1981 Kawasaki GPz550: Restoration

[srsupertrap]

Removed the idle air screws and they were all set at 3/4 turn out . . . this is after clean up.

[srsupertrap]

This Primo impact driver always breaks loose screws easily and never screws anything up



Choke plungers were removed next



Top and bottom brackets along with choke linkage removed


Carb separation


Removed throttle linkage, spacers etc



Check out the needle bearings visible in this photo . . . Safe to Dip?


This cover facing the engine had tamper proof Torx screws which were Loctited in place. Lucky to get them out undamaged.



Got them off w/o damaging the gaskets. I will need new O-rings on that carb body below the choke tube (wrong term)



What a good mess

[srsupertrap]

Mikuni RS27

Made good progress yesterday taking apart the RS27. I carefully took things apart since I know of no source of supply for the gaskets. I will need O-rings but I will be able to run these Carbs. So lots of photos and if anyone has good stock of O-rings let me know.



The carbs were never drained. . . varnish in the bowls & main jets. Plastic floats probably none adjustable right?


Remove the plastic floats, looks pretty good. I break out the magnifying glass standard N100 mains (107.5) & VM pilot jets (32.5). The pilot is probably way too BIG



These were pretty stubborn but with PB Blaster they broke free.



After I remove the four main jet holders, I look at the throttle linkage



As I hoped the varnish had merely fused the jet needle and needle jet together. The photo below shows full travel . . . enough said.



NICE


Remove the float needle & seat assembly . . . O -rings still look ok



Take of the top covers, Carb #3 appears to be the master.



Remove the throttle shaft, remove the slides & mark them.

[srsupertrap]

So, what you're saying is that the sprocket can be one tooth off and you can "degree" the cam into the correct position?

I know you degree the cams after everything is all lined up

I suspect that is the case with the exhaust cam considering it's current skewed position.

[srsupertrap]

I will work on my Z-1 order tomorrow, next I move the Mikuni Flatslides onto the workbench and spray all the linkages & screws with PB blaster to soak overnight. Looks like the none of the screws were ever disturbed.



Installed a new battery in the Mitutyo D/C so we can see the readout again and the intake measures 26.89mm.

Good score ,should be a better bike with these mods,i had one for a few years but got sick to death of its narrow powerband and havin to rev it to death and changing gear constantly.
Dont change anything you dont have to ,so far it seems full of the choice stuff,but I prob would have(from experience, doh) degreed up the engine prior to disturbing the cams to get a base point to start from,too late now but goodluck and keep us all posted on progress

[blowerbike]

i'm just saying things don't always line up exactly...could be a half off front or rear.
if he put's a degree wheel on it and used a positive stop and find's true TDC...
his marks may not be off...if they still are then go a head and check the lobe centers and if they're close to say 102-105 then everything is probably lined up correctly.
being a tooth off changes the cam timing by around 10 degree's give or take.
maybe 8 degree's...maybe 12 degree's ect...

i'm not the best at explaining via typing...
must be an age thing

[Big T]

So, what you're saying is that the sprocket can be one tooth off and you can "degree" the cam into the correct position?

I know you degree the cams after everything is all lined up

[blowerbike]

Why would the sprocket position change just because the cams were degreed?

i should have mentioned "along with after market cams".
throw in chain stretch/different gasket thickness/head milling/chain guide wear.
i seldom had marks line up exactly on modified engines.
once you degree the cam's then you know all is good.
just saying....

[srsupertrap]

when cams are degreed....the factory marks are no longer exactly in the same place because of the slotted sprockets and the lobe center changes that was made.

Agreed, I will verify everything when I get to that point but I suspect the builder is off a tooth. I copied this from Corey's GPz550 manual so everyone will have a better visual to compare the pictures with.

[Nessism]

Why would the sprocket position change just because the cams were degreed?

[blowerbike]

when cams are degreed....the factory marks are no longer exactly in the same place because of the slotted sprockets and the lobe center changes that was made.

[tkent02]

I have a dial indicator if you need to borrow it.

Looks like a really fun bike.

[srsupertrap]

No reply from Moriwaki Engineering (via Escondido Cycle Center). If I don't receive a reply I will adjust the valves to .005 to .008" like some have suggested. I removed the cams this afternoon and found the following

This mark by the screwdriver tip is like the Suzuki arrow indicating alignment with the head; the GPz550 manual shows the X line should point to the lower cam chain pin. It currently points to the upper pin on the link.



According to GPz550 manual, the Intake Cam sprocket Z/5 mark should be flush with the head.



BUT the Z/5 mark should also be centered between the 43rd & 44th cam pin on the same link plate. It's not



Removed the Exhaust Cam, the bolts from #5 Cam Bearing cap were difficult to remove even with vice grip. The 6mm bolts threads were stripped. Going to need Helicoils.



Exhaust Cam came out clean . . . . funny Kawasaki does not recommend using vice grips during the camshaft removal



Now to measure the cam lobe lift: Width of Cam lobe - Cam Base Circles. The Intake & Exhaust both measure 36.25mm


The base circle measures 28.01mm for both the Intake & Exhaust. Subtract the two and the lift is 8.24 or 8.25mm lift. Unfortunately not the same number as the Moriwaki Cam Specs which Jeep Rusty posted. IMO the 8.25 mm lift is not radical which makes it a good street cam



I need a dial indicator with a flexible arm to check the duration and the C/L angle. Works on hold. I suspect the guy who did this engine work was not an expert.

[blowerbike]

IMO 1&3 intakes need to be made the same or near to 2&4.
you could live with the exh. or tighten them up a couple thou.
the cams will be whatever the engine builder degreed them to as far as lobe centers go.
i would get the tools to check the cam timing and you can check the cam lift at the same time.
i'm not sure where to set the lobe centers on an engine of this size or where you want the power to be made.