PDA

View Full Version : $600 1985 Tecate


dcreel
09-29-2008, 04:15 PM
I had a thread a while back about my $600 tecate, and the leaking head gasket. I finally got around to pulling the tank and popping the head. I did find a motoplat racing ignition under the tank. SCORE!!

Now onto the bad news, upon draining the oil, there has been an aluminum piece welded over the old drain hole with a new smaller bolt in it's place. It was leaking a little bit. The bolt had a flat washer, a lock washer and a copper washer on it in that order. I feel a little sick about that..
There was water in the tranny fluid when I drained it.

Popped the head, the top of the piston is scarred all around the edges of the piston, and the dome is as well. The port job is crazy though. I ran it once before I pulled it apart, and it is really fast. I'm blown away by how the piston and dome look despite the way it runs. My buddy has a 01 YZ 125 and it walked all over it.

So now what? New piston and rings of course. Or just a new head gasket and run it? Can the dome be saved? I have an extra but it is much worse. The cylinder porting is awesome, and it runs great given the circumstances with the head gasket. How do I determine the size of the bore? I don't have calipers or a mic.

Help a brother out!! I love this bike!!
On to the carnage pictures.

motoplat ignition
http://i176.photobucket.com/albums/w182/dcreel/100_1840.jpg
http://i176.photobucket.com/albums/w182/dcreel/100_1845.jpg
porting
http://i176.photobucket.com/albums/w182/dcreel/100_1844.jpg
http://i176.photobucket.com/albums/w182/dcreel/100_1846.jpg
Yes.. I just saw the crack in the exhaust port. AWESOME!! :-(
http://i176.photobucket.com/albums/w182/dcreel/100_1855.jpg
piston
http://i176.photobucket.com/albums/w182/dcreel/100_1842.jpg
http://i176.photobucket.com/albums/w182/dcreel/100_1851.jpg
http://i176.photobucket.com/albums/w182/dcreel/100_1849.jpg
Dome
http://i176.photobucket.com/albums/w182/dcreel/100_1843.jpg
http://i176.photobucket.com/albums/w182/dcreel/100_1854.jpg

Video racing the YZ125 just before teardown
http://i176.photobucket.com/albums/w182/dcreel/th_Dragrace.jpg (http://s176.photobucket.com/albums/w182/dcreel/?action=view&current=Dragrace.flv)
200x Basket
09-29-2008, 04:39 PM
that cylinder looks to have been sleeved. that crack most likely will not cause any trouble.
tecat-z
09-29-2008, 05:36 PM
It won't effect a thing. Just make sure to drill small holes in piston in bridge area. The head...... very bad. Needs to be completely recut. Would lead to detonation due to hot spots and poor airflow. Looks like a respectable sleeve job.
fabiodriven
09-29-2008, 05:46 PM
About the cylender scoring- It's tough to tell in the pics, but I'd say my cylender doesn't look much better, and mine starts first kick warm or cold, and definately is NOT slow. About the piston and head, I dunno- If it were mine and it ran good, I'd probly just run it.
scooterroo
09-29-2008, 06:32 PM
nice it has a kx cylinder not a stock t3 cylinder.
fabiodriven
09-29-2008, 06:38 PM
nice it has a kx cylinder not a stock t3 cylinder.

Whoooo! Look at the eye on this guy!
nd4speed
09-29-2008, 06:39 PM
About the cylender scoring- It's tough to tell in the pics, but I'd say my cylender doesn't look much better, and mine starts first kick warm or cold, and definately is NOT slow. About the piston and head, I dunno- If it were mine and it ran good, I'd probly just run it.

Kinda looks like the piston was slapping the head. And may be causing your head gasket leak. My friend bought an LT250R like this a few months back, and when I popped the head it was a hacked up disaster that went in the trash. The piston was hitting the head some. Put a new head on there and he has been riding it all summer.

Don't see any major bore damage. It has compression. Just needs a head gasket.

I would maybe sand some of the pits in the dome, after I figured out if the piston was hitting it.

But hell, if it ran good I would just run it till it broke.
dcreel
09-30-2008, 04:44 AM
What are the visual differences between a kx and kxt cylinder? I guess I have 2 motors with kx cylinders.

I also have another question..

So a few years ago I pulled the running motor out of my 84 tecate at my mom and dads house. It was in there 30 ft by 60 ft shop. I was going to paint the frame and freshen it up. The motor was running great. When I went back to put the motor back in the frame, mud daubers had built a nest in the cylinder. I did not plug the exhaust port. I should have and know better now. I used carb cleaner to spray in the cylinder, and ran the kick starter to force the nest (mud?) out of the cylinder until it seemed clean.

That's where I am at now, I'm afraid to run the motor without pulling the cylinder and cylinder head to check to see if it is all out of the cylinder. But I really don't want to crack open a perfectly running motor.
This is also a KX cylinder ported by Klemm research.

Any ideas? Put it in the bike and run it? See what happens? Or tear it down? I put a new piston and rings in it about 20 hours before this.
fabiodriven
09-30-2008, 08:25 AM
Mud in the cylender?!? And you don't want to crack it open?!? Dude, get yourself a topend gasket kit, crack that puppy open, and CLEAN IT! You shouldn't have even turned it over with mud in there. You wanna scuff the crap outta your bore and cook crank bearings? Then you'll be opening the whole motor instead of just the top end. Shame on you-