Running on one cylinder... Honest opinions

Bench synch puts you in the ballpark, but you will be setting all four up exactly the same-each cylinder has unique properties (not drastically different but different just the same ), so a running synch is required to "catch the ball" to use a baseball metaphor. You will then be matching each cylinder to the other three and creating equal power strokes-so you eliminate those unique properties from the equation.

If you've ever heard an engine go from only benched to running synched you will understand the difference. One sounds like a room of people arguing and the other like Elvis singing "Hunk of Burning Love", ok so not really but you get my point. It's a big difference in the smoothness and power response.

So yes you will want to take it further, but first things first-get your carbs done, floats dry set, wet set, mixture right, valves right, then running synch.

 

This all using the clear tube method right?

 

You can just do the trial and error wet set (clear tube method) with the carbs level in both planes with gas on one carb. Once it's right you can set the other 3 using it's measurement to the carb body. Or you can trial and error set each carb using the clear tube method-it just takes a little longer for the drain and fill and set cycles.

There are several write-ups that take you through this process here and elsewhere and it's pretty much the same process for just about any carb. If you can find one that matches your carbs use that. Just be aware that a small adjustment to the "tang" can change the level a lot, and take enough time to orient yourself about which way you need to go with the level and which tweak will get you there. It will be less frustrating that way. Also since your working with gas, be careful.

 

well that sounds like its gonna be interesting, looks like I have some more reading to do.

 

Here's some reading for you to start with. The first link you have to work through and find the useful info, the other is all useful (or almost), and I believe those are the same carbs you should have.

http://xjbikes.com/Forums/viewtopic/p=215078.html

http://xjbikes.com/Forums/viewtopic/t=9 ... eight.html

I imagine you're feeling like I was before I did this the first time. It seems like it's going to be hard. Well it was a little tricky getting my carbs level in both planes (side to side & front to back), but I finally used some scrap wood and screwed together a quick little jig to hold them more like a manger for the the bottoms. After that it wasn't hard just time consuming. I overadjusted the first time I bent the tang but I took many pictures using a digicam so I could relate what I was doing to what happened and only missed it bad the first time. So don't worry you can handle it.

 

The "clear tube method" refers to setting and verifying the float levels. Even if you use the "matching" technique, they all need to be individually verified using fuel and the clear tube method.

For the running vacuum sync, you will need to block your YICS using either a correct YICS "tool" or you can use an oily rag wound into a rope. I emphasize "correct" because a lot of the DIY plans on the 'web and tools on eBay do NOT properly seal the YICS system off the way it needs to be. The oily rag works better than an incorrectly configured tool.

Then you will need some form of manometer (comparative vacuum gauge) to perform the sync. This can be a "two-bottle" system using baby bottles, tubing and ATV, or a 6' long (yes, feet) hunk of clear tubing zip-tied to a yardstick. Or you can use one vacuum gauge; a pair of vacuum gauges; FOUR vacuum gauges; or a tube-type 4-stick purpose manufactured manometer, like a Morgan CarbTune. You need some way of "comparing" the vacuum signal from the carbs; it can be accomplished many different ways. Unfortunately, the more money you spend on your manometer solution, the quicker and easier the process becomes.

 

Thanks for the info Fitz, I will most likely use the oily rag and the two baby bottle method because I most likely have all the materials laying around. Other than six feet of clear tubing that is. Do you know of a write up or diagram on how to set this up and utilize it?

 

If you own a Vacuum Gauge; you can Vac-Sync the Rack and get them all at the same drag without much fuss.

You need:
Gauge
Hose
Aquarium Air Valves 4-Valve Gang
White China Marker
(4) Vacuum Restricting Hose Unions*

(Carb Cleaner Spray Tubes Epoxied in Hose Unions*

Cut (4) - 2" Sections of Hose to slip on the Manifolds
Insert a RESTRICTING Union in each 2" Section
Attach Hoses to each RESTRICTING Union and run to Aquarium Valves
Run Hose from Valve to Gauge.
(An additional Restricting Union inserted between the Valves and Gauge may be necessary,)

Run cooling fans, ventilation precautions.
Lube the Sync screws.
Close the valves and war her up a bit.
Open the 3-Valve ... Read the Gauge.
The Needle fluctuates with the Intake Cycle.
Mark the Face of the Gauge using the China Marker at the ZENITH of Measured Vacuum.
MAINTAIN CONSTANT RPMS during SYNC.
Shut - 3
Open - 4 <--> Match 4 -to- 3
Close.
Read - 2 (Mark) Close.
Read - 1 <--> Match 1 -to-2. Close all.
Read - 2 <--> Match 2 -t0-3 (1's married to 2 and adjusts w/ 2)

Double check.
Tweak as needed.

 

Thanks alot Rick this will help out alot!

 

Harsh Solvents may damage the "Window" of your Vacuum Gauge if you use it to remove the China Marker.

Tissue dampened with WD-40 will do the trick.
Prepping the Gauge with Scotch Tape works.

Making "Arrows" out of the Sticky-strip of Post-it Notes works.

 

So I decided to pull the carbs off my bike to check them out so how nasty they were. I knew that they were causing a rich fuel condition because all my plugs were fouled with gas. The thing is that I have pods and straight headers. So I pulled them off and cracked them open. They look like they have just been cleaned. I did a clunk test and it passed with flying colors first time. I didnt get a chance to really check out all the little passages but I will get to that tomorrow. The best part is the jets sitting in it. I knew they had to be big because it is running rich. They had #136 main, and #40 pilot (stock). I just recieved my #126 main, and #42 pilot from Chacal today. Which is the correct size according to Chacals chart. So I am pretty happy that I found my root to all evil.

 

That's not the root of ALL EVIL, ....

If you want to have some fun with those Carbs; "Vent" them.

Seal the Kidney-shaped Atmosphere Vents on the Intake Horns.
Fabricate Atmosphere Vents - (2)
Connect 1 & 2 ::: 3 & 4
Drill into side of Horns.
Add Hose - T - Grommets etc.

Atmosphere enters GREEN Opening between Carbs and satisfies the need for Atmosphere allowing the Diaphragm to react to Vacuum and MOST IMPORTANTLY ... Flow through the Main AIR Jet to the Void surrounding the Emulsion Tube.

 

Would you really recommend drilling into the carb bodies? If so what supplies would you recommend?

 

NO. This is an untested, theoretical idea. While Rick's theory seems sound, nobody that I know of has used it successfully as yet, and it's untested to the best of my knowledge.

If you're going to do it, I wouldn't do it to my only rack of carbs. Reversing it would not be easy.

I'm surprised to see it actually being "recommended" rather than posed as the theory that it is.