Maybe silly carb questions...

Hey guys,

(little bit of history: I put clean carbs back on my bike, I need to sync them)

To those who are knowledgeable, I have 2 carb questions.

One, is which way makes the pilot screws leaner, in, or out? This I could probably figure out with the colourtune, but I'd like to ask first anyway.

The second, which is much more important to me, is which way 'gives more vacuum' to a cylinder (specifically, I need to have less vacuum on 4)? The last question I am using to try to figure out if my vacuum guage is not working the way I expect it. When I suck on the tube, the ball goes up, and they oscillate with the engine rhythm, but I tried to adjust the screw, it didn't seem to make a difference? This is my first time ever doing anything like this, so I'm not sure.

I am also having trouble with my bike at idle, it wants to stall. It seems like it is too rich, because it's backfired (I've never heard it do that before!), and the colourtune (on 4) is sometimes sparking yellow. When it's cold, it starts and runs terribly, but as it gets warmer, I can probably only run it with the choke. If I give it throttle it stalls.

I'd call Rick, but I've bothered him QUITE a bit in the recent past, so I'll let him to peace (for the time being!)

Thanks again,

-Matt

 

lean = in. rich = out.
vacuum, what you are trying to achieve is ballance, using #3 as a base.
the screws between the carb bodies are used for this adjustment.

 

Yes, but which way 'adds' vacuum / removes it? I tried to 'turn it in', and I think it added more vacuum. But maybe my guage is not that good...

Edit:

I don't want the legs to be going the other way as the head

 

I use the cause and effect method, turn slightly one way and watch the gauge for results, if it is not the result you were looking for try the other way. Have you bench sinc'ed the rack to get them in the ball park?

 

YEa, they were benched, but I suspect now I've made it so that 4 is no longer bench synched...

 

That's OK bench is just a starting poin tot get you running. Like wiz said just turn till you get it the same as #3 then do the rest of the process.

Now the spoiler Matt - this is an iterative process. You tune your mix for good idle, clean transition off of idle and good plug color. After you get tuned close - sync again. Then tune some more to get dialed in - then sync again.

It's addictive.

 

Hey Bill,

I've started the process, I have a(nother) question... The temperature, and the YICS tool. I don't want to melt it, and what temp should I be doing the sync., etc. at?

When the YICS tool is NOT there, should the vacuum not be exactly equal? I found that my #1 is low and #4 is high, 2 and 3 are pretty equal, but this is with the tool OUT. With the tool in, it was earlier in the day, but it was pretty equal.

My current status is that the bike needs the choke on to idle... and the plugs are Bunsen-blue, with the carbs only bench-synced. I did the plugs first because it was backfiring (#1 was too rich...)

I guess it'll take some time to get this right.

-Matt

 

Yup takes time and patience. You want to sync at operating temperature. I am extra careful with my YICS tool. I sync for a few min then pull it, let it cool and reoil it with Marvel.

I assume you are keeping fans on it to keep it cool too.

Without the tool the carbs can share vacuum, I'm not sure how they would look without the tool. The tool allows you to isolate the carbs. With the tool the idea is they are all equal.

The colortune is a great tool to get a starting point - after that my opinion is plug chops or at least reading your plugs regularly and tweaking is the way yo go.

 

I can hear from the sound that it hesitates at idle, so I know something's afoot. I do have a fan on it, and tomorrow there will be MANY more fans.

So the YICS tool doesn't melt when you have it 'warmed up'? The tool would be too hot to touch then, no? (After a couple minutes of having it in the engine)

 

Yup I pull it with a rag. It can melt but is made to get hot. I try to limit how long it stays hot.

 

Ok, sounds good.

What do you think about the hesitation ... having to use the choke... rich?

 

If you need the Choke ... that means you need MORE Gas. That, ... indicates Lean.
Get it so it will Idle and accelerate without any use of the Enrichment at all.