9 port 81mm cylinder

[Shnapsou]

Hello everybody.
How now this cylinder for Yamaha?
81mm, flat piston, 27cc dômes, +10 mm stroke, 9 port, Exhaust power valve.
I start to rebuild this engine I want to know who machining that
Thanks

 

[Storbeck]

The guy I would be talking to is @Jr.

Knowing nothing about it, looks like a pretty spicy little number to me.

I think I see triple exhaust ports in the aluminum casting but not in the cylinder sleeve. That's odd.

I also see no water passages from exhaust manifold to cylinder, probably because of the triple exhaust ports. So that is definitely something that the builder would need to take into account. That might be why there are so many cooling line connections on the sides of the cylinders.

 

[WFO Speedracer]

The guy I would be talking to is @Jr.

Knowing nothing about it, looks like a pretty spicy little number to me.

I think I see triple exhaust ports in the aluminum casting but not in the cylinder sleeve. That's odd.

I also see no water passages from exhaust manifold to cylinder, probably because of the triple exhaust ports. So that is definitely something that the builder would need to take into account. That might be why there are so many cooling line connections on the sides of the cylinders.

Look like they are using that space for a transfer port.

 

[Shnapsou]

Look like they are using that space for a transfer port.

Yes exact

 

[Storbeck]

It's common to have an auxiliary exhaust ports above transfer ports.

It's kind of the reason you use the triple port arrangement. You can have more exhaust blowdown area with the added exhaust ports but also have a lot of transfer port time area by using more of the cylinder wall for transfer ports.

 

[waxhead]

That's a very cool old school cylinder would love to own it or know more about it

 

[Jr.]

Hello,

This is a very rare Cyl. I have only seen one like it years ago. This cyl was used by factory teams back in the old ProMod days. Back then, there was an 800cc limit. This cyl was originally set up with a +8 stroke x 81.75mm bore to equal 799.4cc. At some point it was reworked? Resleeved, and stroke changed to +10?? I question stroke being +10? Crank in photo is a RAD. They were never made larger than a +8 long rod. I suggest you remeasure stroke. The two aux exhaust ports were not cut into the new sleeves? Not sure why not? Originally this cyl was the work of DASA, before it was DASA,
Dan Lamey would have been the designer behind it. He handled Power for the Factory teams earlier in his career. Not much more I can tell you without having it directly in hand. Certainly a piece of watercraft History!

Paul

 

[waxhead]

Hello,

This is a very rare Cyl. I have only seen one like it years ago. This cyl was used by factory teams back in the old ProMod days. Back then, there was an 800cc limit. This cyl was originally set up with a +8 stroke x 81.75mm bore to equal 799.4cc. At some point it was reworked? Resleeved, and stroke changed to +10?? I question stroke being +10? Crank in photo is a RAD. They were never made larger than a +8 long rod. I suggest you remeasure stroke. The two aux exhaust ports were not cut into the new sleeves? Not sure why not? Originally this cyl was the work of DASA, before it was DASA,
Dan Lamey would have been the designer behind it. He handled Power for the Factory teams earlier in his career. Not much more I can tell you without having it directly in hand. Certainly a piece of watercraft History!

Paul

Yeah it looks liek a lamey for sure. I have never seen one witht he extra exhaust ports in or the extra transfers. Its two more than a normal lamey ever had. Very cool

 

[MTRHEAD]

There was a few of these casting with aux ports forsale on here about 10 years. No sleeves though

 

[waxhead]

Damn I wish i had seen that

 

[TheBuzzard]

Looks very similar to the old protec with the wing ports only with more transfers and powervalves. I had a couple protec but sold them since they were basically race porting and worth more money than the little if any more power that was to be had. The old gen 1 WDK 1200 motors had the tripple exhaust ports too only they were not opened up

 

[MTRHEAD]

PJS Kawasaki supercylinders (last version) had casting for small aux ports as well and the WPP cylinder.

 

[waxhead]

PJS Kawasaki supercylinders (last version) had casting for small aux ports as well and the WPP cylinder.

I have a couple of west coast cinders with the aux port in them and a pjs but I dont have the casting in the pjs one for the ports. Its a reed case cylinder but it must be an early one