85' 1100 hanging idle

[iridewheelies]

I rebuilt the carbs, shimmed the needles, cleaned them a handfull of times. Replaced throttle cables, ensured they arent binding. Bike will start so so easy cold hot, first crank. 12k original miles. I had previously never synced or done really any carb work on big 4cyl 4 carb bikes. Bike sat for a long time. Put a ton of new parts on it. Bench synced the carbs...not very well im sure. Bike runs pretty well i feel the jetting is pretty spot on. No surging sputtering anything pulls well through full rpm range. Ive ridden it a decent amount and i am just not comfortable riding it with the hanging idle. Plugs were not rich. They were kinda lean. Pretty white. I have seen tons and tons of threads on this issue. Idle set at 750-800. Bike will start and idle under 1k rpm, blip the throttle, idle comes down slow, and will not return to ide. Will idle at 2-2200 rpm. Not good. I havent pulled the intake boots, they do not look very cracked but they are original. Im probably looking at a vaccum leak from the boots. Just searching for some advice. I am borrowing a manometer from a friend. Idle curcit is clean. Needles are stock and shimmed, diaphrams are probably original and in great shape. Bike has 4-1 v&h and muffler which probably needs re packed, uni pods. Long post. Figured i would provide the masterminds with all of the details. I forgot what the jetting is i have it written down somewhere but i dont believe the jetting is my issue. Anyways, its a great bike i love it but i feel like im thinking too hard. Has to be vaccum leak making the mixture lean no matter what the mixture screws are. Tried 3.5 out 3 out 2.5 out 2 out 1.5 out. No real change in how the bike reacted but i test rode it like 2-3 mins before turning it off. Just trying to fix the high/hanging idle. Thank you guys. Maybe this thread will provide all the possiblities of a high idle lean condition, i looked at 3 threads and received somewhat different solitions on each thread. Have a good day!

[oldktmdude]

   Check your intake boot "o rings". These are a common cause for high idle issues. I recommend replacing them regardless of their apparent condition. They are over 30 years old and will be over-due for replacement. Intake boots could also be cracked so give them a good looking over as well. Don't bother doing the carb sync until you have sorted your idle problem. Make sure your choke system is also returning fully to the off position. Jetting won't be affecting your high idle, but the mixture adjusting screws can but it sounds as though you have already been there. Check your vacuum hose to the CDI unit for leaks and also the CDI unit itself. Suck on the hose to the CDI to make sure there is no damage to the diaphragm. You can safely disconnect and plug this hose if you have a leakage there. 
   Regards, Pete.

[arendal]

Try with some start spray around intake boot, idle speed will be affected if there is a leak.


oldktmdude - if you suck on the hose for the cdi, should it feel like blocking or should there be constant flow?

[FJmonkey]

Try with some start spray around intake boot, idle speed will be affected if there is a leak.


oldktmdude - if you suck on the hose for the cdi, should it feel like blocking or should there be constant flow?

A constant flow would be a vacuum leak, yes?

[arendal]

FJmonkey - Exactly my though, is it possible to fix vacuum leak in cdi?

[oldktmdude]

Try with some start spray around intake boot, idle speed will be affected if there is a leak.

oldktmdude - if you suck on the hose for the cdi, should it feel like blocking or should there be constant flow?

Spraying start spray on intake boots is not always a good indicator. More often than not it does not work.
You should not be able to suck through the vacuum hose when attached to the CDI.
You do not need the vacuum advance to work in the CDI unit. Mine's been disconnected for over 2 years now. Just be sure the plug the vacuum port on the carbie boot it's attached to.

[arendal]

On my CDI vacuum line there is a oneway valve,(i think) arror pointing toward the CDI. Is this correct?

[Pat Conlon]

Bench synced the carbs...not very well im sure.....

Start here^^^

Then set your idle speed to 1k rpm. 750 is too low.

[iridewheelies]

Bench synced the carbs...not very well im sure.....

Start here^^^

Then set your idle speed to 1k rpm. 750 is too low.

I watched a couple vidoes on bench syncing but however i did not use a feeler gauge. I kinda eyeballed it to where the butterflys were generally open the same amount and they would all open in unison. Any idea what size feeler gauge would be a good start on a bench sync? First time for everything right. Will check vaccum line going to cdi. Pulled off one of the intake boots. They are actually in great shape. The allen head fasteners were definitley "factory tight" inspected the o ring it was flat, fuel had seeped through and was outside of the o ring. My dad has a shop and works on everything. Matched the o rings. I feel like once the bike is back together it will run better than ever. Thanks guys. Just need to do another bench sync. Keep in mind that it did run pretty well just had the hanging idle. Ill do some more reading and will use a feeler gauge this time. Also, which carb should i begin with? Is number one the carb on the left (clutch lever) side ofnthe bike? Also, the bike has a pretty scary speed wobble. Ordered front wheel bearings, but i feel that may not fully cure the issue. 60-80 percent sure the anti dive is still functioning. Thank yall

[iridewheelies]

Amd by speed wobble i mean it is solid with both hands on the bars. One hand off it begins to shake progressivley to cause a nasty terrifying tank slapper if u do not put more pressure back on the bars. 2 hands on 1 hand off the bars is fine. But releasing pressure will cause it to shake, almost as if the forks are out of allignment. Eventually i am going to do a full r1 front end swap so i would rather not throw money at an old set of forks

[FJ_Hooligan]

110% of the time, for me, a front end wobble is a worn front tire.

Does your tire have a center tread groove?

For synching, the #2 carb from the left (while sitting on the bike) is the reference carb.  Match #1 to #2, then match #3 with #4.  Use the center sync screw to match the 3/4 pair to the 1/2 pair.

[iridewheelies]

The front tire is probably a little old, still has pretty good tread. Thanks for the sync advice, but how large should the opening be on the butterflys? Or does it more so matter about how equal the opening is? Thanks

[Old Rider]

For the wobble; Over all the years i have been on my fjs i only had wobble 3 times all on my fj1100 2 times im convinced it was because of heavy loaded luggage bags 1 st time i was catching up with my friend on a long trip going way to fast into a righthand corner that surprised me being more and more curved i was going  into opposite lane and right at the shoulder of the road i got a highside almost throwing me off i got hanging on the side of bike lucky as i was the bike tracked back into the road and wobbled violently with me ending up lying flat on the bike with my legs straight bacwards the wobble stopped (probably because i was lying down) i stopped and had to smoke 2 cigarettes to ease down.
Second time also had heavy luggage bags going fast i hit a bump starting wobbling i lean forward over the tank and it stopped right away.
third time i had no luggagebags but a passenger i was riding kookalao speed on the freeway (young and dumb) suddenly it felt like the road was real slippery the bike started to wobble real bad my friends feet coming up under my armpits i was thinking that if i brake now we will go down hard so i did nothing only eased very slow on the throttle until the bike stppped.The reartire had puntured flat.many times im thinking what if it was the front tire...
Im no expert butThe list of why a bike wobbles can be very long but i think wrong suspension setup wrong tire pressure/worn tires steeringhead bearings is some of the most common.
Always remember if you get a wobble lay down forward and it will stop!
I think the fj is a very stable bike newer had wobble on my fj1200 (no luggage bags)
About the carb sync i think it not possible to get them synced outside the bike.Bench sync is only for get the engine running.

[iridewheelies]

Well i replaced the intake manifold o rings, lubed the throttle cables, and attempted to sync the carbs. I borrowed my buddys gauge set, and i set them all to zero. No matter what i did i couldnt get number 2 carb to the green area on the gauges. I just ended up fucking the butterflys up and had to take the carbs off and re bench sync it. Got that done got the bike running and idling at 1k. Go for aride around neighborhood. 5 mins later, bike is idling at 2k again. Not sure what to do. Really fed up with this bike it will not run right. Ive spent so much time on this turd

[fj1289]

So, 5 minutes later after it is more fully warmed up, the idle is high?

Turn the idle down now that it is fully warm, and use the fast idle while it warms up.  It is not a modern OEM fuel injected engine with a computer controlled idle speed valve — seems like normal behavior to me.