Various Things

[heynow68]

Hi all Lets start with the 1988 FJ1200
Today I did a compression test and it was 150 across the board.
I checked the valve clearance this is what I got.

Exhaust Side:
1.Loose 4   2. loose 4   3. loose 6    4. loose 4    5. 6    6. 6    7. 6    8. 6

Intake Side
1. 6         2. loose 4       3. 4      4. Tight 6      5. loose 4      6. loose 4     7. Tight 6      8. 4


Also on my 1993 I went to sync the carbs as they were not that bad however I think I screwed it up as it was my first time doing it. Carbs 1 and 4 read almost the same and carbs 2 and 3 read almost the same. I know that the initial air mixture screw should be set at 3 turns to start does anybody know where the sync screws should be set at the start. When I try to get carbs 1 & 2 to sync the bike wants to stall when I turn the screw in and when I turn it out the idle speeds up. same thing happens with carbs 3 & 4 I should have left them alone as the bike ran great. Any help would be great.
Thanks Tim   

The vacuum hoses were double check and going to the right carbs.

[FJmonkey]

We need more information to help you. The AFM screws don't need to be adjusted for a carb sync. I assume you are using a 2 port or 4 port monomiter or vacuum guages. As if sitting on the bike, you balance carbs 1 and 2 (the left 2) with the Left side adjusting screw. Then balance carbs 3 and 4 (the Right 2) with the Right side adjusting screw. Then balance the Right side (1&2) to the Left side (3&4). Then fine tune to your satisfaction. There is no specific start point for the screws as the balance adjustment is relative. Or you could say the start point is exactly where they are when you begin the balance procedure.

[racerrad8]

Are those measurements in inches or MM?

Randy - RPM

[heynow68]

We need more information to help you. The AFM screws don't need to be adjusted for a carb sync. I assume you are using a 2 port or 4 port monomiter or vacuum guages. As if sitting on the bike, you balance carbs 1 and 2 (the left 2) with the Left side adjusting screw. Then balance carbs 3 and 4 (the Right 2) with the Right side adjusting screw. Then balance the Right side (1&2) to the Left side (3&4). Then fine tune to your satisfaction. There is no specific start point for the screws as the balance adjustment is relative. Or you could say the start point is exactly where they are when you begin the balance procedure.

I can't seem to get the balance on 1 & 2 together with out the bike wanting to stall and the same when I try to balance carbs 3 & 4 together.

[heynow68]

Hi Randy I think the gauge is in Inches the gauge is really old can hardly read it.

[FJmonkey]

Watch this. It is not an FJ or even an air cooled engine but the process is the same. https://www.youtube.com/watch?v=KHGPqP6G9cA

Regarding the feeler gauge, if the gauge is too hard to read, how do you know what size it is? An inch is 25.4 millimeters, so knowing the standard is as critical as reading the numbers on the gauge.

How long have you done this kind of work on bikes/cars?Knowing this will help us provide you better answers.

[heynow68]

Are those measurements in inches or MM?

Randy - RPM

Exhaust Side:
1.Loose .04   2. loose .04   3. loose .06    4. loose .04    5. .06    6. .06    7. 6    8. .06

Intake Side
1. .06         2. loose .04       3. .04      4. Tight .06      5. loose .04      6. loose .04     7. Tight .06      8. .04

The gauge is in Inches. I know the AFM screws don't have anything with the sync. I am using a 4 port Vacuum Gauge I know there the 3 adjustment screws and that the left screw syncs carb 1&2 and the right side screw syncs carbs 3 & 4 and the center screw syncs all 4 carbs together. Simple.  Lets say Carb # 1 is reading 40 on the gauge and Carb #2 is reading 20 in the gauge. When i try to sync those two carbs only I turn the crew in no movement on the gauges and the bike wants to stall if I turn the screw out the idle speeds up and still no change in the gauge after each movement of the screw the burp the throttle still no change. the same thing is happening with carbs 3 and 4 the Gauge is brand new.
Is the #2 carb the main carb on these bikes? If so I may have to calibrate the 4 gauges to that 1 carb then hook it up to all 4 carbs this will rule out a faulty gauge.

[FJ_Hooligan]

If you're turning the sync screws and the carb vacuum readings aren't responding then something is really wrong.  Very small movements in the sync screws yield BIG changes in the carb vacuum.

If the carbs are that far out try idling the whole assembly up then try to adjust. IIRC, carb #3 is the master (it should be the one that the idle adjustment is moving).

Can you take pictures?

EDIT: One other thing, the choke must be OFF (fully closed) while synching.

[Pat Conlon]

....I know that the initial air mixture screw should be set at 3 turns to start does anybody know where the sync screws should be set at the start. When I try to get carbs 1 & 2 to sync the bike wants to stall when I turn the screw in and when I turn it out the idle speeds up. same thing happens with carbs 3 & 4

Tim, sorry if you know this, but just to be sure, you're not confusing the air/fuel idle screws with the air balance adjusters, are you? 2 different puppies.

The air/ fuel idle screws are on the body of the carb.....the air balance adjusters are on the throttle shaft between the carbs.
You want the air balance adjusters, not the air/fuel idle screws.


^^See the 3 screws marked C^^

As you're sitting on the bike, if #1 and #2 are balanced, use left adjuster to do this (above picture is reversed)....and #3 and 4 are balanced, use right adjuster to do this, the center adjuster (between 2/3) is the one you want. It balances 1/2 with 3/4

The idle screw (sets idle rpm) is located and accessed from below at the fuel bowl level, between carbs 2 and 3 marked above as A (hard to see the letter)

Again, sorry if you already know this, just checking....  Pat

[heynow68]

....I know that the initial air mixture screw should be set at 3 turns to start does anybody know where the sync screws should be set at the start. When I try to get carbs 1 & 2 to sync the bike wants to stall when I turn the screw in and when I turn it out the idle speeds up. same thing happens with carbs 3 & 4

Tim, sorry if you know this, but just to be sure, you're not confusing the air/fuel idle screws with the air balance adjusters, are you? 2 different puppies.

The air/ fuel idle screws are on the body of the carb.....the air balance adjusters are on the throttle shaft between the carbs.
You want the air balance adjusters, not the air/fuel idle screws.


^^See the 3 screws marked C^^



As you're sitting on the bike, if #1 and #2 are balanced, use left adjuster to do this (above picture is reversed)....and #3 and 4 are balanced, use right adjuster to do this, the center adjuster (between 2/3) is the one you want. It balances 1/2 with 3/4

The idle screw (sets idle rpm) is located and accessed from below at the fuel bowl level, between carbs 2 and 3 marked above as A (hard to see the letter)

Again, sorry if you already know this, just checking....  Pat

Thanks Pat I understand all that. I am going to check the Gauge tomorrow to see if it is working proper.

[racerrad8]

I am going to check the Gauge tomorrow to see if it is working proper.

Perfect place to start. Put each gauge on a single intake nipple and verify the same reading for each gauge.

#3 (from the left) is the fixed carb and all others adjust to that carb.

And if you can, get the actual reading from the feeler gauges; not tight or loose.

Those measurements will be what you base the correct, required shim size from. I believe FJmonkey posted a shim chart to document what you have, what you take out and what you need to replace with I can't find that one right now. Maybe it was posted by someone else and that is why I cant find it...

Here is the shim chart to calculate what you require that FJmonkey did post: http://www.fjowners.com/index.php?topic=16002.0

Randy - RPM