Valve clearances

Stevie4scoops · Mar 17, 2023

Why bike manufacturers don't fit self adjusting hydraulic tappets or whatever they call them bugs me.

I know they say they don't work with high revving engines but you don't need to adjust the valve clearances on Porsches/BMW M3s etc so this is nonsense and I believe they could be used on the majority of bikes.

Having to strip so much off bikes just to check the valve clearances is such an expensive waste of time, there must be a better way?

Slipperyeel · Mar 17, 2023

Posh Pete said:
Setting it up on TDC on the wrong stroke. It's easy done ...

Yea, we know that. But we were waiting to here if the op had discovered if this was the cause of their issue (highly likely!)

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Slipperyeel · Mar 17, 2023

SteveC10 said:
Why bike manufacturers don't fit self adjusting hydraulic tappets or whatever they call them bugs me.

I know they say they don't work with high revving engines but you don't need to adjust the valve clearances on Porsches/BMW M3s etc so this is nonsense and I believe they could be used on the majority of bikes.

Having to strip so much off bikes just to check the valve clearances is such an expensive waste of time, there must be a better way?

Well, if it's the TC we're taking about, then as quoted above, it's an infrequent job...

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Stevie4scoops · Mar 17, 2023

Slipperyeel said:
Well, if it's the TC we're taking about, then as quoted above, it's an infrequent job...

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Bikes with inline cylinders are most difficult and time consuming to check/adjust.

GSs are easy but why not do away with needing it altogether?

Slipperyeel · Mar 18, 2023

SteveC10 said:
Bikes with inline cylinders are most difficult and time consuming to check/adjust.

GSs are easy but why not do away with needing it altogether?

Yea, I see your thinking. There must be a reason? Weight? Money? Durability?

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cookie · Mar 18, 2023

Hydraulic adjusters on an overhead cam engine probably makes the engines taller and the valve timing a bit variable? All right on a push rod motor like old Harleys (which do have hydraulic tappets I think).

Mistacat · Mar 18, 2023

cookie said:
Hydraulic adjusters on an overhead cam engine probably makes the engines taller and the valve timing a bit variable? All right on a push rod motor like old Harleys (which do have hydraulic tappets I think).

Yes, Harleys use hydraulic tappets on push rod motors, Kawasaki use hydraulic tappets on overhead cam engines as well i.e. Kawasaki VN1600 V twins.
But as you say it would make the Boxer engine even wider which it does not need.
And for the mileage a TC will do without valve adjustment there is no point and they are so accessible.
Re shimming the cams on a Fireblade or Hayabusa are not nearly as easy.

GrahamWebb · Mar 23, 2023

I did this same job the other day on my 2010, I just bent the feeler gauges a couple of cm from the end so they had the right angle.

Stevie4scoops · Mar 23, 2023

Mistacat said:
Not sure why anyone would try to set it up on TDC when all you have to do is align the 2 marks on the cams, it is that easy on a twin cam.

Agree, once you've seen the marks it all makes sense, is very easy to do and doesn't require any tools.

GrahamWebb · Mar 25, 2023

I did mine after watching this video, I just had to watch it again as had a bit of a moment thinking I had done it wrong. On other bikes the past I have measured between where the top of the valve stem hits the rocker but on the GS its between the cam face and the rocker.

https://youtu.be/8TKhsY_wLM8

One of my valves was actually on the loose side, I could just about get the top of spec feeler gauge through it but only on one side not through the middle.

botus · Mar 26, 2023

nice video - easier than the screw and lock nut - waiting for a new shim would be a pahff though

Stevie4scoops · Mar 27, 2023

botus said:
nice video - easier than the screw and lock nut - waiting for a new shim would be a pahff though

If a clearance is a little tight, rather than wait for a replacement, I rub the shim around on some wet and dry until it's the right thickness.

Alternatively, you may get lucky by swapping some shims around to get them all back in tolerance.

seahorse · Mar 27, 2023

It takes 10 mins to put back together. Then order your shim, then when it arrives, it'll take another 10 mins to be back where you were. If Its all done right you will probably be checking only for many miles

Valve clearances

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