Shim sizes

[darkember]

Would anybody be able to tell me if the shims on these bikes prior to any previous valves clearance checks & changes, ie: from the factory are standard sizes for the exhaust & inlet valves. If so what would those sizes be.

Or are all bikes different when they emerge from the factory with differing shim sizes??

[8541Hawk]

There is no set size for the shims from the factory.

[mattycoops43]

Yup, you just need to measure them, then re arrange/order new as appropriate.

They have sizes etched on, but they are often worn away. they go underneath where there is no movement to wear them (on the bikes I have done anyway)

[darkember]

OK here are my clearance measurements in mm orientation as being sat on the bike:

FRONT Pot:

Inlet:
Left cam: 0.12 (tight)
Right cam: 0.15 (ok)

Exhaust:
Left cam: 0.27 (tight)
Right cam: 0.29 (limit)

REAR Pot:

Inlet:
Left cam: 0.16 (ok)
Right cam: 0.12 (tight)

Exhaust:
Left cam: 0.29 (limit)
Right cam: 0.27 (tight)

Ok by reducing the shim sizes that are in the tight ones at present by 0.05mm will bring the tolerance back to 0.17 for the Inlets & 0.32 for the Exhausts, that is all cool & in hand.

However: notice the 2 exhausts cams that are at 0.29 which is 0.01 off the tight limit, would I be prudent to also reduce those shims and bring that clearance up to 0.34. Or are they best left alone??

[kitsun]

I would do those 2 "borderline" cases any if i were you. the cams are coming off for the others and you might as well get it done all at once.

kit

[tony.mon]

Always aim for a clearance between the loose limit and halfway through the range.
Because clearances tighten, due to valve and seat wear, the clearances will always close.
For that reason, be more concerned about the lower clearance limit.

However, if the clearance is too big, the percussive effect of the constant hammering closed will make the gap bigger, as the head of the valve stem, cam and shim/bucket wear.
So if it's too big it is likely to get bigger, if it's too tight it will likely get tighter.
But as too big just gets rattly, whereas too tight can lead to clearances closing up (when expansion is taken into account due to heat) the valve seat and valve can burn out because the valve is not able to fully close. Also the cam base circle starts to wear, creating lots more problems.

It's a minefield, a bloody minefield.
A wonder we're not all dead in our beds, miracle the things run at all, (goes off muttering, stroking beard and shaking head).

[darkember]

Always aim for a clearance between the loose limit and halfway through the range.
Because clearances tighten, due to valve and seat wear, the clearances will always close.
For that reason, be more concerned about the lower clearance limit.

However, if the clearance is too big, the percussive effect of the constant hammering closed will make the gap bigger, as the head of the valve stem, cam and shim/bucket wear.
So if it's too big it is likely to get bigger, if it's too tight it will likely get tighter.
But as too big just gets rattly, whereas too tight can lead to clearances closing up (when expansion is taken into account due to heat) the valve seat and valve can burn out because the valve is not able to fully close. Also the cam base circle starts to wear, creating lots more problems.

It's a minefield, a bloody minefield.
A wonder we're not all dead in our beds, miracle the things run at all, (goes off muttering, stroking beard and shaking head).

All clear with the above Tony pity they don't make 0.025 shim sizes In your knowledgeable mind as you see I don't have a lot of choice its either leave at 0.29 or move to 0.34, which would be more prudent??

[tony.mon]

Always aim for a clearance between the loose limit and halfway through the range.
Because clearances tighten, due to valve and seat wear, the clearances will always close.
For that reason, be more concerned about the lower clearance limit.

However, if the clearance is too big, the percussive effect of the constant hammering closed will make the gap bigger, as the head of the valve stem, cam and shim/bucket wear.
So if it's too big it is likely to get bigger, if it's too tight it will likely get tighter.
But as too big just gets rattly, whereas too tight can lead to clearances closing up (when expansion is taken into account due to heat) the valve seat and valve can burn out because the valve is not able to fully close. Also the cam base circle starts to wear, creating lots more problems.

It's a minefield, a bloody minefield.
A wonder we're not all dead in our beds, miracle the things run at all, (goes off muttering, stroking beard and shaking head).

All clear with the above Tony pity they don't make 0.025 shim sizes In your knowledgeable mind as you see I don't have a lot of choice its either leave at 0.29 or move to 0.34, which would be more prudent??

You can get the exact sizes you need from a Honda dealer.
It's just the Ebay people that split HotCams sets that list nowt but .05 increments.

[8541Hawk]

You can get the exact sizes you need from a Honda dealer.
It's just the Ebay people that split HotCams sets that list nowt but .05 increments.

+1 that is why I have never bothered with one of those kits. They only have half of the shim sizes.

[tony.mon]

As long as it's within the recommended range it'll be fine until the next valve check Dark.
They don't move much after the first one at 16K or so anyway.

[tony.mon]

By the way, just today I ordered 8 from an ebay supplier for £16, not bad.

Only trouble with a set isd you have to keep it topped up, I try to keep at least 2 of each size.

[darkember]

As long as it's within the recommended range it'll be fine until the next valve check Dark.
They don't move much after the first one at 16K or so anyway.

This is the first one done at 22K hence probably why they are more out than usual. Anybody have a contact to get the Honda sizes for mine that are close to the limits??

[tony.mon]

As long as it's within the recommended range it'll be fine until the next valve check Dark.
They don't move much after the first one at 16K or so anyway.

This is the first one done at 22K hence probably why they are more out than usual. Anybody have a contact to get the Honda sizes for mine that are close to the limits??

Yes, google for your nearest Honda Main Dealer.
Or call David Silvers, they sometimes have the intermediate sizes, so 1.825 between 1.8 and 1.85, for example.
You have to call because their searches are model specific, not generic.

[darkember]

Good news from the local bike shop. All my valve clearances have been done & they have managed to get all inlets to 0.15 & all exhausts to 0.30 without have to buy a single shim. They told me they did it by precision grinding, I will hold judgement until I fire it up. If all is fine then I may have found a rare gold mine of a bike shop

[lloydie]

Good news from the local bike shop. All my valve clearances have been done & they have managed to get all inlets to 0.15 & all exhausts to 0.30 without have to buy a single shim. They told me they did it by precision grinding, I will hold judgement until I fire it up. If all is fine then I may have found a rare gold mine of a bike shop

!!!!! Check them clearances .
If they have ground them it should be fun next time you need shims as it'll be all 8 !!