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Will only run on choke

Started by drivingbored, March 19, 2022, 03:06:25 PM

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drivingbored

Hello all, I have a 1993 FJ1200 abs. This bike was running right for about 2 months then I put it into storage. I put a fuel stabilizer in it, but it still got gummed up and would only run on choke. So I went ahead and got pod filters since I have a 4-1 supertrap exhaust and got new jets Main=117.5 Pilot=40 and could not shim the needle jets because the previous owner stripped all the top screws :(. It will run on choke for about 2 minutes and then die and won't start for a while. When I rejeted the carbs I sprayed some carb cleaner through all the ports then put the new jets on. Also, I have the fuel/air screws out 3 turns right now. Any advice on where I should start?

FJmonkey

My experience on this is too much time between run cycles. Ethanol (our now crappy gas) evaporates fast, so time between run cycles needs to be shorter. I run my FJ to temp at least once every 4 weeks (rides are better). Longer times runs the risk of the idle jets clogging up. When this happens all I can do is drop in some Seafoam and go for a long ride. Wait too long and you will need to pull and clean the carbs.     
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

drivingbored

I did clean everything I could without fully taking apart the carbs. Just took the bowls off and sprayed carb cleaner through all the ports I could reach. I would rather not take them apart and soak them. Anything else I should check before going that far? Fuel pump clogged? Fuel lines? Try and run seafoam through it?

Pat Conlon

The idle circuit's internal passages that are in the carb(s) are plugged.
Disassemble and properly clean.
Half measures will avail you nothing but disappointment.
Spend $24 with RPM and install fresh o rings and throw away those soft JIS screws.
http://rpmracingca.com/proddetail.asp?prod=carbkit


.....or take the carbs off, drain them overnight, box them up and send them to RPM. They'll fix them.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

drivingbored

Approximately how much is it to get it done by RPM?

Pat Conlon

Click on the RPM banner at the top of this page and give them a call tomorrow morning.
Robert will answer all your questions and will personally do all the work on your carbs.

I have owned my FJ since 1984 and I have never had a problem with my carbs and bike storage until after 2010 when E10 ethanol was added to our Calif. pisswater gas. (2012 nationwide) Since then I have had to disassemble and clean my carbs 3 times, so I got pretty good at it with great help from David Raforth (Carb Files) Still on the first couple of times, I have had to take the carbs off and apart twice (first time: 3 times) because of my ill advised short cuts and me just being lazy. I know all about half measures.
For example: It's fucking maddening...do all this work then have your carbs piss gas on your driveway.
When I say...Replace those O rings...there's a reason I say that....so, off they come, new o rings installed, carbs back on....and still pissing gas....aaaaargh! Forgot to check the float heights.
You already know about the buggered JIS screws.
On gummed up carbs the best I could do is disassemble and soak in a tub of cleaner then blow them out with compressed air.  Yes, it worked, eventually...sometimes I would have to do it twice.
What RPM brings to the table is the magic of ultrasound cleaning. A bubble bath is much better than soaking and a blow job.

Finally, don't store your FJ with E10 fuel.
No amount of added fuel stabilizer will help (as you and I have painfully discovered)
Read this: https://samscycle.net/storage-warning-local-gas

Cheers

Pat
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Dads_FJ

Quote from: drivingbored on March 20, 2022, 02:26:24 PM
Approximately how much is it to get it done by RPM?

'bout $200 USD plus s/h.
http://www.fjowners.com/index.php?topic=20226.0

It's well worth it.  I sent a set in for refurbish a few years ago, answered some questions on climate, altitude, riding style and he jetted them.  You get them back turn key - just install, set idle and ride.
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'92 Yamaha TDM850
'80 BMW R100S/Sidecar
'81 Yamaha IT250(H)
'77 Yamaha IT175(D)
'39 BSA WM20

slowpoke2

Quote from: drivingbored on March 19, 2022, 03:06:25 PM
Hello all, I have a 1993 FJ1200 abs. This bike was running right for about 2 months then I put it into storage. I put a fuel stabilizer in it, but it still got gummed up and would only run on choke. So I went ahead and got pod filters since I have a 4-1 supertrap exhaust and got new jets Main=117.5 Pilot=40 and could not shim the needle jets because the previous owner stripped all the top screws :(. It will run on choke for about 2 minutes and then die and won't start for a while. When I rejeted the carbs I sprayed some carb cleaner through all the ports then put the new jets on. Also, I have the fuel/air screws out 3 turns right now. Any advice on where I should start?
Exactly the problem I had....almost 20 years ago.  Normally I always ran ethanol free gas, but that summer I was running the other.  Bike sat for 2 months on a battery tender, but gas in the carbs.  Super hot muggy summer.  It's like August I believe, first ride in forever, couple cranks with full choke, starts right up, but then won't run with choke off. Carbs getting gas, long story short, pulled the carbs, pulled the pilots, 3 are plugged with that nice amber grunge.  Soaking didn't do anything, so I've always used copper wire to gently ream out the orifice, it won't booger it up.  Put everything back together and it ran just fine.  No more ethanol in the bikes ever.  And that was the longest I ever had a bike sit during riding season.

great white

For a proper "cleaning", you either need to use a product like "carb dip" or an ultrasonic cleaner. Spraying "stuff" into holes and such generally doesn't get anything out that wasn't ready to come out anyways. Gas creates a varnish like substance that adheres to everything inside the carb and closes off jets, passages and anything else it's in contact with. Spray cleaners (for the most part) won't even touch these deposits. You're running on choke because the deposits tend to either block or narrow the jets and passages, which means it starts to run lean. throwing on the choke reduces the air into the carbs and brings it back closer to stoich. Take the choke off and it goes dead lean again.

I went the ultrasonic cleaner route a couple years ago and will never go back to any other way.

Pull the carbs down, chuck it all in the cleaner and walk away. come back an hour or so later and everything is spanking new clean. Another bonus to an ultrasonic cleaner over "carb dip" or other caustic cleaners is you can drop components in it with rubber parts and it won't harm them. caustic cleaners melts away more plastic and rubber bits....