Have fitted new guides and ground in new valves. What are the recommended valve clearances nowadays?
I understand that I need to measure the valve stem height and then from a look up chart fit the appropriate size shim but that was based on 2" to 4" thou clearance (0.05 to 0.10 mm)?
So is that the correct valve clearance to be working to?
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Valve clerances
Moderators: KeithZ1R, chrisu, paul doran, Taffus
Work in MM's not thou's.
Go for 0.10mm to 0.15mm ( The 0.5mm lower figure give in earlier manuals is too tight which is why Kawasaki changed it to 0.10mm )
Closer to the upper figure is better and they will close slightly after the first initial run as all the new valves etc settle in .
If you have a selection of shims, build it with some thin ones and then work out the correct shim sizes needed after measuring the gaps with a feeler gauge.
Go for 0.10mm to 0.15mm ( The 0.5mm lower figure give in earlier manuals is too tight which is why Kawasaki changed it to 0.10mm )
Closer to the upper figure is better and they will close slightly after the first initial run as all the new valves etc settle in .
If you have a selection of shims, build it with some thin ones and then work out the correct shim sizes needed after measuring the gaps with a feeler gauge.
Trying to measure the valve stem heights with a digital vernier, get a different reading every time.
The Doremi exh valves measure about 1mm longer than the original ones and I'm getting stem measurements of nearly 38 mm meaning that the shims are going to be around the limit of 2.00 mm?
Will have to get some small ones from the club, and then do as suggested just fit some shims and then work out the exact sizes required, but will be a bit concerned if they require the low 2's? Current shims range from 2.45 to 2.85.
You have indicated that I should be looking for 0.1 to 0.15 mm which will make things potentially more difficult?
The Doremi exh valves measure about 1mm longer than the original ones and I'm getting stem measurements of nearly 38 mm meaning that the shims are going to be around the limit of 2.00 mm?
Will have to get some small ones from the club, and then do as suggested just fit some shims and then work out the exact sizes required, but will be a bit concerned if they require the low 2's? Current shims range from 2.45 to 2.85.
You have indicated that I should be looking for 0.1 to 0.15 mm which will make things potentially more difficult?
)sprint wrote:Trying to measure the valve stem heights with a digital vernier, get a different reading every time.
The Doremi exh valves measure about 1mm longer than the original ones and I'm getting stem measurements of nearly 38 mm meaning that the shims are going to be around the limit of 2.00 mm?
Will have to get some small ones from the club, and then do as suggested just fit some shims and then work out the exact sizes required, but will be a bit concerned if they require the low 2's? Current shims range from 2.45 to 2.85.
You have indicated that I should be looking for 0.1 to 0.15 mm which will make things potentially more difficult?
Measuring with a vernier always gives spurious readings and you really need the correct tool from APE or make one yourself if you have a lathe. ( There are pic's of the tool in my Café racer thread ).
That 38mm is too long though and those valves need tipping before you go any further.
Now is the time to sort it properly other wise you will be pulling it apart again very soon as you will quickly run out of clearance.
You need to get the stems down to around the 37.2 mm minimum installed height and a lot of these pattern valves are too long above the collet groove so it should hopefully not be a problem.
The minimum height from the collet groove to stem tip is 4.2mm but if you need to take off more to achieve the correct stem height then the spring retainers can also be skimmed to prevent the buckets from bottoming out on them.
Unfortunately I do not have access to any machine tools, only what I have in the garage which are basically hand tools.
Can you provide a link to the cafe race site your refereed to for the photo?
Nor do I have ready access to get the tops of the valves skimmed down. Assume that when you are buying well known brands that they are made to fit. Seats have not been cut before and they have not been cut this time only lapped in as I was able to 'draw the guides in to maintain concentricity.
Will probably have to fit the cams to the head while off the engine and see what the clearances are actual like, with only 1 and 3 or 2 and 4 valves fitted at a time, as I do not want to build the engine only to find that it has to be ripped apart again to sort the valve clearances.
Are the any members near the Eastbourne area of East Sussex who may be able to help if needed?
Can you provide a link to the cafe race site your refereed to for the photo?
Nor do I have ready access to get the tops of the valves skimmed down. Assume that when you are buying well known brands that they are made to fit. Seats have not been cut before and they have not been cut this time only lapped in as I was able to 'draw the guides in to maintain concentricity.
Will probably have to fit the cams to the head while off the engine and see what the clearances are actual like, with only 1 and 3 or 2 and 4 valves fitted at a time, as I do not want to build the engine only to find that it has to be ripped apart again to sort the valve clearances.
Are the any members near the Eastbourne area of East Sussex who may be able to help if needed?
sprint wrote: Can you provide a link to the cafe race site your refereed to for the photo?
page 7 of this link.
Rob is very talented as you will see if you look through his thread. I am envious of his talents.
http://www.z1ownersclub.co.uk/forum/vie ... sc&start=0
👀 👀 👀
email - adrianhorsfield@live.co.uk
email - adrianhorsfield@live.co.uk
Why did you fit new valves ?
If the originals weren't bent there should be no reason why they can't be re-used and that will solve your problem.
If the new valves are just longer from the collet groove upwards then any machine shop should be able to tip them for you and no further modifications should be needed.
You just need to work out how much off each one is needed.
With the absence of the height tools I suggest assembling the head as normal, with one cam at a time, without stem seals and just the outer valve spring to make cam rotation on the bench easier.
Install a 2mm shim and note the clearance.
Use that figure to work out how much needs to be taken off each individual valve tip to get say a 3.1mm or 3.2 mm shim in with allowance for the valve clearance.
Just watch that 4.2mm minimum stem tip height .
If the originals weren't bent there should be no reason why they can't be re-used and that will solve your problem.
If the new valves are just longer from the collet groove upwards then any machine shop should be able to tip them for you and no further modifications should be needed.
You just need to work out how much off each one is needed.
With the absence of the height tools I suggest assembling the head as normal, with one cam at a time, without stem seals and just the outer valve spring to make cam rotation on the bench easier.
Install a 2mm shim and note the clearance.
Use that figure to work out how much needs to be taken off each individual valve tip to get say a 3.1mm or 3.2 mm shim in with allowance for the valve clearance.
Just watch that 4.2mm minimum stem tip height .
Sounds like the best plan.
There shouldn't be anything wrong with the original valves and they are miles better quality that the pattern stuff.
I would still look at tipping the valves if possible though, especially those in the lower shim range as I would bet those lower 245's will be closer to 235 once they are re-ground and have the correct clearance which is heading towards the lower end of the range again.
You can afford to take the max 0.3mm off all the valves as that would put the widest shim at around 310mm and the lowers at 270 ish and you would be good for years to come.
There shouldn't be anything wrong with the original valves and they are miles better quality that the pattern stuff.
I would still look at tipping the valves if possible though, especially those in the lower shim range as I would bet those lower 245's will be closer to 235 once they are re-ground and have the correct clearance which is heading towards the lower end of the range again.
You can afford to take the max 0.3mm off all the valves as that would put the widest shim at around 310mm and the lowers at 270 ish and you would be good for years to come.
the easiest thing to do is assemble the head and use a 2mm shim and see what clearence you have, wright down what you have and what you need.
remove the valves and measure the overall lenghth of each valve you take out, look what shims you have then work out what needs to come off each valve, that way your making the valves fit the shims you already have
the guy i use to tip valves charges me £10 to do all eight
DON'T forget to number the valves
remove the valves and measure the overall lenghth of each valve you take out, look what shims you have then work out what needs to come off each valve, that way your making the valves fit the shims you already have
the guy i use to tip valves charges me £10 to do all eight
DON'T forget to number the valves
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