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slipping clutch on 84 fj1100

Started by T Legg, July 30, 2018, 01:41:22 AM

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T Legg


i bought an 84 fj 1100 2 years ago.after getting it running again the first time i really got on it i thought the rear tire broke loose (spinning). After a while i realized the clutch must be slipping but i've never had a clutch slip like this.at about 7000 rpm it will slip and then reengage fully in a microsecond.if i really get on it it may slip two or three times between 7000 -9500 rpms.i first changed to yama lube then even though all the clutch fiber discs were in spec i replaced the whole pack.It still slipped. the metal discs were all flat and showed very little wear. i installed a second clutch spring (along with the original spring still slipped.Finnally i removed the wire retainer and the thin fiber disc and replaced it with a fat one  but it still slips. the only suggestion i didn't try was ruffing up the surface of the metal plates ,but already i have to some times rock the bike back and forth after pulling the clutch in to get the clutch to fully release so i can roll the bike.i haven't had the engine apart i assume it still an 1100 it does have modifications mikuni flatslide carbs 4 into one exhaust individual air cleaners and also lindemann engineering suspension modifications to the rear suspension and at the minimum the front shocks have the antidive  unit removed.it has incredible power between 6500 and 9500 rpm although i imagine all well running fj's do.I dont know what people with 1300+ cc bikes do to solve this problem.i would love any suggestions of what i can do.I ride often with my son who has kawasaki zzr1200 and i have to use my upper rpms to be competetive it sucks when the clutch slips even for the microsecond.   
T Legg

aviationfred

i replaced the whole pack.
the metal discs were all flat and showed very little wear.
i installed a second clutch spring (along with the original spring still slipped.
i removed the wire retainer and the thin fiber disc and replaced it with a fat one



With the changes listed above that you have done, there should be absolutely zero clutch slippage. Your problems are elsewhere. My guess would be.

Slave Cylinder, and/or
Clutch Master Cylinder

When you bleed the clutch, the engagement point should be in the middle of the lever travel. If air is minutely allowed into the system, over the span of a few days or a few weeks, the engagement point with the lever will slowly creep further and further out until the clutch is slipping so bad that you can not get the clutch to not slip under a load.

The solution is to rebuild the clutch slave cylinder and/or the clutch master cylinder. Worse case is replace the slave cylinder and the master cylinder.

My 2 cents.


Fred
I'm not the fastest FJ rider, I am 'half-fast', the fastest slow guy....

Current
2008 VFR800 RC46 Vtec
1996 VFR750 RC36/2
1990 FJ1300 (1297cc) Casper
1990 VFR750 RC36/1 Minnie
1989 FJ1200 Lazarus, the Streetfighter Project
1985 VF500F RC31 Interceptor

oldktmdude

   What gears is it slipping in? Usually FJ's will only slip in 4th and 5th gears, under medium to hard acceleration. If it is in the lower gears it could
be your gearbox has gear engagement problems. Second gear (pre '88 models) is a common offender in this regard. When it "jumps" out of gear
it feels very much like a slipping clutch. If you have doubled the diaphragm spring I doubt that your clutch is slipping (unless you have a major defect with it)
I run a doubled spring on a 1219cc Wiseco engine, 136 hp and 90 ftlbs at the rear wheel and have never had the clutch slip. I have a second gear issue when I get on the throttle hard but never a clutch slip.
   More info might help us help you.
   Regards, Pete.
1985 FJ1100 x2 (1 sold)
2009 TDM 900
1980 Kawasaki Z1R Mk11 (sold and still regretting it)
1979 Kawasaki Z650 (sold)
1985 Suzuki GSXR 400 x2 (next project)
2001 KTM 520 exc (sold)
2004 GasGas Ec300
1981 Honda CB 900 F (sold)
1989 Kawasaki GPX 600 Adventure

T Legg

it is usually in fourth or fifth it may in third i'll have to take a ride tomarrow and see about third.it hasnt in first or second it will spin the rear tire and launches strongly at high rpms from a dead start as long as you release the clutch correctly and has no slipping it slips if you roll on hard at about 45 mph when it hits about 7000 rpm
under hard acceleration. and it will catch immediately with a jerk of acceleration then accelerate normally.when you really hit it hard it may slip two or three times but always for a small fraction of a  second you can accelerate hard from 100 + and up and it nevers slips again . it doesnt feel like it is slipping out of gear. it has never popped out of gear completely although if i ever miss a shift it is from first to second.do these symptoms sound like a slipping gear .its pretty much been the same for the two years ive ridden it about 7000 to 8000 miles so it isnt getting progressively worse   thank you guys for your experience
       
T Legg

aviationfred

I'm not the fastest FJ rider, I am 'half-fast', the fastest slow guy....

Current
2008 VFR800 RC46 Vtec
1996 VFR750 RC36/2
1990 FJ1300 (1297cc) Casper
1990 VFR750 RC36/1 Minnie
1989 FJ1200 Lazarus, the Streetfighter Project
1985 VF500F RC31 Interceptor

T Legg

thanks i already rebuilt the master cylinder when it sprang a leak all over my fairing but i will try the slave cylinder rebuild hopefully it will help or at least eliminate that possibility.if the master cylinder already leaked the slave cylinder probably isnt any newer   
T Legg

Motofun

Way back when.....I upped the ante on my '85 FJ.  Stage III carbs, pod filters and new exhaust.  For my troubles I got the slipping clutch problem also at about 7000 rpm.  A doubled up diaphragm spring solved my issue but the clutch pull was manly...eventually put a FJR clutch on it and it is a little weird but tolerable.
'69 Honda Trail 90
'75 Honda CB400F
'85 Yamaha RZ350
'85 Yamaha FJ1100
'89 Yamaha FJ1200
'09 Yamaha 125 Zuma
'09 Kawasaki KZ110 (grand kids)
'13 Suzuki GSXR 750 (track)
'14 Yamaha FZ-09
'18 Suzuki GSXR 1000R (track)
'23 Yamaha Tenere 7
SOLD: CBX,RZ500,Ninja 650,CB400F,V45 Sabre,CB700SC,R1

ryanschoebel

Quote from: T Legg on July 30, 2018, 04:07:05 AM
thanks i already rebuilt the master cylinder when it sprang a leak all over my fairing but i will try the slave cylinder rebuild hopefully it will help or at least eliminate that possibility.if the master cylinder already leaked the slave cylinder probably isnt any newer   

After that slave rebuild, be very thorough in bleeding the system. Its very difficult to get the air out. A lot of people have had good luck with a speed bleeder valve. I had luck by bleeding it directly from the slave itself, compressing the cylinder by hand. Not easy, but effective.
1985 FJ1100-- Atlas (SOLD)
1984 FJ1100-- Storm

Pat Conlon

Did you soak your new fiber plates before install? Dry fiber plates will slip.
It takes time for the oil to impregnate the dry fiber plates, that's why we presoak them.

On my 1380cc  (~140hp /100 ft.lbs.) I converted over to the Barnett coil spring setup.


http://rpmracingca.com/proddetail.asp?prod=Clutch%3ABarnettPP&cat=39

Instead of the stock 75lb. gold springs that came with the Barnett kit,  I'm using the stiffer 82lb greenies.
http://rpmracingca.com/proddetail.asp?prod=Clutch%3ASpringHD&cat=39

Absolutely no slip in the kookaloo zone.
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

FJ_Hooligan

Hey Pat,

Are you using Barnett fibers or Yamaha fibers?  I've heard of people having problems with the Barnett fibers. 

Just curious.
DavidR.

Pat Conlon

Hey David, I'm using the oem Yamaha fibers. (7 wide, 1 narrow)

Several years ago I did try the Barnett fibers (popular with drag bikes) but I did not like their abrupt engagement.

Also, if going to the coil spring conversion and using the green springs , I suggest the smaller piston (15mm) FJR clutch m/c.
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

Pat Conlon

Hey T Legg, I just thought of something... Several years ago I had the same thing happening to my bike.
In the upper rpm zones I felt what I thought was a momentary clutch slip. A very brief slip just as you described as a "micro second". Turns out it wasn't a clutch slip at all.

After bench testing the coils, wires, plugs, plug caps, coil relay*** and the 2 ignition pick up coils, what I finally traced down was an intermittent 12v power interrupt to the ignition box. Maddening as hell.  :mad:

The circuit that supplies the 12v power to the ignition box runs from the fuse box thru the run/stop switch on the handlebar, then down to the ignition box. The run/stop switch was the culprit.
I finally figured this out by running a temporary jumper wire from the battery (+) directly to the 12v input wire on the ignition box...Went for a ride....Low and behold the problem went away. Smooth power all the way up to 10k.

Then I ran the jumper wire from the fuse box to the ignition box....same result, all is good.
So the interruption problem resides between the fuse box and the ignition box. I unplugged and cleaned all the harness connectors, then finally the run/stop switch.

All is good since then.

Something to think about. I hate intermittent electrical problems.

Cheers. Pat

p.s. go ahead and rebuild your slave to rule that out.
*** If you don't have a coil relay on your bike, with your mods, a coil relay is suggested.
http://www.fjowners.com/index.php?topic=1755.0
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

T Legg

thats interesting my kill switch hasnt worked since i got the bike it runs in either position.ill check it out. thanks
T Legg

T Legg

i am using new yamaha fiber plates the extra thick plate i used was from my old clutch set but they were all in spec when i replaced them
T Legg

Sparky84

Quote from: Pat Conlon on July 30, 2018, 06:37:45 PM
I hate intermittent electrical problems.

Same here Pat, especially in 240v (110 for you) Earth Leakage faults tripping the circuit breaker. 30mA fault is hard to find.

I myself like to see some black charring, that way I know where the fault is  :bomb:
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2