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Thank you both so much for assisting me with advice and valve shims. The bike is now almost reday for the road. I enclose some recently taken pictures from the bike in my garage.
Hi Hans,
good looking bike !
Are you sure the valve cover was fitted before(!) you have set the cam chain tensioner ?
Setting the tension of the cam chain while valve cover is removed and mounted afterwards, that will destroy your engine !
All the best,
MichaelPS: Avoid that by following the right sequence !
Micheal, that’s both the best and the worst photo I’ve seen on here. Please explain why it happened?
Ok, from valve lifter holder to engine damage 😉
It was not my engine before but it is very likely that the previous owner has adjusted the valve clearance. Well, that’s fine but the valve cover is removed.
While doing this service work it is tempting to adjust the cam chain tensioner as well (which is a fatal error!). While the cover is off you can see how the chain get tensioned, you can feel it.
Being happy to have all that done, the valve cover is mounted again. In the top middle there is a cam chain guide that presses the chain down. You can’t set the cover by hand to sit on the sealing surface. Ok, grab the bunch of M6 screws and bolt the cover down. That works but the cam chain is tensioned by far to much.
You can even feel that the engine doesn’t crank over smoothly. Force is needed to crank it. Riding the bike in that condition is a very bad idea and will force the cam chain to break. As it still is in movement and the crankshaft is turning, the chain gets jammed in the crankcase and it breaks the case.
Except from the gear drive the engine is damaged completely:
– The tensioner of the balancer chain broke off and the balancer chain broke too.
– A piece of the engine case got a hole
– some teeth at the crankshaft – to drive the cam chain – broke offIt is very likely that this little error in sequence could be avoided by following the right sequence.
Only tension the cam chain tensioner while the valve cover is in place !The spectakular pics were made after the damage happened and the engine was turned upside down to remove the oil pan. That causes all the loose parts to fall back to the crankcase instead of lying in the oil pan.
Here some more pics:
Got to admit I like a bit of utter destruction occasionally 😉 Thanks for that, hope the word spreads to those who could benefit from it. Not me, the insides of an engine are more or less a total mystery to me, I think I would struggle to change the clutch plates (I actually need to do this right now, but I’ve been avoiding it) 🙁
Oh…. my goodness. What a nasty picture.
Luckily I did not alter or adjust the valve tensioner with the cover off. But just generally…. the chain does feel tight when pressing it down but maybee it should be that way. I will check the tension again according to the work shop manual.
Do you have any advice here…?
When refitting the valve cover you cam chain tensioner should NOT be fitted. you will have noticed when timimg the cams that they do not appear to quite line up properly. There is a reason for that. In the middle of the inside of the valve cover is a rubber skid. When the valve cover is fitted this skid pushes down the cam chain inbetween the camshafts and ‘corrects’ this ‘error’.
Make sure the slack in the cam chain is inbetween the camshaft sprockets. This part should not be tight as you will struggle to get the valve cover to sit flat and seal.
Once the cover is bolted down refit the cam chain tensioner and slowly turn the engine by hand to transfer the slack left between the camshafts to the front of the engine then adjust the cam chain tensioner so that the end plunger is flush with the end of the body at its innermost position.
Hi Andy,
Thanks for your very quick reply. I suppose I need to go through that procedure even though I have not removed the camhshafts? I have only adjusted the valves with the special tool.You mention that the plunger should be flush with the adjuster body at its outermost position. The workshop manual says “innermost position”. Is your advice to leave it a bit looser than what the manual says?
My apologise Hans you are correct.
It is innermost. I have amended my previous post.
Even though you have not removed the camshafts you will have rotated them without the valve cover on so it is at that point you need to be aware of.
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