Now it's looking like a top end : )

Getting your blazingly fast Suzuki powerplant to perform even better!

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Arne
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Now it's looking like a top end : )

Post by Arne »

Just got this back from Eric of Sundial.... I've been measuring it up for a couple nights now, comparing it with some stock 72 cylinders, and several porting diagrams I've got ahold of, and I'm very very happy with it.

Planed and cleaned up head, copper headgasket (from Suzukidave if I remember correctly), pistons with the intake skirt trimmed, intakes cut angled to allow for some big mikunis, cylinders planed on the top / cleaned up on the bottom / ported intake/transfers/exhaust, two base gaskets with a base gasket spacer.

I should have it together and on a dyno this spring, I'm hoping for 80 at the rear tire, and think I have a pretty good shot at it with these (and a few other bits and bobbles of course)

Thanks Eric! Arne

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1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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2STROKECAFE
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Post by 2STROKECAFE »

Wow Arne, looks great! Can't wait to hear how it runs when it is all together. How is the base spacer fabricated. Is it the "silver" colored gasket on the table?
Take care,
Bryan
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Arne
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Post by Arne »

2STROKECAFE wrote:Wow Arne, looks great! Can't wait to hear how it runs when it is all together. How is the base spacer fabricated. Is it the "silver" colored gasket on the table?
Take care,
Bryan
Yep, it's the silver one. Appears to be cut out on a CNC table of some kind, not sure what kind though. Eric has a fabricator that makes them, if you pm him he'd have the info (I don't seem to have the phone numbers or part numbers anymore)
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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Suzukidave
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Post by Suzukidave »

Find a shop that can water jet cut http://suzukidave.myphotos.cc/suzukidav ... -Model.pdf
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tz375
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Post by tz375 »

That looks good Arne. We are eagerly awaiting the dyno charts to see how strong it is.

Don't forget to carefully match the copper gasket to the bores. Suzuki were not too good about holding tolerances back in the day and it is usually necessary to adjust the sleeve nut holes to get a copper gasket to fit.
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Arne
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Post by Arne »

tz375 wrote:That looks good Arne. We are eagerly awaiting the dyno charts to see how strong it is.

Don't forget to carefully match the copper gasket to the bores. Suzuki were not too good about holding tolerances back in the day and it is usually necessary to adjust the sleeve nut holes to get a copper gasket to fit.
Yep, I've already spotted several locations.

I imagine I can hold +0, - 0.5mm on the round around the bores using a hand die grinder (with the 0 going into the cylinder) - is this a tight enough tolerance for the head gasket?
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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Zook-e
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Post by Zook-e »

Cometic Gaskets makes the spacer plate and the base gaskets (metal with a rubberized material covering. They can make the spacer to several different thicknesses.
"If you keep hitting your head against the wall you will eventually put a hole in the wall or your head"

1968 T500 Monoshock, 1972 GT750 Custom, 1973 GT750 Lemans

http://www.sundialmotosports.com
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tz375
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Post by tz375 »

I'm intrigued to see people still using spacers. Unless it's for a race bike, there's enough metal in the exhaust ports and the transfers don't need to be raised unless you really need a lot more time area.

All the numbers I run seem to suggest that the transfers only need to be raised 1.5-2.0mm and a good porter can do that.

What am I missing?
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Arne
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Post by Arne »

tz375 wrote:I'm intrigued to see people still using spacers. Unless it's for a race bike, there's enough metal in the exhaust ports and the transfers don't need to be raised unless you really need a lot more time area.

All the numbers I run seem to suggest that the transfers only need to be raised 1.5-2.0mm and a good porter can do that.

What am I missing?
I assume it's a means to an end. A base gasket is fairly inexpensive whereas a porter's time cutting is fairly expensive.

If the exhaust, transfers, and intakes all need to be raised a bit then a spacer below makes sense.

But it all really comes down to what it puts out, and we'll find that out in a few months!

(plus I think the base spacer is cool)

Thanks - Arne
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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Suzukidave
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Post by Suzukidave »

I wonder if this 72 block has the different from other years transfer timing that i found out when cutting mine up for the reed intakes ? Image
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Arne
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Post by Arne »

Suzukidave wrote:I wonder if this 72 block has the different from other years transfer timing that i found out when cutting mine up for the reed intakes ? Image
Nope, that looks pretty much stock :shock:
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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Suzukidave
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Post by Suzukidave »

What Richard noticed was the 72 transfer ports are already higher than the rest of the yrs GT ( even before i messed with them ) .
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Suzukidave
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Post by Suzukidave »

Arne , could you do a rubbing of your porting with the numbers and post it ?
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Arne
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Post by Arne »

Suzukidave wrote:Arne , could you do a rubbing of your porting with the numbers and post it ?
I've got a set of 72 stock blocks and could do a dimensioned rubbing of those.
1954 Harley ST165 basket in the attic
1972 Suzuki GT750 project in the works
1981 Honda CB750-1000 driver
1982 Honda GL500 easy project
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water cooled
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Post by water cooled »

Nice Arne...looks great! I'm very interested in what you are doing. Do you think Eric might have mapped the ports?

Kevin
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