carb synchronization. after doing it all DAY LONG!

well, it's taken me all day of doing this, where i have ran into many road blocks. Luckily I've managed to find a way past them all. here are a few pics for you all to enjoy



this is the sync gauge i got off of eBay, it was half the price of the Morgan carb tune and another really nice one, it cost me $57 with shipping



BEHOLD! MY STEEL HORSE FROM HELL!!!! :twisted:




a little closer look at it



this is where i mounted the sync gauges. it took me ALOT of time to get it sync'd up to where i got all the needles CLOSE enough, they aren't perfectly matched , but are good enough to not cause any annoying fluttering or uneven idle. (that's all you really want anyway). I'm going to sears later to see if they have any vacuum caps that i can use to plug the nipples on the boots.



after taking the petcock apart and rebuilding it, i decided to take a trip down to Napa to grab me one of these fancy see through fuel filters.


FRESH fuel line from kragen auto parts. much softer than the one before that i took out. and when i was at walmart i bought a few small clamps.


it's much more responsive now when i start it up. IT idles slighly high when it first starts up. and after a few seconds idles at normal. LIKE IT SHOULD! the three screws idea with adjustment is annoying. i wish there were four, but i figured out how to work with it.

a motorcycle is a Wonderful machine! it takes you ANYWHERE You want to go (with the exception of going on top of water or into space, or in the sky). it's also cheap economical, and packs pretty decent storage if you got saddle bags or a magnetic gas tank pouch. of course you all know this. But go ahead and tell me what you guys think

 

the accord coupe found in the background is also mine told you i'm more of a honda guy, little bit off topic from what i did to my bike, but my car needs a new catalytic converter, trying to find one for that and it will be a whole other job. i have an OBSESSION with making things work the way they SHOULD!

 

I found those caps at the local hardware store too.

 

hmm, thanks for the info! i guess it's ACE instead of sears! haha. i've already been there twice today i think. guess this will be my third!

 

i hate to say it but i think your new fuel is really vacuum line

 

the large one in the picture is the fuel line. There is a vacuum line for the petcock but is much smaller. i'm not going to install it today but tomorrow the bike should be up and running.

 

Next time run your bungee cord around the base of the mirror stalks and let the gauges hang between them. That'll isolate the gauges from vibration and reduce the chance you scratch something on the bike.

 

Love Ace, we have one 2 blocks from the house! They sell a ton of metric too but the employees are too stupid to find exactly what you need half the time so if they cant find it I dig around till I do.

 

AGREED! that's exactly what happened to me when i went there. Ended up going to Kraigen instead. they had em, where no more than 4 bucks. not bad, not bad, the fuel filter i installed was leaking, so i went back to NAPA and got another one, After test firing it, it seems to run decent. Still kinda fluttery (mainly because it was cold) i think if i replace the carb diaphragms, it might start up alot better. since the diaphragms are kinda old.

 

Does one not have to sync a YICS engine with the YICS tool? I thought that YICS would give a false balance if the ports are not plugged as it does let fuel mixture pass between cyls... or is it really not a big deal to use a YICS tool?

 

Azrael, you opened up a hot button topic. Some folks think that you don't need to use the tool. Most do but I'll leave it at that.
I personally use the tool as directed by the nice folks who made the bike and know how to look after it.
Good point and food for thought.

 

Personally I agree with following the factory maintenance procedures as well; which includes regular valve adjustments as well as the use of the YICS tool for vacuum balancing.

If you haven't checked/verified/adjusted the valves, getting a good vac sync will be a real challenge.

 

Yeah, I had caught a whif around here that it may be a topic of debate. But I work for Yamaha and our head tech (Yamaha Tech for 30+ years, Yamaha Gold Certified) says you need it to get a perfect sync... So that is what I have and will go by. The fact we have a Yamaha YICS tools helps the decision too

 

Theoretically you can do it without blocking the ports.

As a practical matter the bleed through the YICS passage makes the gauges less precise. I don't recall the XJ specs, but balanced within 2cm mercury is a common spec. Since most vacuum gauges are marked in increments of 1" (2.54cm) mercury you're already pushing the limits of the tool without introducing any extra loss of precision.

 

I'm currently looking at the same set of gauges vs building my own set up w/ clear airline tubing..... my big selling point for the gauges would be that I dont' have to figure out what 1" = on a 2 foot long piece of tubing..... maybe it means 1" on the tube I haven't found that out yet.

I like the gauge idea.

 

You'd be a lot better-off using a Fram Inline Filter with a Paper Filter Elememt than relying in the Filter you have.

Particulate small enough to pass through that Filter will clog Float Valve Beenie-Screens.
Leading to a Fuel Bowl that doesn't fill as fast as it should.

When selecting Parts to use on the Bike, ... don't let "Cosmetics" be the determining factor.

 

thanks rick, i'll keep that in mind for when a replacement is due. Already saw a bunch of metal flakes get caught into this one. After syncing them, there still is a bit of fluttering. and a bit of throttle lag, i think it might be the old diaphragms. Other than that the bike is in pretty good shape.

 

i use the clear tube method. $3 to build.

you don't need to measure 1" increments.

what you need to do is simply balance the fluid level between the two sides.

if the fluid is balanced and level. the carbs are pulling the same vacuum.
if one carb pulls more vacuum then the other. the fluid will pull higher on that one pulling more vacuum.

take a 10 ft. peace of clear hose. 1/4 inch. fold it in half. (not kinking it though). add 2 - 3 oz. of oil. connect each hose end to each carb. and syncronize. since there's 4 carbs. your going to need 2 X 10 ft. section of clear tubing. one tube for carb 1 and 2. the other for carb 3 and 4. then take one tube off. and connect the remaining tube to carb 2 and 3.

the type of gauges posted in the picture. are for automotive applications. 4, 6, or 8 cylinders.
not single carb applications. the needles bounce WAY too much.

there are tons of posts on building your own cheap sync tool. each has there own way.

 

Hey there, where are you located?

 

I have a 85' xj700, finally got the correct carbs. put on it and hooked up the same gauges you have. Needles fuctuate like crazy. What have I done wrong? The inline valves are for? Idles ok, but want to make it as good as I can. I also understand the ycis is another issue. Please help.

Eric
Sonoma, CA

 

Sonoma? Well, I guess we won't be able to work on it together ...

Silly question, but do you have a YICS tool in use?

The inline valves on the gauges are what you need to play with to get rid of the bouncing. Slowly tighten them down one at a time until the needles still respond to change but are holding fairly steady. Other options include putting things in line which will restrict the airflow in other ways, such as a *really* tiny hole ...