XJ650 Maxim: Running rich? Petcock?

Hey ya'll -

Just installed my new fuse box (it works, and is charming!), and while doing so, I remove the air filter cover - I noticed that the air filter unit is pretty soaked in gas.

The bike runs great, and runs as well as it had when I first picked it up from it's maiden tune up performed by my mechanic. Theoretically, the valves should be within spec, and the carbs should be adjusted (I have no reason to believe them to be off based on it's ride) - but I had always had my suspicions that it was running a touch on the rich side.

My diagnosis of the situation makes me want to check out the petcock - perhaps it is letting too much gas through from old or worn rubber? I already have plans to de-rust the tank (very minimal rust in there, but I want perfect) and paint it black to match the paint I put on the side covers - perhaps I'll rebuild the petcock and either replace or rebuild the inline filter currently installed.

I plan to purchase or make a manometer to check the carb's state of tune asap and do a valve inspection in about 2k miles (keeping to schedule).

Does colortune replace the need for a manometer? or would that be an additional expense? I do want the best for my bike, and to have it run as well as possible, and it sounds like colortune helps a lot. Thoughts?

Is this sound logic or is there something else I should be considering?

After all is buttoned up - should I replace my air filter? it was replaced only ~3k or so ago - but does the gas soaking spoil it?

Thanks in advance!

 

Theoretically and should be generally won't cut it.

Your petcock is not in the business of regulating the amount of fuel flow; it can't provide "too much fuel." The petcock supplies fuel, period. The vacuum-op thing is a convenience; if your floats are working properly you could leave it on PRI and nothing bad would happen.

The float valves in the carbs control the flow of fuel into the float bowls.

If you have a fuel-soaked air filter, you've got a FLOAT issue of some sort (stuck or not correctly adjusted.) Worse, there's a really good chance that said "extra" fuel is also polluting your oil. Open your oil filler cap, stick your nose in and have a whiff. If it smells of gasoline and not just warm oil, you'll need to stop running the motor and change the oil.

Either you have a stuck/sticking float, or the mechanic didn't realize the need to precisely wet-set the float levels. If the latter, how sure are you he checked/adjusted the valve clearances?

A ColorTune doesn't replace the manometer; they serve two different purposes. You use a manometer to vacuum sync the carbs; you use the ColorTune to fine tune the mixtures of each carb (often throwing off the sync slightly requiring a revisit with the manometer.)

I would recommend that you replace the air filter, by all means. After you fix the carbs' float valve issue.

 

if you think your running rich, why not pull the plugs and see what they look like. Better yet post pictures of them so we can let you know what we think?

 

Ok - so it's the floats? Is that the only thing that would cause a wet air filter? If I'm gonna get into the rack of carbs, what else should I do while I'm there? I figure I should do any cleaning necessary if I've got the rack off the bike - but what are some common replacement parts I should just go ahead and replace while I'm there? What tools should I purchase to start this project? I've got nothing in my carb tuning tool kit (also excluding experience). Hopefully I can find or get the info I need to fire an order off to chacal later today and get this all sorted next week.

There is a bit of a gas smell to the motor - should I discontinue my use of the bike entirely till I get this all hunky dorey?

I had plans to do my spin on oil filter conversion, change oil, then change oil and filter again in 300 miles to sorta clean the motor internally - should I wait until after I get this fixed?

 

Also: does this relate to whether it's running rich? Or are these two things independent. I realize it seems like a silly question, but that'd clear things up for me.

 

If you have a float valve stuck open, or float height set too high, yes it will cause a very rich condition.

If a float valve sticks there is a very good chance that the crankcase has gas in with the oil, which thins out the oil. Thin oil + no protection for the engine, so do not run it like this. I would park it while you get the carbs sorted out and get the spin on kit and change oil, filter, and air filter all at the same time.

And if there is gas in the crankcase you will want to change the oil again after a couple hundred miles.

But the first thing you have to tackle is the float issue, otherwise you'll just be doing all the other work over once the carbs are done.

 

Nice - thanks for that. After getting BigFitz's reply, I decided to do some more research surrounding floats - and it looks like that's the right diagnosis -but I have no way to check for it at this point with what I have on hand. I definitely am exhibiting all the symptoms, though, and with gas in the crankcase, I am gonna be riding my bicycle or my girlfriends rebel 250 for a little while (Sh*t!)

I have placed an inquiry with chacal purchase:
-Carbtune pro
-Aux fuel tank
-Fuel level tube guage
-float height ruler
-lower end deluxe rebuild kit (needles, gaskets, clips)
-new uni filter
-filter cleaner and oil
-colortune -Why not?


Before he gets back to me - are there some other things ya'll might suggest to complete the task?

 

If this is the first time you personally will be inside the carbs, you may want to replace all screw with allen head screws, as well as float bowl drain screws.
The drain screws you'll want to get from chacal.

The rest of the screws, if you have a quality bolt shop around, just go there and tell them how many of which bolts you need. I replaced all the screws in my carbs for about $6, but I didn't use stainless steel. I probably will be replacing them again, with stainless, since I ride rain or shine.

You may also want to invest in some sandpaper and a Dremel.

Oh, and make sure you get the kits with float bowl gaskets in them.

Maybe new throttle shaft seals and fuel rail orings, but you won't be able to tell there condition unless you split the rack, and if you split the rack, plan on replacing them anyway.

And also possibly new pilot screw orings and washers.

 

That's a neat idea (stainless hardware). I will see how my hardware looks after disassembly and I'll take it from there. If it's mostly in good shape, I'll probably just reuse it.

Another question - assuming you've done this before - did you replace the needles? Did you use the full metal needles designed for E85 or other high ethanol content? Or did you use the OEM or aftermarket rubber tipped? What is your state's ethanol content? How has it held up?

I thought so long on it, it kept me from getting my order out till this morning. Ultimately I decided to go rubber, thinking that it would give me more wiggle room as far as adjustment is concerned (granted, I am indeed trying for perfection here - so If I can, I will try and get my fuel level spot on) to have a needle material that has SOME give.

I figure if they only last a few years in CA's E10 gasoline, then I will just have to find another reason to go into the carbs (like aftermarket exhaust, or interest in punishment, like pod filters.)

Also: I ordered a deluxe bottom end rebuild kit for the carbs - should I pull the rack and install all those parts FIRST? Or should I install all the new parts to one carb, check it for fuel level til it is correct, then install the other parts and set floats to the first one's measurement?

I have checked out the "Fuel levels" pdf - and based on that article, it seems like doing one first seems like the best course of action, But I want to know what others have done

 

If you follow the instructions (RickCoMatic, BigFitz, etc) to the letter you might get lucky and get it right the first time. I'm no novice to working on machines, but I've had mine off several times and will remove them for the last time--I hope--this weekend. Cleaning should not be a problem--adjusting them might be, at least that has been my issue. I did not have to break the rack since no o-rings were leaking. All my float needles, seats, etc were in good shape and did not require replacement. When I got it all back together it started and idled well, but ran very rich and I got 33 mpg instead of the 45+ I was expecting. It turned out being the float levels, even though I had wet set them with the clear tube method. I finally measured the float heights with a float meter and set them to the factory specs and when I checked them with the clear tube they were still within specs and mileage increased to 40 mpg and only one cylinder is still a little rich. I say all of this only to emphasis that viewing the clear tube can be tricky, and the carbs absolutely have to be level or you will get a bad reading. Also, if you get air in the tube it will give a bad reading. So if you set the float heights to factory specs and the wet check is way off, start looking for reason.

I made the manometer using two baby bottles according to the instructions someone posted. It works great, just be sure to use the glass bottles since the plastic ones will collapse from the vacuum.