Tecate's new head gasket blown?

[hang&rattle]

Got the new rebuilt motor back last night after work and put it in. Fired up after about 20 kicks. Let it run about 7-10 minutes to get hot and shut off and let completely cool (what I was told to do by the shop who built it), and did it again. Water is dripping out of the head bolts, especially the rear below motor mount. The shop said no problem and said they would take care of it, but I needed knowledge on why & who this has happened to, is it common? Please explain if you can, I need to learn more because I'm going to attempt a rebuild on my own and are alot of thing I just don't understand yet. Kinda pointed to the worst where a puddle forms when engine is hot. Tecate is lookin' like some thing at least, these ol' rigs after 25 years are incredible machines.....Oh, this is the new Tecate I haven't even got home yet. Impulse buy, whoops, wanted an 82' 250r and accidentally ended up with another. :lol:

[nd4speed]

I dont like using torque specs for old motors and I leave the head stay bolts loose until the head gasket is seated and head bolts have been re-tightened real good

Had this problem on LT250R once and bought and 86 KX250 with the head gasket leaking at head stay.

[hang&rattle]

So go a couple of pounds under torque specs, let it get hot, then cool and tighten down nd4speed? Now remember, I am green with a h2o cooled motor so that's why I had a small shop build it, if I screw it up it will acutally be pretty pricey$. And do they 'seat' after a couple of times heating and cooling down?

[Slingblade]

"When I put a motor back together this is always my method
I use two coats of spray copper coat on each side of the gasket and let it dry for 10-15 minutes. Assemble the head, torque the 8mm nuts to 20-22 ft/lbs and torque the front three 6mm bolts by hand.
I then finish the motor and DO NOT PUT ANY COOLANT INTO THE QUAD. I start the motor with no coolant or water and run until the cylinder and head are warm to the touch. Just good and warm, not blazing hot. The coolant does not lubricate the motor, the pre-mix does, and it will not hurt it to run for a few minutes. Won't hurt the water pump either. I then re-torque the head while it is warm and the metal in the head gasket is soft. let it cool, add coolant and I very rarely ever get a leaky head gasket."


This is a post on another forum from Dave Roberts at ILR racing. Mine leaked at the head before I rebuilt it, used this method and not one drop since, Like nd4speed said, leave those mounting bolts loose during the process. These torque specs are for an 86-87 t-3 or a Tecate 4 so check your specs.

[nd4speed]

I over tighten my stuff. I bought a torque wrench and used it and lost base and head gaskets, so I went back to just tightening by feel. Once things are warped and cases halves misaligned, I think torque specs go out the window. My problem happened on NOS cylinder and NOS head with new studs and new nuts. The nuts loosened up.

Now someone will chime in they have used manual torque specs their whole life without a problem and if they went beyond the specs it would ruin everything.

Usually my head gaskets melt and bond the head 2 the cylinder. The motor wants to twist like a gyro and sometimes head stays can cause problems. I've ran a motor with no head stay.

I often use copper spray gasket and take a large file and draw it down the head to flatten it some. Taping sand paper to thick glass or granite and sanding in figure 8 would be best.

[hang&rattle]

Thanks you guys. I found some more info on Kawieriders after even more searching that is exactly what you gentlemen have said. The copperspray seems a must, because as nd4speed mentioned, how flat and even are these surfaces after 25 years? And no coolent, and not too hot on start up. The little shop that did the rebuild will be referred this information, Thank you very much.

[Dirtcrasher]

No one removes any high spots and that usually causes a leak. I always take the studs out and run a toolmakers stone over all the mating surfaces. You can visually watch the high spots disappear as you run the stone over it; I keep it lubed with WD40 while getting it perfectly flat.

The 19 yo kid they hired for 10$ an hour can also be a problem. They usually won't be doing a 3 stage criss cross head or cylinder nut pattern which is very important on anything but especially a liquid cooled trike.

I personally have never used copped spray or RTV on any gasket surfaces. You don't have to be perfect to be thorough...........

[Vootie]

Did the shop use an oem head gasket, or a cheapie aftermarket one? I had the same prob with my T3, even after smoothing the cylinder and head, with a cheapie head gasket. Switched it out to an oem and used torque specs from the manual (18 ft/lbs I think) and no problems since. Also, after the motor has gone through a couple heat cycles, it's common practice to re-check the torque on the cylinder head.

[hang&rattle]

The head gasket was my fault. The shop told me what parts they needed and let me order them to save money (even they had aftermarket). I was rushed by them and having problems with my credit card on the oem. So I paypal'd e-bay ones to get them faster. I was told only oem, but couldn't pull em' off in time unfortunately. That could be it too. It was a high compression piston (extremely, was even sorta hard to kick over) and was putting out some high psi. Thanks Vootie. Thanks Dirtcrasher, honestly, I don't think they did to much prep work, and the younger kid may have put it back together, but he is actually a decent mechanic, and works on classic bikes, but maybe a bit inexperienced. The old Kawasaki mechanic builds all 70's and 80's kdx's etc, and started the build, but who knows who finished it up. It's called Mr. Salvage in Great Falls MT. We are a little short on services in a state of under 900,000, so it's the only old time shop I could come up with. Now have a guy (farmer) in Billings that loves to rebuild 2-strokes, but alot of distance and just found him out.

[RacerRichie]

cant skimp on gastkets I think we have all learned that lesson at one time or another.
nice trike

[3Razors]

Was this cylinder sleeved? If so, whoever sleeved could have done a homied job and the sleeve/cylinder aren't decked perfectly flat, very few shops do it right. And good luck for anyone that doesn't use a torque wrench on the head bolts, if you have leaks either you have a bum torque wrench, cheap gasket, not flat surfaces or any combo of the 3. And stay away from gasket sealer on headgaskets unless its a copper gasket. The good gaskets come from the factory with a sealer (rubber coating) already on them, when you coat them again it compromises the sealing nature. Want no leaks? Get either a oem or vesrah gasket, cometic is a coinflip imo not worth the hassle and k&s is a joke, then use a good torque wrench and torque to factory specs..not the one that you used to tighten lug nuts and left it set on 80ft pounds for a week in the toolbox, and finally make sure that both the cylinder and head are completely flat before putting it all together. Take it for a brief ride and double check the torque. Now its done, just as good as it came from the factory.

[Tecate 50]

Was this cylinder sleeved? If so, whoever sleeved could have done a homied job and the sleeve/cylinder aren't decked perfectly flat, very few shops do it right. And good luck for anyone that doesn't use a torque wrench on the head bolts, if you have leaks either you have a bum torque wrench, cheap gasket, not flat surfaces or any combo of the 3. And stay away from gasket sealer on headgaskets unless its a copper gasket. The good gaskets come from the factory with a sealer (rubber coating) already on them, when you coat them again it compromises the sealing nature. Want no leaks? Get either a oem or vesrah gasket, cometic is a coinflip imo not worth the hassle and k&s is a joke, then use a good torque wrench and torque to factory specs..not the one that you used to tighten lug nuts and left it set on 80ft pounds for a week in the toolbox, and finally make sure that both the cylinder and head are completely flat before putting it all together. Take it for a brief ride and double check the torque. Now its done, just as good as it came from the factory.

Amen on that.....OEM gasket, dialed torque wrench, good clean mating surfaces......call it a day!

[nd4speed]

Yeah the copper spray gasket is totally not necessary. Save your money. I often use the spary on other gaskets so they are easier to peel or scrape off later. (I cant remember the last time I used it on a head gasket)

The head gasket is made to melt and bond the surfaces. Once the bond is broke after melt- Start over.

I use what ever gaskets are cheap, but I have bought a lot of Vesrah sets. I have used K&S with success but I would not put them near the top of the quality list.