cam chain guide question

aloha guys,
Is it possible to replace the front and rear cam chain guides on a xj700 without splitting the case? I need to replace my cam chain and figured why do it and not replace the guides. Any help is appreciated.

 

The front and top guides can be. Don't know about the rear. You will have to remove the camshafts to do the front or rear. You may be able to get the front out by slipping the sprocket off it's mount, I haven't tried that. How many miles on your engine? And just to be certain I am talking about the XJ700 air cooled engine and not the XJ700X water cooled engine. Note that you don't have to remove the camshafts to replace the chain itself. The old one can be seperated at a link and the new one attached. Then rotate the crankshaft to pull the new one in.

 

Thanks Blue Max,
yes I am talking about a xj700 air cooled, about 68,000 miles on bike. I have chain slap and see marks on valve cover where chain is hitting it. Tried to tighten adjuster and even replaced it, chain wont stay tight. when you said to remove sprocket from its mount were you refering to the cam sprocket? I plan on removing camshafts to remove and install new chain. Hope i dont loose count on number of revolutions i turn the crank :roll:
Aloha,
kalani

 

You won't need to count anything.

I would take the time to inspect the valve shims and record the values on each valve for your next valve adjustment.

After you get your new chain in place, line up the timing mark on the left side crank shaft cover to the T mark. Put your cam's back in (with oil), the sprockets are not bolted to cams at this point. Line up the timing dots on the cams with the arrows on the bearing covers. Take the slack out of the chain and bolt up the exhaust sprocket first, then the intake.

That was just a summary of the proceedure, if you want the actual pages I can copy and paste the info if you PM me your email.

 

I replaced both guides in my 650 Turbo this summer. There was not enough room to pull the front guide out of the motor while it was in the frame. The rear guide was held in place with a pin and locknut arrangement. Theoretically, I guess you can slack off the pin, pull the rear guide toward the front of the engine and pull it out, but I really don't think that there is enough room to do it, with or without the cams and chain removed. Personally, I wouldn't try it. You will not get the front guide in with the cams in place and tightened down. The front guide must go in first. It is the easiest, since it simply slides into place and sits in a special slot in the bottom case. Oddly enough, I had the same problem as you, the chain was hitting the top cover, leaving scuff marks and buzzing between 3000-5000 rpm. Turns out, the front guide had broken about 1" - 2" down from the top of the valve cover gasket surface, preventing the chain from tensioning properly. When I pulled the old chain, it was the same length as the new one.

 

my question about counting the revolutions came from the assumption that number one cylinder fires every other time the crank passes the "T" mark, the other times it is on the exhaust stroke, dont want to assemble the cams to have it on the exhaust stroke when the ignition wants to fire, or does the crank mark pass "T" only on compression stroke?
am i confused? lol, yes i am.
also, Mac...
how does one replace the rear chain guide?
thanks for all the replies guys.
kalani

 

The coils fire on both the compression stroke and the exhaust stroke on our machines. This is referred to as the "lost" spark method. So it fires every time the "T" mark passes. Simple enough and it causes no harm.

I'll guess at the second question. The Haynes manual suggests removal of the guides after removal of the head and cylinders so your in for a bit of work. The rear chain guide is held in place by a long bolt located behind the cylinder bank, in line with the chain rotation plane. This bolt sets the tension of the tensioner's lower piviot point. Removal of the bolt allows the mechanic to slide the tensioner blade out. In practice, you can pull the front one without too much effort but I'll be a monkey's uncle if I can remember if the rear will pull out easily without removing the head. Anyone else?