XS500E Cam timing marks

[vintagehistoric]

Hello:

I'm new to the forum and looking for a little guidance on putting the motor back together.

The head was off, so the timing chain had a link removed and this is the chain that was in the motor. I have a new link, but have trouble getting the exhaust cam to the book specified 1 to 1.5mm past the cap mark.

The intake cam lines up at about 1mm to the left of the mark per the XS500A,B,C repair manual, but the exhaust falls at either 1mm the wrong side of the mark or about 5mm to the correct side of the mark.

Am I missing something? Can't be chain stretch if the intake lines up, as this is on the tension side of the chain. Any help would be appreciated.

Regards,

Scott

[JimR]

Hello:

I'm new to the forum and looking for a little guidance on putting the motor back together.

The head was off, so the timing chain had a link removed and this is the chain that was in the motor. I have a new link, but have trouble getting the exhaust cam to the book specified 1 to 1.5mm past the cap mark.

The intake cam lines up at about 1mm to the left of the mark per the XS500A,B,C repair manual, but the exhaust falls at either 1mm the wrong side of the mark or about 5mm to the correct side of the mark.

Am I missing something? Can't be chain stretch if the intake lines up, as this is on the tension side of the chain. Any help would be appreciated.

Regards,

Scott

Welcome Scott

and I think you are missing loads

First off I would not soft link the cam chain the XS500 has .. you are asking for problems, best result is to get a new one that has not been tampered with (endless)

can you insure the slipper tensioners are in good condition ?

don't forget to turn the engine towards the tensioner about 2 turns before applying the tensioner then recheck the valve timing, with a worn chain the cam where the slack is will go out of spec, perhaps you could supply photo's of the cam marks at LT (compression) to see if it is within spec or not.

is your motor a split head version or single head ?

when the engine was new all marks would line up this 5mm one way and a 1 mm another sort of makes a worn chain or tensioner or worst case a worn head, Plastigauge the cam to cap to insure the head , caps & cams are good.

if the motor is a split head you have other things to consider (secondary head gasket etc) but lets cross that bridge if required

[vintagehistoric]

Hello Jim:

Thanks for the speedy reply. I'm not sure what you mean by "soft link", but the link I have is an endless style that needs to be riveted. A new chain from Yamaha here is almost $150! The cam journals checked out round and the bearing surfaces were very nice. If you have a clearance spec for journal bearing, I can check it. The cams feel well located with no slop.

This is the late style head which is one piece. The tensioner looks to be in good condition and has plenty of movement and springs back sharply.

I will try reversing the motion on the motor to see if this impacts the cam location when rotating in the proper direction. I guess this is to make the tensioner properly locate?

However, since the number of links between the cams is fixed and the pulling force goes from the intake to the exhaust, isn't the only way to change the location of the cam timing mark relative to the cap mark is to rotate the cam one tooth? That's what I did yesterday to measure the distance from the cap mark to the pip in the cam. I even disengaged the chain from the bottom sprocket and pulled it to be longer to one side, reassembled everything, then took it apart and did the same for the opposite side. Rotated the motor in operating direction a couple of turns each time as well. Got the same two distances from the timing mark no matter what I tried.

I still can't think it is worn out parts, as the intake lines up well and the chain has no slack or slop on the run up from the crank.

Perhaps I'm stuck inside "my box" and need some guidance to get outside the box!

Thanks

Scott

[JimR]

Hello Jim:

Thanks for the speedy reply. I'm not sure what you mean by "soft link", but the link I have is an endless style that needs to be riveted. A new chain from Yamaha here is almost $150! The cam journals checked out round and the bearing surfaces were very nice. If you have a clearance spec for journal bearing, I can check it. The cams feel well located with no slop.

This is the late style head which is one piece. The tensioner looks to be in good condition and has plenty of movement and springs back sharply.

I will try reversing the motion on the motor to see if this impacts the cam location when rotating in the proper direction. I guess this is to make the tensioner properly locate?

However, since the number of links between the cams is fixed and the pulling force goes from the intake to the exhaust, isn't the only way to change the location of the cam timing mark relative to the cap mark is to rotate the cam one tooth? That's what I did yesterday to measure the distance from the cap mark to the pip in the cam. I even disengaged the chain from the bottom sprocket and pulled it to be longer to one side, reassembled everything, then took it apart and did the same for the opposite side. Rotated the motor in operating direction a couple of turns each time as well. Got the same two distances from the timing mark no matter what I tried.

I still can't think it is worn out parts, as the intake lines up well and the chain has no slack or slop on the run up from the crank.

Perhaps I'm stuck inside "my box" and need some guidance to get outside the box!

Thanks

Scott

hi Scott

Try this :- align the exhaust cam correctly at TDC and hold it with a spanner/tool to stop it moving.then adjust the intake cam to its marks using a spanner to keep the chain in tension from the exhaust cam (you may find you get about half a tooth out. then apply the chain tensioner. spin the motor over counter clock (viewed from the right) a few times and then recheck the valve timing, you may find the you have the timing close enough. Back in the day when a motor was striped a cam chain was fitted anyway as any small wear in the chain meant difficulties !