Kz750e to 810 build questions

Gd750 wrote: oh you dont run an oil cooler at all? what about an air scoop/under cowl? what motor did you put the 810 into? a 750E or 750R1 or other? do you use this bike on the track or street? thanks

No oil cooler at all. This was on a 1984 ZX750E1 turbo which had a small cooler as standard. I deleted the standard oil cooler in favour of a large intercooler. This bike ran on the street in the UK but also put in five back-to-back runs well over 200mph at a 2 mile runway in 2006. The bike was making around 250hp and had no cooling issues on Kendall GT-1 20/50.

Lorcan wrote:

Gd750 wrote: oh you dont run an oil cooler at all? what about an air scoop/under cowl? what motor did you put the 810 into? a 750E or 750R1 or other? do you use this bike on the track or street? thanks

No oil cooler at all. This was on a 1984 ZX750E1 turbo which had a small cooler as standard. I deleted the standard oil cooler in favour of a large intercooler. This bike ran on the street in the UK but also put in five back-to-back runs well over 200mph at a 2 mile runway in 2006. The bike was making around 250hp and had no cooling issues on Kendall GT-1 20/50.

Would it make a difference with your bike being a turbo with compression ratios around 8:1 vs 10.25:1? I dont really know how this influences heat production..

Once you start making boost with a turbo it could easily be the equivelant of 15:1 compression motor,its when the motor is idling and compressor has slowed back down that youre basically running a low comp motor.

Gd750 wrote:

wireman wrote: Ive never had mechanical issues caused by the synthetic,but I definately agree good gaskets area must! :laugh:
If youve got a pin hole anyplace in a gasket the synthetic oil will find it.
Depending on how hot it gets where youre at you will drop oil temps,I made a believer out of omr about the temp differance living there in pheonix he noticed a significant drop between the synthetic oil and adding oil cooler.

wow it was that significant? what kind of synthetic are you referring to? would this have any affect on the behavior of my clutch? <-- something i was told once...

Ive run synthetic oil with wet motorcycle clutches since early/mid 80s without a problem.
Ive seen the inside of enough engines from bikes/cars and boats over the years,many of them were run extremely hard and I honestly say the motors that ran synthetic oil looked much better internally compared to the dino bone oil motors with basically same abuse/maintenance done to them.

wireman wrote: Once you start making boost with a turbo it could easily be the equivelant of 15:1 compression motor,its when the motor is idling and compressor has slowed back down that youre basically running a low comp motor.

ah yes i didnt even consider the reason that turbo motors require a lower comp ratio. thanks for the info that makes perfect sense.

as for the motor oil i have always been partial to lucas as im sure everyone has their favorite but it sounds like no harm could be done from a comparison.

what do you think about head work in terms of port and polish? i know this can be incredibly beneficial if done properly but how do you feel about a careful home job?

Without a flow bench or a template you're porting blind. You'll have no idea if you're doing good or doing harm.

A turbo does not require low compression, it just depends on how much hp you want. Mr Turbo (Terry Kiser) has a article on his site where they put a turbo on a stock ZX14.

Gd750 wrote:

wireman wrote: Once you start making boost with a turbo it could easily be the equivelant of 15:1 compression motor,its when the motor is idling and compressor has slowed back down that youre basically running a low comp motor.

ah yes i didnt even consider the reason that turbo motors require a lower comp ratio. thanks for the info that makes perfect sense.

as for the motor oil i have always been partial to lucas as im sure everyone has their favorite but it sounds like no harm could be done from a comparison.

what do you think about head work in terms of port and polish? i know this can be incredibly beneficial if done properly but how do you feel about a careful home job?

You just need to use a little common sense is the biggest thing with cleaning up a head.
You can just clean up the inside of the castings without carving material in big chunks,its when people try to recreate a port by just going nuts with a die grinder that gets them into trouble.
Dont go in and start moving mountains in the bowl area directly under the valve ,thats the hardest to fix once its screwed up.
Ive got an early 80s kz 750 head coming my way in next week hopefully,once I get it sitting on the bench Ill see if I can point out some basic dos and donts on it.

And yes Ive ridden a few 10.25:1 motors with a turbo on top of them,theyre quite spunky to say the least ! :laugh:

great! id appreciate that Wireman. i've done a fair share of reading about porting and it seems that everyone has their own best method. what's getting me concerned is the polar opposites in opinion when it comes to the "polishing". i didnt plan to go in and completely undo all of the work that kawasaki researched and applied to the head by chiseling out my own new head design. but some guys will say to shine the interior to a mirror finish and some will say to leave a rough surface on the ports to keep fuel atomized on its way into the chamber. i dont want to take on the task of porting/polishing on my own if i wouldnt really see any benefit without paying someone with a way of measuring improvements to be sure.

I leave the intake ports rough,but thats just the way it was beaten into my head way back when.

thanks for all the advice. did you (WM) or anyone have an opinion on what APE jay said on the use of stock camshafts with this 810 and how it would raise cylinder pressure? if the cylinder pressure is too high am i running a higher risk for detonation? or would the stock cams be fine just not optimal?

All your doing with the 810 kit is making the engine larger with a small bump in compression. Don't overthink it and worry about the cylinder pressures.
The OEM's do this all the time without issues. The same little KZ650 engine was made into the KZ700 then the KZ750 and they eventually turned it into the turbo 750. Most of them used the same cam profiles as the KZ650.