84-85 tecate cylinder difference kxt / kx questions answered

[T3 LOPES]

Here are pics of production 83-84 kx cylinders vs 84-85 tecate cylinders. Tecate cylinder pics are the ones on the left, kx pics are on the right. When looking into the exhaust ports you will see the kx cylinder is heart shaped with a (bridge) separating the port to keep the rings from snaging since the port is much wider then standard tecate cylinder. Tecate cylinder is oval and wide open. KX cylinder has two extra small exhaust boost ports "one per side: above the standard tecate side ports. Intake bell and transfer ports are identical on both tecate and kx cylinders, so the cylinders have the same ability to flow on the intake side. The exhaust is where the power is found. Since all engines operate with peak efficieny coming from a balanced flow of air through it, this has to be a balanced ratio which the kx cylinder maximizes. Putting a big carb on a detuned (restricted) tecate cylinder interupts this flow since it can't purge exhaust fast enough, and throttle response will be slow off idle and top end will suffer greatly. These kx cylinders are an easy way to gain 5-7 hp with a 38mm carb and careful tuning. With this simple mod you will have no problem beating any relatively stock 250 trike. The last pic is a shot of two kx cylinders on the right, the center is 72mm or 265cc which really fattens up the power everywhere. Before you buy make sure it has this bridge so you dont get let down since the outsides of both are identical. It is the only way to be 100%. And remember these cylinders were all nikasil plated when new and is the best way to go if you need to renew one. However if it has already been sleeved go for a nice clean overbore since it can never be plated again. Hope this answers some of your questions. So let the hunt begin for these power packed monsters!!!!!!:w00t:

[Tyler]

20 years ago a buddy of mine did the KX jug and 38mm carb swap to his 85 Tecate. It was money well spent. Add a good pipe and it was a very fast machine. I totally forgot just how much better the KX setup was. Thanks for shareing the info.

[hadar]

I just got one off ebay for $75 hope It's the right thing. If not, he says he will take it back and refund. I have a 38mm flat slide that didn't work so great w/ my kxt, perhaps now it will. Hope I didn't get screwed, what do you think?

http://images6.theimagehosting.com/kx250 84.th.jpg (http://server6.theimagehosting.com/image.php?img=kx250 84.jpg)

[T3 LOPES]

Hadar , its hard to tell from your pic. take a pic of your exaust port , where your pipe slips in to the cylinder there should be a metal bridge. From the top of your pic you can not see the extra exaust boost port.

[hadar]

Yeah, it's kind of a gamble, he said it's an 84 kx250 cylinder. I had to take a chance. I want my 84 to frighten me at wot.:twisted:

[Dirtcrasher]

I just got one off ebay for $75 hope It's the right thing. If not, he says he will take it back and refund. I have a 38mm flat slide that didn't work so great w/ my kxt, perhaps now it will. Hope I didn't get screwed, what do you think?

http://images6.theimagehosting.com/kx250 84.th.jpg (http://server6.theimagehosting.com/image.php?img=kx250 84.jpg)


Not a great pic but, It sure looks like you have the extra exhaust port area on the side. So, I'd say KX for sure - just look for the bridge.

[3Razors]

I have that setup on my 84 Tecate with a 38mm mikuni flatslide, bassani pipe, and kx ignition setup. It is a hot little bike! We dynoed it just for kicks once and it pulled 52hp to the rear wheels.

[scooterroo]

well after further review, the one i was looking at on ebay, is a kxt cylinder, thanks for info lopez. someday i will find one.

[Red Rider]

Not a great pic but, It sure looks like you have the extra exhaust port area on the side. So, I'd say KX for sure - just look for the bridge.I don't know what you're looking at Dirtcrasher, but I don't see the extra "boost ports" that T3 Lopes so clearly pointed out. Based on Lopes' side by side comparison, my moneys on KXT cylinder.

[hadar]

Well, it's real hard to tell from that pic. As soon as it comes in, I will post a better one. I sure hope it's what he said it was. If it is a kxt cylinder he's going to get it back. Now it's time to play the waiting game.

[Dirtcrasher]

I don't know what you're looking at Dirtcrasher, but I don't see the extra "boost ports" that T3 Lopes so clearly pointed out. Based on Lopes' side by side comparison, my moneys on KXT cylinder.


In the picture I saw on the right a small ovalled out egg beyound the usual port area. However, now that I look again - that ovalled out egg I'm looking at seems to be the intake port - is there a smiley for DUUUUUHHHHH??

I'm amazed how the KX and KXT cylinders are completey identical on the outside. You would think there would be some small diffrence somewhere.

[Tecate250]

Wow Thanks for finally clearing this topic. Are the trannys the same on both machines? Only the kx being lighter, chain and sprockets, and the tires make them faster?

[T3 LOPES]

As far as I know they have the same ratios. Tecate gears are beefier than the KX because the Tecates were heavier. Tecat-z explained it better in the post (KX TRANS?) The kx motor put out much more power then the tecate, as well it is lighter and its a dirt bike. I'd say thats why they are so much faster.

[Tecate250]

So would it be a reversal with using a tecate bottom end on a kx 250 jug? In a kx? Ive heard a rumor about the tecates having bad trannys? I had my t4 tranny lock up? But the rumor was kawasaki using there kx trannys in there atvs, and the trannys let go under the load?

[T3 LOPES]

Yes the kx jug bolts right on. The Tecate motor would fit right in a 83 84 KX. I have had no problems with my Tecate trans. The KX trannys are not as heavy duty as the Tecate trans are but they both work just fine. I run a KXT trans and my buddy runs a KX trans in sand with paddles and never had a problem .

[cr480r]

the kx cylinder on ebay is tecate cylinder. I contacted the seller about a couple of his listings, he doesn't know his parts. Even from the picture shown it is clearly a tecate part. I was looking at a kx cylinder while I was comparing the picture.

[BigGreenMachine]

Great read and pics. Did Sprock Racing ever complete their bigbore KX cylinder??

I have my 250 motor here and will definately pick up a KX cylinder for it when I get the chance. Think I may drop it in a 300EX chassis instead of a bigger fourstroke.Maybe some green fenders to keep with the green machine theme...

[cr480r]

I have a non-kips engine laying around too. My kx cylinder for it needs a lot of work before it can be used. I was thinking of putting it in a 85/86 lt250. The frame is already made for the side exiting exhaust. A blaster would be a fun one too

[Tecate250]

Thanks t3 lopes. That cleared up alot.
Ill know everything about this beast, then it will take my life.

lol

[hadar]

Damn it all. Turns out that the cylinder I bought was a kxt. He said he would refund $, but still. Oh well, it looks like the hunt continues. Perhaps someday.

[BigGreenMachine]

Keep looking, it'll turn up somewhere. Half the fun is looking, good deal on getting your cash back too.

I only need the KX cylinder, got the ignition a while ago and have a new 38mil flatslide. I can't wait to try it all out. Think when the time comes I'll be using a KX500 reed cage as well. Should flow more then the Tecate cage and I'm gonna use my Vforce II in the KX500.

[T3 LOPES]

Hadar, you will definitly fine 1 . Just keep your eyes open and BAM there it will be . Thats how I found mine, for 30$ and 30$ shipping, 60 bucks . I couldn't pass it up. I love these freaken Tecates.

[Tecate250]

did kawasaki ever use a stator likr the tecate on any of there 2 strokes? I have a smaller stator. Is this the 83-84 stator?

[BigGreenMachine]

You have the 83/84 KX250 flywheel/stator and CDI (black box). It fits the Tecate and makes the bike rev up and down faster resulting in faster acceleration. I have the same setup, never got the chance to run it though.

http://img.photobucket.com/albums/v514/BigGreenMachine/IMG_0260.jpg

[Tecate250]

why did they use a different,smaller setup? I noticed that the magents are bolted on. Can these be replaced? Also the same magneto is almost identical as a cr 80 mag.

[cr480r]

They use a smaller flywheel on bikes so they are responsive and rev quickly, The atv's used a heavier flywheel for many reasons, one is to run the lighting system, two is so it doesnt stall as easy(kind of a pain in the a** with a grabby clutch), and I think another reason is for safety. I put an 85' kx ignition system on my tecate and it really woke it up, It required slippping the clutch alot more, and traction was not as good. I dont think I would replace a functional tecate ignition, but I would definately buy KX if I was replacing faulty parts or rode at the dunes much.

[BigGreenMachine]

Does the KXT piston/rings work in these cylinders?

[scooterroo]

i have heard conflicting reports. some people have said yes, that the kx and kxt piston is the same part number. yet some tell me they are totally different. i will eb using the complete kx setup with the kx piston and rings. that along with the kx ignition i got off you, the bassani pipe and answer hottip silencer, and the vforce reeds and 38mm carb, the thing oughta be a snot rocket.

[tecat-z]

All tecate part #'s have been superseeded by the kx #'s. Remember, The intakes are the same between cylinders. I have had both tecate pistons and kx pistons and they have always been the same physically. Cranks, rods, cases, etc are all the same. Don't let this confuse you. I've built several engines from cases up and wisecos are all the same#. And yes if you do it right, they are very quick. Infact quicker than i had imagined. My strong running tecate cylinder engine of last year doesn't have a chance against my nicasil kx equipped engine. You do however loose some roll on power in the mid range, where the t3 cylinder would pull through a bit harder, but then sign off early. Kx engines are meant to be ridden in the high rpm range more than later PV equipped cylinders. They make power, and lots of it but you have to be more aggressive to use it. In the sand it should fly. We'll find out this weekend.

[BigGreenMachine]

Scott I wish I kept that ignition. LOL Sold my 500 and going to tear into my KXT once I track down the stuff I need. Would like to do a KX cylinder swap.

The midrange loss concerns me. There was nothing gained in the midrange tecat-z? How does the bottom end compare? I trail ride a lot and play on some wide open beaches/sand piles and like the top end/mid power. Maybe the KXT flywheel would give me an effective bottom/mid for the trail riding I do?

[tecat-z]

These cylinders were designed to produce high horsepower at high rpm. In motocross the engine is kept on the pipe virtually 100% of the time. Low to mid power is not nearly as important as high engine speed and overev. I wouldn't consider this state of tune if you mainly ride casually in trails and rugged terrain. Engine vibrates more at idle with the loss of flywheel effect, though it still pulls away from stop smoothly and not much different than heavy tecate flywheel. I am not using any tecate ignition components. T3lopes is using ricky stator flywheel and stator, with oem coil an cdi and it's running real hard as well. Just got it dialed on Sunday. Just got my 20-10-10, 9 paddle skat-trak haulers. Hope this bike will pull em????? Will find out real soon.

[ccdhowell]

Would love you to elaborate on the KX cylinder when you've had a chance to run it a bit. I have one waiting in the wings. How does the KX cylinder affect jetting? Seems as though you'd jet maybe one main richer for the added flow at the top end. Is that what you found or no? chris

[tecat-z]

I've already run it quite a bit gettin it dialed and its very impressive. Has an enormous hit when it comes on the pipe which is what slingshots bikes out of turns. Again, this is mainly a sand type engine for me, where high HP and RPM is key to keeping speed up. Carburetion is handled via an esr 38mm Keihin Airstryker. A very common carb. These carbs have got to be the easiest mixers to work on and dial. I am impressed with it so far and have a 48 pilot, stock needle on second groove from top, and a 195 main.

[hayesmo33]

hey all im new here i just bought a 85 tecate 3 off ebay 780$ i think it has a kx motor and not the tecae motor:mad: whats the differnt in the motors?what all kx years will fit it looks as if they made front motor mounts.i just wont to get the right parts ive already order a carb factory air box before i was told it was the wrong motor hope it all fits? the more imfo i get the better

[scooterroo]

the 83/84 kx motors swap right in to the 84/85 t3. the trannies i believe are geared a bit different, and the ditinquishing character of the mtoor is the bridge on the exhaust port. if there is a bridge it is a kx cylinder, if there isnt a bridge just an open port it is a t3 motor.

[nd4speed]

hey all im new here i just bought a 85 tecate 3 off ebay 780$ i think it has a kx motor and not the tecae motor:mad: whats the differnt in the motors?what all kx years will fit it looks as if they made front motor mounts.i just wont to get the right parts ive already order a carb factory air box before i was told it was the wrong motor hope it all fits? the more imfo i get the better

Look at my motor swap threaD:

http://www.3wheelerworldforums.com/showthread.php?t=60994

[hayesmo33]

Hey all i have another question for you all will delta v force reeds fit right in the 85 tecate? if so do i order them for kx250 cant seem to find meny parts for this bike hope to find a pipe and or silencer!!!

[scooterroo]

try dg if you want a new pipe and silencer, they are about the only ones left that make them still. or post a want ad in classifieds, im sure someone would have one for you. t3s are alot harder to find parts for then other bikes...but the parts are there. and oh yeah, vforce 3 reeds slip right in nice, and yes you can order them for the kx or the kxt model...check dennis kirk.

[hayesmo33]

hey im trying to get my carb dialed in its stock carb the one that came on the bike in 85. but the guy i got it from had a pipe reed big bore and so on.im just trying to learn how to jet it or where to start he said start with main jet 165??everything else wouled be fine he said the jet in it was way to big other then air filter my bike is the way it came in 85.please help reason i got differnt carb was becuse it cut out at top end.like it was runing out of gas. thank you Hayes murray 2 more wks she be at saint joe park in mo.hoping it will be runing good

[heyy]

But if your going to go through this why not just replace the piston also, if I'm corrct didn't the 84/85 pistons have a low compression like 8.5-1... Could u use a stock 86/87 piston they have a little higher comp. Or do u have to go aftermarket?

[tecat-z]

All pistons are the same, and have been so for years. In other words 84-87 kxt and 83-86 kx 250. Same bore X stroke. "stock" oem pistons only come in 70mm, and are discontinued. Wiseco is your best alternative.

[heyy]

But then what gives the later tecates the bump in compresion? Is it the head itself?

[cr480r]

But then what gives the later tecates the bump in compresion? Is it the head itself?
It could be.. but if you are comparing the manufacturers claimed corrected compresion ratios then the difference could likely be due to porting changes..

[cr480r]

i bet if a person added aux. exhaust ports to a tecate cylinder it would be superior to the kx cylinder... There is a reason KX250's havent used a bridged exhaust port since 1985... anyone ever tried this? or seen or heard of it being done?

[tecat-z]

Much of the reason for them not using that layout on newer designed 2 strokes is that the oems have adopted the small bore long stroke design,and the use of the p/v. Old 2strokes all favored a much larger bore to stroke ratio. But, big bore pro-x cylinders still use triple port exhaust layout..