Buckets and shims?

[Cooler]

Folks,

I am getting mixed messages from local dealers on the servicing of my 1990 Kawasaki gpz550.

The bike has done 28,000 miles with a valve clearance service at 10,000.

One dealer says get the shims checked every 8000 miles.

Another dealer says, don't worry, if they are not rattling then there's plenty of miles left before another big service.

What's the gen on this? a big service is £350 around here and I don't want to rush into that if not needed. OTOH I don't want to mess up the bike.

Any answers?

C.

[Skier]

Folks,

I am getting mixed messages from local dealers on the servicing of my 1990 Kawasaki gpz550.

The bike has done 28,000 miles with a valve clearance service at 10,000.

One dealer says get the shims checked every 8000 miles.

Another dealer says, don't worry, if they are not rattling then there's plenty of miles left before another big service.

What's the gen on this? a big service is £350 around here and I don't want to rush into that if not needed. OTOH I don't want to mess up the bike.

Any answers?

C.

Your owner's manual should tell you. Sounds like you need to have them checked, though!

Rattling valves are better than quiet valves. Quiet valves means there isn't any clearance between the shims and the cam lobes. Valves get tighter over time. Generally rattling means there's still clearance and that's good.

[telefunkin]

I'd really recommend picking up a service manual to find out for sure. You'll probably be able to check it yourself with the manual and a set of feeler gauges.

I think that model is DOHC so they're pretty easy to get at. Removing the tank should pretty much give you full access to the valve cover.

I have a DOHC kawi 650 and my manual calls for every 5000 miles

[Cooler]

Folks,

I am getting mixed messages from local dealers on the servicing of my 1990 Kawasaki gpz550.

The bike has done 28,000 miles with a valve clearance service at 10,000.

One dealer says get the shims checked every 8000 miles.

Another dealer says, don't worry, if they are not rattling then there's plenty of miles left before another big service.

What's the gen on this? a big service is £350 around here and I don't want to rush into that if not needed. OTOH I don't want to mess up the bike.

Any answers?

C.

Your owner's manual should tell you. Sounds like you need to have them checked, though!

Rattling valves are better than quiet valves. Quiet valves means there isn't any clearance between the shims and the cam lobes. Valves get tighter over time. Generally rattling means there's still clearance and that's good.

Skier,

Good grief, I have just got hold of a works manual. Both the owners manual and works manual recommend checking the valve clearances every 500 miles!!

I wasn't expecting this.

Looking at the diagrams, it's hard to see how the valves would tighten over time. I'm used to the old 'tappets' which were always loosening. I wonder what the mechanical process is here?

C.

[Gadjet]

The valve seats get pounded down, allowing the valve to move closer to the camshaft - this reduces the clearance between the cam lobes and the valve shims.

[Cooler]

The valve seats get pounded down, allowing the valve to move closer to the camshaft - this reduces the clearance between the cam lobes and the valve shims.

Gadjet,

Yes, I get it. As the valve seats wear the valve seats deeper and at the other end gets closer to the camshaft. So, when it gets so close that the valve can't seat properly there will be leakage around the valve seat and loss of power and burning the valve and seat.

I guess with the old tappets that I was always adjusting, the wear would also be on the pushrods, thus shortening them a bit and opening the adjustable gap at the top of the pushrod. Sometimes a pushrod engine was so worn that no amount of adjustment would silence the tappets; this would probably be wear at the bottom where the 'camshaft' was?

C.

[Skier]

Folks,

I am getting mixed messages from local dealers on the servicing of my 1990 Kawasaki gpz550.

The bike has done 28,000 miles with a valve clearance service at 10,000.

One dealer says get the shims checked every 8000 miles.

Another dealer says, don't worry, if they are not rattling then there's plenty of miles left before another big service.

What's the gen on this? a big service is £350 around here and I don't want to rush into that if not needed. OTOH I don't want to mess up the bike.

Any answers?

C.

Yow, that's a short interval! You may be able to stretch it safely to 750 miles if you shim the valves to the loose side of the middle of spec.
Your owner's manual should tell you. Sounds like you need to have them checked, though!

Rattling valves are better than quiet valves. Quiet valves means there isn't any clearance between the shims and the cam lobes. Valves get tighter over time. Generally rattling means there's still clearance and that's good.

Skier,

Good grief, I have just got hold of a works manual. Both the owners manual and works manual recommend checking the valve clearances every 500 miles!!

I wasn't expecting this.

Looking at the diagrams, it's hard to see how the valves would tighten over time. I'm used to the old 'tappets' which were always loosening. I wonder what the mechanical process is here?

C.

(edit) Messed something up here.

You may be able to safely extend the inspection interval by shimming the valves slightly to the loose end of spec.

[toolbox]

dont forget that as an engine wears the valves themselves start to cone.

[crazypj]

Folks,

I am getting mixed messages from local dealers on the servicing of my 1990 Kawasaki gpz550.

The bike has done 28,000 miles with a valve clearance service at 10,000.

One dealer says get the shims checked every 8000 miles.

Another dealer says, don't worry, if they are not rattling then there's plenty of miles left before another big service.

What's the gen on this? a big service is £350 around here and I don't want to rush into that if not needed. OTOH I don't want to mess up the bike.

Any answers?

C.

Dealer who told you if they are not rattling everything is fine is to be avoided at all costs as he doesn't have a clue what he's talking about.
The cams have to come out as you have shim under bucket adjustment. (13mm diameter shims, like in the Z650)
It can be done in about 2.5 hrs.
About 8,000 miles sounds right but if you have 28,000 miles on it (18,000 since last adjustment) there is a possibility of exhaust valves burning.
As the valve seats wear the valve clearance decreases, so, it gets quieter not louder. I have factory service manual for KZ400/500/550
500 miles is first service only, then its 5,000 KM or 3,000 miles. I found its OK to miss a couple of valve adjustments if they are all set to top clearance, 8 thou intake, 10 thou exhaust orabout 12,000 miles between adjustments up to 30,000 and 15,000 after that ( the valves wear slower)
From the post above, the old type screw adjusters have a point contact of a couple of thou diameter, the bucket and shim has a line contact the width of the cam lobe plus the buckets/shims rotate so in effect have zero wear
PJ

[Skier]

Whoops, I read 8,000 as 800. The 8,000 miles between valve inspections is about right for most bikes.