timing chain fun

Hello.

I'll try to be short, I think I know what to do but just want to bounce this off some people before I throw more money down.

Head gasket replacement. Joy. so I am at the point where I am doing the timing and having a finicky time at that. But that is not the problem. When I rotate the chain counter clockwise twice and the chain engages, everything moves. Does go out of sync but I know that there is some finesse and will try and get everything on the mark. However, when I move clockwise the chain slips off the lower socket deep in the engine and then I am in danger of valve damage etc and have to start all over again. I Follow the manual religiously. Is there something I am missing? or is the chain so stretched that it can no longer be automatically tensioned? I think the latter, but bike shops are closed for another day and could still try a thing or two before ordering another chain. The bike ran great before the tear down. Just had a gross leak at the front. Actually did not lose much oil just thought it should be done before it got worse.

I ask because sometimes you order a part and then nothing changes. Just want to avoid a longer rebuild.

popester

XJ 650 81

 

Have you got both the chain guides back in ?

 

hi wizard,

I'm in Canada so my response time might be off as its about 1am here and I should be going to bed. Anywho, yes both guides are in place. Only question I have about those is. The front guide, should there be a little tension when in the lower holding casting recess when pushing it into position? That is how it is now. The other option is that it just slides in with no tension.

Thanks for the response by the way

popester

 

There is a definite position that it locates into, are you sure the chain is on the bottom sprocket OK ?

 

this will help with the front tensioner.

 

Wow that is great that you have those pictures, I have the bike on the frame so a little hard to get a torch in there but I will try. I'll have another crack at it tomorrow to see if its in the right position then let you know my progress.
Thanks a tun...

 

I checked that the chain guide was in the right place and yes it is. I also talked to a Yamaha dealer/mechanic and he said that giving the age and mileage of the bike and also that it should never go clockwise in it's built life that I should not worry too much about it as even if I put a new chain in it will slip around as well. I think that was a pretty lame answer but never the less I will move on and just not move it clockwise. Though this has been a problem as doing the valve clearance. The inlet side is impossible to not move it clockwise to replace the shims. So back at it again with the cams off to replace one shim and get a new one.

 

It's okay to move it clockwise. Theres no variable valve timing to screw up, just go slow with the directional changes.

Also take out the spark plugs.

You don't want to rotate is clockwise to tension the chain through. Do that counterclockwise.

 

Usually that is the case, not mine. when I move it clockwise the chain slips off the lower sprocket and throws the timing out. With or without the automatic chain tensioner. I also move it very very carefully.

 

Maybe your tensioner is done for. Have you removed it to check the action? Could be binding, or stuck somehow.

 

The automatic tensioner is fine. But thanks for the suggestions.

 

If your Timing Chain "Slips" or otherwise disengages from the Lower Sprocket...
You have a >> Tension / Guide << problem.

The Front Guide is secured at it's Top which has a Locating Dowel that sits in a Receiving Slot.

The Rear Guide has a similar arrangement at the Bottom.
The Rear Guide needs to be "Inserted and Locked" within the Receiving Slot.

There is a Bolt and Lock Nut on the Case below the Tensioner,
To secure the Rear Guide:
Loosen the Locking Hex Nut.
Turn the Bolt Out to allow the Lower End of the Rear Guide to firmly seat within the Receiving Slot.
Turn the Bolt back IN ... to Lock and Secure the Rear Guide from disengaging from the Anchor Slot.

Lock the Bolt using the Hex Nut Lock.

The Plant MUST be able to be have the Crank moved Clock AND Anti-clockwise.

Anti-clockwise movement is NECESSARY to present Timing Chain Slack before the Tensioner for proper adjustment.

The Timing Chain has a "Life-expectancy" of 55-60,000 Miles when a NEW Chain replaces the Original.

 

Thank you for all the feedback, this forum is awesome. I have managed to get everything working, timing and valve shim adjustment. As stated in my previous post I did and still do have the front tensioner in the correct position. But I did somthing slightly different today which seems to have fixed whatever was the issue. Got all the timing marks in place, rotated counter clockwise twice with the tensioner in place, went to C mark to see the tension. Then I moved it clockwise very slowly, bingo no slippage. Was able to do my shim adjustment without any problems. DONE. Also, I putt it in neutral, I had it in gear with a buddy lifting the back tire when rotating. Don't know why I had it in gear the first place. For some reason it just slipped my mind. Thanks to all, happy riding.

popester XJ650 81

 

Okay not done. I had to do another valve adjustment as the engine was a bit noisy and getting too hot. The shims were just within range on the tight size so decided to give them a bit of room and now they are just within range on the large side. that fixed that, when I start the bike it runs. When I tried to tune the carbs the bike seized and went out of time. Awesome. So did it again and put it back in time put it together starts just fine until I do the tuning again and it slips out of time and seizes. When it does go out of sync I had my finger over the air hose to try and start the engine. Why the heck would this throw it out of time? I think the chain needs to be replaced and if so your supposed to change the cogs etc. If it comes to this I think I am going to part out the bike as its just not worth it. If anyone has a better idea please let me know.

Cheers,

Popester Xj650 81

 

In specs ... on the loose side, ... is OK.
It's better to hear the ticking than risk burning a valve.

 

So should I just get a new chain? The guides are correctly in place, the rear guide was never removed. When the bike is seized it goes clockwise but is obviously slipping off the lower cog, does not go counter clockwise. Should it ever come of the lower cog even when seized?

Popester XJ650 81

 

Hi,
When you have the cam cover off, how much slack is in the chain?

It should be TIGHT if everything is working well.
If you can flop it around and you are sure the rear tensioner is taking up as much slack as it can possibly take up, then the chain is very stretched.

I have the auto tensioner on my bike and after a fair bit of messing about I took the spring out and manually pushed the tensioner in to take up the slack on a brand new chain as the spring didn't seem to have enough tension to do the job for me. (my chain wasn't slipping mind you, just really noisy).

 

The chain is fairly tight and the automatic tensioner is all the way out to gain as much tensioning as possible. I am just hoping that the cog below is not worn out.

 

I hope for your sake that the cog isn't worn out.

If it was me I would put a new cam chain in and see what that did for me.

Buy a chain breaker and a new chain and you are off! Dead easy!

 

Back to my original post, the chain can be off to one side of the lower sprocket & still feel like it is on properly.

 

I think that is my best bet is to buy a new chain and pray that the cogs not toast and on top of that my valves aren't bent. Wizard thanks for the reply but I have ridden the bike before I tried to tune it. When it came to tuning, it backfires or something and throws it out of timing. I also made pretty damn sure that it was on after I received your first post. I have done the timing, started the bike and ridden it twice before trying to tune and then, fizzle.... Out of time. Have to order a new chain, will keep you posted. Thanks!

Popester
Xj650 81

 

The original chain should be good for 50,000 miles.
Do the "Lift-test" as recommended.

The Chain should be tight at the Bridge between the Cams.
If there is slack, ... do a Manual reset of the Tensioner.
Then test again.

 

Hi Rick,

the original km on the bike is unknown and I have tried resetting the tensioner many times and there was a little slack between the bridge. Not enough for me to worry about at the time but obviously should have. I have ordered a new chain and will have to wait a week upon install. Need a break from it anyway as doing the same thing over and over is insane.

Thanks for all the advice, will let you know my progress once installed.

Cheers,

Popester
Xj 650 81

 

Okay, better late than never. I replaced the timing chain. And because I did not do it sooner I had to replace a bent valve as well. Thank god that it was just one bent valve and not all of them. I have put it all back together and have been riding it for over a month and all is great. Bike runs better than ever.


Thanks for all the help.

Popester Xj650 81

 

Just to clear up this posting I will submit what I did to fix the problem.

Replaced the timing chain. Had to replace a valve because the chain was stretched, it bent only one valve. I was lucky. I lapped all the valves put it all back together and I have been riding it over the summer and it works like a charm. I also bought a colortune spark plug and adjusted all the fuel mixture and it runs better than ever. It took me about 20 minutes.

Thanks for all the help,

Jason