sinc carbs tool

[las1200]

Hi everyone,

Please need advice.
I'm trying to sinc carbs on my FJ. Searching for a cheap way I saw some ideas posted and made one oil and 5mm tubing tool to measure all 4 carbs at once.

Something very very similar to this...
Yamaha FJ1200 Carb Sync 101609

I used 2 stroke oil but result were very disapointing. The oil fast got filled with tiny air bubbles, shaking alot, and started getting sucked by carbs.
Waited for oil to settle down again and tried several times with same result.
Then I thought air might be getting in thru those 2 'T' connectors so made new tool for 2 carbs sinc only (no 'T's).
Same result, oil gets bubbly and kreeps up to the carbs.
Am I missing something?

Thanks

[FJmonkey]

I think transmission fluid is better, wait till others chime in that have more first hand knowledge. You also might need to put some restrictors in the line to dampen the full force of the vacuum.

[las1200]

restrictors?
please describe that.
thanks

[FJmonkey]

http://www.powerchutes.com/manometer.asp
http://www.fjowners.com/index.php?topic=302.msg2227#msg2227
Did some searches for ya....Have read through and see if this helps.

[mijohnso]

I made a tool like the one you pictured, and it works like a charm. To simplify things, I used one tube (so you can sync 2 carbs at once). This eliminated the need of all of the t's in the setup, and I think it makes for a more accurate reading (takes a bit longer because you have to sync carbs 1 and 2, then 3 and 4, then 3 and 2, and each time you have to switch the tubes over). Mine gets a few air bubbles in it when i do it, but not too much (I am just using motor oil).

The "restrictor" is just a damper in the system to reduce the "hops" you probably see when syncing. Basically you need something with that goes in the tube that has a small hole in it, and you will need one for each tube (4 in your case, 2 in mine). Some people us old jets they have lying around. I used a break off adapter which allows you to fit different size tubing together. Essentially, I wandered around the hardware store until i found something that would fit in the tube and had a hole in it. I would imagine the lack of restrictors is your problem.

That being said, If you can get it to work, it works as good or better than the $100 systems others talk about on the forum (morgan carbtune is the most popular), it is just a little less portable and takes a little more fiddle time. I tuned my carbs with this method, then tried to retune with a morgan carbtune. I found out that my original tune was spot on!

Good luck!

[las1200]

I know understand clearly a damper/restrictor. Searching for something that works.
Found 4 seringe's needles and removed metal needle leaving plastic attachment as a good restrictor, I think. Fits perfectly tight inside tubing.

In prevoius attempt I've changed all 3 carbs tunning bolts off their original position. So I wonder if should reset all 3 and how?
Thanks,

[andyb]

ATF or gearlube.

Really a hassle and slow if you make one that only does two carbs at a time.  Make one that does all 4 and it's a bunch easier to use. 

[Marsh White]

Really a hassle and slow if you make one that only does two carbs at a time.  Make one that does all 4 and it's a bunch easier to use. 

My opinion is EXACTLY the opposite of that.  I find it MUCH more of a hassle with one that does 4 at once...you'll find that you have to be REALLY quick moving that screwdriver around to different adjustment screws to keep it from sucking the oil up to the top of one tube / out of the other tube, etc.  Really a hassle. 

[Dan Filetti]

Or you could spend the $100 and buy the Morgan Carbtune and do all 4 at once.  You'll have the tool for life, and, last time I checked, stainless steel bars don't tend to get accidentally sucked into the intake. 

http://www.carbtune.com/

Just sayin.

Dan

[Brook]

........ I use the two large jars with trans. fuild and clear hose system !!  two carbs. at a time.

[Travis398]

Or you could spend the $100

Just sayin.

Dan

That's what I was thinking, you could spend $100 in time trying to make it work.

and it sure is nice seeing all 4 at the same time (just for peace of mind)

[mijohnso]

Like I said, I did it with my method ($10 30 minutes getting supplies, 10 minutes to build, 30 minutes to sync) and it worked just as well as with a Morgan Carbtune ($100, 1 week shipping, 10 minutes to figure out where all the parts go, 20 minutes to sync). The only advantage I see of the carbtune is portability. I had no problems with oil getting sucked up in the engine (my tubes were long enough to easily prevent this, and I did the 2 carbs at a time method).

Save the $100 and use someone's carbtune at a rally to make sure you did it right.

[andyb]

The morgan carbtune is a nice unit, but it's vastly overpriced.  But for the money, you're done buying synch tools forever (unless you're a CBX owner or something!).

My opinion is EXACTLY the opposite of that.  I find it MUCH more of a hassle with one that does 4 at once...you'll find that you have to be REALLY quick moving that screwdriver around to different adjustment screws to keep it from sucking the oil up to the top of one tube / out of the other tube, etc.  Really a hassle. 

No way!  Make it taller, use heavier fluid, use more restriction, use a clamp/vicegrips on two of them, then.  I don't care for having to stop, shut the bike off, disconnect everything, swap fittings around on a hot motor, then try to restart and get it back to exactly the same RPM, and trying to do this on 3 pairs, double checking so 6 total, before the bike overheats?  You can get really good results, as the homemade version seemed quite a lot more accurate than the Morgan, but that made mine pretty huge... I just hung about 20' of tubing from the garage ceiling, so lots of time and very easy to see where things were.

[mikeholzer]

Funny, with my Carbtune I have the whole process finished in 20 minutes. That includes the waiting for my garage door to open, setting up the fans (I use 2 box fans), removing the seat, unbolting the tank, rotating it 180°, strapping it down... you get the idea. And, it fits neatly in my tool box. And it doesn't leak. That tool was some of the best $100 I've ever spent, but I've also never regretted any tool purchase.

Just my opinion on the subject. Individual results may vary.

[las1200]

ok. heaving better results with better restrictors and longer tubing. Oil doesnt shake but stil a bit sensitive.
Still hard to sinc cause oil is still too fast climbing on one carb. No time to adjust...
Is it crucial to have absolutly identical restrictors in all 4 tubes? I'm not confident on my restrictors...
Either my bike is pretty off sinc or restrictors give unbalanced readings due to restricotrs.
Should I use some sort of vent (by means of a tee on each tube) to ease even more reading?
For starters prior to sinc should I set 3 screws in special setting or go wright away balance 3-4, 1,2 then screw 2?
thanks

for the carbtune I'm tented to buy but still trying the cheap way.