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I hav a overheating with my track EX. It would overheat when the engine was stock when it was realy pushed hard.

I thought it might have a blown head gasket. I bored it out one mm. did a valve and resurfaced the head and installed CR carbs. I still had the same problem. I went to a ZX7 radiator. That didn't help. I removed the center from the thermostat, no change. The water pump is working fine.

Any ideas?
 

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Faulty temperature sensor or guage?

Please, take the following question with a dose of sugar...
Nobody put a custon fairing in front of the radiator did they? :eek:
 

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Yes I know exactly whats wrong. Inspite of what you said, you have a head gasket that's leaking High pressure gas into the cooling system and blowing water over the side as the system becomes overpresurized.

Ex engines are flexy fliers just like the chassis. Once taken apart the head and cylinders will never match up. Since the head gasket is non compressable the surfaces must be perfectlly flat. You said you re surfaced the head, but even if they did a good job, (suspect) thats only half of what's needed.

You must Lapp the head and the cylinder surfaces flat, clean the gasket with laquer thinner and Skotch brite or steel wool till it's bare metal. Paint both side of it with a rattle can (color optional) re assemble. Increase the head bolt torque to 40 lbs'. Put in a new 180 degree thermostat.
I have fixed many engines in the condition you describe, trust me.
I have pictures of the lapping process Email me and I'll send them to you.

FOG

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How about that. Why couldn't a person custom cut compressible head gasket material that would allow bypassing the lapping steps?

Which makes me wonder... are these engines an interference design, like several brands of cars... where the valves could hit the pistons if the cam timing gets far off? When Santa [/color]brings me a manual I won't ask such questions... I hope.
 

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MrSciTrek said:
How about that. Why couldn't a person custom cut compressible head gasket material that would allow bypassing the lapping steps?

Which makes me wonder... are these engines an interference design, like several brands of cars... where the valves could hit the pistons if the cam timing gets far off? When Santa [/color]brings me a manual I won't ask such questions... I hope.
You can and they do work, but you loose CR and Power The stock gasket is only .007 thick and the drain back and water passages in the head are very close to the combustion chamber and are hard to seal. Remember were talking about Combustion gases at several thousand PSI.

And yes this is a interferance design.


FOG
 

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Knightslugger said:
What brand of abrasive do you suggest for lapping?
It's not important, but usually Silicon Carbide of about 100 Grit, but any type of valve lapping compound from an Auto Store will do.

FOG
 

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Fog, have you ever tried eliminating the head gasket? At .007" and hard, it begs the question, why have it at all?

I have had some experience with gasket design and faults. One of the problems that occurs is the clamping force rapidly diminishing as you move further from the bolts.

Back in the eighties I wanted to try a no head gasket design on some small block Chevy engines that I used to build for sprint cars. They were notorious for blowing the gasket between the center two cylinders where the space was narrow, the span between the bolts was great, and the meat for rigidity was small. Either individual captured seals at each water passage with metal to metal elsewhere, jumper pipes external from the block to the head, or possibly even just totally seperate circulation of the water in the head and block. Experience with air cooled bike motors and especially VW motors were part of the inspiration. Never tried it, partially because of time but also budget, not being able to afford risking that many expensive parts. I still think it was a sound idea but lost confidence when those large volume engine builders who could afford the experiment and could really benefit from the knowledge, had never done it. But then again, I've seen other obvious solutions to problems escape introduction for years and when finally tried, worked well.

Now I'm musing over past frivolities. Anyway, ever tried it?
 

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"Now I'm musing over past frivolities. Anyway, ever tried it?"

No, because most of the engines I built were for customers and I just stuck to what I knew worked.
But the Idea has Merritt. I have often thought that the paint on the gasket was responsible for most of the sealing. and was tempted to try just paint, but I never did.

The more engines I built, the more disappointed I became with this design. It has so many shortcomings that limit what it can do, (and can be done). This is the reason I try to discorage and Performance enhancing mods. The engine can't take the power it produces in stock form.

FOG
 

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I know this is an old topic, but I'm a noob and wary of getting label as one of those that starts anew everytime my bike hiccups.

FOG, have heard from yourself and several other sources that this motor can't hardly handle the power it makes now. I would like to increase dependability and am willing to forsake power. I imagine most of the shortcomings are inherent of the design, but is there anything I can do that would put less stress on internal members(acheive better longevity) and provide better gas mileage,(with less power of course).

I am wondering because I bought the bike hoping to be able to get atleast 50K miles out of it, but at 10K I'm already starting to have my doubts. I love the bike, but wonder if I shoulda bought a Honda ( no offense K lovers, and they don't offer anything like the EX I can afford anyways).

My bike is now overheating. It has not been seperated (block and head), but I did of course drain the coolant to adjust valves. All of the coolant did not make it back in despite several attempts to run it until thermostat opened(and circulation starts) and then add more. I did not make the mistake of adding cold coolant to a hot motor, but am wondering if I can let it run from cold with cap open, check circulation, and mix in.

Am also about to take off the water pump and check impellers as it looks pretty accessible, but of course I still don't have service manual so I hope I'm not getting into anything serious. (also wondering if it needs another gasket or rtv since I will have to get back on in the morning)

Also the coolant lines going into the block seemed to have some goo(silicone) on them when I took them off to take off valve cover. I did not put anything back on in my haste, am unsure if I might be loosing coolant there, but system is full everytime I check it (thrice daily)

Thanks for help

-Damon
 

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Lets deal with the overheating first. I sounds like you haven't filled it yet. With the engine running open the radiator cap and pour in as much coolant as you can get in (While your looking in there watch to see how the coolant rushes past the open cap when you blip the throttle. Then close the cap and fill the expansion bottle to the top run the engine till hot or go for a ride. Then cool the bike off but do not open the cap. observe how much coolant is drawn back into the engine. If the level in the expansion tank falls below the "LOW" mark add more and repeat the heat cycling.
When you were looking at the coolant rushing past the open cap, DID it? If not you impeller may have sheared. This is a common failure as the impeller is driven by a tiny 5mm screw. A bump on the outside of the cover or corrosion or freezing will defiantly break the screw. That part is replacable as the extension to the Balance shaft is replac able without taking the motor apart.

Test and report.

As far as de tuning goes just keep the revs below 9800 and change oil regularly and you'll get the best from it. But as I said before. These things are disposable bike designed to get newbies into the showroom and hooked on K's Not long lived service modules. Get a Honda for that.
Anything over 20 k Miles is very good service. Yeah I know there are some out there with a lot more, Yada Yada, please don't chime in here.

FOG
 

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Water rushes past when I blip the throttle.

I guess this means both water pump and thermostat are fine, and we're looking at an unfilled system as ya'll have deduced.

I filled it up yesterday when I changed oil and tightened/lubed chain.

It rode fine on the highway for an hour and a half, then got a little warm in town, but did not overheat. Sucked water back down to low line before I walked away to go study, although it's hard to see the lines without taking the fairing off.

It has never actually overheated, but I imagine the temp sensor isn't real effective when there isn't enough coolant as half the time it may just be measuring air/vapor temp which isn't a good reflection of what's really going on.

I will refill the reservoir again before heading home this afternoon, and see if it does any better.
 

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Your not overheating unless it's blowing coolant over the side. Mearly getting warm or warmer is not cause for concern. This is quite normal and should stablize somewhat in the middle ranges of the gage. They delibretally don't put numbers on the gage to keep customers from calling the dealer with " my engines runs at 165.7 where the manual says 180 can you fix it?"

FOG
 

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Ok, that's comforting, one of my main concerns was that these might be like the little hondas in that one overheat and they're pretty well cooked. This came to mind after hearing how stressed the little twin is already.

I just noticed it's definitely out of norm. Mine usually stays at about a quarter of the way up the guage, where you can still see almost all of the "thermometer in water" symbol, since I ride mostly highway(boring I know). And it has never gotten even over half in town or traffic. Now it gets to about 4/5ths, just shy of where I'd pull of the road, and the fan runs for a good while after I shut it off. Also smell coolant pretty often.

I was more concerned about lack of circulation due to a bad pump or stuck thermostat as I know this can mean hotter temps in some parts than others. Was also wondering if when I'm on the highway, even if cooling system isn't up to par, if I'm safe due to air cooling. Knowing the motor is designed to be water cooled I doubt this, but just want to know if I might be incurring serious damage. It costs about $20 a day more to take the car, but I kinda like to take care of my bike.

Thanks again FOG

btw, what does FOG stand for (I have a guess, but you won't like it)
 

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The Only thing in your report that sounds a little abnormal is the Coolant smell, This should not happen, Since you've been messing with the system , just watch it for a while, the smell could be from coolant spilled, and is gradually drying/burnning up. It should dissapate if a while. If you continue to smell coolant you'll need to invistigate the leak.

F. O. G. stands for Fast Old Guy A moniker I got from my racing days.

FOG
 

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haha, cool, I like that

will continue to watch it
 

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I thought the idea that a bike engine is toast after 20k was left behind in the 70s... US auto engines finally shed their "100k" limit (if that) that they carried for decades and its not uncommon for an American V8 to have over 125k and still working well...
 

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This morning during my pre-ride I notice mineral deposits (dried water spots) on the right side (#1 cylinder) cooling fins. I had originally considered the hypothesis that I didn't get a proper seal on the block inlet tubes after valve job, but had discounted this after nothing serious happened and noone responded about it in previous inquiry.

I was already down the road when I thought to check right leg of yesterday's jeans, so will do it when I get home. It didn't warm up more than halfway this morning, and it's a little hard to get my shin up to my nose here in the office. I kneeled next to the bike and didn't see any moisture or smell anything sweeter than it should have been.

ON MOTORS:

I have a friend that is looking hard for a good camaro with an LS1. There are 7-8 year old models around here with 150K miles that look and run perfect and owners are asking $8-10K.

I had heard this bike could get up to 55K miles before the timing chain gave out, and was hoping to joing that club, or go even further. I'm afraid now even if it goes that long, dependability will be a factor and it will be like my mom's old jaguar, spending half it's time in the garage, and usually on the nice days you would want to take it out.

Looking back I should have considered an FZR that already had 20K, but was well maintained, as I have seen strong running examples of those with over 60K.

I do like my EXer though, and it is serving me pretty well despite the occasional quirk. I changed the oil every 2500, check pressures and lube/tighten chain once a week, and the motor basically lives at 6K rpm. Maybe there is hope, although I'm sure internal tolerances start to go after 15 or so years of production.
 
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