Replacing timing chain

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dgwilson

dgwilson

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I am about to replace the timing chain on my mk11 . After reading the thread by mike916sp I want to make sure everything goes ok.
Can you advise me of the steps required to make this job easy. I want to avoid all the pitfalls that an inexperienced young un might fall into.
 
It's not a difficult job, but do buy a workshop manual. It's older guys like me who do things back-to-front not you young'uns. Bloody brain fade senior moments call 'em what you like. Anyhow, just follow the instructions and double check you'll do just fine.
I usually set the timing chain a little tighter than 3/16" total movement.

Cash
 
OK i have a new timing chain, I took another look at my manual and another look inside the timing case. If I just put a socket on the cam shaft sprocket nut and try to undo it it will turn the cam , camchain and idle gear and maybe strip the worm drive thread. how is this done to change the chain without dismantling anything else and without stripping and wrecking other parts. (I don't even want to take the oil pump off?) ??
 
Put it in third gear and jam down the rear brake pedal, you should be able to undo everything then.

Cash
 
dgwilson said:
and maybe strip the worm drive thread.
Click to expand...


I'm not sure I follow? If the crank starts to turn then the oil pump gear turns, the same as it would normally do?



dgwilson said:
(I don't even want to take the oil pump off?)
Click to expand...


Removing the oil pump to check for excessive end-float is something I certainly would want to do, if that had not been done for a while?




cash said:
Put it in third gear and jam down the rear brake pedal, you should be able to undo everything then.
Click to expand...


I would always opt to use fourth gear, as the sleeve gear is locked to the mainshaft, so no stress goes through the box itself?
 
I am being cautious after reading The trouble Mike916SP had stretching his new timing chain and stripping the worm gear. But after rereading his thread I see he was taking off the worm drive nut to realign the idle sprocket and camshaft with the correct crankshaft position.
So I don't have to touch that crankshaft nut and gears.

It looks to me like the idler sprocket should just pull off( no nut holding it on its shaft) ? The Clymer manual doesn't explain this apart from saying to undo the camshaft end nut and pull the timing chain and both sprockets off?
 
dgwilson said:
It looks to me like the idler sprocket should just pull off( no nut holding it on its shaft) ? The Clymer manual doesn't explain this apart from saying to undo the camshaft end nut and pull the timing chain and both sprockets off?
Click to expand...

Yes, the idler should just slide off the spindle.
 
Thanks guys, and if all goes well with no interuptions from kids etc I might take a look at that oil pump.
 
I had a window of opportunity this afternoon . removed the camshaft Nut . Made a puller to remove the camshaft sprocket.Started to slide both sprockets off their shafts and wouldn't you know it? the worm drive on the crankshaft just interfers with the idler sprocket!! :roll:
So off comes the pump.
But the Nut holding the Worm gear on the crankshaft is sooo tight it wo'nt budge.
I'm not mistaken, this is left hand thread :?:
Did I read somewhere of two guy's struggle to remove this nut and when they finally gave up all hope of removing it without damage to something else a dirty great lever bar and brute force showed it who was boss :?:
 
Yeah, it's got a left hand thread. You need to stop the crankshaft turning somehow. If you have the top end off you can put a steel rod into one of the crankshaft balance holes. If you do this, put some padding between it and the crankcase so you don't damage the crankcase.

I recall my Paul Dunstall manual saying to use a spare timing cover , with the front cut off, to support the idle shaft while you tighten up the camshaft nut.
 
If the top end is off, the best way (according to the book), is to slip a 1/2" ratchet extension through the rod ends, then rotate the crank until it settles on the cases, with some padding to avoid damage.

The nut is one with the worm gear, and it's definitely left-hand thread.
 
I have a ring spanner about 14" long and an extension about 8" levering this nut. The book says use even pressure on it but its just slipping through the clutch, the brake is holding the rear wheel through 4TH gear.
A motor mechanic says he would use his air rattle gun to undo it but i'm not keen on that idea?
Maybe the indian rope trick would work!!
 
Not sure what the Indian rope trick is, but a pneumatic impact wrench would work.

LEFT HAND THREAD - make sure it's set to turn RIGHT.
 
The indian rope trick. Poke a rope into the cylinder until its full.This then locks the engine. aparently its been used by other guys on this forum with some success.
 
dgwilson said:
The indian rope trick. Poke a rope into the cylinder until its full.This then locks the engine. aparently its been used by other guys on this forum with some success.
Click to expand...

I'd think you'd want to make sure the cylinder you're stuffing rope into is on the compression stroke otherwise you'll have valves poking into the rope and getting pushed around when they are off their seats which would do them no good at all.
 
This is right . I haven't used this method myself but it is mentioned on a couple of previous threads.
I suppose if you get desperate enough you would try anything that sounds feasable :shock:
 
Another weekend and another opportunity to remove that crank worm drive nut. I decided to remove the righthand header pipe so it was out of the way of the ring spanner. What a difference a new day and a prayer makes. Second heave on the spanner and I thought it had slipped off the rather skinny nut but lo and behold it cracked it loose. :D So all should be plain sailing to install the new chain and ignition.
oops hope i didn't speak too soon. I'll find out another day at the next opportunity. :D
 
grandpaul said:
Not sure what the Indian rope trick is, but a pneumatic impact wrench would work.

LEFT HAND THREAD - make sure it's set to turn RIGHT.
Click to expand...

If you try this one be very very carefull. The socket can imact right on the starters of the actual worm drives themselves. They will break off under the impact if the depth of the socket is not spot on. I know - I had it happen and it cost me for a new gear. Its certainly a method I would never try again.
 
new timing chain

It's only taken a month to replace the timing chain and get the cover back on !!. I thought i'd put the old points and bob weights back in just to see if there was any noticable changes. The old original chain felt looser and was definately worn.
The idle is steady at 1000rpm so thats a great improvement the old chain had it hunting all over the place. I have only ridden it around town and need to go on a good run to fully see the difference.
Next week i'll install the Trispark.
 
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