Pretty much screwed.

[sav0r (CL MotoTech)]

I am pretty sure there is somebody on the GT750 facebook group that loans their puller out.

[teazer]

GT750 can stick like sh*t to a blanket.  Heat, penetrating oil and patience work.  And the key trick is to lift it a little, loosen the lift nuts/bolts and smack the barrel back down with a B.F. rubber mallet.  Rinse and repeat to break it loose.

I recall that form a decade or so ago.  Not sure who it was or if that's still available.

[soonerbillz]

Here's my next patient on the rusted stuck cylinder line.
My 71 RT1 360.
This one I dragged from the weeds behind a fallen down shed. I gave 50 bucks for it.  Guy said it was his dad's and was parked there long before he was born.
Stuck piston(hoping that's all) .. been soaking in evaporust about 3 weeks now.

[irk_miller]

I've wondered how effective Evapo-rust or phosphoric acid can be in the scenario, since both create a chemical reaction that converts the metal instead of eating it away. 

I got lucky with a Bighorn I sold this summer.  It had been sitting in a North Carolina yard for God knows how long.  Managed to unstick the piston and get it running within a day.   Funny how it works with 2 strokes.  It's either stuck like your experiencing, or it's like I experienced with the Bighorn.  Very little in-between.

[Dvsrd]

http://www.medial.se/suzuki/cyl-removal/

this is the method I was referring to.   

Thanks! I just sent the link to the guy that struggles with his GT

[Striker1423]

Look Up GT750Idiot on Youtube and he has a plate he uses on the GT750's. Has done countless bikes using the massive puller plate without issue.

[soonerbillz]

I've wondered how effective Evapo-rust or phosphoric acid can be in the scenario, since both create a chemical reaction that converts the metal instead of eating it away. 

I got lucky with a Bighorn I sold this summer.  It had been sitting in a North Carolina yard for God knows how long.  Managed to unstick the piston and get it running within a day.   Funny how it works with 2 strokes.  It's either stuck like your experiencing, or it's like I experienced with the Bighorn.  Very little in-between.

To be honest I'm not impressed with EVAPORUST as a penetrant though as a rust remover it does very well and is nowhere as caustic as muratic acid.
I think the homebrew acetone/atf mix is as effective as a penetrant if not more so.
I find that it is a case of cast iron against steel or cast iron such as in the case of these two engines. The R5 studs rusting solid to the cast iron cylinder and the RT1 cast iron piston rings to the liner and the environment they are in.  If either has been inside and out of the weather even if they were stuck I think getting them to break free would have been much easier.
The fact that they were exposed to constant wet conditions made the corrosion much more extreme.
A penetrant of any value would be much more effective in the former vs the latter.

[rodneya]

Look Up GT750Idiot on Youtube and he has a plate he uses on the GT750's. Has done countless bikes using the massive puller plate without issue.

I wonder if that plate method would work on a RD type motor by using two studs to bolt the plate down, and the other two to lift the cylinder.

[irk_miller]

Has anyone tried hitting the top of the piston with a needle gun?  The vibration is pretty substantial.  It would cup the top of the piston, but rust turns to dust under heavy vibration.  It's the 10X expansion that's the issue, which puts everything under intense pressure.  I'm sure we've all seen rust jacking in masonry and concrete.  Takes a lot of pressure to pop concrete. 

[Striker1423]

I still recommend a regular mechanics air hammer. Makes short work of rusty crap...

[m in sc]

needle guns are gnarly tools but they work great. the do vibrate the shit out of some crud.

[Dvsrd]

Look Up GT750Idiot on Youtube and he has a plate he uses on the GT750's. Has done countless bikes using the massive puller plate without issue.

I wonder if that plate method would work on a RD type motor by using two studs to bolt the plate down, and the other two to lift the cylinder.

How would you attach the cylinder to a plate? Since all 4 studs (per cylinder) are threaded into the crankcase.

[Striker1423]

Good point... you would need to tap the bolt holes on the cylinder a few threads... a plate wouldn't really be needed then.