New owner

[laakkeet]

Didn’t have the patience to wait for a JIS set so I smoothed the end of a phillips head with a bench grinder. Went little by little, testing the fit as I went and it worked suprisingly well. Atleast good enough not to mess the screws.

Got the advance unit cleaned up, greased the rod and the bushings on the advance side. Things were pretty dry in there.

As expected, the gasket was done for and tbh the seal has seen better days too. I put the seal back for now, but gotta keep an eye on it and order a replacement if needed.

At this point I also went and bought couple rolls of gasket paper and cut a new one. I’ve put up ordering the gaskets as I wanted to stack up as much parts I need on my initial order, but it’s gotten to the point where I cant finish anything as I dont have a gasket for it

And scraping the remains of the old gaskets is slowly but surely becoming my nemesis on this project. Off to buy new blade for my exacto tomorrow. Luckily I havent scraped things too badly, I hope.

Both of the weights had some of the plating missing where it hits the stopper, so that could explain the ”copper dust” as I found no rust anywhere either.

Put things back together and off to the next one!

I also cleanes and lubed my clutch cable, adjusted it and it still feels off. Took off the right side cover and the plates seem to be rather stuck together. Also felt like I could move them abit by hand so ill take that apart next to check the plates and alignment.

Aaand the gasket cracks when I touch it, shocker!

 

[5twins]

If you clean up the end of the cam where the seal lip rides with a Scotch-Brite pad, sometimes that will cure a minor oil leak. There's a bushing with grooves in it's I.D. on both ends of the cam and you want to grease them both.

 

[laakkeet]

I went ahead to check the valve clearance and timing, as the bike tried to kick back alot when I originally got it running.

I set up the tail light to points to get a rough timing and things are off. The light comes on when rotor is as shown in the pic.

When I turn the rotor to F mark, the exhaust side tappet has slack but the intake side doesnt. To get both tappets loose, I have to rotate the rotor about to where its in the pic.

Just as I wrote this, it occured to me that I probably didnt align the locating pins correctly when I serviced the advance unit, so i’ll have to check that tomorrow. Or if someone has more insight on the matter please educate me

Other than that, I cut bunch of gaskets and now it holds oil again!

Went trough the carbs for a second time, needle jet was stuck on the other carb and pilot jet was glogged on the other. Got those fixed. Still need to get new floats but hoping to get the engine running with these, so I can run it to warm couple times to get everything lubricated and moving.

 

[5twins]

If the pic of your advance unit in post #61 is how you have it assembled now, then I think it's correct. There's a slash mark on the little center disc and one on the advance unit backing plate that must be aligned, and yours look like they are .....

For setting the valves, you may simply have been on the wrong TDC stroke. During the engine's 4 strokes, it reaches TDC twice. One time is on the compression stroke, and this is where you want to check/set the valves. The second TDC is on the exhaust stroke, just after the piston has finished pushing the spent gases out the exhaust valve. Both valves will be tight then. The exhaust is nearly finished closing and the intake is about to start opening. Your exhaust may have been loose because you are supposed to check and set the valves at the "T" mark, not the "F" mark. So, to get to the correct TDC for valve setting and checking, you would need to rotate the engine another full turn or 360°. This will bring you up on the compression stroke for that cylinder.

But I guess I should explain things a bit more as you seem pretty new to this stuff, lol. Even though the pistons rise and fall together, the cylinders are not on the same stroke. When one comes up to TDC on it's compression stroke, the other will be at TDC on it's exhaust stroke. That means only one cylinder can have it's valves checked/set. To do the other one, you need to rotate the motor another full turn to bring it to TDC on it's compression stroke.

Really, it's harder to explain than it is to do, lol. Put the motor on the "T" mark (TDC) and try to wiggle all 4 rockers. On one cylinder they will be loose and wiggle, on the other cylinder they will be tight. The cylinder with the loose ones is the one that's at TDC on it's compression stroke and can have the valves checked/set. To do the other cylinder, rotate the motor 360° (one full turn) to the "T" mark again, and then you can check/set those valves.

 

[laakkeet]

Thanks for the indepth reply! You are corect, I am pretty new to some of this stuff but eager to learn

Checked my advance assembly and I had aligned the lines correctly.

I was going to do it pretty much as you described, after reading bunch of posts here and going trough the manual. But I explained my problem poorly on the last post.

When I align to the Top Dead Center mark, rocker on the exhaust side valve has wiggle but the intake valve rocker is tight. However the intake valve on the other cylinder side has wiggle room.

When I turn the engine 360 degrees, same situation but mirrored. As in: align to tdc, left side exhaust valve rocker is loose and intake tight. Right side exhaust valve tight but intake has wiggle.

On top of that, I checked the timing out of curiosity and it was way off like shown in the last post.

I tried searching and read trough the manuals but I am clueless how to proceed.

 

[Its been a long time]

Something doesn't feel right to me with this. At TDC one cylinder is on compression with both valves closed. The other cylinder is on valve overlap with both valves slightly open.

Also I suspect the ignition timing is being checked incorrectly. I think the position being shown is when the points just close again rather than when the points just open. The coil fires the plugs at the moment the points open. Looking at the marks, the timing is supposedly set around 90 degrees away from where it should be. I don't think it's a coincidence that the points have about a 90 degree dwell period.

Something here is not right. Without looking at the engine I am not sure what is wrong.

 

[Tiggertoo]

There is an alternative way of adjusting the valves by rotating the engine to find when the gap is largest and adjusting it at that point;

Not sure why this link is not working but you can search for

Yamaha XS650 valve adjustment made easy by Lanny Mobley​

I did my valve clearances last night using the T mark to find TDC. I also tried the method in the link out of curiosity too, though for me the largest gap was at the T mark anyway so seemed a bit of a faff messing with different gauges. Iaakeet's engine does seem a bit peculiar, I suppose it could just be because the intake valve is tight because it has no gap at all? Doesn't explain why the intake on the opposite cylinder would be loose though unless that one has an excessive gap too. Remember the gap is only there to ensure there is no pressure on the valves (causing it to open slightly) during combustion. I think this vid explains it:

 

[gggGary]

Remove spark plugs to adjust valves, confirm TDC mark on rotor matches piston is at top of travel. A straw or such in the plug hole is "good enough" to see the piston is at TDC when the mark says it is. No steel rods or bolts in plug hole.

 

[5twins]

OK, I think some of your valves are set too tight. That's why you can't find a TDC with both valves loose on one cylinder. So I'll run you through a simple procedure to determine when a cylinder is on the TDC compression stroke and can have it's valves set/checked. Remove both spark plugs and all 4 valve covers. Use a wrench on the crank bolt, not a ratchet, because sometimes the closing valves "push" the engine along and it will want to run past the timing marks. With a ratchet you can't stop this but with a wrench you can. We'll do the left cylinder first because it's easier to watch the valves and rockers as you turn the motor over with the wrench. So, start turning the motor in the direction of rotation (counterclockwise) and watch the rockers and valves as you do so. Watch for the intake valve to open and close, then the exhaust. You've just run through the intake and exhaust strokes. After the exhaust opens and closes, keep turning the motor over until the intake opens and closes again. You'll now be coming up on the compression stroke so start watching the timing marks and stop when the rotor mark aligns with the "T" mark. If you go past it, the exhaust valve will start opening again, and you'll have to run through the procedure again. You don't want to turn the motor backwards (clockwise), against it's direction of rotation. So, once you have the "T" mark aligned, after the intake valve opens and closes but before the exhaust valve opens again, the cylinder is at TDC on the compression stroke and you can set it's valves. To get the other cylinder in the right position, rotate the motor one full revolution or 360°, to the "T" mark again. Then you can set the valves on it.

 

[laakkeet]

Thanks all!

I found the TDC but it’s way off the mark. Same with the ignition timing. Rockers are loose on tdc and opposing side is tight so all good on that department. Its just ways off.

Adjusted the valve clearances while I was at it, exhaust side was ok on both sides and intake was a tad loose on both sides.

I took a short vids to showcase the situation:

I’m unsure how to go from here. I assume I cant just slap a new mark on the rotor and go from there and this is something I need to fix

 

[Its been a long time]

Thanks all!

I found the TDC but it’s way off the mark. Same with the ignition timing. Rockers are loose on tdc and opposing side is tight so all good on that department. Its just ways off.

Adjusted the valve clearances while I was at it, exhaust side was ok on both sides and intake was a tad loose on both sides.

I took a short vids to showcase the situation:

I’m unsure how to go from here. I assume I cant just slap a new mark on the rotor and go from there and this is something I need to fix

The only thing I can think of is that the rotor has been installed but the key missed out. I would be wanting to understand exactly what's going on with those timing marks. If it is assembled properly then it's not really possible for the timing marks to be wrong. My guess is there's an issue with the rotor key.

 

[Raymond]

I’m unsure how to go from here. I assume I cant just slap a new mark on the rotor and go from there . . .

You could do a lot worse than that. Or make a mark on the generator to correspond with tdc on the rotor. As long as you end up with a reliable way to set the engine to tdc. Indelible pen or mark with a chisel/suffering screwdriver.

Crossed with @Its been a long time - should do that first to hopefully clear up the mystery.

 

[Jim]

When rewinding the rotor, there's nothing to stop you from pressing it back together with the timing mark clocked completely wrong. Seen it done a few times.
Agree with suggestion above to pull the rotor and check for the woodruff key. If the key is installed, shoot some pics of the rotor... front back and side. I'll be able to tell if it was rewound and clocked wrong.

 

[Jim]

Btw, be sure and use the correct puller to remove the rotor. They'll bend a lot easier than you'd think.

 

[laakkeet]

Thanks all!
I definetly want to know whats going on with the marks, so going to pull the rotor. I’ll post the pics after for you Jim.

Btw, be sure and use the correct puller to remove the rotor. They'll bend a lot easier than you'd think.

I can either pull the trigger on my parts order fron heiden and add the rotor puller they offer or get a generic magneto puller locally, but would need to find more specs to get one that works. I could add a woodruff key to the order too, just to be sure as its cheap.

I’ve been putting off the parts order to get everything I need on it, but I could check the brakes over the weekend and I should be pretty set on all the parts for now. Atleast until the next suprise lol.

 

[jetmechmarty]

r or get a generic magneto puller locally,

Don’t! Use the correct puller.

 

[laakkeet]

Don’t! Use the correct puller.

Alrighto, I'll order the correct one from Heiden. Thanks!