TOPIC:

40 year old threads. I'm surprised I don't have more than I do. Never used a torque wrench on M6 bolts. Always have "incerts" on hand.
Steve

I have a good story. I ordered the APE .410 cams and they mistakenly sent me the .435s. Assuming they were correct, and not even looking at the numbers stamped in the cam ends, I installed them on the head (off the block) to do an initial clearance adjustment. First thing I noticed, as I rotated the cams, was the shims popping up on one side of the bucket -- almost coming out of the bucket. The higher lift lobes contact the shims too far off dead center to keep them seated in the bucket. Therefore the need for shim under. If I installed and fired the engine with .435s and shim over, it would not have been pretty.

VTEC wrote: First thing I noticed, as I rotated the cams, was the shims popping up on one side of the bucket -- almost coming out of the bucket. The higher lift lobes contact the shims too far off dead center to keep them seated in the bucket. Therefore the need for shim under.

That is the "clicking I mentioned , the shim being pushed down into the groove on top of the bucket then snapping back down.

The .435 has a reduced base circle, so the nose is only .010" further out on the shim, but it is enough to tilt the shim.

CoreyClough wrote: RD Valve Springs.
rdvalvespring.com/

Corey, I am surprised at you. And to think we have your photo on the wall in the lobby.

old_kaw wrote: I think I get it now.. The shims over the buckets >could< come out of place in the event of the valves were to "float" for some reason, or just not follow the cam lobe back down to the base circle properly. Of course, I would ass-u-me, that in the case of valve float on one of these engines that something even more catastrophic may be happening or about to happen at the same time.

It is called spitting a shim. It will send it right thru the cylinder head leaving a nasty hole to weld up.

Big Jay wrote:

CoreyClough wrote: RD Valve Springs.
rdvalvespring.com/

Corey, I am surprised at you. And to think we have your photo on the wall in the lobby.

No disrespect to APE at all Jay, as I was not aware APE made springs for the smaller cc GPz550. The bigger bikes, yes. I always have sent springs with my heads when I had APE rebuild them, whether they were for racing or street use, and will continue to send parts there for machining in the future, as I'm not finished with motorcycles yet. I believe the VSP550 Springs are for 550 lift cams, right?

Big Jay wrote:

old_kaw wrote: I think I get it now.. The shims over the buckets >could< come out of place in the event of the valves were to "float" for some reason, or just not follow the cam lobe back down to the base circle properly. Of course, I would ass-u-me, that in the case of valve float on one of these engines that something even more catastrophic may be happening or about to happen at the same time.

It is called spitting a shim. It will send it right thru the cylinder head leaving a nasty hole to weld up.

Thanks for all of the great replies stories and explanations to this newbie in the art of modifying these engines, and the pitfalls thereof. I am glad that I already lived through my "hot rod racing" days, because my bike is extremely reliable AND fast. I get in enough trouble as it is. it starts every time, makes it home under it's own power, and runs like a bat outa hell.

I did make one observation throughout this thread.. it would seem that "spitting a shim" kinda turns the go fast parts into go slow parts with a hole in your head as a bonus.

Pushing it home is no fun.

Stock works for me.


Not really lacking power anyway. Note: I did not burn off this tire on purpose like the loud and slow crowd, that's from cranking the throttle.

I get 5000 miles if I'm lucky. Using the power is good for the soul.
Steve

CoreyClough wrote:

Big Jay wrote:

CoreyClough wrote: RD Valve Springs.
rdvalvespring.com/

Corey, I am surprised at you. And to think we have your photo on the wall in the lobby.

No disrespect to APE at all Jay, as I was not aware APE made springs for the smaller cc GPz550. The bigger bikes, yes. I always have sent springs with my heads when I had APE rebuild them, whether they were for racing or street use, and will continue to send parts there for machining in the future, as I'm not finished with motorcycles yet. I believe the VSP550 Springs are for 550 lift cams, right?

. Cory, Didn't realize you were referring to the 550 in your comment.

Big Jay wrote:

CoreyClough wrote:

Big Jay wrote:

CoreyClough wrote: RD Valve Springs.
rdvalvespring.com/

Corey, I am surprised at you. And to think we have your photo on the wall in the lobby.

No disrespect to APE at all Jay, as I was not aware APE made springs for the smaller cc GPz550. The bigger bikes, yes. I always have sent springs with my heads when I had APE rebuild them, whether they were for racing or street use, and will continue to send parts there for machining in the future, as I'm not finished with motorcycles yet. I believe the VSP550 Springs are for 550 lift cams, right?

. Cory, Didn't realize you were referring to the 550 in your comment.

Yes Jay. Sorry. I should have added that info in my reply.

The shim spitting issue is all to do with the shim rocking in the groove when the cam sweeps too close to the edge and if you are unlucky it gets flicked out like tiddly winks and punches a hole though the head or worse.
I think it may have been RC engineering that made a bucket without the groove and also some of the race lads would fill it with silver solder and problem solved.
I'm surprised that with the ongoing popularity of these engines one of the KZ performance parts manufacturers isn't producing groovless buckets
Only issue was that it made the shims harder to remove at service time .