1981 Kawasaki GPz550: Restoration

[blowerbike]

yes you would see the weld up from the side of the lobe.
i can't tell from the pics myself.
if you could measure the lift and compare to factory specs that would get you headed in the right direction.

also the casting letter's/numbers might not help.
look on the cam flange where the sprockets bolt on and look on the end on the cams.

also if the cams was of much increase in size you would see clearance work around the bucket's and maybe on the valve cover over the lobes.

lastly...
if the cams was degreed then the bolts can be anywhere in the sprocket slot...that may be where the exh. cam was set when installed.

[Big T]

Hmm, 615 kit, Moriwaki cams, mikuni flatsides, Yosh exhaust

That thing may be faster than your Suzuki

[srsupertrap]

Is that and M E oriented logo?
Could be Moriwaki Engineering.

Thanks JEEPRUSTY for posting that information, I will have a closer look when I get home tonight and try to take a better picture too

Okay, here is a stupid question is Moriwaki Engineering still in business?

[SailorJack]

Awesome thread. Always wanted a lil GPZ550. Stock though. All that aftermaket stuff is cool but I have no use for it. Plus it just complicates a restoration/rebuild.

Good luck though. Looks like you have all the help you could need here and on the GPz forum.

Subrscibed. Looking forward to the updates.

[Big T]

Okay, here is a stupid question is Moriwaki Engineering still in business?

Google is your friend

http://www.moriwaki.co.jp/global/

http://www.moriwaki.co.jp/global/partner/02.html

[azr]

One of these days I'm going to have to get one of these. After seeing yours Todd I've had a real itching to have one. We don't see them up for sale very often around these parts, it's probably the same everywhere I guess. Not sure what their production numbers were like back in the day.

[srsupertrap]

Is that and M E oriented logo?
Could be Moriwaki Engineering.

What do you think? I think we have an answer . . .

I also sent a picture to Escondido Cycle Center in CA. which is a Moriwaki importer. Scott said he would forward the picture to Moriwaki Japan to verify.



Another picture



PS: They never replied . . .

[JEEPRUSTY]

excllnt we have a winer
that is the bike of my dreams I recall 30 some yrs ago the articles for hopping up these lil bikes.

First gen 550 gpz is the bike of my dreams.
It probably the only mc that I would go without lunch for

[Big T]

One of these days I'm going to have to get one of these. After seeing yours Todd I've had a real itching to have one. We don't see them up for sale very often around these parts, it's probably the same everywhere I guess. Not sure what their production numbers were like back in the day.

Rob,

They sold thousands of them over the years

They were very popular, especially with racers and canyon racers, as the 81 was ground breaking machine. As a result, most were crashed/blown up. I know of 2 others locally

The 82-85 unitrack models are more common as the became less competitive as racers with the rise of the 500 Interceptor and 550 Seca

[JEEPRUSTY]

To say noting of the uber powerful and sublime gs550e 83 onwards.

[srsupertrap]

Thanks JeepRusty

Guys, I need the Moriwaki cam valve lash specification also. If anyone has the Moriwaki cams installation instructions in their magazine collection, aftermarket catalog, performance archive etc please let me know. I have Andrews GS1000 specs (.004 - .006") but that's no help here

I decided to check the valve lash and found some interesting measurements



Looks like the Intake Cams were adjusted to give maximum lift. While the Exhaust Cams were set very loose to perhaps prevent burning a valve? Measurement (In)



Let's review the Moriwaki cam timing specs that JeepRusty found below. Assume I have the street cams would you guys agree with the following cam centerline calculation?

Intake: R1(BTDC) + R2(ABDC) + 180/2 - R1 where R1 = 15 & R2 = 45
15 + 45 + 180/2 - 15 = 105 Centerline

Exhaust: R1(BBDC) + R2(ATDC) + 180/2 - R2 where R1 = 40 & R2 = 13
40 + 13 + 180/2 - 13 = 103.5 Centerline

I got this info from http://medlem.spray.se/biker661/Camtiming/htm (Opps no longer there, I have the hard copy)

[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.

[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.

[tkent02]

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

Looks like a really fun bike.

[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.