High Idle when engine is warm ***SOLUTION FOUND ***

Re: High Idle when engine is warm

Is replacing those a difficult job?
Something someone with 0 experience a standard house tool kit of ratchets and screwdrivers and the repair manual could do?

 

Re: High Idle when engine is warm

INVOLVED but not difficult as long as you take your time and read the manual AND ask questions if unsure.

S!

 

Re: High Idle when engine is warm

oddball is right, it's not rocket science but you have to get an understanding of what you are doing before you break the rack.

The screws holding the butterflies can be difficult to remove, and making sure everything is properly aligned when you re-assemble is imperative.

You can find all of the information you need on these forums to make the job pretty much painless.

 

Re: High Idle when engine is warm

RevChris, you are getting unwanted air in the system, check the carb boots & the shaft seals.
The popping is a lean condition. Wiz.

 

Re: High Idle when engine is warm

Yea, thanks for all the replies. Im glad to hear this is something that some work at home can be done on. However I'm not feeling too confident right now. I've been reading and don't even have the slightest idea on what most of thee things are ... breaking the rack, carb boots , butterflies , shaft seals..... no idea. And the manual doesn't relay feel like it helps , the carb chapter tells how to disassemble the carb but doesn't go into disconnecting it from the rest of the bike , it just say "disconnect from motorcycle"... yearg

Seem I have a lot of reading ahead of me. Given my inexperience I am worried that unless there is a chapter called "replacing X step by step" that I'm just gonna bust everything...

Maybe the best solution for me is to take it out to my Yamaha guy and tell him its running lean when it heats up.

 

Re: High Idle when engine is warm

Sounds like you need a good carb overhaul. You will need to find the right guy who will be honest and do a good job. You will pay alot to get this done. Just make sure your getting your moneys worth.

 

Re: High Idle when engine is warm

After a couple hours of investigation I think I found the reason for my rev problem. The throttle shaft seal on the outside carb was detoriated see pic.
At least I hope this is the cause.



Chacal; do you have these seals for sale????

 

Re: High Idle when engine is warm

I went out and noticed rubber seals that seem to connect the carbs to the engine. (I think) they have little cracks in them... could this be letting the air in?

 

Re: High Idle when engine is warm

RevChris:

Those seals are definitely in need of replacing. Yes, Chacal will have the seals. Thats where I got mine. The cracks on the intake boots should not be an issue until they go all the way thru the boot and actually allow air to enter. Some guys spread black RTV sealant over the cracks to help them seal.

 

Re: High Idle when engine is warm

Those could be just surface cracks. They don't go through most of the time.

 

Re: High Idle when engine is warm

He Revchris,

This is also causing problems, the engine sucks additional air through the inlet rubbers and cause the engine run higher.
I replaced these but that was not the reason for my high revs at Idle, as you can see above I found a bad throttle shaft seal. This could also cause high revs at Idle and I hope this is THE cause !!!!

 

Re: High Idle when engine is warm

Sounds like it could be one of many things causing my particular case. Or a combination of things. Hope its not too much money to have fixed.

Firefox I hope what you just found in your investigation solves your problem.

 

Re: High Idle when engine is warm

I've been reading through the Haynes manual and am starting to think I actually have a shot of doing this myself. Because I don't have a garage or anything I suppose I'm going to have to wait for a nice warm weekend day to get at it.

Just a couple of starting questions (I feel like sucha thread hijacker, but I have the exact same symptoms so Its okay right ) ,
If I were to apply this stuff http://tiny.cc/b3sXS to the cracks on the rubber boots (I think) as suggested should it stand up to the heat?
Is there anywhere else I can apply this stuff to keep air out or is its max temp too low to stand up to application in other areas?

Also because it might be pointless to take the bike apart without any spare parts around would a "Carb kit" be the right place to start in terms of spare parts being available.
Maybe something like this http://tiny.cc/AJbPa ?

I appreciate the assistance alot!

 

Re: High Idle when engine is warm

I was having the same symptom - idling around 3K when hot AND the exhaust smelling like it was running rich on a cylinder :? .

Mn-Maxims and I are tearing down and completely rebuilding my carbs. We're replacing pretty much all the rubber seals, gaskets and o-rings on them because some are brittle and falling apart, while some are just old enough that they're not sealing right and the rest are somewhere in between.

For example - When we had the carbs split, we shone a tiny flashlight in by the butterfly valve and could see small amounts of light leaking past the throttle shaft seals, even though they looked perfectly fine to the naked eye. Well, if light's getting through, so is air, and replaced they will be as soon as the parts order arrives.

Before you tear down your carbs and start ordering parts (in either order), read this first if you haven't already - In the church of clean
This wouldn't hurt either - THE SECRET LIFE OF CARBURETORS Covers the basics of understanding how the whole thing works together.

 

Re: High Idle when engine is warm

Correct CCW to richen. One other thing to look at. What kind of shape is the inlet system up stream from the carb inlets? Are there air leaks on the boots between the air box and the carb inlets? Is the seal around the air filter to air box intact? Old air filters with bad seals can allow raw unfiltered air into the carb inlets. This upsets the very delicate balance of airflow thru the XJs induction system

 

Re: High Idle when engine is warm ***SOLUTION FOUND****

Finally found what's causing my engine revs go up towards 4-5K from Idle when the engine is warm.
It was the throttle shaft seal, see picture in previous reply. After replacing it temporarly with O-seals it runs like never before, it's a perfect sound how it runs now, nice and stable Idle (never had that before).

What my experience is that when encountering the rev problem check al parts that can cause airleaks on the vacuum side 8)

I'm a happy camper again and can ride again

 

I seem to have fixed half of my issue, I adjusted the idle rpm dial down and haven't had the engine rev up anymore even after a good hot drive.

It used to idle around 2k and when hot head toward 3-4k , now it idles near 1100 and head upto 1500-2k when it gets hot.

The Exhaust pop hasn't stopped when I'm decelerating/higher rpms at speed but we will see if I can't remedy this when I replace the soiled air filter / check the seals.

 

Just want to add some of my experiences I had during this repair nightmare.
I found that the high rpm could by lowered by pushing on the sync adj screws, the rpm would go down and stayed for 10 sec down and started increasing again. This was when I still had the vacuum leakage.

After repairing the vacuum leakage, the rpm's were still high and I tried again to push on the sync adj screws but could only lower then 500-1000 rpm and when releasing the adj screw it raised instant.
At this time it was just a matter of adjusting the idle screw and mixture and it runs perfect now.

This was something I noticed and want to share with you guys, it took me too long to get the bike running as it suppose too and almost gave up on it.
But happy I didn't.

 

Turning the pilot screw CCW makes it leaner. You are opening up and more air is coming in. CW or in makes it richer. Rule of thumb is if the screw is on the engine side it regulates air, if it was on the air cleaner side it regulates fuel. Turn the pilot screw out from two and a half and get max idle, then turn it back in until it just lowers the idle a touch. This will give you a touch rich which is the way to go. Check all the plugs if you want, but your ear will tell you it is just a touch rich. Some say a half turn in from max, but I found that max idle is from 3 to four turns out, so I slowly turn back to about three, then slowly turn in a touch until I hear a slight change, but idle is still at it's max. A slightly deeper sound before rpms drop.

 

Hi,

I am in the process of trying to snyc my carbs. I have 82 Seca 650 with yics. i have put the mixture screws down to the bottom, turned them out 2.5 turns.

I have a carbtune hooked to all 4 carbs, yics tool in, and i am having trouble trying to get the carbs to balance.

1 & 4 are high, 2 & 3 low, when I adjust the balance screw the idle sneaks up, my idle seems to have no control, motor sneaks up and turning the idle down has no effect.

Is there a base point for the balance like the mixture?

Can I do this without the YICS tool?