Wanted Looking for piston rings for XJ700

Well, seems like I'm not alone in this journey. I got 1985 XJ700 with blown piston rings. If anyone has any in hood condition or maybe even new ones please let me know. Or maybe you know someone who makes custom rings, that will work too.

Engine wasn't running for two years. And last time it was running it smoked. So when I tried to start it carbs were messed up so I'm waiting for parts to rebuild them. But about engine, I checked the compression and it was below 80psi. Added a bit of transmission fluid and it picked up compression up to 110-120. And thats in all cylinders.

Any ideas or advices?

 

Check the valve clearances first before you change piston rings, then do another compression check.

 

Ok, will do. Bc this motorcycle has only 16xxx.

 

Piston rings should be fine at that low mileage. Probably needing some ATF and acetone mix down the spark plug holes for a few days to free the rings up due to the bike not being used. I would definately check the valve clearances first. They have to be adjusted correctly before any carburettor work is done. Do you have a Haynes Manual for your bike?

 

I have manual that I bought online. Its a pdf file with scans from old book. And it doesn't have a first page lol so I dont know if it's Haynes or not. Carbs are leaking like crazy, that's why I'm rebuilding them.

 

The main reason I referred to the valve clearances is so that you can syncronise your carburettors once you rebuild them, and to see if the compression figures increase further in the meantime. Most of the time the engine does not need dismantling, and in your case with such a low mileage and similar compression between cylinders that is a good sign.

 

Thats kinda what I thought. I looked up symptoms and it fits the picture. At least as if for now I know what to do. Will be back after I get those few things done

 

The valves go deeper into the valve seats on low mileage engines. Shim changes are not needed as much on higher mileage engines although they should still be checked at 8000 mile intervals according to my Haynes manual. Check the easy things first.

 

With only about 15k on it, it’s really only at about time for the first clearance check.... it’s not gonna be that far out of spec yet. Not saying some won’t be, but they’re not going to be in critical condition yet. Ive seen plenty where they’re about 35k and haven’t been checked—— That’s bad.

I would be trying to use fluids through the plug holes first, to try and get things loosened and freed up.

Just because it blew smoke doesn’t necessarily mean you need a set of piston rings. There’s other reasons an engine will blow smoke.

if the engine is already being opened, then yeah, do shins while you’re already in there.
Dfox

 

It’s recommended that airheads get checked about every 5k mi (+\-, imho), and liquid cooled’s about every 15k.......

 

Well gentlemen.. here is the results of valve clearance check:

1 cylinder
Exhaust 005. out of spec
Intake 006

2 cylinder
Exhaust 007. out of spec
Intake 005

3 cylinder
Exhaust 006. out of spec
Intake 006

4 cylinder
Exhaust 006. out of spec
Intake 0025. out of spec

 

Metric...... in mm please

 

1 cylinder
Exh 0.13mm
Intake 0.15mm

2 cylinder
Exh 0.18mm
Intake 0.13mm

3 cylinder
Exh 0.15mm
Intake 0.15mm

4 cylinder
Exh 0.15mm
Intake 0.06mm

 

Ok, now pull each out, 1 at a time —
Flip it over, record the number stamped on it, then put it back. Give us the numbers, and we’ll help you get the right sizes for shim swap.

 

Cylinder 1
Exhaus shim Y276

Cylinder 2
Exhaus shim Y275

Cylinder 3
Exhaus shim Y265

Cylinder 4
Exhaus shim Y265
Intake shim Y270

 

I’ll crunch numbers this evening for you, unless someone else feels like beating me to it.

I’d recommend you pull the in-spec shins to get those sizes, as well. That way, next time you have to do it, you have ALL of them recorded already. Your job will take less than half as long .

 

Are the clearances the same on all XJ engines? I assume they are?

 

Air heads, yes...Liquidcooleds have different numbers

 

Okay l don't have the shim chart.

 

I have a shim chart from original Yamaha manual for XJ700

 

But even here i don't see the numbers i need.

 

Not the correct chart

 

Do you have a right chart?

 

Here’s the chart:



I got in later than I expected. I’ll run numbers in the morning.

BTW, exhaust 1 is a typo.... you meant 275 right?

 

Good question. It actually looked like 276. I can double check tomorrow.

 

The manual for the 700x says 26.600 miles but I think the 15k that you mentioned is a wiser choice...

 

I Believe the ‘accepted’ time is the 25k approximation is for the first check.... then every 15k after that, even though the 26.6k is from yamaha.

26.6 is a loonnggg time between checks, imho

 

+1

 

Cylinder 1 270

 

So by the looks of it I need 2x 260 and 2x 265.. does anyone has any, or knows anyone who has shims?

 

Elijah.....I’m working on your numbers right now......question on cyl 2:

you said 2 exhaust is out of spec, and gave numbers, but if it is the intake that is out of spec unless you wrote something else wrong. Can you correct #2 both E and I for me

current— awaiting cyl 2 double-check:

Dfox

 

I made mistake when I wrote that its out of spec. Numbers are correct.

 

I’ll look to see if I have any 260’s

updated pic: