Inside my engine

[89katana750]

So I did my valve clearance and took some pics while I was at it. I am concerned about the lobes (not too concerned) because of the mild scratchings. Also I noticed the guy before me lost on of the gasket pins and just filled it up with silicone (bottom right). And the spark plug gaskets were also siliconed. Its amazing how you can figure out what people did before you.

73000km is on the engine

[Yellow]

My cam lobes are also a bit pitted, though somewhat less than yours... but 73 tkm is quite a lot, mine has 34 tkm's - if the meter is to be trusted, I don't trust anything anymore of the BS the PO said about how well it's been taken care of.

I wasn't to worried about mine either, but I'm by no way an expert... Let them chime in.

You might want to call the PO up to make sure he didn't lose the locating dowel into the engine.

[arsenic]

yeah it is possible for a machine shop to weld, reground and harden the cam lobes. The pitting really dosen't look all that bad. there is no heat discoloration. Check for flat spots, score marks or chipped area. If you have a micrometer, the cam lobe height should be:
Intake
Standard -- 33.594 - 33.634 mm
Minimum -- 33.300 mm

Exhaust
Standard -- 32.882 - 32.922 mm
Minimum -- 32.590 mm

Thats the specs for the 89-95 750

[arsenic]

Okay I'm bored so I'll list all the GSX-R lobe specs. By the way I was reading your profile, and I don't know how it works in Canada, but in the US the insurance goes by the frame # so if you put a bandit engine in there the insurnce will still be for a 750. Thats why it's best to take a 600 frame a slam a gisxxer 1127 in there, the insurance cost will be based on a 600. Any way:

Intake
85 -87(UK)
Standard -- 33.563 - 33.603
Minimum -- 33.207

86 - 87(US)
Standard -- 33.594 - 33.634
Minimum -- 33.300

88 - 89
Standard -- 33.878 - 33.918
Minimum -- 33.580

90
Standard -- 33.876 - 33.936
Minimum -- 33.580

91 - 92
Standard -- 33.896 - 33.944
Minimum -- 33.600

Exhaust
86 - 87(US)
Standard -- 32.882 - 32.992
Minimum -- 32.590

85 - 87(UK)
Standard -- 33.146 - 33.186
Minimum -- 32.850

88
Standard -- 33.533 - 33.573
Minimum -- 33.240

89
Standard -- 33.604 - 33.664
Minimum -- 33.310

90
Standard -- 32.872 - 32.932
Minimum -- 32.580

91 - 92
Standard -- 32.906 - 32.954
Minimum -- 32.610

[The CyberPoet]

That cam pitting happened either from sitting unused for a very very long period of time, or far more likely, from using an oil high in sulfated ash content and parking somewhere where it got condensation frequently (sulfated ash + condensation can form sulfuric acid, which attacks the metals; the valve action at the spot works away the then-weakened-metals).

When Keith is up and about, I would think you could always get another set of cams from him. My concerns would be that the bearings (both cam bearings and main journal bearings) are probably similarly pitted.

Cheers
=-= The CyberPoet

[89katana750]

That would save a lot of insurance dollars eh? Somewhere in the range of $7000-$8000 a year.
Im not going to repair much of the engine parts, the guy who had the bike before me didn't really take care of it. It would just cost me additional moneys. Repair one thing, then another and by then end of it I will have to rebuild the engine.

By the way, how much would used cams go for? with the bearings and such. I think the bearings are a bit worn down because when I turning the engine over when doing the valve clearance it was pretty stiff at times. (not sure how stiff is too stiff)