help!: cam chain slipped from crankshaft sprocket

Hi everyone. I had to remove the head ( my first time) to change the valve oil seals. I reinstalled the head ( new head gasket) and the cam shaft and when I turned the crank I noticed the the chain wasn't moving. The manual never warns about the possibility of the chain not staying on the sprocket. My question: do I need the take the head off again or is there another way?
Thanks
Juniorglide

 

cam chain 1 piece, or does it have a master link?
is your cam chain tensioner removed?
motor still in frame?
you could remove the sprockets from cam and try to get it back onto the crank

it is a small sprocket

 

The manual dos actually warn that the chain may become dislodged from the crankshaft sprocket (though like most details it's just glossed over).
You won't have to remove the head to correct this, but you will have to be carful to not drop the chain.
Remove the valve cover. Remove the camshaft sprockets, and remove the chain from those sprockets. You should then have enough room to lower the chain and ease it back onto the crankshaft sprocket. If not then you'll have to pull the camshafts off (attach a good length of wire to the chain so it can be retrieved in case you drop it)
Once the chain is back in place be sure to set the cam timing, and check it by rotating the engine by hand.

 

OK . I had removed one camshaft to get enough slack to maneuver the chain. Will remove the other camshaft and report back. Thanks.

 

Report: I removed both camshaft and I' m attempting to put the cam chain back on the crank sprocket,
but whenever I feel I'm on to something, the chain turns easily. If it were mated to the sprocket, it should be stiff.
My question: could it be that I'm on the sprocket and that the sprocket itself has disconnected from the crankshaft?

 

remove left side crank cover and see if you are turning the crank with the chain it should move with the chain. I assume you have removed the spark plugs for this, or it would be hard to move crank because of compression

 

it is a small sprocket

 

Yes the side cover is off as I had to move the crank @tdc to remove the cam shafts. The crank moves but not the chain. It's frustrating, I changed the head gasket,installed new valve oil seals, lapped the valves but forgot to make sure the chain was hooked properly. Is it a matter of patience to get the chain back on?

 

The crankshaft sprocket is cut into the crankshaft. It can't be removed, and can't slip.
Take your time. Patience is key. You'll have to visualize what's happening woth the chain. I like to lift the cahin up fully and run it around the crankshaft by hand for a few inchs to make sure that the links aren't kinked before trying to get it onto the sprocket.

 

Thanks. Will report if I succeed...
Junior

 

Hope you get it sorted Junior.

I have to fully strip my 750 motor over the Christmas holidays so I have been reading every bit of info on the site that I can find.
I have a few other things planed for the bike so I will be reading some more , it is like the war and peace of bike forums with such a wealth of information.

 

No matter the reason for the teardown, replace the alternator chain guide, and the starter clutch springs and rollers while she's apart.

 

Ye thanks K-moe already have the bits ready along with a lot of other over priced o-rings after reading yours and others previous post.

I am also going to spray the engine black while it is apart .

Even though the bike has only done 11.000 miles it has been sat for over 11 years in the USA according to the tax form under the seat.

 

You just have to get " the feel"..... once you get it onto the teeth, you'll be fine. I'd pull the plugs so you're not fighting against compression.. you be able to do it.... just have patience.

 

You will, not the first person nor the last to have the chain slip off. Plenty of good advice in the thread.

 

Thanks for the kind words! I love my bike and I would hate this to mean the end of her career. Every night I spend 15-20 minutes dangling that chain and bringing it up hoping it will catch the sprocket but it doesn't. I tried shining a light down the tunnel to try and aim at it but the frame is in the way. I'll give it another few weeks and I may the take head off again to get better access to it. I just hope I don't damage the head gasket doing so. Anybody has suggestions to increase my success rate?
Thanks in advance

 

You're welcome--that's why we're here. You'll get it--it will just take time, experience, and feel. I wonder if maybe you are sliding by the side of the teeth, and you haven't gotten over far enough to have the chain engage yet. You may need to pull the oil pan off to see up in there from underneath, and you may also want to consider pulling the chain tensioner off, toto allow more flexibility in the back of the tunnel til you get the chain back on.

Glad you love the bike! With only 11,000 mi, it's barely even broken in yet. You have about 300,000 mi or more to go yet......lol.

Other suggestions to increase your success? Yeah----- DO NOT take it to a sho-. That would be a sure way to never have your bike running right again.

 

Be the chain.

Zen and the Art of Motorcycle Maintenance

Use The Force young Skywalker.

Seriously, the curse of the human condition is we often over-think things (guilty here!), just keep it simple. . . Chain on sprocket. Loop it down, open the loop, slide it on.

You can do it!

 

With a strong light and a mirror I can see the back tensioner pushing the chain on the shaft instead of on the sprocket meaning I can never bring the chain far enough on the carb side. I'm gonna check the manual to see if the back tensioner can be removed and put back with the head installed.

 

You can, just remove the cam chain tensioner and the guide will fall back enough to get the chain back on. Once the chain is on and all the timing marks are aligned put the tensioner back in .

 

I'm sorry, I meant rear chain guide, not tensioner. The tensioner is off and I see the curvature of the carb side chain guide is pushing the chain towards the shaft.
I will try from the underside, removing the oil pan.
Thanks
By the way, in my moments of despair, I was looking to see which new bike could replace the xj750 and the combination of good looks and performance, shaft drive, nice shiny front exhaust pipes, decent gas tank volume and general narrow silhouette is just not out there on the new bike market. I have no choice but to put back this bike on the road!

 

4 cylinder cruiser seems to be a thing of the past. For some reason, Japanese companies have decided to play "follow the leader" with a company that makes inferior products. Profit margins and sales volume dictating design as opposed to a desire to make the best products?

 

The rear chain guide can be removed seperately. There is a special bolt and locknut right below the tensioner. Now before you go messing with that, get a serevice manual so you can fully understand the procedure (it's a bit long to type out here). I'm reasonably certian that you don't need to remove the guide though. With the tensioner removed it can be pivoted back pretty far.

 

The basic rule in durable goods is to make what the public will buy. Too much focus on making "the best" product puts companies under (Buell and Vincent come to mind), just like putting too much focus on profit margin at the expense of updating products will (Triumph, BSA, et. al.).
The only inferior V-Twin that I can think of in today's market is made by that one big T-shirt-and-matching-chaps company, and it isn't too bad of an engine (the troublesome parts are expensive to fix though).

There are a few options other than the v-twin.
V-4 (Vmax, which to my mind is more cruiser than sport, even if Yamaha says different)
Parallel Twin (the funky-looking Honda NM4, the Ninja 500 derived Kawasaki Vulcan S)
Single (Suzuki S40)
Triple (Triumph Rocket III)
Flat 6 (Honda Valkyrie)

All of the above sell in relatively low numbers in the U.S.. The big issue is that we are not a big market anymore; not enough motorcyclists, and not enough of us can afford to buy new bikes. The result... a sea of V-twins, because that's what sells.

 

report: success! After K-Moe mentionned that the back chain guide could be moved out of the way, I attached a metal rod against it and also removed the front guide to make room for the chain. After a few trials it caught the sprocket and voila!
Thanks to all for the support.
Juniorglide

 

Good work, makes you want to do the happy dance!

 

Told ya so----

 

I'm saving this thread as I have the same problem. 2 months ago I purchased a non running 1982 xj650 Maxim, seller said it was running fine and just suddenly stopped running, got it cheap so I figured if I got it figured out, great, if not, oh well. Long story short, took the valve cover off a couple of days ago only to find the cams and timing chain were not rotating when I rotated the crank with a wrench. So I broke out the laptop and borescope and had a look down the chain channel, uh oh, chain not on crank sprocket. Off work at 6am this morning (10 hour shifts) and started working on the bike just after I got home. 4 hours later I had no luck and finally gave up thinking I was never going to get it fixed. Then I find this thread and it gave me renewed hope, I'll be working on bike again after I get home from work tomorrow, hopefully I get the chain on the sprocket this time. Also, someone mentioned pulling the oil pan in order to gain access to the crank sprocket. How is that possible? I pulled the oil pan with the same intention, but no luck (did get to clean all the gunk out of the oil pan though).

 

sorta like threading a needle in a wind storm