Cheese and Rice! I am going crazy with this issue!

[dracko]

I am curious about this IC ignitor though... I applied a vac to it to measure and it doesn't hold vacuum at all.. Is this normal..?

[Pat Conlon]

Common for the old diaphragms to leak in the ignitors. The vacuum advance function of the ignitor happens at closed throttle, part of the emissions system, and the loss of this advance will have no impact on the performance of the bike.

Cap off the vacuum port on the intake manifold which serves the ignitor, it can only help with your issues.

I'm not saying that it will solve them, I think you have more going on...
With the fuel tank off, have you looked at your throttle cables and linkages? Are the cables routed correctly?
Turn your handle bars back and forth, look for hang ups on your linkage.

It might be something mechanical causing your woes.

[dracko]

I always try and inspect the simple things first and  a cable issue is was first on that list. I made sure it was moving back and forth smoothly with the tank off as you suggested..

Thanks for the info on the ignitor unit I definitely will cap that line off to see if anything changes. . I was hoping that it was the problem as I have eliminated all possibilities that I could think of.. 

Next on my list is gonna be pulling the carbs I guess and thats a whole other diagnosis tree! Thanks so much for the advice and please if anyone has anymore suggestions I am all ears..  Bike is thirty years old who knows what has been done to it or worn out..

[dracko]

I do know that a valve adjustment was done on it by the previous owner. I wonder if an improper adjustment would cause this issue or improper torque applied to the valve cover bolts. Any thoughts on that???

[Pat Conlon]

No, the torque on your valve cover bolts won't affect the symptoms.

If you're going to dive into the carbs, check the o rings (or lack of) on the air idle screws.

If it's not mechanical, then I agree with your instinct, air is getting in somewhere.

[ribbert]

I do know that a valve adjustment was done on it by the previous owner. I wonder if an improper adjustment would cause this issue or improper torque applied to the valve cover bolts. Any thoughts on that???

Dracko, these are strange comments for a mechanic of 10 years and an odd problem to seek help with. There are only a small number of things that would cause this. Describing symptoms over the net is always difficult and you should be able to trouble shoot this yourself. Think through in you head what makes engine revs increase.
As far as a vacuum leak goes, where is it going to get the fuel and air to rev that hard if the butterflies are closed?

However, if you are looking for advice, start with the simple and obvious. Is there a little bit of play in the throttle cables (at the carbies), that is, are the carbies fully closing when the throttle is returned and are they frayed? Are the throttles in fact closing?
You say there is no binding with the cables. If it was not returning fully this would not be felt at the throttle and could only be determined at the carbies. It doesn't take much with no load on the motor.
Is the bike new to you and did it come with this problem? Did it start to happen only after some work was done?

Eliminate the simple and obvious stuff first.

If you are experienced with cars and other bikes the FJ won't trouble you, they are the lawnmower of the motorbike world when it comes to simplicity and accessability.

Good luck.

Noel

[ribbert]

Once off the choke and idling fine if I rev it up it will stick..

I just saw this, it should give you a clue. If it will idle fine until you rev it and then not return that narrows the field of possibilities.

Noel

[roverfj1200]

I will throw in my 2 cents here. Early FJs have no fuel pump? Sounds a bit like fuel starvation to me. But the carbs sticking to is a good starting point.

Cheers.

[Bones]

they are the lawnmower of the motorbike world when it comes to simplicity and accessability.

Good luck.

Noel

A 130hp lawnmower,  Yeah..... Bring it on

[dracko]

Oh bro its not strange at all lol.. you have to understand that in my industry expertise in areas mechanical is just as vast as expertise in alll things medical. . My experience with older bikes like this is somewhat limited. I am a diesel technician by the way.. Expert on cng and lng alternative fuel systems.. Your philosophy is correct though start with the simple stuff and work your way through the tree.. which I have done for the most part.. But before I dive into things further I thought it wise to put my "mechanics ego" aside and ask for some thoughts opinions ideas no matter how far fetched so that I do not over look anything.
A leak at the valve cover would surely be oil rather then vacuum but somwbody I spoke with at work felt that it could be an issue   i asked just to be sure.  So what I have check thus far is throttle cables, good. Carb choke is operating as it should the rail moves propper with out any issue or binding. Vacuum lines are all correctly installed and new. Unused vacuum ports are capped off with new boots.. carb intake boots were carefull inspected for cracks holes damage.. O-rings were replaced and the manifold surface was cleaned to ensure a good tight seal.

The ignitor does not hold vacuum when tested.. as suggested earlier I am going to cap the line and eliminate that off the list.. also the carb plungers I am going to check agian aswell and  they should sink down slowly  when pushed up as opposed to falling straight down agian immediately. . This was checked when I first purchased the bike but it has sat for 8 months or so probably needs to be rechecked..

[ribbert]

Oh bro its not strange at all lol..

No problem, that explains it. Plenty of petrol engine experience here and a very helpful mob.

Noel

[FJscott]

even though cables look ok I would try disconnecting the throttle cables at the carbs and see if problem persists

[FJmonkey]

Since you can get it to idle normally after warming up and backing off the choke. I would spray WD-40 or similar product around common vacuum leak areas. If you can get the idle to change by spraying a certain spot then you found a leak.

[dracko]

*Sighs*  So this weekend I retraced my steps and added a few in there for good measure. I checked and rechecked evrything and I did what was suggested by everyone. I capped off all but one vacuum line that leads to the fuel tank petcock. I rechecked my boots the vac ports clamps and throttle cable. I pulled the top hats off of the carbs and checked every single diaphram. I found a pin hole in the diaphram on carb 1. I called around to checked the price of a new one and I still haven't been able to pick my jaw back up from the floor after hearing what they quoted me. 

In any which case I was told that the issue with the pin hole would not cause the idle to race like that. After briefly explaining my situation and what I checked I was told that an improper valve adjustment could cause a high idle issue. Obviously as the engine warms up its tolerances change, if valves are to tight it could cause the issue I am having thus says the cranky old motorcycle technician at Steeles Cycle.

I have done valve adjustments on Cummins and John Deere engines quite a few times before, never seen tight valves give you a racing idle before but thats a diesel engine not a 30 year old Yamaha.

Sooo... What do you guys think? Ever hear of tight valves causing an issue like this...?

I can post video and pics also if that helps btw.

I do want to thank everybody for your help and input aswell.

[FJ111200]

What about the pilot air screws?

They should be about 2 and a half turns out.  Any less and this could cause the high idle issue.   JAT.