Small valve clearances

289 Views 14 Replies 4 Participants Last post by RobShed, 2 d ago

Dmytro

Discussion Starter · 12 d ago

Hi all. On the forum, motorcycle owners ask how to solve the problem with large valve clearances. My situation is the opposite. I took measurements and saw that on all the valves I have gaps less than they should be. With what it can be connected? If we take into account that the gaps are only adjustable to a smaller size, by replacing the worn tablet. The mileage of the motorcycle is 31,000 kilometers (but I can't be sure if it's correct).
TNT 1130 2005.

cylinder #1
Suction Left 0.25mm Right 0.25mm
Exhaust L 0.28mm R 0.30mm

cylinder#2
Suction L 0.25mm R 0.28mm
Exhaust L 0.33mm R 0.35mm

cylinder #3
Suction L 0.25mm R 0.25mm
Exhaust L 0.33mm R 0.35mm

1 - 15 of 15 Posts

Engenia

· #2 · 12 d ago

Dmytro said:
With what it can be connected? If we take into account that the gaps are only adjustable to a smaller size, by replacing the worn tablet...

There is a range of shims available, from 1.20 to 2.50 in 0.02 mm increments.
Although they do get damaged by valve stem in the Tornado by the 1000 N springs, the normal wear is the erosion of the valve - valve seat, which will reduce the gap - a.k.a. valve recession.
The hammering of the valve stem creates an indent, that increases the gap.
You can only tell what's going on by removing the cams to gain access to the shims.
In the past, knowing that the shims will indent, I have set the gaps to be on the small side, expecting the gap to grow. The hammering hardens the shim, reducing the gap growth over 5 - 10,000 km. If you can get to 10,000 without the gap going out of spec, it'll stay in spec for another 10 to 40,000 kms.
Precision Shims, in Melbourne, now have a 'D2' shim hard enough to withstand the hammering abuse, but you have to ask for it specifically. With these shims, I set the gaps mid-range. The only gap movement will be reduction due to valve recession.

Dmytro

Discussion Starter · #3 · 9 d ago

Engenia said:
There is a range of shims available, from 1.20 to 2.50 in 0.02 mm increments.
Although they do get damaged by valve stem in the Tornado by the 1000 N springs, the normal wear is the erosion of the valve - valve seat, which will reduce the gap - a.k.a. valve recession.
The hammering of the valve stem creates an indent, that increases the gap.
You can only tell what's going on by removing the cams to gain access to the shims.
In the past, knowing that the shims will indent, I have set the gaps to be on the small side, expecting the gap to grow. The hammering hardens the shim, reducing the gap growth over 5 - 10,000 km. If you can get to 10,000 without the gap going out of spec, it'll stay in spec for another 10 to 40,000 kms.
Precision Shims, in Melbourne, now have a 'D2' shim hard enough to withstand the hammering abuse, but you have to ask for it specifically. With these shims, I set the gaps mid-range. The only gap movement will be reduction due to valve recession.

Hello.
I researched this problem a little. Because I don't know much about engines.
Did I understand correctly that you are proposing to increase valve clearances by replacing (R14213001B) LIFTER BUCKET with smaller shims?

Engenia

· #4 · 9 d ago

The shim sits under the bucket. Between the valve stem and the underside of the bucket. Smaller shim = bigger gap

Human body Font Parallel Art Diagram

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Dmytro

Discussion Starter · #5 · 7 d ago

Engenia said:
The shim sits under the bucket. Between the valve stem and the underside of the bucket. Smaller shim = bigger gap

Hello. Do I understand correctly? The ideal solution to this problem is to replace the valve seat? Since after adjusting the valve clearance with the valve adjusting shim, the valve still does not seat properly when closed.

Engenia

· #6 · 6 d ago

If you remove the shim completely & the valve still doesn't close, ie. the gap is still zero, then you have a much larger problem which can only be solved by replacing the seat.
But you DO have a gap with the shims in place. All you apparently need to do to increase the gap is to install thinner shims.
I'm confused.
I'm not sure what your problem is.

Dmytro

Discussion Starter · #7 · 6 d ago

Engenia said:
If you remove the shim completely & the valve still doesn't close, ie. the gap is still zero, then you have a much larger problem which can only be solved by replacing the seat.
But you DO have a gap with the shims in place. All you apparently need to do to increase the gap is to install thinner shims.
I'm confused.
I'm not sure what your problem is.

I think that you are confused because you know much more than me)))
My questions are based not on arguing, but on lack of knowledge.
In addition, due to lack of experience, I do not know how critical the problem can be.
Thanks for the answer. I think I now understand how this part of the engine works.

Gustav Gog

· #8 · 6 d ago

Any pointers as to where the shims may be purchased from? I seem to have drawn a blank.

Engenia said:
There is a range of shims available, from 1.20 to 2.50 in 0.02 mm increments.
Although they do get damaged by valve stem in the Tornado by the 1000 N springs, the normal wear is the erosion of the valve - valve seat, which will reduce the gap - a.k.a. valve recession.
The hammering of the valve stem creates an indent, that increases the gap.
You can only tell what's going on by removing the cams to gain access to the shims.
In the past, knowing that the shims will indent, I have set the gaps to be on the small side, expecting the gap to grow. The hammering hardens the shim, reducing the gap growth over 5 - 10,000 km. If you can get to 10,000 without the gap going out of spec, it'll stay in spec for another 10 to 40,000 kms.
Precision Shims, in Melbourne, now have a 'D2' shim hard enough to withstand the hammering abuse, but you have to ask for it specifically. With these shims, I set the gaps mid-range. The only gap movement will be reduction due to valve recession.

Engenia

· #9 · 5 d ago

I get mine from Precision Shims Australia. They are the only company I know of that make a shim hard enough to survive the Tornado's valve springs. The TNT isn't as brutal and doesn't suffer the same problem.
Maniac will have them, but I've never brought them from Alex.

Reactions: 1

Gustav Gog

· #10 · 5 d ago

Appreciate the reply. It’s a proper exponential curve for me. Did we ever find out the diameter of the shims.

Engenia said:
I get mine from Precision Shims Australia. They are the only company I know of that make a shim hard enough to survive the Tornado's valve springs. The TNT isn't as brutal and doesn't suffer the same problem.
Maniac will have them, but I've never brought them from Alex.

Engenia

· #11 · 5 d ago

8.0 mm

Reactions: 1

Gustav Gog

· #12 · 5 d ago

Thanks for that. Another piece of the TnT 899 beast jigsaw slots into place.
Just got to work out now if I'm really losing power above 7.5k or if just imagining it. 🫣

Engenia said:
8.0 mm

Dmytro

Discussion Starter · #13 · 2 d ago

Apparently the valve pad with a diameter of 8mm is installed in few places. I can't find 8mm anywhere. And branded Benelli in my country you can not even look for. I found them in an online shop in Germany. But due to the situation in the country, it may take 3-4 weeks for delivery now.
Do you think it is possible to reduce the thickness of the valve pad to the desired size on sandpaper 800?

Engenia

· #14 · 2 d ago

Dmytro said:
Do you think it is possible to reduce the thickness of the valve pad to the desired size on sandpaper 800?

Possible, but impossible to retain parallel faces. You need a surface grinder.
Better to contact Paul at Precision Shims. The TNT doesn't need his special D2 shims.
Paul will send them out the same day, unless he has no stock of the size you need. In which case he'll make it and send it out pronto. He's very good.

Reactions: 1

RobShed

· #15 · 2 d ago

'Lapping' correctly requires a jig

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