Cam Caps must match head - why?

So what's the solution. I've got a mixed set of caps and head.

Caps are cut originally to fit the particular head they are on. Using a cap from a different engine could result in a misfit. That said, "Must" is probably too strong a term. I once mistakenly reversed #3 and 4 caps and ran the bike for an entire summer....only discovering my mistake when I checked the valves during routine maintenance the following winter. There were no issues. My thought....put the non stock caps on but check the bearing clearances to ensure they are adequate.

On a slightly different point, I've often wondered why KHI didn't install threaded steel inserts in the cam bolt holes to eliminate stripping the threads during installation.

They didn't think these bikes would be around as long as they are. They decided to build bikes that couldn't be rebuilt as easy as the larger fours. Now they're going to reproduce heads and other parts? Hmmmmmm. :whistle:
Gotta give them credit for a job well done whether they like it or not. :laugh:
Steve

Kawboy3 wrote: So what's the solution. I've got a mixed set of caps and head.

Drop the cam in the head with no valves or springs fitted and preferably use new shells for maximum accuracy and ideally arm yourself with some plastigauge and an internal bore gauge.
Do one cap at a time starting with matching numbered caps ( 1 in 1 etc ) and slowly tighten the bolts.
If the cap nips the cam try another cap until you find one that tightens and the cam still spins.
Repeat for the other caps.
Remember that caps 1 and 3 govern cam end float so you can only use 1's and 3's on the left side of the head.
There are steps that can be taken to ease off a tight cap and it's 50% common sense and 50% mechanical aptitude and if a person has to ask how to do that it's probably best taken to someone else to fix.

I have the same issue with a head I'm getting ready to use. A friend suggested if tight to use a small brake hone to make the bores larger. He said that's what they did with R22 heads.
Steve

Interest topic! Lately I've seen a bunch of capless heads on ebay, and people seem to be buying them. Seen my share of walking shells. Hardrock I have studded many of Z1 heads, But only one cam per head. If memory serves me right, do them both and the finished height of studs will not allow cam installation/removal. I don't really trust the "helicoil" brand inserts. Just doesn't feel right/solid when a bolt is threaded thru it, no load of course. Studs, M6 flange nuts corner drilled and safety wired for insurance.

Keeping the cam caps with the head they came off of is a top priority when taking a motor apart. I ALWAYS put the cam caps back on the head as soon as I pulled it off a motor. The method described by zed1015 for finding the correct cam caps is the only surefire way of doing it. I have seen some major dilemmas on motors where the builder mixed up the cam caps. I have seen a few motors that would barely spin over because of super tight cam caps!!!!! Then watch the mechanic panic and go through cam caps after cam caps till he found a set that let the motor turn over normally!!!!!

I posted this little trick on how not to strip out the threads for the cam cap bolts on my build thread of when I put my old Superbike back together. Instead of using the standard 6x45 cam cap bolts . I start off with 6X50mm or 6X55mm bolts at first to start to bring down the cam caps. That way you are using a lot more threads on the bolt holes when you first start bringing the cam caps down. When you get within about a 1/8 of an inch from the cam caps touching the head. Replace the longer bolts ONE BY ONE with the standard 6X45mm cam cap bolts. This is a must when you have a motor with cams that have like .410 lift or more!!!!! I have .440 lift cams in my Kz motor right now, and if I use the standard 6X45mm bolts, I would be grabbing only like 2 or 3 threads as I started to bring the cam caps down into place!!! I have NEVER come close to stripping out any of my cam cap bolt threads since I have been putting Kz900/1000 motors together using this method with the longer bolts!!!

When I do find a head with stripped out threads, the ONLY thing I will use to restore the threads are Time-Serts. It is the only type of repair that works when you have to keep pulling your cams when you do your valve adjustment.

I have NEVER used more than 85 INCH POUNDS on my cam cap bolts.

.440 lift intake cam in place on motor.

Here are the longer bolts I use to start to bring down my cam caps next to the standard bolts.

The cam caps must be kept with the original head. I would not buy a head without the caps on it. That's just plain junk once the caps are lost.

The cams caps are line bored with the caps in place and are not interchangeable.

I fixed a motor once that a genius I know had robbed some crank bearings from a junkyard motor with the main bearing caps and used them. They were shiny clean, and the original crank caps were old and crusty with burnt on oil. It didn't run 300 miles until it spun a main bearing. I cleaned up the original main caps, and installed ANOTHER set of main beatings, then it ran like a champ. He said he thought it turned a little hard. lol

Did my GPZ 1100 UT cam replacement as Dr. Gamma described, works like a charm.
Engine Sounds very crispy and revs on the lightest touch on the throttle grip now. And my Marving race baffle sounds really a little bit to loud now.
Incredible how 1,60 mm more cam lift effect the engine performance.

Sometimes I am in awe of the knowledge some people have on this forum and other times I have to wonder. Back in my day of working in an automotive dealership there were some very simple rules to keep you out of trouble. Mark everything as you take it apart, specifically engines and put them in marked boxes so you don't lose or mix up components. I can't imagine the grief it would have caused to lose or mixup a cam bearing cover or main bearing cap. Even pushrods and lifters were so marked as to avoid any chance of mixing them up. I even went as far as marking the bearing cap bolts so they went right back into the holes they came out of. There was no guessing on this stuff. Time consuming? Yes, but worth it in the end. How on earth can anyone lose a cam bearing cap? Even if you are taking a junk motor apart to save good pieces it's just common sense to reinstall parts where they came from. Different times I guess.

Rick H.

Rick H. wrote: Sometimes I am in awe of the knowledge some people have on this forum and other times I have to wonder. Back in my day of working in an automotive dealership there were some very simple rules to keep you out of trouble. Mark everything as you take it apart, specifically engines and put them in marked boxes so you don't lose or mix up components. I can't imagine the grief it would have caused to lose or mixup a cam bearing cover or main bearing cap. Even pushrods and lifters were so marked as to avoid any chance of mixing them up. I even went as far as marking the bearing cap bolts so they went right back into the holes they came out of. There was no guessing on this stuff. Time consuming? Yes, but worth it in the end. How on earth can anyone lose a cam bearing cap? Even if you are taking a junk motor apart to save good pieces it's just common sense to reinstall parts where they came from. Different times I guess.

Rick H.

What amazes me is the fact that some folks don't put KZ caps back in the correct spots even though they have the position number cast into them. It would seem like that would make mixing them up impossible, but .................. :laugh: Ed

I also worked at several dealerships in the past, much like Rick Stated. Other people's stuff is not normally the best place to "learn". I started my career in a 2 year college auto mechanics course that numbering line bored parts is part of the first semester curriculum. (along with the paying the tuition and student loans) People are not born with technical knowledge,yet some seem to think the more alcohol they furnish or consume magically makes them a better tech. :S

Tech 101 so to speak is parts numbering. On a engine rebuild you flip the motor upside down on the engine stand and go down the main and rod caps with number stamps since none of the parts (usually) are numbered at the factory. Most have main cap numbers cast into them, BUT not all. The rods have to have both pieces hit with the stamp, then reassembly also orients the rod in the proper manner if the numbering is facing you when assembled. This procedure actrually saves time when putting it all back together, and prevents comebacks with failed bearings.

Also marking starter housings and any other parts that can be mixed up, because when you have a pile of parts, it helps to know how it all was oriented. All that is needed for that is a center punch and a few taps of a hammer.