idle/running difficulty

First off, let me say that I've been lurking on these boards for a good long while and have read and re-read many posts dealing with my problem but as of yet have been unable to solve it. If I repeat a previously asked question: sorry ahead of time. I swear I used search.

Some background: I have a 85 XJ700 Maxim that I bought 2.5 months ago. She started right up in the cold, idled perfectly with and without the choke and ran great too. After I brought it home I tore apart, cleaned (per Rick's instructions) and rebuilt the carbs. They pass the clunk test perfectly and have been through a bench sync. Float bowls have been set at right about 17.5mm. I also tore apart, cleaned and rebuilt the petcock and put an inline filter in place. After all this has been done, the bike sat 2 months over winter. I pulled it out last week to try and start it, after I got some fuel into the carbs, she fired up great and ran at about 3000 - 4000 RPM with the choke full on (35 degrees out). I got it warmed up and tried to take it down the driveway but I had to keep feeding it some throttle to keep it running or it would die. I rode for all of 1 minute before I got too cold and put it into storage.

Fast forward one and a half weeks to today. I put the (freshly charged) battery back in the bike, hook everything up and try to start it. Now, she barely runs at 2000 rpm with choke full on. Whenever I try and let the choke off it would die. Whenever I tried to give it some throttle (with the choke on or off) it would die. After awhile even with the choke on the bike would die. I would be able to start it, 5 seconds would pass and then DEAD. This boggles my mind. Oh, if it matters it was about 60 degrees out today.

Now, this is what I have done:
checked and rechecked the carbs, everything is shiny and clean. The rubber boots all look fine, no cracks or tears. The pilot screws are set at about 2.5 turns out (the carbs were previously put in synch and adjusted by a dealership the PO took her to) and the valve clearance has also been checked at a dealership by the PO. I put in a fresh new air filter, new plugs, new oil and filter and did some minor cleaning here and there.

I know that my idle adjustment screw needs to be fiddled with (I accidentally unscrewed it all the way out when cleaning the carbs), but what else can be causing these problems that I should check? Oh, and how many turns out is the default setting for the idle adjustment screw?

Once again, excuse my new-ness.

 

Kinda sounds like it's starving for fuel. check the petcock flow, and check the fuel line for kinks. sometimes fuel lines get pinched when you re-install the tank... especially after you add an inline filter. don't ask how I know...

 

I have one of those clear lines on it now for the sole purpose of seeing how much fuel is flowing through it. On "on" the fuel trickles out, sometimes in bursts, as the engine needs it.

I tried setting it to prime and then the whole line becomes filled with fuel, but the engine seems to be sucking it down rather fast, too.

The inline filter made the line bend at a funny angle (which I have already straightened) but it was never kinked. Any other ideas?

 

Did you put Stabil in the fuel before it sat for 2 months?

Its possible your carbs are gunked up.

 

I fit trickles in the ON position check your vacuum line is good and test your petcock. May be having issues there.

On prime you say it seems to b esucking down fuel but does the problem go away?

 

Checked the fuel line, no kinks.
HalfCentury: When it was stored, I took the gas tank and the carbs off the bike (to clean them and what not), so there was no Stabil in there.

bill: The problem is persistent even when the petcock is set to prime. I fixed the slow leak in the petcock last night (needed to add some extra springiness in to the spring pushing down on the plunger/diaphragm) but the problem still persists.

I am going to take the carbs off again, clean everything all over again and reset the float heights just in case. Besides the clunk test and making sure all air/fuel passages are completely clean and shiny (including the emulsion tube) is there anything else in particular I should check when the carbs are off?

 

If it runs off enrichment but not the other circuits (e.g. no idle or throttle response), the level in the bowls has to be way too low, or there's a massive vacuum leak somewhere and the engine is sucking air and virtually no fuel.

check the float levels with a clear tube once the carbs are primed. they should be within 2mm or so of the bowl/carb mating surface. monitor them once you start the bike and see if they maintain a certain level or just drop to nothing.

also... how are the spark plugs? clean? got good spark?

 

stereomind: I was reading into it more and may have made a mistake setting the float heights. I'm going to pull apart the carbs this week and take a look one more time to make sure they were set correctly.

 

So, I fiddled with the carbs again and found several of the pilot jets to be clogged. I think the sea foam I put in there loosened up some sediment and caused it clog the jets.

Had some help tuning it after that and realized that float 1 and 4 were set too high/rich.

All in all, set the floats properly, cleaned the carbs and changed the diaphragm on the petcock (it was leaking) and now this thing hauls!!! Went on my first ride today, it's 28 out and snowing but it was a blast!

 

Cool glad you worked through the issues!