ESE's works engine tuner

[Kickaha]

Has to be safer than a plenum with half a liter of unleaded sloshing around in it.

Bu the explosion won't be anywhere near as spectacular

[TZ350]

This is a copper squish band, not a brass det ring. Hard brass is used in det rings as its not easily eroded away, copper is to soft for a det ring.

Pic-02 a 95 TZ250 copper squish band head, its the first time I have seen a picture of one, interesting that Yamaha used this idea in their race bikes...............

OK, so now we know we didn't think of it first, but its satisfying to see that we came up with our own one by ourselves Pic-01.

With the copper squish area and alloy chamber it looks much like the Yamaha factory race head...........so its true, great minds do think alike..........

I have no idea how long they used it, but even production racers are subject to economics I guess and it is probably more useful in an air cooled engine anyway .............

[gatch]

Why the copper on the squish band area ? Don't you want to keep the heat IN the cylinder ?

[TZ350]

Why the copper on the squish band area ? Don't you want to keep the heat IN the cylinder ?

That's true, you do want to keep the heat in the combusted gas so its increased pressure pushes the piston down. Any loss of heat from the gas reduces the push on the piston.

A cool squish band reduces the chance of end gas detonation and by its close proximity to the piston helps cool that too.

But once any heat energy reaches the combustion chamber shell either by radiation or conduction then it has to be removed by the cooling system ASAP.

A reflective material like polished aluminum reflects radiated heat back into the chamber. Some chambers are designed in a way that increases the boundary layer as another way of keeping more heat in the combusted gas, the boundary layer acts like a blanket and insulates the combustion chamber wall from the hot combustion gas.

But detonation disturbs the boundary layer and allows greater conduction from the hot gas to the combustion chamber wall and that's the reason why engines overheat when there is continuous detonation happening.

[SS90]

This is a copper squish band, not a brass det ring.

Pic-02 a 95 TZ250 copper squish band head, its the first time I have seen a picture of one, interesting that Yamaha used this idea in their race bikes...............

OK, so now we know we didn't think of it first, but its satisfying to see that we came up with our own one by ourselves Pic-01.

With the copper squish area and alloy chamber it looks much like the Yamaha factory race head...........so its true, great minds do think alike..........

I have no idea how long they used it, but even production racers are subject to economics I guess and it is probably more useful in an air cooled engine anyway .............

Any information on this head.... was it made by Yamaha?

I have never heard of, nor seen one before.

Is there any information to show that it was designed not simply as a det ring?

[Kickaha]

Any information on this head.... was it made by Yamaha?

I have never heard of, nor seen one before.

Is there any information to show that it was designed not simply as a det ring?

It's factory Yamaha, that TZ motor I had in the Superkart had them, the chamber was a different shape to the earlier TZ heads and I was told it was an "unleaded head"

[gatch]

That's true, you do want to keep the heat in the combusted gas so its increased pressure pushes the piston down. Any loss of heat from the gas reduces the push on the piston.

A cool squish band reduces the chance of end gas detonation and by its close proximity to the piston helps cool that too.

But once any heat energy reaches the combustion chamber shell either by radiation or conduction then it has to be removed by the cooling system ASAP.

A reflective material like polished aluminum reflects radiated heat back into the chamber. Some chambers are designed in a way that increases the boundary layer as another way of keeping more heat in the combusted gas, the boundary layer acts like a blanket and insulates the combustion chamber wall from the hot combustion gas.

But detonation disturbs the boundary layer and allows greater conduction from the hot gas to the combustion chamber wall and that's the reason why engines overheat when there is continuous detonation happening.

I understand detonation etc.

Maybe its just me not knowing the science, but it seems odd you would want to conduct heat into the head. Why not use as you say, polished ally ? Or does that copper get polished up ?

[SS90]

It's factory Yamaha, that TZ motor I had in the Superkart had them, the chamber was a different shape to the earlier TZ heads and I was told it was an "unleaded head"

That might be correct.....

I remember my 95 125 came with an unleaded head that looked similar shape (made ok power on av gas)

a quick internerd search, and I found this for a 3xv TZ unleaded head.

[Kickaha]

and I found this for a 3xv TZ unleaded head.

Uneducated peasant, there is no such thing as a 3XV TZ, the TZ V twins were all designated 4DP

Although the cases were virtually the same and all the bits interchanged, there was at least one road legal 3XV TZR250 built with 4DP TZ250 top end bits, etc bolted on

The heads are probably from 1997

[SS90]

Uneducated peasant, there is no such thing as a 3XV TZ, the TZ V twins were all designated 4DP

Although the cases were virtually the same and all the bits interchanged, there was at least one road legal 3XV TZR250 built with 4DP TZ250 top end bits, etc bolted on

The heads are probably from 1997

3XV with 4DP top end, wasn't that ex Ricky Porter now Rod Hawes' bike?

That definitely has TZR road cases.

You know I am confused easy........ I was thinking of your age in roman numerals.

[Buckets4Me]

http://www.trademe.co.nz/Trade-Me-Mo...-311346415.htm

and I thought Team E.S.E had enough stuff lying around

[bucketracer]

http://www.trademe.co.nz/Trade-Me-Mo...-311346415.htm

and I thought Team E.S.E had enough stuff lying around

There has to be something useful or just fun to have in that lot.............

[gatch]

There has to be something useful or just fun to have in that lot.............

What rim width is ideal for slicks ?

I don't know what the rim widths on my spada are, but the stock tire sizes are 100/80-17 front and 140/70-17 rear, which would probably make it too wide for 125 slicks yes ?

[TZ350]

What rim width is ideal for slicks ?

I don't know what the rim widths on my spada are, but the stock tire sizes are 100/80-17 front and 140/70-17 rear, which would probably make it too wide for 125 slicks yes ?

We run secondhand GP125 slicks on our buckets, we use 2.5x17"F and 3.5x17R rims, these are the recommended sizes by Dunlop. Rims for slicks seem to be wider than for road tires, possibly because of the slicks lower profile. A lot of the FXR150 boys run narrower rims OK with slicks and on my 50 I run 2.15F and 2.5R rims, and both wheels are shod with front slicks from a GP125.

[gatch]

We run secondhand GP125 slicks on our buckets, we use 2.5x17"F and 3.5x17R rims, these are the recommended sizes by Dunlop. Rims for slicks seem to be wider than for road tires, possibly because of the slicks lower profile. A lot of the FXR150 boys run narrower rims OK with slicks and on my 50 I run 2.15F and 2.5R rims, and both wheels are shod with front slicks from a GP125.

Maybe I could get away with just putting slicks on my spada rims then ? Some wire wheels would be neat though, heaps lighter as has been demonstrated..