What did you build this week?

sav0r

Member
Got this GT750 head machining about nipped in the bud. For anybody not familiar with a stock GT750 head, this is quite the upgrade.

Just need to surface the spark plug sealing surfaces, thread the holes, and install steel inserts.

 

sav0r

Member
The chambers cleaned up nice with some Emory cloth. Overall I’m very pleased. Can’t wait to see how it runs.
 

sav0r

Member
Thats a standard head the was welded up by my father. He gave me squish size and combustion chamber volume specs, I created a model of a combustion chamber that met those specs. I then used that model to create the program to mill the combustion chambers and spark plug holes, as well as face the head off and take care of a few other little things.

Here's the head before being machined.

 

CarbsAndCylinders

Careful With That Axe Eugene
Thats a standard head the was welded up by my father. He gave me squish size and combustion chamber volume specs, I created a model of a combustion chamber that met those specs. I then used that model to create the program to mill the combustion chambers and spark plug holes, as well as face the head off and take care of a few other little things.

Here's the head before being machined.

Impressive!
 

teazer

Well-Known Member
DTT BOTM WINNER
Primary drive is between two and three to keep the clutch tucked in and transmission centered. Kawasaki triples have the drive off the crank end and need a longer gearbox output shaft to get the chain run right. This arrangement is nice but makes the crank longer.

So to keep it as narrow as possible, the transfer ports are twisted (rotated) and that complicates things a bit more.
 

sav0r

Member
I was typing a response but teazer beat me to it. Getting the dimensions worked out to do this project was a bitch. I have three heads available to me, and when you start measuring that first that becomes apparent is that they vary wildly. So I ended up scrapping all my previously put together models (hours of work) and started over just last week. To deal with this I bought a CMM plugin for my mill control and instead of measuring heads I measured the cylinder. Then I imported that data into CAD, and started again. Having the cylinder data made everything so much easier, I wish I had started this way from the get-go.

Pic of probing the bolt holes and cylinders. You can probably see that if the parts were much larger they wouldn't fit on my mill. Some days I'll get a big boy machine, today is not that day.
 

Redbird

Dolor est Magister Optimus
DTT BOTM WINNER
Primary drive is between two and three to keep the clutch tucked in and transmission centered. Kawasaki triples have the drive off the crank end and need a longer gearbox output shaft to get the chain run right. This arrangement is nice but makes the crank longer.

So to keep it as narrow as possible, the transfer ports are twisted (rotated) and that complicates things a bit more.
Thanks Teazer (and Savor)... makes sense now ;)
And yea... "complicates". I was searching the GT750 heads and barrels, and noticed how the ports are basically twisted in order to give the appearance of even spacing.
Engineering is a fascinating profession :p
 
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