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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: big_b on July 26, 2010, 03:56:47 PM

Title: Hard to start when cold
Post by: big_b on July 26, 2010, 03:56:47 PM
My 85 FJ1100is now a real pain to start when cold ... I have the carbs adjusted adjusted about 3 screws out ...  AS Far as I can tell the petcock on the tank is working (I just replaced it)

After I get it started (usually running down the battery first) it will run and start up nicely until it cools all the way down again ...

No air leaks .. compression is good ...

What else can I check ? Is 3 screws out a good adjustments with Vance and Hines exhaust ?

Any ideas ?
Title: Re: Hard to start when cold
Post by: hpras on July 26, 2010, 06:02:29 PM
Enrichening circuit clogged up?
Title: Re: Hard to start when cold
Post by: big_b on July 26, 2010, 08:56:49 PM
Found the problem .. The choke cable slipped on the "hold-down" by the carbs .. so the choke was not opening all the way ...  It fired right up after I fixed that ...

Now It does stumble a little below 2000 RPM and cleans out nicely above that ... It does back fire a little up acceleration .. I have increased the mixture with no improvement.. I am beginning to suspect a clogged jet in one of the carbs ...

I am going to have the carbs cleaned by a mechanic this week .. How much is the cost to clean the carbs on these bikes usually run ?

Thanks !
Title: Re: Hard to start when cold
Post by: SlowOldGuy on July 26, 2010, 09:09:26 PM
Check with RPM Randy FIRST!!!!
I believe he offers an ultrasonic carb cleaning service.  Most dealers won't touch anything as old as an FJ.

DavidR.
Title: Re: Hard to start when cold
Post by: Flying Scotsman on August 07, 2010, 09:33:46 PM
How is the fj runing now ?.My 1100 has been a bitch to start when cold,if i did not ride it daily which I do when it is not raining.I am in need of a carb sinc.I was looking at the carbs and saw that the 4 screws on top were all out a different # of turns.They increased by 1/8th turn each carb.Turned them all out the same and turned them all out 1 more turn.It now starts quite easy and runs better at low rpm.What does turning the screws in do and what does turning them out do as far as leaning out or richening up the low speed mixture.I turned them out what did I change.
Title: Re: Hard to start when cold
Post by: jack02 on August 07, 2010, 11:47:05 PM
FS you made your idle mix richer;turning the screws in weakens it. I once had a problem like big b's,but in reverse. Loads of rough running,cutting out and the like were eventually traced to a choke cable which had one of the strands of individual wires come adrift and snag on the cables sheath. This meant that the choke was permanently on to some degree or another,the situation not being given away by the action of the choke knob which appeared to be working as normal.
Title: Re: Hard to start when cold
Post by: Flying Scotsman on August 08, 2010, 10:05:34 AM
Thats what I was thinking I am at 2.5 turns out on all 4 now.I think I am still quite rich so I will be adjusting them all in next time I take the tank off.Bike started easy again this morning.I will be buying a manometer or making a home made version so I can sinc the carbs.Before I turned the screws out evenly bike would be a bitch to start but would run ok when it did.I would drain the battery often trying to start her if she sat any amount of time.
I think if I lean out the idle mixture and sync the carbs she will run much better still lol.