Advertised Drop In Cams NOT Dropping In

In the past year, I've run into 3 different drop in grind cams that DO NOT drop in. 2 from one manufacturer and one from another.

On every one, it's #4 exhaust and #1 Intake tappet bores where they rub. They rub he valve cover bolt hole boss pretty hard.....

On another set of .400" lift cams, the sprocket bosses were thicker than normal and rubbed in the cam chain tunnel.

So watch out if you're buying drop in cams. Looks things over very carefuly. Q.C. [like most everything these days] ain't what it used to be...

Larry, I have no experience with drop in cams, but I do have a lot of experience working in machine shops. All I will say is that when the sh!t hits the fan, the first thing to get dropped is the QC. I'm guessing that over the last two years with business being slow, there are a lot of QC guys in the street. At one point I worked in a shop with no QC whatsoever for about 7 months. The parts went straight from the machine to the finish shop and on to the customer. The last guy to put a mic on the part was the guy who made it. Unacceptable!

Since you deal with these companies all of the time have they been standing behind their product? Which brand are you not having problems with? I understand if you don't want to post up the problem cams. As a lot of guys would be glad to know, to save all of the work of tearing it down, expecting to crank it up without machine work.

testarossa wrote:

Larry, I have no experience with drop in cams, but I do have a lot of experience working in machine shops. All I will say is that when the sh!t hits the fan, the first thing to get dropped is the QC.

What a conicidence, same story for the electronics industry, auto makers, and every other business I know of.:laugh:

Thats a valuable heads up when most guys (me included) are accustomed to trusting the parts MFG's. Bolting in a new set of cams and learning too late there is a problem on engine start can ruin a mans month!

That's what you get when the real machinist's are replaced with button pushers to save money! Us "real machinist" who came from running manual machines are getting to be extinct. I used to have a boss that thought the best cnc guys were the ones that never touched a manual in their life. What an ass he was.

You aren't kidding dshelly. I had a former boss with that mentality at my current shop. His strategy didn't work out. It cost him his job, and all of his "warm bodies" went with him. Now we are left with all of the real machinists in our shop. It's a really cool environment now. The new boss has been there and he appreciates men with true skill. I run a cnc primarily now, but without my Bridgeport and engine lathe experience, I wouldn't be half the machinist that I am now.

So Larry, if we shoot you a pm when we're ready to buy cams, then you'll steer us straight, right? I wouldn't expect you to trash talk a company publicly. You are in a different position that most of the members here.

Guys,

All I can say is check things close guys. You guys with the maching shop experience are right on top of the situation. It's exactly like you described it when you pull the parts out of the box.

MV Agusta is my dream company! What I wouldn't give to be able to move to Italy and work for those people

ive always believed in clearancing the cam bucket area anytime a head is apart anyway for possible future buildups,saves headaches later when you have a motor broke in and want to wake it up a little

I have never sold drop in cams, so I can't coment on that aspect, but a few years ago the KZ cam blanks had the sprocket flange area widened to help with a cracking at the bolt holes that some were having.

The first attempt was a little too much and the back side of the flange would hit the head on some castings. It was adjusted shortly after and is not now a problem.

There are some bolt-in's (appx .380+") that don't hit the head, but they suggest the Valve to Piston Clearance be checked. (can be done with motor assembled)

I would think if the lobes are hitting the head, I would check the Valve to Piston Clearance for sure. (shouldn't be done with motor assembled)

Oh what the heck, the only thing you are risking is some New Valves, Gaskets, Labor (and/or) Piston & Head damage.

Whats In Your Wallet?

PLUMMEN wrote:

ive always believed in clearancing the cam bucket area anytime a head is apart anyway for possible future buildups,saves headaches later when you have a motor broke in and want to wake it up a little

Hey Plummen,
Could you post some photos or info for those of us who might be interested in clearancing for the future. I'm certainly capable of figuring out the clearance when I do get my cams, but admittedly, I'm a newb to these motors, so for the sake of us newbs, where and how much clearance. It just so happens that I could do this right now since I have my motor apart. I will probably assemble it in the next week, so I need to decide soon, if I want to modify.

Jay, that's good to hear that the tolerance modification was made with some justification. Anyone with a manufacturing background will acknowledge that this is normal. You make incremental revision changes toward a final, polished, finished product that works. However, normally, this will happen "behind the curtain" and the end consumer shouldn't be subjected to prototype trials. Sadly, as said by bountyhunter, and I can back his statement up. In today's world, as a consumer, you are often the guinea pig. If you have ever purchased a first year model car, then you know what we are talking about.

I think that the main thing to take from this thread is the very important point that Larry raises. If you put a part into your bike that doesn't have an OEM Kawasaki label on the package, then you had better check it out to make sure that it functions properly. Porchev914 highlights a possible tragic situation. KZR member buys aftermarket cams for his bike that are sold as "drop-ins", so he drops them in without ever checking anything. Then he starts the bike for the first time, and hears a horrific grinding noise, and kills it. Upon pulling the oil pan, he discovers loads of metal shavings and decides to rip apart the whole motor to see what's wrong. Just that simple decision to split a case could be enough to cost an average guy a whole year of riding, and possibly be the reason that his bike ends up for sale on CL with "carb problems".