mechanic I went to to re-connect my clutch cable messed with them. I'm taking the car back to the guy that tuned them the last time. Did it entirely by ear and the car ran smoother than it had since I got it.

Rich,
See if the guy will let you hang out and watch him. Better yet - offer a few extra bucks to have him show you how to do it.

I watched him last time, but he specifically refused to explain what he was doing. Knowledge and experience are worth $ and I really couldn't fault him for that.

Rich, if I ever go out West, I'll show you for free, or maybe a beer!

Come out to Carlisle next year, sounds like we need a clinic.