have been trying to start for over a week now

i keep re-reading the orignal post and i noticed you said you didn't start it the first day due to rain. is this bike kept outside, or in a garage?

 

today i changed the oil, it was very black. i also puored about a tablespoon in each cylinder, put a rag in the holes and turned the engine a few times. my dumbarse grabbed the wrong gauge to go with the hose on the compression tester at work, so i had no way to test compression at that time. i put all the plugs and wires back and while the tank was off, i rigged up a hose that connected the nipples on intake manifold boot 1, 3, and 4, seeing as how #2 was connected to the petcock. this time i sprayed starting fluid in the hose that connected the three boots and attempted to fire her up and it actually tried starting! i tried again and gave the throttle a little twist and it started up, but it didnt rev high with the choke fully closed, i had to twist the throttle quite a bit before it would idle high. i let it sit for a few minutes running and then hopped on and went. same issue with coming to a stop, i have to choke it. i fooled with the idle screw and it just wont hold idle at a decent rpm. i'm going to come to the conclusion and agree with skeeter (and based on what most everyone has said on this post at least once) that i have a problem with fuel delivery from the carbs... a bad one

 

congrats! (i think?)

i take it once the bike is warmed up, it is easy to start (like before, if it stalls at a stop?)

 

yes, i have to have choke fully closed and it seems to start right up. i'll do some more homework on adjusting jets and what-not

 

Sounds like the low idle jets are clogged! take one carb at a time apart and use carb cleaner and forced air to clean all ports and jets! wear safty glasses when useing cleaner

 

I have 3 XJ 550s and the most likely cause is the enrichment circuit - I had a terrible time getting the enrichment jets out of at least 4 sets of carbs that were on my bikes - 90% of them weld themselves into the threads over time and if they are never removed from new forget it - you will strip the slot on top really easily. So the trick that worked for me was to wiggle a very thin (and I mean VERY THIN) wire from a wire brush in the hole in each jet in each float chamber until you clear the crud that is bound to be in there.... you will feel the wire gradually break through this tiny brass hole then you can squirt cleaner through and you should see it spray out the front of carb. After doing that you will be stunned at the difference - your bike will start with a flick of the starter and will purr like a kitten - i am sure

 

i pulled the carbs and checked the bowls, i held a pen light to the enrichment circuit well and light shined right thru :? i sprayed parts cleaner in it and blew compressed air thru it anyways. is there a method to cleaning the tube that drops down into the well?

 

You're going to need to pull the rack and do the carbs right, the shortcuts and "quick fixes" aren't going to work.

You now know you have a carb issue; you need to fix it right. The "choke" isn't a choke, it's an enrichment circuit; if you need to run with it on all the time then you're not getting enough fuel the correct way.

Something is clogged, plugged, or your float levels are way off, or a combination of all three.

You also need to check all your valve clearances immediately; I'm still concerned with the low compression numbers and tight valves will make an XJ very difficult to start even if the carbs are right.

 

Try using a heat gun to heat the body of the carb. This usually works but have had occasion to drill and use an EZ out on the remainder. Another important factor is to have a very sharp screwdriver. I like to use the one for carb syncing. It's strong as h*** with a big knurled handle on the end.

 

I think it may be a combination of carbs and valve clearances. Fitz definitely has a good suggestion with that!

 

yep, i'm going to check valve clearances this weekend probably... oh how i dread it

oh BTW, i overlooked the idle mixture screws in front of the carb hats, and i had to turn almost all of them 5-6 360* turns before they bottomed out...might have been affecting anything?

 

well, the clearance is tight, i cant get my smallest feeler(.008") in between the base of the cam lobe (not the apex) and the shim. what do i do from here? are shims something available at most yamaha dealers? do i just guess at what sizes i need for a starting point? and should i be able to get that bucket tool at the dealer?

and also, by the valve tolerances getting tighter, how does this affect the ease of cranking? is it basically like having a cam with very short duration? or vice-versa?

 

What about a plugged gas cap? I was skimming along some of the old posts and someone had a non start issue that was the result of a plugged gas cap.

It is a simple thing but could be the source of your problems.

Give it a try..

Rob

 

You should have started by doing a Compression Test before fooling around with the Valves.

If you have some latent issue that causes the Compression to be very bad, having adjusted the valves before finding out you have a scored Cylinder Wall or a Burned Valve will have been a generous waste of time.

You do not need to adjust any valve within specs.
Tight or loose valves will not alter Cam Duration.
For that, ... you alter the Cam.

Test Compression
Good: Continue.
Bad: Rectify.

Spark is good.
Compression is good.
Use Starting Fluid to see if the situation is Fuel or Ignition.
Runs a moment on Starter Fluid means FUEL Delivery issue.

Does not respond in any way to Cranking with Start Fluid means
you troubleshoot Ignition.

If after Testing Compression is Marginally low, ... Ck + Adj Valves.

Checking Valve Clearances on a "Don't Start Bike" is putting the Cart before the Horse.

Work on the Bike like you do it for a living.
The Don't Strart Bike will be parked in front of your toolbox.
The Work Order may only say: "Won't Start"
1. Fuel ... The first thing you check. It could be silly.
2. Sparks ... Next. Plugs, Check Battery and fuses.
3. Air ... Make sure the Air Cleaner + Box are clear.
4. Compression Test.
Shop Manager or Foreman will review the results and decide what to do after going over the results with you.

 

Rick is right about putting the cart before the horse.

In answer to your questions above, in order: You re-shim; yes Yamaha dealers carry them but will rape you, contact chacal; no, you don't guess, you remove the too-tight shim and read the thickness; then you choose a new shim based on what was in there, and its clearance compared to what it should be. There is a chart for that, it's in my valve adjustment article. http://xjbikes.com/Forums/viewtopic/t=14827.html And yes, the tool is probably available at your local stealership but you can get them pretty much anywhere else for le$$.

 

so the dealership said they dont have the tool in stock, unless they didnt know what i was talking about. i guess i should take a picture of it down there to them and see if they recognize it then. what are the clearance specs so i know which shims i need to remove and replace?

 

ok, here are the valve specs (i used the zip tie method). i did the SAE to metric conversion for you guys:

cyl 1 intake: .10/ 275 exh: .13 / 265
cyl 2 intake: .08/ 275 exh: .13 / 270
cyl 3 intake: .06 / 275 exh: .15 / 270
cyl 4 intake: .08 / 275 exh: .15 / 270

any thoughts?

 

well, after all the headache, i installed a new battery after replacing valve shims, and complete carb cleaning. i had to fool around with the idle mixture screws, but i finally got it to fire up. only thing is that i had to disconnect the headlight so it wouldnt come on while trying to crank. i could turn it over and as soon as it "popped off" one good time, the headlight would come on and it wouldnt pop anymore while trying to crank. i got a wild hair and unplugged the headlight and sure as hell, it fired up after a few cycles. take in mind the battery is brand new and has 12.82 volts cold. should i wire in a switch for the headlight to keep it from coming on? i have checked all wires and everything is tight and clean.