Search High and Low, Can't find answer

First off, this forum rocks. Has been a total help.

As some of you know, I have been tring to get my TCI fixed. Finaly got that. The beast is running. I now have a new problem. When bike was down, I tore in to the carbs and cleaned everything. All ports are free and clear. I didn't remove the jets themselves, just cleaned them and sprayed air through all openings. When I try to start it, It will only fire up if I put my arm across the whole rack. It is like the added sucction pulls the gas in to fire. It has great intake pressure. Would any of you guys know what would cause this problem? I can get it to start without my arm across the carb rack if I use starting fluid.

 

Re: Search High and Low, Can'y find answer

At the front of each carburetor there is a brass tube that sticks down into a little well at the front of the float bowl. That is the pick up for the enrichment circuit (it's turned on by the "choke" lever).

At the bottom of the little well the tube goes into there is a small orifice into the float bowl. That little orifice is the first thing that plugs up. You need to clean that orifice with a fine wire and some carb cleaner so cleaner will flow through it.

Be careful, as the natural way to hold the bowl causes carb cleaner to squirt into your left eye (right eye if left-handed) when the orifice is open. Point it away from you.

It's also possible you don't have the "choke" cable connected or adjusted properly.

 

Re: Search High and Low, Can'y find answer

The choke cable is on. That was the first thing I checked. When the lever is at full chock, the four little brass plugers are fully in the up position. When I had the carb bowls off, I ran a paper clip through the tiny hole in the bottom of the bowl. I will pull the bowls again, and spray cleaner through it. See what that does. Thanks for the heads up on the eye danger. I hope these fixes the problem. I dont want to have to replace my tool kit with a can of easy start.

 

Re: Search High and Low, Can'y find answer

Sounds very much like a vacuum leak. Check to make sure the carbs are seated properly and the clamps are in place.

 

Re: Search High and Low, Can'y find answer

A paper clip is about 5x as large as the size of the orifice in the starter jet! I hope you DIDN'T pass it through the jet, as you're going to be needing replacement fuel bowls pretty soon (or you can start practicing now on manipulating the choke lever a tenth of a millimeter at a time!)

 

Re: Search High and Low, Can'y find answer

I might have passed it through a different orffices then. It went through very easyly. I will pull the carbs back down and see what I got. It is raining today, so I will hopefully get it done tomorrow. Tried to bring them in the house, and the misses had a duck. LOL. All clamps are in place. Had it running, and sprayed easy start on and around the carb boots. The idel didnt change. If I remember correctly, that is an easy way to check for a vaccum leak, Right?

 

Re: Search High and Low, Can'y find answer

OK, tried a little experiment before tearing back in to the carbs. I ditched the pod filters, put the factory air box back on, with a new filter. After a few cranks, it started right up and is idealing perfect. Not racing at a stop, great throttle responce, awsome power. If anyone is reading this, and thinking about pod filters, I wouldnt do it. It is more trouble then it is worth. If you dont have a shed, carport, or garage, And you leave it out with out a cover....It will get water in the carbs. If you are using factory jets, It is hard to get to ideal right(I guess it is getting to much air). My next step is to engineer a form of "ram air" for the box. I have been measuring and think I can use a thin gauged sheet metal, and form a tube that will fit into the intake of the box, run it down the back of the box, and under. It would come out under the bike(since I have good ground clearance, I am going to run it under the frame, and up just a little in front of the motor.) I plan on getting a mesh, like window screen, and make a frame on the front opening of the ram air tube to help keep bugs and junk out of the tube. If I get it to work right,and fit, I will post the steps on making a ram air kit.

I have searched, and havent found anything like this on the xj's, nor any bike for that fact.

 

Just be aware, that ANY modification that moves/allows/makes available more AIR into the carbs os going to have the same effects as using pods. All engines burn air at about a 14-to-1 ratio to fuel, so in almost all engines (of any size, and type) the biggest restriction to increased power is the amount of airflow available to the engine and NOT the amount of fuel flow.

That's why you can put an aftermarket, free-flow exhaust (4 into 1, etc.) on these bikes and it doesn't normally require you to re-jet the carbs, or if so, just barely. It's the airflow restriction that the stock airbox/filter system provides that prevents the system from going lean, and requiring all the re-jetting and tuning. A free-flowing exhaust without a free-flowing intake tract makes little or no difference. Open up the intake system.....a K&N filter, drilling holes in the stock airbox, pods, etc.....and then even WITH the stock exhaust, you're immediately into the whole tuning situation.

The stock airbox/filter can be thought of as a governor, or a "choke" on the amount of airflow that the engine is allowed to see. Internal combustion engines are, after all, merely air pumps (self-powered air pumps, very useful air pumps, air pumps that you can attach an internal "PTO" transmission system to in order to extract useful work out of them, but air pumps nonetheless).

Just something to keep in mind!