Rough running FJ1100

[Gord]

I have never checked valve clearances or done a compression test before, but I done them today, and here are the results.

No1 cylinder In = 0.10 / 0.10-0.15 50psi
No 1 cylinder Out=0.15-0.20

No2 cylinder In = 0.05-0.10 / 0.10-0.15 60psi
No2 cylinder Out = 0.15-0.20 / 0.15-0.20

No3 cylinder In = 0.05-0.10 / 0.05-0.10 60psi
No3 cylinder Out = 0.10-0.15 / 0.10-0.15

No4 cylinder In = 0.10-0.15 / 0.10-0.15 60psi
No4 cylinder Out = 0.10-0.15 / 0.5

The bike is starting and ticking over fine, but it spits back through the carbs and the exhaust if I rev it high.
The compression tester was just a cheap thing that you hold over the spark plug hole, the battery was weak and was not spinning the engine very well, not sure if this affects the results? I tested the compression while the starter was turning the engine over.

Does this mean anything to you guys?

Does an FJ1200 engine slip straight into the 1100 frame, does it need the 1200 wiring loom etc?

Thanks for your help so far :-)

[FJ1100mjk]

From the Yamaha Service Manual, the valve clearances (measured cold/room temperature) should be:

INTAKE ===> 0.11 to 0.15 mm
EXHAUST ===> 0.16 to 0.20 mm

Looks like you have a few tight ones, and that could cause a low compression reading for their respective cylinders. Go back through them again and adjust them to specifications above. Then perform your compression checks again. I would not be confident with the readings that you're getting with the type of pressure gauge that you're using. Beg, borrow, or buy the better screw-in type for the next round of testing. You probably should have a battery with a better state of charge to spin the motor over too.

Did you hold the throttle wide open when you cranked the engine for the compression checks? If not, do so, as not doing this can greatly affect your compression tests' readings.

An earlier model (86, and 87) engine would bolt into your FJ1100 frame with minimal hassles as they do not have the rubber mounts that the later models had. Not sure what year that type of mounting started though.

I have both an '85 and an '87, and with a couple of small exceptions (none that come to mind that would be show-stoppers), your FJ1100's wiring loom should be all right for putting in an earlier (86 or 87) 1200 engine.

I am sure that others here will chime in with their advice and experiences.

Good luck.

[FJ111200]

An earlier model (86, and 87) engine would bolt into your FJ1100 frame with minimal hassles as they do not have the rubber mounts that the later models had. Not sure what year that type of mounting started though.

I have both an '85 and an '87, and with a couple of small exceptions (none that come to mind that would be show-stoppers), your FJ1100's wiring loom should be all right for putting in an earlier (86 or 87) 1200 engine.

I am sure that others here will chime in with their advice and experiences.

Good luck.

A 1200 3CV will bolt in aswell, I know because I used one on my 1100. I think the later 3XW have different mounting points.
I thought the 1100 loom would work but found out I needed the 1200 one to make it run properly.
Originally I used 1100 loom, ignitor box and pick ups on the 3CV but it will be perform much better using the early 1200 1TX loom for the ignitor to plug into. The ignition coils and pick up coils are also a perfect match from the 36Y 1100 's to the 1TX 1200's. 

[Gord]

I'm going to do the compression test again, using a screw in type tester, and a fully charged battery.

A couple of questions, do i take all of the plugs out, do I hold the throttle wide open?
Is there anything else I need to know?

[FJ1100mjk]

I'm going to do the compression test again, using a screw in type tester, and a fully charged battery.

A couple of questions, do i take all of the plugs out, do I hold the throttle wide open?
Is there anything else I need to know?

Here you go...

http://www.howtomotorcyclerepair.com/how-to-motorcycle-compression-test/

Good luck!

[Gord]

Cheers,

I did the test with the engine cold, all plugs in and throttle closed, I'm hoping for better results next time!

[Gord]

I managed to pick up an FJ1200 engine and some bits for very little money, so decided to take a chance.
I swapped the 1100 engine for the 1990 1200 engine, by they are heavy bastards to lift into the frame.

Fitted the engine and found that the loom I had bought from eBay was slightly different, they must have changed on the 1990 3CV bike. So after figuring out which loom I needed (looking at lots of pics of looms) I ordered another from eBay. I couldn't get a spark with the 3CV ignitor box, but I could on 2 cylinders with the 1100 ignitor. So I ordered another 3CV ignitor, by this point I couldn't be bothered with it and pushed it to the back of the garage, where it stayed until this morning.

I dragged it out of the garage this morning, looked at everything with a fresh set of eyes and saw a few things that weren't quite right. Anyway, I got it running, running very rough, but it's running and sounding far healthier than the 1100 engine did. The trike is in bits, it's a mess and needs lots of time putting into it, but I'm a big step forward now.

[Tiger]

  Well done smoggy    ...