KawasakiTrax Community
Tech Information => General Help => Topic started by: 440RX on February 05, 2015, 05:15:17 PM
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Any thoughts on why this happened? New seals & crank bearings. Used pistons and cylinders with new rings. Only about 5 miles on and this happened at mid throttle. Stock jetting ,oil pump tested and pumping as per spec. I have 4 other used cylinders that came with 2 separate invaders and all 4 have the same issue on exhaust side .
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Do you have scrape marks on 3-4 ''sides'' of the piston...? Because it looks like a ''cold seizure''.......did you warm up the sled long enough before heading out...? And did you hold throttle midway without varying throttle position...?
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That would be my guess too... we all have our own riding styles/technique, but warming up the engine is a must. The 80' 4/6 engine (especially) had problems with cold seizure and for that reason Kawasaki updated their pistons with a skirt "coating". Also, check your oil pump for adequate flow from idle to WOT. I am probably the only Kawi guy who does this, but I also mix 70:1 syn in the tank for precaution. Just preference. ;)
Warm up for at least on minute or until coolant temp is up. Tory
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Sorry, re read your post and saw that your pump checked out fine.
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Tory, glad to see i'm not the only one pre-mixing my tanks also....i do a 100:1 in each tankfull as a precaution..!
With my Ceptor, when the temp is warm to the hand in the trunk box floor, that tells me the coolant has gained enough temperature, has made it around the whole coolant system and that pistons and cylinders have expanded proprely......which means it's time to let her loose... :-)
PS We are in the deep freeze here...... :-( but sleds like it .... :-)
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thought I had here warmed up good. I constantly was varying throttle position with very short burps at wot. mostly was mid throttle . marks just on the 2 sides (between exhaust port and transfers) Plugs look nice both dark tan. I also received the following post on another site:
(Apparently the update was never done on that sled, kawi had a problem from the start, with no bypass in the cooling system thermostat, as you take off the cly. heats up and expands along with the piston but then the thermostat opens up and a rush of ice cold anti freeze shrinks up the cly. and sticks the expanded piston, kawi's fix was back then a bypass built into thermostat housing but back then the quick fix (until kawi got us the parts) was to drill a 1/4 hole in the thermostat itself so some anti freeze is always circulating, I will look thru my books to find the bulletin, if I find it I will post it or just do the fix with the drill bit it worked) .
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I've heard the same thing, but have never performed the modification. I run the same engine in my J/D Liquifires and haven't had the problems you've experienced. I dunno... I've seen plenty of "cold seizure" cyl markings. It sounds like you've covered all bases w/warm up etc., so I really don't know what to tell you. Check your ring end gaps? I'd consider running a bit wider end gaps? FYI... I don't run cheap oil. You get what you pay for. I use Klotz R50 in the tank (Castor base) with the Techniplate inj. in the oil resevoir. No problems and I have four Liquid Kawi engines running hard right now. :)
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Long story short---go easy until the temp gage says warm??
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I must have the update ?
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I agree that this appears to be a cold seizure.
Also, running pre-mix can cause a slightly lean condition because some of the gas flowing through the carb has been replaced by the oil.
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I've read many books on performance two stroke tuning and "yes" running a premix may lead to a "slightly" lean condition, but IMO as a general rule more oil "within reason" has been proved to actually gain horsepower on the dyno. We all do what we feel is beneficial and it the case of oil ... I do what works for me. ;) Can of worms.
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An air leak will also cause piston scuffing, but generally I've seen this happen on the intake side of the piston.... like a intake leak (boot) or seal leak (sucking in air).
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I agree that some oil can generate a little more power but I believe this is the result of being slightly lean on gas. The best performance I got from a 440 was caused by a slightly leaky crank seal causing a lean condition, just before the piston melted down.
For years I ran a little pre-mix and didn't seem to cause any harm. I constantly was playing with jetting to get the best out of the engine because of elevation changes going up the mountain and I did run EGT's.
Sure miss riding!
Just added this. Hope it helps:
http://gothotrocks.com/kawasakitemp/piston.htm
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imo lean burn...running a stock airbox?i'd like to see that thermostat bulletin
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Just for conversation sake... A. Graham Bell "Two Stroke Performance Tuning" is a great book. He talks about oil types, mixtures, etc. Very good read! I am one of those type of guys who has to "read it to believe it". I 've heard some pretty crazy (and scary) advice and opinions over the years and this guy explains his results scientifically and through testing very well. I will warn you... this isn't your wife's romance novel!! LOL
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IMO its a three bears situation:
Too much oil = HP decrease
Not enough oil = HP decrease
Somewhere in between = best HP
I agree with Boom, mixing gas = leaner burn. But in most cases it's negligible.
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Popcorn. Guess I'll throw my books in the garbage...
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Not throwin' any jabs here, or intending to upset anyone. Feel free to sound off, because I don't have all the facts at hand that I would prefer. I have been perplexed with this "pre-mix" issue in conjunction with oil injection, after reading posts on several snowmobile sites.
30 some years ago, I popped the carbs off of my Invader and my Sno Jet in the fall to clean them. I didn't have the intelligence to use any type of fuel stabilizer (back then) in the spring. The Invaders carbs, using straight gas, had the most disgusting build up of green "pond scum" in the float bowls. The Sno Jet used 40/1 pre-mix, and the float bowl was absolutely pristine.
Pretty much ever since, I have added about 3 oz. of oil to 5 gal. of gas (3.2 oz. is a 200/1 ratio) to all of my injected sleds, and continued to use the injection system.
I like the fact that this provides a tiny bit of lubrication to the throttle slides, and may help prevent corrosion in the float bowl when you inevitably get some water in the tank. I see Dandby7 is mixing at 100/1, Tory is going 70/1. I say pick your poison. I know, it defeats the "gas and go" convenience of injection, but I don't mind.
We could all agree that there is some "perfect" oil/fuel ratio that exists at a given moment in time. An Invader, cruising at 40 mph...maybe it's 70/1. There has to be enough oil, under varying loads, to adequately protect the motor.
I hear ya' when you say adding oil to the tank displaces some of the fuel. Lesse', if I have a regular Mikuni with a 300 main jet, and I pre-mix the tank at 50/1 (a 2 percent solution) I have effectively displaced 2 percent of the gas, or reduced the main jet "effectively" to a 294 jet. If I'm borderline lean, I just seized a piston.
BUT...2 stroke oil burns....it COMBUSTS in the combustion chamber, along with the gas. I don't know this, but I bet the oil burns at a lower flash point temperature than gas. So, your perfect EGT of 1100 degrees just dropped to 1090. HOW can the addition of a tiny, additional amount of oil to the mixture contribute to what we consider the classic "lean burn down"?
I will leave it up to you to discuss the miniscule change in the viscosity of the fluids and any effect on the flow thru the jets.
There is some "perfect" fuel/oil mix that exists...it depends on your goals. What may be the most sensible for emissions may not be best for engine longevity, or maximum HP. I think most of us would agree, a LIL' bit extra oil promotes engine life and probably frees up the motor a tiny bit. Frankly, we adjust the oil injection pumps and cables and we're probably lucky if we are within 10 percent of IDEAL. Gas mixture is a little more dicey. But, it's up to us to discover what mixture, jetting, etc. works best.
So, have at it. I'm all ears. I learn sumthin' every day. Trouble is I forget more these days. :D
Sorry, back to unfortunate 440RX and the piston failure. It sure sounds like you did everything correctly and competently to expect a motor that ran well, and then this happened. I wouldn't worry about an oil problem. The intake side of the piston would have been all scarred up from lack of oil. It sure looks like that PTO piston got hot. I see a guy responded to your post on "Vintagesleds" discussing a bent connecting rod causing him grief. Certainly possible. I rather think you need to re-visit why the PTO side probably ran lean...hey, we have all been there and done that, despite trying to be careful. Some tiny air leak on that side, or, tear into that carb again to make sure all is well....no speck of debris found its way into a jet, no float hanging up, etc. Hang in there!
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Whoops, failed to add one more thing. If you add enough oil to the mix and displaced some gas, the energy level of the mix (BTUs) will certainly be reduced. 2 Stroke oil can't have as much energy as gas. Again, up to us to find that ideal equation with oil mix and carb jetting.
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I will look at engine again (very carefully) .I have 1 NOS cylinder so maybe take the good PTO side Cyl,piston, head , carb and place on mag side and place NOS cylinder and other items on PTO side and see what happens.. Make sure I warm up well .If it does again on mag side more than likely in bottom end? If it does on PTO side to my NOS cylinder. something up Top(Carb?). Maybe all will be fine.
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on the oil/lean burn issue.....i delivered and lake test run literally 100's of mercury 2 stroke outboards since 1975, 40 hp on up, always mixed at 25/1 as per factory specs, [back in the 50/1 shake and bake days ;D], doubt if the factory wants new motors run lean.....
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Due to running the K&N air breathers, I am thinking of Plugging off the econo jet and placing a main jet in needle jet location. I read somewhere hear to do this. Will that work ? What Main Jet? 280?
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Really looks like a cold seizure. Feel your radiator before you take off running. Old plug color can take a while to mark correctly. How cold was it outside when you toasted the piston and cylinder wall?
Guessing a 280 main with a plugged econ jet is dangerous. On the razor (racer) edge 20°F change shifts the main jet approximately 5 points this way or that. 1000ft elevation change shifts approximately 5 points this or that. Rich is fat but your piston stays in your cylinder not flowing out your exhaust.
Start knowingly rich. Warm your motor to operating temp. Put in new plug. WOT for five full seconds. Kill switch while WOT. Pull plug. Inspect the grounding strap. Where the line is identified between shinny new and dull burned, tells you exactly where you are rich, right or lean. A lot of work but then that is what R&D cost. Fuel injection once dialed rules (also Holtzman engineering). Two strokes and carburetor info can only be shared if they run the same motor, temps/elevation (called air density) with exact intake to pipe.
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Have often thought how nice it would be to have a good fuel injection on a Kawasaki.
Also would be nice to have a "Dial-a-jet".
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Boom if you find yourself getting another sled get the Holtzman Atacc. It auto adjusts for temperature and altitude (old school FI). Dial-a-jet you have to dial around.
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Does the Holtzman system work the same as Ski-Doo's DPM used in the early/mid 2000's?
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Holtzman uses a carburetor vacuum source controlling the float bowl pressure to meter the fuel. Maybe specialized plastics that expand and contract manipulating the control, surely it must be propriety information.
Worst case when it fails the safeguard is the motor ends up too rich.
Just read up on DPM and it sounds like it uses sensors not varying expansions, but both vary the bowl pressure.
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Well , I finally am going to start on fixing the engine again. I just opened hood after almost a year and noticed the crank case was full of oil. I would assume that it came in from the center bearing oilier. Nothing has came out the oil injection at the cylinders.(the mag side was unhooked from cylinder with no oil spot from line and the pto side was dry at the intake ) shouldn't the check valve for the center bearing injection have kept this from happening? I tried to blow through the line from the oil pump to the center check valve and could not blow through. Bad check valve? Bad oil pump?Plan on starting rebuild Tomorrow.
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All the 2 cycle oil I have you cannot see thru??
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It is SkiDoo 2cycle oil (Mineral oil) I use it in all my carbed sleds with great results .
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Hmmmm, that's a bit unusual. I wonder if the fact you had the cylinder injection lines disconnected it allowed the system to "vent" ever so slightly over a years time.
I assume your oil injection tank has drained to the point of being virtually empty?
Those check valves in the banjo fitting are pretty effective with fluid (oil) against them, but they're not absolutely perfect.
If some air pressure could leak past the 2 check valves you had disconnected, I could see how the oil might have siphoned out of the oil tank.
I would really not worry too much if that is what happened. Get the engine re-done and hook everything back up, and the oil injection will probably be fine.
Those banjo fittings, with their check valves, would bear watching, but chances are they may be OK.
A curious clue you mentioned was that one cylinder injection line was empty.....air fed backwards toward the pump.....maybe.
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I have read someplace that compressed air on a banjo fitting is not a good thing.
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are the banjo check valves available anywhere?
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Oil system Banjo: Same as Banjo for the 86 Polaris Indy 400. Polaris Part # 3083894 From the "parts interchange" list.
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Thanks for the part #. Just ordered 3 new ones
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Thanks for the part #. Just ordered 3 new ones
Be sure to let us know if they really are the correct ones.
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well not having much luck yet. >:( . Was sent wrong pistons(LTD's). hopefully will have right one on Saturday. Check valve package came in mail today.I opened and received crank seals instead. I am beginning to wonder if i am actually supposed to fix this.
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Received the right pistons and started putting together !!! The cylinders are sleeved .020 over . I had to hone the cylinders out some with my stiff back hone,piston clearance was way to tight for me. I have them now at .003 -.0035 clearance and ring gap at .012 - .013 trying to keep it on the looser side of tolerance.Does any one know what the squish clearance should be . I have a set of 80'LTD and a set of liquifire head gaskets. The liquifire gaskets are .004 thinner. I could be wrong but aren't the Liquifire heads different than the Invader with a bigger volume in combustion chamber. Is the squish band cut different than the Invader heads and the thinner gaskets are used for proper clearance. Are the LTD gaskets thicker than the standard Invader Gaskets? Any Recommendations.
I did receive some new Polaris Check Valves and they are about identical to The Kawi's
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I like the 4/6 head gasket better than the stock invader. We have a 440 Invader that was sleeved and could not get it to seal until we used the 4/6 gaskets.
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+1 for the 4/6 gaskets. IMO they are the best available, even better than the OEM Liquifire gaskets.
I think that the squish was supposed to be .070", but I could be remembering wrong. Wait for Interceptor398 to respond, he knows what it should be!
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Finished engine today, Used the 4/6 head gaskets. Did pressure test at 10 lbs air. HELD PERFECT!!! . Going back in sled and going to check carbs and hopefully fire up this weekend. Just wish there was some snow to try out.
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Just thought, hopefully I didn't mess up the check valves. by feeding air through like I did .See previous picture .I fed line into each other and 1 from impulse to other check valve.
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I fired up Invader today seem to run good .Just idling, I revved up a couple times . I have a couple gal. 32 to 1 mix in tank for break in. I have clear line from oil pump to cylinder check valve and am seeing some air bubbles I did let idle with pump at max open for a couple minutes and still see a couple. I Thought I had all the air out of the line from the tank,I guess I will look a little closer tomorrow. After shutting down I turned engine over by rotating clutch by hand and could feel something not right ( a kind of scraping sound/feel) I thought O no not again.I pulled exhaust and looked inside cylinders and felt the areas that got messed up in the previous cylinders and everything looks great. After wiggling clutch back and forth it seems to be coming from the flywheel area only in one position (I could hear it better in that area with my Stethoscopes ). I guess I better pull rewind tomorrow also
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Hang in there and keep wrenching. There is no better feeling wind freezing your eyelids open.
Magnets may have picked up some metal debris when assembling. Sucks to take out the flywheel with the motor in the machine (bad). Worst case, and don't bother with a snivel, two hours and you can have the motor out and back in confirming nothing hiding under the flywheel. Experience speaking. It is the Friday night two beers down, going mobiling in the morning, then let the curses fly.
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To update, I pulled flywheel and found the flywheel rubbing 1 side of the lighting coil. Screw was a little loose and allowed coil to move just enough to rub. Loosened coil pushed up and re tightened. ALL GOOD !!! Runs great. Putting away until next winter. Hopefully we get good snow for 2016-2017 winter. Thanks for everyone's help
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Always good to know what the issue "was"!