Mother Bleepin Carbs... I am in over my head, HELP!

I have taken them apart twice now... first time without a manual, and the second with the manual but I cannot get them to feed fuel and air to the bike properly. I already replaced the plugs, oil, filters, and cleaned every imaginable piece of the bike that would impact performance. What am I doing and how do I do it better? Please forgive my exasperation as I just want this beautiful old bike to run again!

 

What kind of bike? Exactly what kind problem is it? No fuel to carbs, overflowing carbs, bad throdle response, Have you checked your air filters and intake box for any problems.

We can help you achieve your goal for a running XJ

 

Ha, sorry about not including the bike specs! I am running a 1982 Yamaha Seca XJ650 RJ. As for what exactly is happening all I can tell you is that I don't have a stock gas tank on the bike, rather a makeshift tank I built using the original petcock and a plastic canister. I have heard that the petcock can cause fuel delivery problems if the fuel regulator is stuck or damaged so I cleaned it and hopefully that is working correctly, but here is a picture of the device:


Anways... the bike turns over fine and it starts to fire, but you can hear that not all the cylinders are firing. I read that the float needle jet needs to be clear and free moving for the fuel levels to stay optimal, so I am in the process of re-cleaning the carbs to fix any issues there. What I would like to know is if anyone has any detailed directions on how to tune and sync carbs without any tools designed for it (not sure if you can do this, but I have heard of it being done)

You can check out my restoration thread at:
http://www.xjbikes.com/Forums/viewtopic/t=12352.html

Thanks in advance to anyone who can help!

 

will it start with starting fluid?

 

I haven't tried starting fluid... actually I haven't even tried starting it with the new plugs and oil. I will try all this tonight after work and report what happens. What I really need is some advice on is how to get the carburetor functional. I know that I unscrewed the sync springs on the carbs during my first cleaning and later read that they shouldn't be touched after factory tuning (so I am clearly an noob). I also missed cleaning a couple places in the carbs that were shown to me in the Haynes manual that I got, so I am going to finish cleaning them tonight. The poor old girl wants to run, but I am like a twelve year old trying to perform brain surgery when it comes to fixing motors. I guess I have to learn somehow

 

Mike, I strongly suggest reading RICKOMATICS Old School Carb cleaning thread in the FAQ SUGGESTIONS. Very helpful.

 

Let me add to read and perform the clunk test and bench sync both by Rick. Also look at the threads on cleaning the VERY tiny starter jets.

The carbs a bit of a pain but very doable.

 

Just curious, what is the clunk test? I have heard people refer to it... but I can't seem to find a tutorial or description as to what it is out on the site.

 

Here you go

http://www.xjbikes.com/Forums/viewtopic ... +test.html

Basics are you polish the piston slides then make sure the pistons slide from top of travel to bottom with a resounding clunk and absolutely no hesitation.

 

This is just fantastic, but I was reading the Haynes manual and found a picture of a plate covering the air jets in the top portion of the carb:

This plate was not inside any of my carbs when I took them apart so I was under the impression that it didn't exist until I saw this picture. would this have a great affect on the performance of the carbs? (I am going to assume the answer is yes)

 

dont worry, they arent in mine either. some people have them, some dont.

just like chest hair.

 

Whew thats a relief!

 

At some point, Yamaha just stopped installing them. I'm not sure of the dates but I've sets of carbs with and without. No difference that I can note between the two as far as performance.