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85 fj1100 idles high when hot

Started by Ericcurreri, September 01, 2016, 05:59:51 AM

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Ericcurreri

Finally got my 85 fj1100 running after it sat for around 18 years. 1 cylinder was frozen broke it free rebuilt carbs and changed oil and gas.starts idles fine but will start to gst hot and jump to 4000 rpm. My friend said its just over heating and that will cause it . Also appears thw oil cooler is not working. Is that the reason or is something else happening

4everFJ

If it overheats and idles high.

1: Clean carbs
2. Make sure they are CLEAN.
3: Check valve clearances.
4: Check for vacuum leaks.
5: Adjust carb mixture screws
6: Sync carbs.
7: Repeat 3 and 4 until it is perfect.

If the above is perfect, the FJ will not easily overheat, idle will stay low, throttle response will be good and it will start easy both cold and warm.

How do you determine the oilcooler isn't working? Is it cold?
1985 - Yamaha FJ1100 36Y
1978 - Yamaha SR500
1983 - Kawasaki GPZ550 (sold)
1977 - Kawasaki Z400 (sold)

Ericcurreri

Carbs were cleaned and went through ultra sonic bath. Synced carbs last night werent too far off vacume hoses seem to be ok and the caps are ok.didnt check valve clearences. Like the intake and exhuast valves?

jscgdunn

Regarding running hot, how long are you leaving it running while tinkering with it.  Keep in mind this is and air cooled mota so it cannot stand at idle for extended periods o time without a large fan to move air past it.
92 FJ1200 2008 ZX14 Forks, wheels, 2008 cbr 600 RR swingarm
92 FJ1200 2009 R1 Swinger, Forks, Wheels, 2013 CBR 1000 Shock
90 FJ 1200 (Son # 2), Stock
89 FJ 1200 Built from parts: (Brother bought it) mostly 92 parts inc. motor
84 FJ 1100 (Son #1), 89 forks wheels, blue spots

balky1

Quote from: Ericcurreri on September 01, 2016, 07:40:57 AM
Carbs were cleaned and went through ultra sonic bath. Synced carbs last night werent too far off vacume hoses seem to be ok and the caps are ok.didnt check valve clearences. Like the intake and exhuast valves?

My problems with carbs taught me that the above highlighted words are not good enough. Check the intake manifolds. When you removed the carbs from that old rubber, it is possible that some got broken or the rubber got so stiff that it won't seal anymore when you install the carbs (had that problem). Take a start spray and check for vacuum leaks. Replace all lines, vacuum and fuel ones (they are old enough  :smile: ).


FJ 1100, 1985

Ericcurreri

Did have a fan in front of it didnt seem to do much but also my oil cooler is not even hot. Gonna check the intake boot and rings see if thats leaking or not. Havent driven the bike yet about to put the clutch master back on tbe bike tn

4everFJ

Not good if your oilcooler is cold..

Could indicate an oil circulation problem, which would also cause it to get very hot  :sorry:
1985 - Yamaha FJ1100 36Y
1978 - Yamaha SR500
1983 - Kawasaki GPZ550 (sold)
1977 - Kawasaki Z400 (sold)

Mr. Grumpy

Had the same trouble with my 90 FJ1200 I bought over craigslist.
Turned out to be exhaust valve clearance was too tight.
Started by cleaning and carb synch and found out the clearance was the big issue.


Quote from: Ericcurreri on September 01, 2016, 05:59:51 AM
Finally got my 85 fj1100 running after it sat for around 18 years. 1 cylinder was frozen broke it free rebuilt carbs and changed oil and gas.starts idles fine but will start to gst hot and jump to 4000 rpm. My friend said its just over heating and that will cause it . Also appears thw oil cooler is not working. Is that the reason or is something else happening

Pat Conlon

Quote from: Ericcurreri on September 01, 2016, 05:59:51 AM
Finally got my 85 fj1100 running after it sat for around 18 years.

Yep, valve adjust, clean carbs and sync to start....after 18 years I would replace all those carb rubber O rings. They dry out and harden.
I would pay particular attention to the carb manifold O rings and the O rings on your air idle adjuster screws.
You may have one (or more) leaking causing a lean condition.

Get this kit:


http://rpmracingca.com/proddetail.asp?prod=carbkit

It has everything you need and at $22 to do all 4 carbs is an absolute screaming deal. Just replacing those soft JIS Phillips head screws with Stainless Steel Allen head screws is worth the price of admission. All the O rings included is just frosting on the cake.

Re: Oil cooler, you may have some hardened crud in those lines. I would drop the oil pan, oil screen and disconnect the oil cooler lines for a through cleaning. After 18 years who knows what type of crud you have down there?

Hope this helps.
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

Ericcurreri

Also think my clutch might be too stiff i put a rebuilt master on it heard it moving a little then blew the master seal. I have one more should i try it?

giantkiller

Quote from: Pat Conlon on September 01, 2016, 09:22:00 PM
Quote from: Ericcurreri on September 01, 2016, 05:59:51 AM
Finally got my 85 fj1100 running after it sat for around 18 years.

Yep, valve adjust, clean carbs and sync to start....after 18 years I would replace all those carb rubber O rings. They dry out and harden.
I would pay particular attention to the carb manifold O rings and the O rings on your air idle adjuster screws.
You may have one (or more) leaking causing a lean condition.

Get this kit:


http://rpmracingca.com/proddetail.asp?prod=carbkit

It has everything you need and at $22 to do all 4 carbs is an absolute screaming deal. Just replacing those soft JIS Phillips head screws with Stainless Steel Allen head screws is worth the price of admission. All the O rings included is just frosting on the cake.

Re: Oil cooler, you may have some hardened crud in those lines. I would drop the oil pan, oil screen and disconnect the oil cooler lines for a through cleaning. After 18 years who knows what type of crud you have down there?

Hope this helps.
+1 on the intake o rings. Had high idle problem.  Tried spraying. No effect. Had orings from Randy's kit replaced them. Problem went away.
86 fj1350r
86 fj1380t turbo drag toy (soon)
87 fj1200 865 miles crashed for parts
89 fj1200 touring 2up
87 fzr1000 crashed
87 fzr750r Human Race teams world endurance champion
93 fzr600 Vance n hines ltd for sale
Custom chopper I built
Mini chopper I built for my daughter just like the big 1

Ericcurreri

Compression test

1: 71psi. 2: 76psi. 3: 75psi. 4: 80psi

Gonna check valve clearance next

Pat Conlon

Engine warm? (@ operating temp) Throttle wide open?
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

Ericcurreri

No i should redo that then im checking valve clearence right now il redo after