650/750 head ...which one is which

How do i tell the difference between a 650 and a 750 head? Probably a stupud question.... But i bought a 750 head on ebay for my 650-810 project and I just want to be sure that this is in fact a 750 head b-4 i take it apart.

It should not have the provisions for the cam chain sprocket mount between the cams.
Mark

some of the 750s had these provisions (4 bolt holes) i thought, thats how u can use a 750 head on a 650 i thought?? am i wrong?

thank you

I could be wrong and someone please let me know if I am but the 750's had 2mm larger valves than a 650. Do you have a 650 head for comparison?

I do have the original head for comparison. I guess i have to take the valves out for comparison. not a problem i guess, i had to do it sometime. just wanted a way to tell b-4 i tore it apart. I held one of mu valves up to the 750's and they looked the same to my untrained eye. the lifters are the same size and everything though ey?

i got the head because i was told that a 750 head flows better. do i really just need the cams off of this thing for my 650 head or will the whole 750 head be better...?

thank you for sharing your knowledge and for any insight.

Yes Bluemeanie the intakes are 2mm bigger, I think the exhausts are only 1mm bigger. The 750 motor my barrels came from the head does not have the mounting points. Some may be different.
Mark

The 750 head will flow slightly better due to larger valves and more cam. You could also use the 750 cams in the 650 head (swap sprockets). Also, the GPZ750 cams are very nice but have no provision for the tach gear drive. As far as visual I believe the 750-650 heads look vertually identical.

Did the US market 750's have the same smog setup that the 650's did after the 1978 models ?? That MIGHT be one way to differentiate between heads because of the extra port ???

Yes they did.

Well it is a 750 head, but upon disassembly i noticed that the vlaves dont fit the guides as well as my 650. I dont know what to do now. do i put the 750 cams into my 650 head till i get the $ to deal with the 750 guides/valves or do i just wait?

also i have noticed on the 750 head that there is a hole/passage right next to the guides on the exhaust side. does this have something to do with the smog setup u are talking about? what are these holes all about? they look like a passage upto the valve cover.

EGR

Exhaust Gas Recirculation

Like a car, it sent some of the exhaust back into the combustion chamber to lower combustion chamber temperatures.

On a car it helps reduce detonation at part throttle. Not real sure how it worked on a Kaw.

According to what little I know about the setup, it was not an EGR setup but rather a fresh air injection system intended to introduce fresh air into the exhaust stream AFTER the exhaust valve. This arrangement was supposed to promote additional oxidation (combustion) of the unburned hydrocarbons in the exhaust gases as well as turning carbon monoxide (CO) into carbon dioxide (CO2).
You should be able to see the port up inside the exhaust passage between the valve and the outlet from the head.