Bits required for cam chain change

[madoc]

I have a 1980 XS650G
Seems like the chain and guides are toast.

I have read all the threads on wot needs to be done and how to do it (thanks)

I believe I will need:

• cam chain -spilt link
• Cam chain guide
• Cam chain tensioner
• cylinder head nut washers
• couple of cam seals
• gasket kit

It has a ton of compression and I don't really want to mess with the bottom end, unless I have to. It also also not blowing out any smoke at all, but I figured on changing the valve stem oil seals (because they are with the gasket kit) and cleaning/grinding the valves.

Is there anything I have missed that I need to have ?

How long should I factor in to do the job .. ?
I am surprised that the bl**dy engine has to come out for this sort of work..but if that's what needs to happen .. then fine. Is there anything I should change as a precaution while the engine is out ... the bikes mileage is unknown but it's external condition is dead original and very, very clean (original exhaust system still there)

cheers

 

[5twins]

You may not need to change out the cam seals. If they're not leaking, I wouldn't change them. That is a seal you can access anytime with the engine in the frame if need be later. Just clean up the ends of the cam shaft where the seals ride while you have things apart. Buffing them shiny with a green Scotchbrite pad works well.

The rear cam chain guide is usually OK. It may have some slight grooves worn into it from the chain but this part rarely goes bad or gets replaced. The front guide is a different story. It pretty much always needs replacing.

 

[madoc]

Ok. thanks. Some money saved
Are there any other seals/bearings that I've missed ?
Did I forget exhaust gaskets ..

How long to get the engine out ? The carbs seem very tightly packed in there ?
I've done cam-chains on other bikes and usually it's a solid morning's work (more if you have problems) .. the XS seems pretty straight-forward and mine is easier for having the ignition on the crank and not up with the cams

Silly me for buying a bike with awful top end racket and optimistically hoping I could adjust/service it out

 

[5twins]

With all the cleaning involved, de-carbonizing, etc., I usually spend several days on one. I go a bit further though usually than most. I clean the ports up with a Dremel. You'll see what I mean when you get yours apart. They're just plain awful from the factory.

Exhaust gaskets should be in the complete gasket set. If not, they're readily available. You can probably pull the motor in about an hour. Yes, take the carbs off first. They can be wrestled out after popping them out of the manifolds but pulling a manifold off then will make it easier.

 

[TwoManyXS1Bs]

Just an advisory: If the head doesn't release cleanly from the cylinder, then:

Chunks of headgasket will be stuck to the cylinder, you'll have to work around the studs.

Muscling the head off may release and tear the base gasket, which will later leak.

Trying to pry off the head can lead to broken fins...

 

[madoc]

I thought about 5twins comment about likley not having to do the rear chain guide.
To be fair, I was watching some youtube clips and given you seem to take most of the nuts off to get the rocker cover off then I'd be lucky to not disturb the head. I'd be mad not to lift the head at this point, really, and change the rear chain guide; so I am planning on that.

My girlfriend is handy with the spanners, so if the barrel base get's disturbed then lifting and dropping barrels back on (without piston ring clamps) is do-able between us. If the barrel has to come off then I'd likely hone and re-ring, it also allows a check on big end play.

The trouble is knowing when to stop eh

I am up to £208 now on parts and gaskets and so I'd *like* to stop there

 

[TwoManyXS1Bs]

Our shop policy was to at least hone & re-ring whenever pistons were pulled. Can't guarantee reseating with originals going back in, plus it's false economy not to do so...

 

[5twins]

You'll really want to pull the barrels off. The front guide has to be perfectly centered and vertical when you mount it. The only way to accomplish that is to measure off the sides of it to the edges of the cam chain tunnel, both at the top and at the bottom. If you don't measure, you could get it mounted in there cocked. To measure at the bottom, the jugs have to be off.

You don't need a ring compressor tool for these motors. The bottoms of the sleeves are beveled so it's easy to work each piston in ring by ring just squeezing them with your fingers and rocking the piston back and forth slightly as you push it in. The trick is to install both pistons into the bores first with the jugs still off, then lower the cylinder w/ pistons installed down onto the rods and push the pins through.

To aid in this, I fabbed up a little set of support blocks to hold the cylinder at just the right height so the pins can be fitted through the rods .....

The blocks are 4 3/8" high by 2 5/8" wide and connected together by a length of all-thread. Once the pins are fitted, you remove the nut on one end of the all-thread and the blocks can be separated and pulled from beneath the cylinders.

 

[madoc]

just over an hour to prep the engine for lifting
As gleaned from this forum, the sump oil strainer is breached.
The oil down there didn't look to be full of anything ...........

however here is the smoking gun .. aluminum and rubber in the top gauze.



The small amounts of mileage, over the past years, have no doubt been down to nobody being willing to drop out the engine and sort out the noise. Hopefully no damage to the oil pump or anything else but I am scared as the top gauze is AFTER the pump .. right .. ?