Sanity check

Murray Mint · 10-05-2019, 08:16 PM

Hi guys, having researched the subject and while I’ve got the carbs off I thought id check the valve clearances. I’ve used the screwdriver pushing down on the closing rocker to measure the closing clearance as per the Ducati Tech video.

Would someone be so kind to sanity check my findings.

Valve clearances. 1993 900

Vertical cylinder
In opener 0.14mm. 0.02 over spec
In closer 0.29mm
Difference 0.15mm. 0.10 over spec

Ex opener 0.13mm. Within tolerance
Ex closer 0.18mm
Difference 0.05mm. Within tolerance

Horizontal cylinder
In opener 0.13mm. 0.01 over spec
In closer 0.13mm
Difference 0.00mm. Too tight, needs to be 0.03 - 0.05

Ex opener 0.15mm. Within tolerance
Ex closer 0.21mm
Difference 0.06mm. 0.01 over spec

Macflurry · 11-05-2019, 12:28 AM

Looks like you're using Ducatis spec's and yes your readings look good.

Opening Rocker

Inlet, mm/in. 0.10-0.12
Exhaust, mm/in. 0.12-0.15

Closing Rocker

Inlet and exhaust, mm/in. 0.03-0.05

But it does depend whose spec's you take to measure by. I did put a post up that covers a few peoples different spec's: http://www.ukmonster.co.uk/monster/s...ad.php?t=56856

What I also found was that when the new shims turned up they were anything up to 0.16mm out from the size that they said they were and I ended up spending a lot of time with wet and dry paper on a glass board sanding them back into spec'!!

Murray Mint · 20-05-2019, 08:50 PM

So I have measured the clearances three times so far just to make sure that they are consistent and yes they are, I do however have an anomaly, when I measure the inlet opener shim on the vertical cylinder I found that depending on the orientation of the shim there is a tight spot.

I marked the shim with a white marker and found that there is an area of rotation of about 1/3 of a turn where the shim is at is loosest, see picture below. has anyone experienced this before? should I use this "loose" spot to measure the valve clearance?

Dukedesmo · 21-05-2019, 08:22 AM

Quote:

Originally Posted by Murray Mint

I marked the shim with a white marker and found that there is an area of rotation of about 1/3 of a turn where the shim is at is loosest, see picture below. has anyone experienced this before? should I use this "loose" spot to measure the valve clearance?

Not noticed but have seen a difference when spring clip fitted or not.

What sort of difference are we talking about?

Murray Mint · 21-05-2019, 11:21 AM

The difference is about .07mm, ill post some pics later.

Macflurry · 21-05-2019, 11:43 AM

If someone has sanded down the shims previously they may be uneven or if any dirt is under the shim.
I've even read people saying any oil in there will put your reading off.

I personally would take the max/ min reading and then go with whichever is worse.

10-05-2019, 08:16 PM	#1
Murray Mint Member Join Date: Jul 2009 Location: Crawley Bike: M900 Posts: 106	Sanity check Hi guys, having researched the subject and while I’ve got the carbs off I thought id check the valve clearances. I’ve used the screwdriver pushing down on the closing rocker to measure the closing clearance as per the Ducati Tech video. Would someone be so kind to sanity check my findings. Valve clearances. 1993 900 Vertical cylinder In opener 0.14mm. 0.02 over spec In closer 0.29mm Difference 0.15mm. 0.10 over spec Ex opener 0.13mm. Within tolerance Ex closer 0.18mm Difference 0.05mm. Within tolerance Horizontal cylinder In opener 0.13mm. 0.01 over spec In closer 0.13mm Difference 0.00mm. Too tight, needs to be 0.03 - 0.05 Ex opener 0.15mm. Within tolerance Ex closer 0.21mm Difference 0.06mm. 0.01 over spec

20-05-2019, 08:50 PM	#3
Murray Mint Member Join Date: Jul 2009 Location: Crawley Bike: M900 Posts: 106	So I have measured the clearances three times so far just to make sure that they are consistent and yes they are, I do however have an anomaly, when I measure the inlet opener shim on the vertical cylinder I found that depending on the orientation of the shim there is a tight spot. I marked the shim with a white marker and found that there is an area of rotation of about 1/3 of a turn where the shim is at is loosest, see picture below. has anyone experienced this before? should I use this "loose" spot to measure the valve clearance? Last edited by Murray Mint; 20-05-2019 at 08:52 PM..

11-05-2019, 12:28 AM	#2
Macflurry Registered User Join Date: Mar 2018 Location: Blakeney Bike: M900 Posts: 134	Looks like you're using Ducatis spec's and yes your readings look good. Opening Rocker Inlet, mm/in. 0.10-0.12 Exhaust, mm/in. 0.12-0.15 Closing Rocker Inlet and exhaust, mm/in. 0.03-0.05 But it does depend whose spec's you take to measure by. I did put a post up that covers a few peoples different spec's: http://www.ukmonster.co.uk/monster/s...ad.php?t=56856 What I also found was that when the new shims turned up they were anything up to 0.16mm out from the size that they said they were and I ended up spending a lot of time with wet and dry paper on a glass board sanding them back into spec'!!

21-05-2019, 11:21 AM	#5
Murray Mint Member Join Date: Jul 2009 Location: Crawley Bike: M900 Posts: 106	The difference is about .07mm, ill post some pics later.

21-05-2019, 11:43 AM	#6
Macflurry Registered User Join Date: Mar 2018 Location: Blakeney Bike: M900 Posts: 134	If someone has sanded down the shims previously they may be uneven or if any dirt is under the shim. I've even read people saying any oil in there will put your reading off. I personally would take the max/ min reading and then go with whichever is worse.