850 vs high compression 750

[crapwacker]

Any thoughts?

[tkent02]

What exactly are you thinking about?

[reddirtrider]

Get an 1100.

[bwringer]

Need criteria and context...

But just making a guess here (you're not drag racing), I'd much rather ride the machine that hasn't been modified.

So the 850.

[Dogma]

Yah, pump in the cheap gas. Never mind that high-compression headache.

[crapwacker]

Just a thought, there's for sale, but I have 850 jugs and pistons already. I'm sure the new set will climb much higher, but I was just kicking it around, as I have a 750 gasket set, but not the 850 head gasket. Either way, it's just one of those project idea things.

[tkent02]

Just a thought, there's for sale, but I have 850 jugs and pistons already. I'm sure the new set will climb much higher, but I was just kicking it around, as I have a 750 gasket set, but not the 850 head gasket. Either way, it's just one of those project idea things.

Do it .

[crapwacker]

Do it .

Which one; either?

[tkent02]

850 top end on the 750.

[gssuzukixxx]

It looks to me that if you put 850 cylinders and pistons under a 750 head you will get close to 10:1 compression. The stock CR for the 750 is 8.8:1 with a 187cc cylinder so if you increase the swept volume to 212cc it should bump the CR up to about 9.8:1.

So as far as the original question is concerned it is more like "high compression 850 vs high compression 750".

Brian

[Guest]

It looks to me that if you put 850 cylinders and pistons under a 750 head you will get close to 10:1 compression. The stock CR for the 750 is 8.8:1 with a 187cc cylinder so if you increase the swept volume to 212cc it should bump the CR up to about 9.8:1.

So as far as the original question is concerned it is more like "high compression 850 vs high compression 750".

Brian

I don't get it? Compression should stay the same as, the 750 and 850 head are the same.

Unless you get high comp wiseco oversize 750 pistons.

[gssuzukixxx]

I don't get it? Compression should stay the same as, the 750 and 850 head are the same.

Unless you get high comp wiseco oversize 750 pistons.

Well compression ratio is the ratio between the volume of the cylinder + combution chamber when the piston is at the bottom of the stroke vs the volume of the combution chamber when the piston is at TDC. So if you keep the combution chamber volume the same and increase displacement then you will increase the CR.

I know that people say the 750 and 850 heads are the same but the 850 head would have to have a large volume for the 2 motors to have the same CR.

Brian

[gssuzukixxx]

Well compression ratio is the ratio between the volume of the cylinder + combution chamber when the piston is at the bottom of the stroke vs the volume of the combution chamber when the piston is at TDC. So if you keep the combution chamber volume the same and increase displacement then you will increase the CR.

I know that people say the 750 and 850 heads are the same but the 850 head would have to have a large volume for the 2 motors to have the same CR.

Brian

Sorry I meant to say "larger combustion chamber volume for the 2 motors to have the same CR."

[850 Combat]

I have always figured that the extra compression is a significant part of the extra responsiveness of the 1000 over the 850. Do both...

[49er]

Well compression ratio is the ratio between the volume of the cylinder + combution chamber when the piston is at the bottom of the stroke vs the volume of the combution chamber when the piston is at TDC. So if you keep the combution chamber volume the same and increase displacement then you will increase the CR.

I know that people say the 750 and 850 heads are the same but the 850 head would have to have a large volume for the 2 motors to have the same CR.

Brian

Both heads are the same. Both stock Cr's are quoted at 8.8-1. But the bores on the 850 are 4 mm larger!! How could that be?

Could it be that the piston crowns are shallower on the 850 pistons????