Z1R oil cooler

[Peter55]

Hello all.
The 1978 Z1R I am restoring has got an oil cooler, which I want to remove. I haven’t seen it mentioned in the parts book or manual so I guess it was fitted by the previous owner.
The two pipes feeding it come from a point behind the barrels.
Can I just take the pipes off from this point and plug the two openings or does it need a circulation of some kind.

[zed1015]

You can't just block off the oil gallery.
You need to re-fit a stock pressure switch ( see pic ) in place of the cooler pipe fittings ( or just connect the two with a short loop of hose if you don't want 100% original) otherwise you will starve the engine of oil.

images.jpg (5.13 KiB) Viewed 2938 times

[Peter55]

Thanks Z1015
The previous owner must have fitted the part from a later model.
Do you know where I might be able get the part from.
Cheers Peter

[zed1015]

The oil cooler and fittings are aftermarket performance parts and not stock parts from a later model.
Original oil pressure switches are listed on Ebay but asking on the forum in the wanted section will likely get you one from a member.
The switch from any Z1 through to Z1000mk2 kickstart equipped engine will fit.
The cooler fittings are also worth a few quid so selling those would more than cover the cost of the pressure switch or form the basis of a trade..

[Peter55]

Thanks very much Zed1015
Yes I found one at Z Power so I’ve bought that one.
Cheers Peter

[zed9]

Oil coolers were often fitted with engine mods such as bigger and or high compression pistons with hot cams which can increase engine temps. When bored out to about 1050 or 1100 for example with standard liners they get a little thin so dont dissipate heat quite as well.

If stripping engine would be a good time to check for any mods before selling fittings.

[Peter55]

Hi Zed9
Interesting, I’ve stripped the carbs and re-jetted them back to standard.
The previous owner had fitted a 120 main jet, other than that, the jets were stock.
The only obvious mod is the straight through exhaust which I don’t think would warrant such a large main jet, would a big bore conversion or race cam/high comp pistons require a main jet that size?
I was hoping that I wouldn’t have to strip the engine, it’s only done 8500 miles.
I’m going to check the valve clearances so I’ll see the cams, will there be any clues / numbers as to whether they are standard or performance.
Would a compression test tell me if it has high comp pistons and if so what would I be looking for.
Cheers

[zed9]

Larger main jet may have been fitted due to exhaust and if air filter has been removed with velocity stacks fitted. You might want to check if air corrector jets have been fitted to carbs on the side of air filter, search on here for air corrector jets for more info.
I dont know what marks Z1R cams have on them but plenty on here will, performance cams will have makers marks on them so best checked when doing valvle clearance. Sounds like a very low milage one you have and if its not smoking or burning oil i would not strip it down.

High compression pistons would normally show a higher compression reading than standard but its difficult to say as piston and bore wear could affect this. Removing right hand spark plug and looking at piston near TDC you might see a higher dome than standard ones.

[Peter55]

Thanks Zed9.
I’ll keep this thread posted as I dig deeper but, I hope I don’t have to go to far into the engine.

[Al]

Oil coolers can be a mixed blessing. There is a significant pressure drop across oil coolers, particularly the cheap ones... this on a system that runs very very low oil pressure. There are also fewer alternate routes through a smaller one if blocked by just a small amount of debris. Taken together with an old oil cooler with fibres, carbon, oil line fragments and general smolge after many years of service and you may get cooler oil but much less of it. I would get it running with no oil cooler first to see what it does and then if needs be re-instate the oil cooler if neccessary but perhaps a new one and look to replace those lines with proper stuff.
AL

[Peter55]

Thanks A1
I think that’s what I’m going to do.
I’ve fitted the new pressure switch pipe.
Refit the carbs and see if I can get it running, if it runs and sounds okay I’ll finish the restoration and ride it to see if it has an overheating problem.

[Peter55]

Hello All
So far so good, I fitted the carbs without the air box and it started second push on the button, number two cylinder backfiring through the carb with a visual air leak between the head and the inlet rubber.
A bit concerned about the oil pressure showing a max of 15psi but a look in the manual cleared that concern.
Fitted four new inlet rubbers and considering the air box is not there it sounds very good.
Battery charging at 14.2 volts.
I tried the gears and although it crunched a bit, they are all there.
I’m going to check the valve clearances and remove the oil pan to see if there’s anything to worry about in there.
Unless the previous owner has modified it at all, hopefully that’s all I need to do in the engine department.
Cheers Peter.

[Al]

Great result and the clutch wasnt stuck!!!
If you take the sump off you could have a look at the underside of the pistons and see about any burning or overheating there and see if you can see if the crank has been welded on the big end pins. Either might highlight any mods or uplift in output to see if there is any justification for the addition of the oil cooler.
AL

[Peter55]

Thanks Al
Good thinking, I’ll do that.
Deliberating whether to get the frame painted, it’s a bit tatty in places and I think I might regret it if I dont, bigger job than I intended, engine out etc, but my time is cheap, still deliberating.
Cheers