Cam choices

In my 78 KZ build thread I gave the cam specs I thought I was going to use but decided not to for a couple reasons. 1. I didn't feel like the cams were up to standards. 2. I felt the specs on it a little too radical being a .418 lift that was stated I could still run SOT. I really don't want to convert to SUB so I am looking for some other choices. Quick rundown of my engine so far is it's an 81" 1000 J model with oversized valves, heavy duty springs [no port work] and MTC 10.5 to 1 1075 pistons. I don't know the history of this engine but on teardown it was found to have a twisted crank and a broken exhaust valve. It now has a good 82" crank and Del West valves. I am assuming the cams are stock but not sure how to tell and I don't have a problem with using them and running race gas however there should be some more alternatives. One is I think I can get a set of cams from a 82' GPZ1100B1 . 
Would this be a better choice than stock 1000 cams? My other consideration is the K410 grind with 266 degrees duration and .410 lift on both cams. With this it might be possible to run premium pump gas but still not opposed to race gas. I appreciate any input as I am a bit of a novice on the j engines.

84' ZX1100A .375 lift cams may be an option to consider:



🧐
 

daveo wrote:

84' ZX1100A .375 lift cams may be an option to consider:

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Those seem to be hard to come by.

Formula264 wrote:

daveo wrote:

84' ZX1100A .375 lift cams may be an option to consider:

🧐
Those seem to be hard to come by.

I think you may find Daveo just happens to have a set he may be selling 

The only stock cams worth fitting are from the 83-85 GPZ1100 Unitrack  as others have stated.
All other stock cams are pretty much a similar spec as the J.
For after market cams anything around 410 lift will give good results and will work with shim on top.
The limiting factor for running shim on top is the sweep of the cam lobe across the shim and the groove under it around the perimeter on the top of the lifter bucket.
Too high a lift will put the tip of the cam lobe close to the edge of the shim which will push it down into the groove around the bucket which can then cause the shim to get flicked out like tiddlywinks.
Back in the day racers used to fill the groove with silver solder etc to prevent this and RC engineering used to make and sell their own lightened buckets without the groove.
As for fuel type, it is mainly the compression ratio and not cam spec which determines the octane rating you will need for it's anti knock properties.
Most of my Zeds run 410 lift fast road cams and around 10.5 -1 comp and are fine on pump gas..
 

zed1015 wrote:

...tiddlywinks...
 

      Lol!

When I was looking for cams for my 1200cc build I found that too many people were looking for used .410" lift and under Z1 camshafts. At that time everything like that seemed expensive or too many people bidding up prices on Ebay. No body was looking for anything above that 410 range except for drag racers.

Since I have always been a 650 guy, shim under buckets are all I have ever worked with so I am use to that and am set up to work with that tappet system. 

.418" lift is very iffy especially for a street bike if your trying to stay with the shim over system. Some cam sets are advertised as having a certain lift number but actually don't achieve that when measured with a micrometer or set up on the head with dial indicator and degree wheel. 

I ended up buying some NOS RC400 cams which are advertised as having .425" lift but actually measured between .418-.420" which was OK for me since I wanted to build with 650 buckets. It sounds like the cams you are describing are Andrews 3X grind which I have been told can be hard to set up as far as PTV clearance on some aftermarket piston domes.

The only issue with these higher lift cams is the duration can be large which will shift the usable power to the upper part of the rev range. Most don't really start to make power till 6-7K RPM as they are usually racing grinds.

I only bought the RC cams because they were reasonable money and cheaper than all the new 410 cams out there. If I did not find those I probably would have picked something a bit tamer and less race orientated.