XJ550 Starting Problem and Spark Plug Advice

[e_sloan]

Last night on my way home from the gym everything was fine.

This morning I went to start her up, she has been wanting alot of warmup time as of late (15 mins). She ran with 3/4 choke for about 10 minutes then the RPMs started to drop. I tried opening the choke fully but it was too late, the engine stuttered and died.

I tried to start her back up it would turn over and sometime catch and idle at about 500 if I kept it full throttle but would quickly die with a odd sound coming out of the exhaust 20 seconds after dying. Kinda like backfire but a soft one.

I am hoping I just flooded the engine, unfortunately I can't check because I can't find a damn ratchet that will fit my damn spark plug, ANY ADVICE. I have tried 8 different sockets and none fit. The folks at my local auto store where no help as they carry plugs for bikes (not mine NGK D83A) but have no idea which sockets fit.

I am going to try to start her up again when I get home from work. I really hope its flodded as I was trying to put off all the major work, like carb rebuild, until winter when I have all the time in the world to do it.

[randy]

Sounds like you flooded it and fouled the plugs. 10 minutes is a LOOONG time to leave the choke on. I usually choke it enough to start, then back it off as soon as it will idle on it's own.

New plugs are in your future, unless you have a plug cleaner.

HTH

Randy

[e_sloan]

So what size of socket do I need to get the plugs out? My yamaha toolkit is obviously not the original because the damn spark wrench is too small.

The thing I don't quite understand is that with the choke fully on this morning it was idling at a little over 1000RPM, normally its wailing away at 3-4000RPM with full choke.

[chevy45412001]

have to ask

Sorrry ,but i have to ask this question. Does it have fuel? In the tank? Are you sure,did you physicaly check?Try a 13/16 wrench.Reason i ask is that sounds like a bike running out of gas.Don't ask me how i know that.

[TheDjost]

Like Chevy said, I think it sounds like the engine is starving for gas.

Do you have vacuum petcocks? Try running it on prime for a while. You may have a vacuum leak and the petcocks may not be opening fully. Also, check the tank vent in the fuel cap.

BTW: once the engine is warm enough that you can feel the heat on the fins with your hands, you can take the choke off. More choke will just flood the engine and foul the plugs. If the engine is run rich too long, the excess gas will deposit carbon in the combustion chamber and on the plugs, wich will make the engine hard to start (if at all).

-Justin

[e_sloan]

I took out the spark plugs, cleaned and regapped them. Besides a crapload of carbon they all seemed in good shape. I started her up and she is running fine, had to adjust the idle a bit after she fully warmed up.


I am new to bikes and new to the problematic starting of the old yamahas. I have found that after my initial start in the morning any start I have no problems if I turn the choke all the way off and just blip the throttle while starting. She starts everytime.

But, morning starting is when she gives me all the trouble.

BTW The tank is full of gas I have spent many times scratching my head on the side of the highway wondering why my bike died. Now the first thing I check is the gas.

TheJost: I don't have a vent in the fuel cap. At least not to my knowledge.

I have checked all the carb and petcock hoses and all are fine, i recently gave my carb boots a coating of sealant which helped the starts alot.

I will try the fin touching tomorow when I start her. My starting procedure in the morning is basically full choke, clutch in, neutral, tap the starter button and she starts to wail at 3-4000RPM. I Close the choke until she is sitting at about 2000RPM. This is when the waiting begins, I Usually have to let it sit there for a good 5-10 minutes before I can fully close the choke without stalling the bike.

The upper engine tapping is pretty loud in the morning as well, I will get my valves adjusted once I can find a mechanic who is willing to work on a bike as old as mine.

[ASchulhoff]

i have a 1982 maxim xj550

I go threw the same thing each time i first start my bike for the day... then some times if it sits for a while i have to do it again but not as long.

the carb boots on my bike are craked and leaking air as well, so i to sealed them up with a silicon sealer tonight, maybe that will help the ruff starting.

i've actualy draind the battery a few morrnings trying to get the first start. i was thinking i might need to soak and rebuild the carb... not really sure

[TopCatGr58]

Getting all choked up!

Hey there ASchulhoff,

IF in fact your boots were leaking, then that would definitely affect your ability to get it started. With leaking boots, it can't develop enough vacuum to draw the fuel thru the choke circuit, and IF you turn the throttle open, you are actually reducing the effecitve vacuum, cause you're opening up the butterflies drawing air straight thru the center of the carbs throats, and NOT thru the choke circuit! The silicone sealer will work well, and should improve the starting IF they were leaking!

There is also a small jet in the float bowl of the carbs that feeds the choke circuit, and it can get clogged, preventing the fuel flow and that can also contribute to the starting problem. There are several threads in the Tech Disc. area with accompanying photos to help you see what we're talking about!
T.C.