Help with 84 Tecate Engine

[Frankencelery]

My '84 Tecate is poor running and has low compression (about 120psi), so today my son and I pulled the engine to try to get started on repairs. We got the engine out and the head and cylinder pulled. Doesn't look too bad to the eye, but I'm a complete noob when it comes to this stuff. The piston measures a 69.93mm by my el-cheapo digital gauge, but I can't do the cylinder with my equipment. I'm going to have to take it to a pro with the right stuff to measure the cylinder, but there's definitely a ridge there. I'm kind of out of my element here...is there someone here on 3WW that does this kind of work and can help me get this thing back in spec?

230292

I've got a service manual, but it assumes a level of competence that I don't really have. :lol:

[Keith Salyer]

That has a chrome bore and it will have some coloration differences but as long as there isn't a ridge or a gouge in the liner a new piston kit and gaskets should get you going again.

[christph]

120 psi is definitely too low--I'm surprised it even ran at that pressure. You should be in the 165 to 180 range for a healthy stock engine. You need to know that the Tecates came with an "electrofusion" coating, a treatment on the aluminum that hardens the surface. This means you just can't bore the cylinder and put in the next size piston. If the coating is worn through, you will need to get it recoated with Nikasil (see link below) because they don't do electrofusion coating anymore. I called them recently about my Tecate cylinder and your looking at around $350. Or, you could call LA sleeve and get a steel sleeve installed. There you are looking at about $350 with parts and labor. Of course, if the coating is still good you may just need a new piston and rings. A new piston will cost around $150, not including the head and base gasket. I bet you could do this yourself. Replacing a piston on a two stroke is not that hard. Just follow your service manual and watch a few Youtube videos. Good luck.


http://www.mt-llc.com/

http://www.lasleeve.cc/index.cfm?model=KXT-250&model_ID=154

[El Camexican]

Hard to say from the photo, but it looks likes it might be wearing pretty thin. If there are vertical scratches that can be felt with a fingernail, or you can feel a distinct ridge with your fingernail, particularly if you can feel it on the sides of the cylinder where wear is usually minimal, it make be time to recoat that cylinder, or get it sleeved.

There is a John Tice on here that seems to do beautiful cylinder work, or if you decide to get it redone with nikasil you can try Mark at Kustom Kraft. He offers a 290 option as well http://www.kustom-kraft.com/collections/kawasaki-kits/1985+kxt250

The great thing about what you have now is that as stated earlier if there isn't any damage or physical ridge (visual ridge is normal) you can just clean it up with muriatic acid and put a new piston and rings in it. You may not even need a new piston. The pro you take it to will be able to advise you better that can be done here from a photo.

[Frankencelery]

Thanks. While I didn't expect anyone to diagnose from a picture, I did want to show the ridge. The majority of the cylinder is actually very smooth, but the ridge seems quite pronounced to my admittedly inexperienced touch, so I was already assuming it was going to have to be redone. I didn't know that it was going to be THAT expensive though. Yikes! They don't give that plating away, do they?

The engine also was blowing oil out around the base gasket. I'm not sure I understand how this thing operates well enough to know whether or not that would effect compression as measured by a gauge. Two-stroke has a lot less moving parts, and yet seems like it operates like voodoo witchcraft to me.

[El Camexican]

Thanks. While I didn't expect anyone to diagnose from a picture, I did want to show the ridge. The majority of the cylinder is actually very smooth, but the ridge seems quite pronounced to my admittedly inexperienced touch, so I was already assuming it was going to have to be redone. I didn't know that it was going to be THAT expensive though. Yikes! They don't give that plating away, do they?

The engine also was blowing oil out around the base gasket. I'm not sure I understand how this thing operates well enough to know whether or not that would effect compression as measured by a gauge. Two-stroke has a lot less moving parts, and yet seems like it operates like voodoo witchcraft to me.

The price posted usually includes a piston and rings. If the ridge is mainly on the exhaust side and the rest is smooth you could likely just put new rings in it and get another 50 to 100 hours out of it IF everything else is good (you'd need to know what make of piston is in there to buy the rings) and you want to keep the costs as low as possible. Can you post some photos of your piston?

That base gasket leak is a VERY bad thing and possibly the reason for your poor running engine as it also leaks inward. Learn about pressure testing your engine, you would be a fool not to do it after the rebuild. 2 strokes are super simple, don't sell your self short, read up on them a bit, its just an air pump. All the holes do is allow the piston to move the air from the carb to inside the engine, then from under the piston to above the piston and finally out the exhaust port.

[John Tice]

The Quad guys have had problems with a corner of the cylinders at the base gasket breaking off for years. When a new sleeve is installed a very light cut may be machined off the bottom of the cylinder to ensure squareness & flatness of the base gasket surface. Whoever repairs the cylinder, bring this issue to their attention so it isn’t overlooked.

http://i1152.photobucket.com/albums/p497/johntice1/P5130103.jpg (http://s1152.photobucket.com/user/johntice1/media/P5130103.jpg.html)

[Frankencelery]

So does that mean that the base gets warped, and should be machined flat again?

[Frankencelery]

Thanks. I brought it to our local machine shop, Hickman Racing. When I handed it to him, he said "Tecate?". I took this as a good sign! They don't do the plating, but they send it off to someone who does, probably the folks you guys already mentioned to me. He's ordering a piston for me too, so they can match them up.

So, on the seal issue, do I need to be looking at crank seals too? I assume the case halves need to be split for that, right?

[cr480r]

Yes you are right. You have to split cases to replace the seals on Kawasakis

[Frankencelery]

Yes you are right. You have to split cases to replace the seals on Kawasakis

I guess I knew that, but was hoping I had remembered wrong. Splitting the cases is not something I'm going to want to do myself, so I guess while it's apart, I might want to have that done too.

[christph]

Consider it money well spent. Tecates didn't have the build quality and reliability of the Hondas but once you get them up and running they are as fun as hell. The engine accelerates like nothing else. Pure, violent power.

[jonolanracin]

Hard to say from the photo, but it looks likes it might be wearing pretty thin. If there are vertical scratches that can be felt with a fingernail, or you can feel a distinct ridge with your fingernail, particularly if you can feel it on the sides of the cylinder where wear is usually minimal, it make be time to recoat that cylinder, or get it sleeved.

There is a John Tice on here that seems to do beautiful cylinder work, or if you decide to get it redone with nikasil you can try Mark at Kustom Kraft. He offers a 290 option as well http://www.kustom-kraft.com/collections/kawasaki-kits/1985+kxt250

The great thing about what you have now is that as stated earlier if there isn't any damage or physical ridge (visual ridge is normal) you can just clean it up with muriatic acid and put a new piston and rings in it. You may not even need a new piston. The pro you take it to will be able to advise you better that can be done here from a photo.
Haha i have a 85 tec cylinder with kustom kraft engraved on it and had never been able to find any info on them . it was a great running bike till rod went down and im rebuildi g it now thanks for info on kustom kraft

[Frankencelery]

Got the cylinder back. Looks like brand new. While I was taking pictures, my wife called out, "Are you almost done taking pictures of your equipment?" I had to laugh out loud.

231974231975

[christph]

Who did the work? Did you get it Nikasiled?

[Frankencelery]

Yes I did. We have a local place in Des Moines called Hickman Racing. They just sent it off somewhere. They told me the name, but I can't remember who it was. Maybe US Chrome...

[350for350]

US Chrome is a big company. I have a friend who sends his cylinders there.