"Pork Chop" Cranks for GT/TR750

Kris Bernstein · Post by **Kris Bernstein** » Tue Jun 23, 2009 10:57 am

Of course! Turn the ID of a steel tube to the OD of the piston and bore holes for a dummy pin to isolate the piston in the mill. I could use a ball end mill to duplicate the radius of the Suzuki piston cutaways. Way too simple and no program to write!!!!

Kris

Kris Bernstein · Post by **Kris Bernstein** » Tue Jun 23, 2009 11:02 am

I think Dave is right about getting the reeds as close as possible to the bore of the cylinder. It is going to be a compromise with this old motor but I am going to try to do this without "hitting water" as it were. I might not be able to do it but we'll see...

Kris

Suzukidave · Post by **Suzukidave** » Wed Jun 24, 2009 4:21 am

Kris , i dont know if you are sitting in on this topic but its getting pretty interesting http://www.motorcycleracer.net/phpBB2/v ... php?t=1506

Kris Bernstein · Post by **Kris Bernstein** » Fri Jul 10, 2009 9:50 am

TZ375,

Did you ever recover the picture of the Osolot piston jig?

Thanks

Kris

tz375 · Post by **tz375** » Fri Jul 10, 2009 2:49 pm

Kris,

My new monitor for the desktop just arrived as did teh memory and hard drive for my laptop, so i should be able to gig those pictures out real soon.

tz375 · Post by **tz375** » Fri Jul 10, 2009 2:56 pm

try this

and

Kris Bernstein · Post by **Kris Bernstein** » Sat Jul 11, 2009 7:41 am

Simple, yet elegant. Usually the best resolution to any engineering issue.
Thanks so much for sharing.
Do you know if the 75mm pistons require re-sleeving or is there enough meat in the original iron liner to do these?

Kris

Suzukidave · Post by **Suzukidave** » Sat Jul 11, 2009 8:07 am

If i were to start with a "blank" piston like those wouldnt the new thinking with piston tops be flat , i know that would aslo require a new "topHat " squish head design also ??

Suzukidave · Post by **Suzukidave** » Thu Jul 16, 2009 5:59 pm

Or maybe toroid

Kris Bernstein · Post by **Kris Bernstein** » Thu Jul 16, 2009 8:19 pm

What's the head to Dave and what evil plans have you for it?

Kris

Suzukidave · Post by **Suzukidave** » Fri Jul 17, 2009 4:06 am

Kris , the picture i picked up off Ebay as a good example of the state of the art toroid head design . I think it was from a 1300cc PWC engine , i think i have dug myself a big enough hole that i have to get out of with my engine now and getting it together and running in its current state of mods is my goal

tz375 · Post by **tz375** » Fri Jul 17, 2009 10:32 pm

Kris, when you start playing with head shapes, don't forget that unleaded seems to work better with a flat top and leaded with a tapered chamber. Toroidal shapes are designed to put the plug close to the center so it burns faster.

Unfortunately it also increases the ratio of surface area:volume which results in more heat being transferred to the water instead of being used to generate useful work. The faster burn should help with slow burning ethanol mixes but the burn rate improvement is probably less than the heat loss effect on a race bike.

Just another compromise to deal with.

And we really need someone here to be trying this stuff out and sharing the knowledge. It's all about creating a wider, deeper pool of knowledge to draw from.

Suzukidave · Post by **Suzukidave** » Sat Jul 18, 2009 7:07 am

Richard , the only guy i know that could possibly do different head shapes and try the on a dyno would be Bill . If he only had a 1 cylinder GT750 engine he could run tests on his dyno .

Suzukidave · Post by **Suzukidave** » Sat Jul 18, 2009 7:10 am

tz375 · Post by **tz375** » Sat Jul 18, 2009 11:18 pm

Dave,

I think that Brett has a single cylinder GT750 set up for his dyno.

I have to get the single cylinder GT crank pressed up. I have the right ignition system etc and spare cases, and don't need water pump or tacho etc for the dyno (I can use an electric pulse pump and electronic tacho or teh dyno tacho).

I can't remember what the capacity of Bill's engine dyno is, but I though it was limited to about 125cc or less.

He could of course try different heads and a range of fuels on one of his small motors, but I don't know how well that would translate to our big bore high primary CR motors.

I don't have a dyno so I need to talk to the sled guys in Kenosha about making up an engine cradle to fit their dyno to test some ideas.

All it takes is those two simple ingredients - Time and Money.

"Pork Chop" Cranks for GT/TR750

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Reeds and intake opening location

Osolot Piston Jig?

Osolot Piston Jig?

Yamaha Head