Valve ajustment

Here is a close up of a couple of the valves to show you what they look like.I have read that "Robertson square head screws" are handy to help with the adjustment,as if you get the right size they fit the square that needs to be adjusted when the nut is loose.



This is certainly what needs doing to make it easier to ajust valves.Take the throttle bodies off.


 
Make sure you block these holes up before you start any work.This job is now ready for tomorrow as you must wait until the engine is cold,very cold before you do any adjustments.

  I'm looking forward to you're findings on the clearance's before you've adjusted them to within their correct tolerance's  

As always Alfie looking forward to the next update from you.  

Hi Lads and lasses well spent all day today checking and putting bike back together,first of all the valves were all in tolerance,the mileage on my bike is 16897miles as speedo is showing.
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A couple of good tips for you are,when you are putting your throttle bodies back,remember to reconnect your vacuum hoses to the IAP Sensors,there are two.
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Also when you are putting everything back together make sure that you put the cylinder head cover caps (chrome) back on first the one next to radiator,this must be done before you put the air filter tube in place otherwise you can't get at the bolt.
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I found the best way to check the valves was,working on the rear engine first (1) the one next to the seat,checking the inlet valves,while turning the engine in the correct way check that the inlet valves are both coming to the top (fully open) TDC  then check your inspection hole to see that R/T is in sight,if you have someone to help you it would be easier.

I am lucky to have the time to do these jobs without worrying about time,but if you are doing the valves for the first time,the night before you do them take everything off that needs to come off,and start the job the next day,as the valves have to be stone cold,I would say it would take around two hours,taking your time.Do not loosen the valves before you check them for as in my case you might not have to adjust them.I hope this helps.

Bloody good call Alfie.   

Great stuff Alfie    

Good job Alfie  

great bit ov tinkering job well done  

Hi, just wondered, you mention in your description about making sure you turn the engine in the right direction, what is the right direction? I have a VS 800 and the Clymer manual states turning the engine clockwise yet on a bike forum I've read, there's a detailed explanation which states to turn the engine counter clockwise. What is correct?

Thanks

Hi Jim I personally always rotate the engine anticlockwise,the reason being in my opinion is that is the way the engine spins normally.This is only my interpretation and has worked for me,hope this helps.

Good stuff Alfie !

I am in full agreement with Alfie, The reason why you turn the engine in the direction of normal ( engine running) rotation is that the timing chain connecting the crank shaft and the cam shaft is tight/straight on one side and slack on the other (timing chain tensioner side ) the camshaft/valves are timed this way,, if you turn the engine the wrong way ( against rotation ) the tight/straight and slack side change places and inevitably there is some slop in the chain ( the tight side is now trying to compress the timing chain tensioner as apposed to the tensioner pushing against the chain to take up the slack ) which puts the timing between the cam and crankshaft out slightly which when adjusting valves means that your crank shaft has rotated slightly/few degrees, before the camshaft moves, and shows that it is on the TDC mark but due to the slop/slackness in the chain the cam shaft is running slightly behind  so will probably not be in the correct place so the cam lobs will be in the wrong place and valve clearances will be incorrect.
I have known this to make a big difference especially if the cam chain is worn or the tensioner is worn ( Kawasaki GT 750 ! ! ! ). A lot of modern engines have hydraulic tensioners but when the engine is not running and the engine is turned against normal rotation they can compress quite a bit. You also have the problem of engines with more than one timing chains as in our case, we can adjust /check valve clearances on more than one cylinder whilst at the same TDC setting.
Another way of looking at this is a normal chain driven motorcycle when the bike is being driven the chain turns the rear wheel and the top of the chain is tight/straight  and the bottom is slack(thrown down) but as soon as you come off the drive and go onto the over run the rear wheel then tries to drive the engine making the bottom of the chain tight/straight and the free play/slop moves to the top.


In the real world and when the engine is in good fettle it doesn't make much difference and in the case of gear driven timing is fairly negligible  but I think it pays to stick to best practice.
I hope this helps and makes sense, it is so much easier to explain this in person, and drawing Wally-grams on a piece of paper, than to try and write it.

John thank you for that explanation,I personally did not know the theory behind the reason it was just the fact the engine turns that way so it must be right.Once again as people say you never stop learning, even after 50 years of tinkering with engines, good write up and explanation.

Interesting read, but my understanding is that valve clearances are set when the valves are closed, so the centre of the base circle of the cam lobe is the part that is aligned to the valve that is being adjusted (Or it's operating linkage - as in the rockers on our engines).

The tip of the cam lobe provides the maximum opening of the valve - & there is no clearance when the cam lobe is opening or closing the valve.

The base circle of a typical 'stock' cam is constant for several degrees (at least 45 degrees either side of centre) and the cam spins at half the crank speed - so in reality there should not be any significant difference in the actual clearance whether you set the valves using clockwise or counter clockwise directions (As any crank - cam miss-alignment is still within the common radius of the base circle of the cam so the clearance will be the same) - PROVIDING that you stay with the same direction. It is poor practice to miss 'the TDC mark' & rotate it backwards to have another go - you should continue to turn the crank in the same direction till you complete the 4-stroke cycle.  For the best accuracy you MUST always turn the crank in the same direction for the check & adjustments of all the valves.

Describing in words makes it sound more complicated than it is - pity I could not draw a diagram to help (Could consider doing that later if it helps anyone)

I do not wish for these comments to detract from what John says above, because his descriptors for the 'tight' & 'slack' sides of a drive chain (or chain on over-run) are excellent. I would fully endorse John's comments about sticking to recognised 'good practice', and agree that if in doubt (i.e. no published guidance) then it is logical to set the valves using the natural rotation direction of the engine as it replicates how all the components will interact in running conditions.

In reality this 'slack' & 'tight' side effect will cause some 'drift' of the cam timing relative to the crank movement, but that should only have a modest effect on the engines power/performance. But again, John's recommendation of turning the crank in the normal direction of running sets it as close to Mr Suzuki's intention as we can get.

Hope that might 'lift the lid' on some of the workings of our engines    Yam