1984 Yamaha fj 1100

[mikedastonfj1100]

I have recently inherited the 84 fj 1100.. Started digging into it to see why it was not running.. Found no compression in any of the cylinders, cracked carb bodies, and bad cdi box..

here is what I have done so far:

new dynatec cdi ignition and pickup coil
new accel spark plug coils and spark plugs
new carburetors

what I want to know is all of the needle and screw sittings.. No one has really answered that question I have had for a long time... Any help would be awesome

[movenon]

I have recently inherited the 84 fj 1100.. Started digging into it to see why it was not running.. Found no compression in any of the cylinders, cracked carb bodies, and bad cdi box..

here is what I have done so far:

new dynatec cdi ignition and pickup coil
new accel spark plug coils and spark plugs
new carburetors

what I want to know is all of the needle and screw sittings.. No one has really answered that question I have had for a long time... Any help would be awesome

Welcome,  The fuel air screws for a starting point set at 2 1/2 turns out.  Sounds like you have a project !!  No compression ?  Please explain a little more if you can. Cracked carb body's ?  If you can post some pictures.

How did you conclude that you had a bad TCI / CDI box ? Do you have a Yamaha Service Manual ?

If you haven't done so already go up into the introductions area and introduce yourself.  Lots of good members to help you out.  Let us know where you are located.

George

[Arnie]

Mike,

IF you have NO compression in any of the cylinders, you need to find out why FIRST.

Don't put any (more) money into carbs, settings, ignition, until after you know why it has no compression.
Possible causes are very bad head gasket, or badly cracked head, totally worn rings, bent valves, totally worn valve stem guides and seals.

These are items that may make you choose to abandon this bike.  And, no matter how well it can carburate, or how big and fat the spark may be, if you got NO compression the engine will just not run.

[mikedastonfj1100]

Well for the cdi problem I found no fire at any of the spark plugs. Traced the plugs to the coils, no fire at the coils:(.. Ok, traced the wires to the cdi box, no fire out but fire in to the box:) saw the cdi is vaccum controlled.. Decided I wanted to update to electronic controlled.. As for the coils I saw they looked kinda old and worn out... So I replaced them with accel coils.. Have used accel coils on other bikes and cars and found no issues..problem solved for the "no fire" issue:) took the bike to a mech, he told me that there is no compression in any of the cylinders:(... Ok, now I'm thinking of buying a used engine, bad or good.. Taking two bad engines and make a good one... Haven't done much since the mechanic.... Also have individual air filters as an added upgraded... Guy I got the bike from said if I got it running I could have it...the only screws I could see are the ones where the throttle adjustments are and inside the float bowls... Is there any others I might be missing...

[FJmonkey]

Zero compression eh? I guess it won't matter much if you get some compression back when you squirt some oil in the cylinders and test again. Just in case you get that part sorted out, the air/fuel mix screws are plugged by the factory. You may need to drill them out to access the screws. They are on top near each intake manifold, under an aluminum plug in the carb body. Pulling these plugs has been documented here, try the search function, I find all kinds of good stuff when I search.

[mikedastonfj1100]

An added note to this last post is i took the spark plug out and looked through the plug hole with a light today, from what I could see the top of the piston looked burnt... From that I'm guessing it ran out of oil at one time or another... I might be wrong, I'm gonna take the cylinder head off after the weather clears up in the next day or so...

[movenon]

Well for the cdi problem I found no fire at any of the spark plugs. Traced the plugs to the coils, no fire at the coils:(.. Ok, traced the wires to the cdi box, no fire out but fire in to the box:) saw the cdi is vaccum controlled.. Decided I wanted to update to electronic controlled.. As for the coils I saw they looked kinda old and worn out... So I replaced them with accel coils.. Have used accel coils on other bikes and cars and found no issues..problem solved for the "no fire" issue:) took the bike to a mech, he told me that there is no compression in any of the cylinders:(... Ok, now I'm thinking of buying a used engine, bad or good.. Taking two bad engines and make a good one... Haven't done much since the mechanic.... Also have individual air filters as an added upgraded... Guy I got the bike from said if I got it running I could have it...the only screws I could see are the ones where the throttle adjustments are and inside the float bowls... Is there any others I might be missing...

There are no screw adjustments inside the bowl.  On the out side there are 3 larger screws that are for syncing the carbs.  Each carb on the engine side has a fuel/air adjustment.  As Arnie said sometimes they are capped, but in these days that is a rare. The caps can be removed. On the engine side under the carbs in the center there is a star wheel to adjust the idle.

Obviously with no compression the motor will never run.  IMO you would be better off just buying another bike with a good engine in it.  Free can sometimes be expensive.... You can buy a nice FJ between 1500 and 2500.00..... At least here (I don't know where you are located).  Occasionally you see an FJ for less than a 1000.00.

I believe the vacuum line going to the TCI is for emissions only.  Some just disconnect it.  At least on mine it doesn't help or hurt it.  On or off can't tell the difference. 

If you have no compression in any of the cylinders then I would suggest that it was massively mistreated and if that's the case,  what is the condition of the gear box etc... 

[Capn Ron]

An added note to this last post is i took the spark plug out and looked through the plug hole with a light today, from what I could see the top of the piston looked burnt... From that I'm guessing it ran out of oil at one time or another... I might be wrong, I'm gonna take the cylinder head off after the weather clears up in the next day or so...

Piston looked burnt?  Here's a shot of two of my pistons at around 20,000 miles.  They're supposed to look burnt.



The one on the left has just been cleaned up a little during the rebuild.  All four looked exactly like that.

As for the NO compression on ANY cylinder?  We're all looking forward to the answer there, so please keep us posted as to what you find.  I can't imagine...other than a valve in EVERY cylinder stuck in an open position?....someone forgot to install rings on the last rebuild?  ...head is just sitting loose on the cylinders with no gasket?  EVERY piston has a big hole in it?  Definitely a head-scratcher.

Cap'n Ron. . .

[fj johnnie]

 If it sat for a long time the condensation inside the cylinder can cause the rings to rust and or seize, which will also cause no compression. This is the first issue to deal with. IMO.

[movenon]

If it sat for a long time the condensation inside the cylinder can cause the rings to rust and or seize, which will also cause no compression. This is the first issue to deal with. IMO.

Pictures please. It will be interesting.
George

[mikedastonfj1100]

It has sat in my driveway for a little over 2 years now... I will post pics as soon as the weather clears.. It is bad over here in Louisiana...

[ribbert]

It is unusual to have no compression in all 4 cylinders of a motor that spins over to the point that the first thing I would do is verify it, before doing anything else.

The simplest way to do that is take the plugs out, move the plug leads away from where you hand will be and push you thumb over the plug hole, pushing down hard. Spin it over. If you can't hold your thumb over it without it being blown off, it has enough compression to start. If you can hold it there while cranking without air escaping past your finger, it probably doesn't have enough to start. A trained ear could tell you the same thing by listening to it spin over with the plugs in.

It is possible your mechanic was being loose with his terminology. No compression meaning low compression.

The motor was running immediately before the condition it's in now, so what has happened to stop it when it was running or since it was parked?  There are things that will effect an unused motor, one is rust, and that will only be on the cylinders with the valves open and is usually the valves stems it effects, not the rings and not all four at once. This is far less common with far fewer consequences than widely believed. The other is the intake or air filter becoming blocked. This can show a dramatic drop in compression readings, as will a cold engine.

Frozen rings are when the ring rusts to the cylinder wall, not contracted into the ring lands on the piston, so if it's spinning over, they aren't frozen.

Just sitting in you drive for a couple of years with the exhausts, carbies and air cleaner mounted I can't see how rust will effect all 4 cylinders. The spare motor I am running in my own bike at the moment had been left in the rain, tilted forward with no carbies. Two inlet ports and one cylinder were full of water and rust. Two valves had blistering rust on the stems that I flicked off with a screw driver. Even with that sort of rust it was running on all cylinders within 30 secs of starting.

Some of the suggestions involve the wearing of different engine parts.  A motor can't wear itself beyond the point of running.

Back to my original point. Clean out or remove the air filter element, make sure it is spinning over on the starter at normal speed and verify it has no compression before chasing anything else. Next thing  I would do is quick random check of some valve clearances.

No compression on all 4 cylinders? Most unusual. There are a number of other things it could be (like the PO just sitting the head and barrels on it, I've seen that!, carbies fitted with the rags still stuffed in the ports etc) but let's not jump ahead of ourselves. Verify the basics first.

What do you mean by cracked carbies?

Noel

[Tiger]

Hmmmmmm, no compression on all four cylinders IMHO...I think, given the money you have thrown at your old girl already, I would go out and beg, steal or borrow a compression tester before I went any further. It will at least give YOU a starting point to work from...

John

[andyb]

That motor is stuffed.  Dont' spend money on anything yet, start looking for motors while you do a teardown and see what the damage is.

FJ motors are difficult to find, unfortunately.

[mikedastonfj1100]

To capn Ron...

I see the two pistons u have.. What did u use to clean them with?