650 Timing Chain

[Guest]

Hi Guys,

The new timing chain for the Katana has arrived.

Trouble is, it's a solid crimp link as opposed to a hollow rivet link.

My existing chain tool will only handle rivet links - It will split it, but not join it!

Is there a DIY way of doing it? (something I'm hoping to avoid if I can) or what tool will I need to do the job?

Obviously it needs to be done properly....

Thanks,

J

[Nessism]

Unless the engine has 100k miles on it the chain is most likely fine. Did you measure the length per the service manual, and if so, what length did you measure? You might be shooting yourself in the foot with this chain changing business.

As for changing the chain, sorry can't help. Think you need special equipment and/or the right kind of master link with crimpable pin.

[G0FHM]

Ed,

I've said this before in another thread.... It's well and truly knackered, has a major slack spot (1/2" up and down movement between the sprockets) and that spot can be heard coming across the top as it comes round.

The engine is high mileage (69k), and I'm not prepared to risk it for the sake of a £30 for a chain!

J

[Nessism]

Ed,

I've said this before in another thread.... It's well and truly knackered, has a major slack spot (1/2" up and down movement between the sprockets) and that spot can be heard coming across the top as it comes round.

The engine is high mileage (69k), and I'm not prepared to risk it for the sake of a £30 for a chain!

J

You can't judge by how much the chain moves between the cams. Measure between pins per the manual then judge. Bet you the chain measures in spec. It's always the UK guys that think their cam chain is knackered. Must be some thing in the water over there.

[G0FHM]

Well I have read a line in a book that says 650 timing chains are very well known to be noisy, and have led to many a top end rebuild, only for the owner to still have the noise when it has been done... So I know all about the noise properties!

I'll bet a pound to a pinch of wotsit it's knackered.... Turn it to a good section between the cams and there is minimum up and down movement!

I'll borrow my calipers back over the weekend and check it.... But I don't hold out much hope of it being any good!

J

[tkent02]

Come on Ed, you know 100,000 miles of wear can happen in a minute if it's run dry, overheated, run with crap oil and never changed, or a number of other things can happen to it. While some chains last forever, not all do. Cam chains have been known to break, even on lower mileage bikes. I have one in my shop right now with a broken cam chain. You could hear the chain clicking over the sprockets at idle for thousands of miles before it broke.
It's not pretty. Quite knackered, actually. The whole engine is.

But the part about the good section running tight leads me to suspect the cam chain sprockets also. Could be either one I think. Dunno.

Sorry can't help with the master link technique. I haven't ever done it except with endless chains or the rivet type links. I have heard there are some cam chains sold with the easy clip type masters, but they are frowned upon by people who do engines.

Maybe the best answer is to flip the engine over, remove the bottom case and put in a new endless chain? If it's worth doing it may be worth doing right.

[Steve]

Maybe the best answer is to flip the engine over, remove the bottom case and put in a new endless chain? If it's worth doing it may be worth doing right.

I have never changed an endless cam chain, but don't you have to slip it over the end of the crank?

Wouldn't that also require removing the top of the engine so you can completely remove the crank and slide the chain over the pistons?

.

[tkent02]

Wouldn't that also require removing the top of the engine so you can completely remove the crank and slide the chain over the pistons?

.

Engine upside down. Remove bottom case half. Lift up crankshaft by one end. Replace chain. Lower crankshaft. Replace case half with Threebond or whatever.
Put the engine right side up and install the camshafts and vave cover.

No need to open the top end at all, other than to fish the new chain through the valve cover and put the cams in place. Everything below the valve cover can stay there.

[Nessism]

Judging chain wear by how much slack there is between the cams is a faulty technique. The cams park themselves depending on what valve is pushing on what lobe, which can advance or retard the cam(s) enough to create/eliminate slack between them. The only way to properly judge cam chain wear is to measure. Preemptively changing the chain at 69k isn't the worst decision I've read about here, but make sure the proper tools are used to join the chain or better yet, split the crankcase and use an endless chain.

[Steve]

Engine upside down. Remove bottom case half. Lift up crankshaft by one end. Replace chain. Lower crankshaft. Replace case half with Threebond or whatever.

Sounds too easy. Still trying to wrap my mind around how to get the chain to the middle of the crank without also going past two pistons and connecting rods.

.

[tkent02]

Sounds too easy. Still trying to wrap my mind around how to get the chain to the middle of the crank without also going past two pistons and connecting rods.

.

Oh yeah. You lift the pistons up and out with the crank. Put them back in once the new chain is on, leaving it all connected. I haven't actually done it, but I looked at one of my opened up engines while I read a thread about it a while ago, it all seemed like it would work. The guys saying it worked were some of the guys who do engine work a lot more often than I do.

[Steve]

Oh yeah. You lift the pistons up and out with the crank. Put them back in once the new chain is on, leaving it all connected.

Apparently much like funneling the rings into the bottoms of the cylinders when doing a top-end rebuild, but without the expense of the top-end gaskets.

Having gone through a few top-end jobs (am doing one right now, in fact), and having seen how difficult it is to feed the rings into the tapered ends of the cylinders when I can actually reach them, I can only imagine the 'fun' of trying to do that when the crank is blocking your view and access.

.

[tkent02]

Looking at the engine sitting on my bench, it didn't look all that hard. Two people required for sure, but it didn't look bad. The sleeves stick out below the case, there is the same amount of space between the piston top and the crankshaft as there is right side up. One guy holds the crank while the other stuffs the rings in. I have a 550/675 engine to assemble this week if I get to it, maybe I'll do it that way as an experiment. Finding the second set of hands and enough round tuits will be the hard part either way.

[G0FHM]

New chain fitted, and done.

Big improvement - The noise has stopped.

Looking at the old chain, the lateral movement is severe. It was well worn, and I made a good call by deciding to replace it.

Having shown the old one to a bike mechanic of 20 years experience, he said he had never seen one that bad, that hadn't already failed!

Looks like I dodged a bullet there!

J

[G0FHM]

By the way, I borrowed the correct tool for the job.

Like a drive chain tool, but much smaller and with different sized tips to mushroom the ends of the pins.

I did it the "quick and durty" way of removing the cams and linking the 2 chains together and threading it through on the crank. That was a bit of a heart in mouth moment ;-) Cam sprockets look good - No abnormal wear or "hooking" apparent. Obviously I cannot say the same for the crank sprocket, as I haven't seen it!

I've done it this way "for now", as it's riding season and it's more than my life is worth to have it off the road for any amount of time (Hell hath no wrath like a woman without a bike).

Over the winter I will be pulling the engine and splitting the cases to change the gear cluster anyway, so an endless chain may well find it's way in. I want to do a complete stripdown and check and if required change any bottom end related bits (not that there is much wrong - The oil pressure light goes off before it fires!).

I did the top end a while ago and installed new rings, and have imposed a 4000rpm limit for 800 miles (which is probably more than it will cover this summer anyway), so hopefully all will stay good.

J