I broke something else - cam cap heliarc repair?

My normally clean mouth emitted some choice four letter words this morning when I broke one of my cam caps. I'm just glad there were no kids around. Here's a question for you guys: is it fixable? I've heard that heliarc welding can be used to fix stuff like this. The challenge will be matching the machined surfaces. I'll attach a pic for your info. If it's not fixable, anybody got a J-engine head that I can cannibalize? Unfortunately, Kawasaki doesn't sell the cam caps by themselves - they only come with a complete head - list price $1200...

Oh! I almost forgot. Since I will (hopefully) be getting a used part, I'm curious about compatibility. I know the older KZs/Z1s use the same bushing inserts. Will a cap from one of them be compatible with my J head? What about from other KZ engines?

Cheers,

Maverick



Post edited by: Maverick, at: 2006/05/14 01:12

Post edited by: Maverick, at: 2006/05/14 01:23

Post edited by: Maverick, at: 2006/05/14 01:45

You should be able to take this to a good welding shop. Make sure they bolt or clamp the part down to a straight metal surface, at each bolt hole. Also make sure they warm the whole part up. Getting heat into the piece is very important before they start to weld. Like i said make sure its a good welding shop! By doing this it will keep its shape and size.

the head and caps are line bored together as a set thats why they dont sell seperate parts.the problem with weldis the cap is broke right where one of the bearings rides at,which is going to affect your clearances on that bearing i think.if you can get an other head cheap enough i think id bite the bullet and buy it.ive got another j-motor/gz head but its a big valve big ported monster that wouldnt work very good on a small motor. goodluck,happy wrenching!

wireman is right, I have seen people put caps on from differant heads and work, but I would want to get it line bored just to keep things right. I wouldnt even think about welding up the old one

BSKZ650 wrote:

wireman is right, I have seen people put caps on from differant heads and work, but I would want to get it line bored just to keep things right. I wouldnt even think about welding up the old one

ive cheated on the old heads by swapping cam caps and plasti-gauging them,but theres enough junk/cracked kz style heads laying around to get caps off of but youll go through a lot of them to find a cap thats close.buy another head.

If one has enough cam caqps laying around, you can try one after another and chances are you will find one that works. I have done that. As long as the cam turns freely when it is bolted down, you will be OK.

Jay

I use any cam cap i can find and rev to 12000 every 5sec, and i have never had a problem with these things. Cam only turns half crank speed and that helps. Those japs are pretty darn good. dont worry and buy a cap from someone check clearance and Goooo!

Post edited by: nads.com, at: 2006/05/14 21:08

Thanks for the tips everybody!

Now I get why these old kaw heads have the cam caps in the ends! Just a result of machining the cam bearings...

I've also heard that I could probably just use it the way it is... Seems to make sense to me... Does it really need to be in one piece? Particularly because the corner I broke off isn't one of the doweled corners. Since the cam bearing is what the cam is riding in, as long as that is held down it should be ok. Maybe the bolt will take a little more lateral stress, but it's grade 8 steel, so it should handle it, right?

DO IT ONCE AND DO IT RIGHT!!!! Dont get bit bt that warm weather bug that makes you rush through something to go out riding.The way that cap looks I my self would NOT use it.Looks as if the bearing might spin and then you could get into more $$$ and less riding this summer because you motor is down from doing 1/2 ass work and rushing the bougus repair.Just my $.02 worth.I hate doing the same job twice.

i agree with rammy, i bought a bike once that just everything in the motor was jimmy rigged......one of the head bolts was wayyy bigger than the other three, just all kinds of reidiculous stuff that was causing problems. I did everything over again, and it felt good knowing that i had a decent motor. If you put that in the way it is, you will always be worrying about it, and it could do more damage if it breaks....and you will regret it! do it right the first time! Tho, I think you would be able to get away with another cap that has the same or close clearances........

APE Jay wrote:
If one has enough cam caqps laying around, you can try one after another and chances are you will find one that works. I have done that. As long as the cam turns freely when it is bolted down, you will be OK.

Absolutely agree with this -you probably won't have to search too long either.As Jay said as long as the cam turns in the head FREELY,you'll be OK.The myth of having to replace a head if you bust a cam cap is just that.Or a story to sell $1200 replacement heads...

OK guys... You talked me into replacing it. I'm taking the broken cap to a welder this afternoon to see what he can do. If that doesn't work, I've found a couple of guys that have a some caps laying around that I could buy.

Thanks for the feedback!

Maverick.