WHY PHAZER2 MELTDOWN??

[racerrob]

Okay Yammi gurus, here we go, thoughts & opinions as to why did she go
poof!! :cussing:

Okay, my 3rd ride of the season, but 1st ride for my wife & her 93 Phazer2 which has under 400 miles on fresh pistons that are 2 years old.
Sled only has 2400 total miles.

Fresh fuel, same settings as the last 2 seasons, temp was around 28-30 degrees. Did some boondocking of trail 1st for around 3-4 miles. 2-3" fresh snow, good solid base. Then jumped on the trail for a couple miles, got up to 50 or so for a mile, then off the trail, then back on ran for another 2 miles, not hard & then she heard the motor starting to sound "funny, knocking" noise, around 40mph, she slowed, motor started to run rough, she stopped & here is what we found after we towed it back & loaded for home & in the shop.

Good compression fan side, only 20-30 pto side. Here are the pics.
Now my ideas are:
A) Left Carb sucked dirt, leaned out...?
B) I noticed that there is some oil in the pan left side, is there a crank seal that could be leaking, sucked air in lieu of oil, leaned out & poof??

And then, the "knocking" noise, did I also lose the crank bearings?? Did not get that far into it yet, am guessing as bad as it "ratteld" when I spun it over with the electric start, probably so. Hmmmmmmmmm.:2dontknow

Thanks, Rob

[Ike]

Seems like an air leak to me.

I´d take the cylinders off just to be safe. If it was an airleak from the bearing, you need to change all of them.

Ike

[mark the shark]

The way the top of the piston and head are all chunked up it looks like something got sucked into the left cylinder?

Shark

[pete]

i would pull jugs something got into that cylinder either from the airbox,broken ring,maybe the anti rotation pin came out of the piston.how bad is the jug hurt just my 2 cents
randy

[luckyone]

something got in the cylinder. buttpin fell out,circlip or needlecage bearing went. did you replace them when you installed new pistons or use the old ones?

[Ken]

I think your going to have to look a bit further. I'd also post over at TY, probably a lot more experience with this motor.

[racerrob]

Will know more tonight, got it tore down this far last night to see what the hell happened. All of the input has been great.

Ken: Yes, I also posted at TY, got some great input there too. Like you said more Phazer guys over there. Also, will pm you on the other stuff later today.

Pete: There is a .002" to .003" score on the exhaust port side where whatever got in the cylinder worked up & down for a bit.:cussing:
Will know more when I pull it tonight just how bad the jug might be.

Mark & luckyone: Yep that seems to be the general consensus, small clip or whatever from the rings, possibly let them turn or, the needle bearing thing is a possibility. RE: when the rings where done last time, I do not know if they
did anything in the bottom end. I got the sled right after "the job was done"
& was told it was done.....sooooo.......who knows how far they went.
I can assure you that I will be doing it right all the way through this time since I am doing it myself. Wont be the fastest job, but I will be carfeul to cover ALL bases. I hate it when a sled goes down this time of year. We are just hitting the good spring riding season & we have not ridden much this year. The last "meltdown" of a sled I had was back in 92 with an Exciter2 we had just ported & polished. Ran her too lean.....learned a leason then, DONT SCREW with perfectly good motors !!!:frech32:

Ike: Will be looking at that during tear down.......going all the way!!

Again thanks for the input. Am glad it was not a "lean issue" or my 1st fear was the gas quality thing!!

Rob

[VMAX535]

R-R,

Worked on alot of these 485cc motors in the 80's and 90's. One thing for sure was the crank seals always went on them. Usually the pto side. Fan cooled motors have greater piston and ring clearances then water cooled engines. When a seal starts leaking the first sign with this motor was that the idle rpm would increase. Sometimes you could even hear it missing (popping). If the motor is run for a lenght of time with a leaky seal a destructive lean condition will occur. This expands the piston but since the fan cooled engines have more clearance then the WC motors they don't sieze as fast. What I have seen happen is that the area between the top ring and the piston crown on the exhaust port side erodes and/or piece of piston or ring brakes off and goes up and down the cylinder scoring it, then gets stuck in the combustion chamber for awhile until it gets works it's way out to the exhaust. But the damage is done.

In any case if you can't find a concrete reason why if failed. Pull the crank out, make sure it doesn't have excessive runout and replace the seals. Upon rebuild it is always a good idea to do a leak down test before firing it up.

I hope it's not a complete rebuild for you but breaking down sure does suck.

Best of luck.

/Dan

[racerrob]

Hey Max535:
When you have a crank seal leaking, would there be the oily residue as I have pictured in my early post? I noticed when the sled was dead on the trail & I was removing the belt for the tow back to the trailer that there was oil dripping down below the pto side & after removing the clutch it was real visible. Since I tend to keep my sleds pretty darn clean, this surprised me to see this. So, if the seal is gone, would ya drop oil like this??

Your description sure coincides with what seems to have happened. While the lean condition is not shown on the plug per se, the piston sure shows it was not getting oil at the end & like others have noted, the ball peening of the piston top is from something breaking loose & getting pounded by the piston.


Another note of interest is when I removed the pipe, I heard a small
"tinkle" inside of the pipe, like a tiny piece of something is in it, most likely whatever the hell went out the exhuast port!!:cussing:

Here is the pic of the oil under the pto side.The interesting part is the oil does not seem to be leaking out around the pto shaft area at all. :2dontknow

But, I guess it does not matter too much since I will be going through the whole darn thing now & will replace & rebuild but, its always interesting to find out "why"..........dammit!!!
Motor is coming out tonight so will see what else I find!!:frech32:

Thanks again for the replys, helps a bunch

Rob

[VMAX535]

Rob,

The 480 cc motor used a gear mounted on the pto crank side. As shown in your picture. This gear powers a worm gear which inturn spins the oil pump. When you put the clutch on, it slides into the housing and picks up on the seal (also shown in the picture). The other side of the housing is via a gasket to the crankcase. The oil leak may be between the crankcase and the gear housing?? Usually it tracks from where the clutch fits into the housing. Another place I have seen it leak is from the tach drive. There is a small seal there you may want to replace when you have it apart. To get back to your question the crankcase seal if leaking may ooze a bit, but would flow into the gear housing not directly to the belly pan. With that said this gear housing is not air tight and would allow the motor to suck air if the crankcase seal is shot.

[pete]

no broken ring both pins still in piston from the veiw looks like end of a ring or rotation pin possible screw from reed cage check close
Randy

[SamueLJackson]

Check this - piston diagnostic guide

http://www.pwab.org/PISTONDIAGNOSTICGUIDE.htm

[racerrob]

Hey Samuel J...:goodp:
Nice find on the article, copied & printed for my stash!!

Will post findings of the rest of the motor later tonight!!

Awesome input from all you guys, this is what I love about this site.
Lots of ideas & trains of thought....keeps a guy thinking & looking!!

Rob

[v4eva]

the oil is probably coming from the exhuast and working its way over.once it started missing there would have been unburned oil running out the exhaust port.

the piston damage could be from nasty detonation.the reason i say that is while it looks at first like something went through,the head looks to be damage free.i would think if something was bashing around in there,there would be corasponding damage to the head.

[racerrob]

V4eva: Looks like the oil was coming from under the motor based on how it looks now that I got the motor out. And, the sled was not missing or sputtering. It was a "quick" event. My wife is pretty atune to how motors should sound & she got off the throttle as soon as it sounded "funny", so the sled was running good until boom.

Now what I did find in the tear down is the rod bearing for this piston is completely gone, so as someone posted earlier, it looks to be a rod bearing failure & some of the needle bearings went through the that cylinder.
I am attaching pics of the shrapnel I shook out of the Y pipe & pics of the piston, rod & crank case assy. the sharpnel in the Y pipe must be what I also heard in the pipe itself when I removed it last night. It looks alot like the dents in the piston huh.:cussing:
You will note the discoloration on the rod end & up the rod. It got real hot when the bearings failed. Do not know how bad the crank is as I have not split the case yet. Hopefully, the crank is salvageable. There is roughly 1/4"-3/8" play in the rod to crank shaft connection right now. The cylinder walls actually dont look too bad. Will have to hone it out.

Mic'd the cylinder diameter to see what size was in there. Mic'd at 72.45 on the top side & 72.50mm on the bottom, checked it a few times hmmm??
So it was bored over once so will probably have to go to the next size.

Now, why did the rod bearing fail, 2400 mile sled, sucking air somewhere ??

Rob

[racerrob]

Okay, there is a fair amount of oil in the belly pan as the pics show. Now,
the pto-oil pump side of the motor showed oil dropping down, but could not find a definate spot. Whole bottom of the crank case had a coating of oil.
Here is also a pic of the oil pump gear & there is a grease like oil here, so is that the leak?? Wierd.

[racerrob]

Sooo...are there any tricks or things to be aware of for removing the stator when you dont have the official "stator removal tool" as shown in the manual??

Thanks, Rob

[v4eva]

wow.for sure a lack of oil.perhaps the pto oil line came off or an issue with the pump itself?i had the same thing happen on a 340 enticer,luckey for me the piston seized before the bottom end disintegrated.quick hone and a new piston and i was back in business.unhooked the oil pump and just ran premix after that.still have that machine and still runs like a champ.

you talking about pulling the flywheel?i beleive the stater itself is held on with 3 screws.when pulling the flywheel,make sure u dont thread the bolts in to far or u will destroy the stater.

[racerrob]

Not to stir up any more compression things here, but what is the typical
compression on the 485cc??

I just purchased a 94ST "donor" sled for the motor only & this motor
which has 2400 miles per the odometer is pushing 120psi, measured with a screw in gage etc. Plus, when you pull it over, it feels like the old Exciter SX motor!!
(yep, cheaper to buy a whole sled, swap the motors, then part out the donor sled than buy the rebuild parts etc!!:cussing: )

So, will also have a complete Phazer2 ST to part out, whoo hoo, more work!!

Just curious on the compression thing,

Rob

[Skinner]

I once had a stoked up 85 Phaz that I burned up three times before we figured it out. It was an intermittent oil pump problem which I was told was not possible. Either the pump works or it don't. That is NOT the case. After we were through this motor top to bottom, the only thing left was the pump. After watching it run on the bench for hours we finally were able to see a few small bubbles start to show up in the line. We then replaced the pump and had no more problems. When I go through a motor today, it gets a new pump whether it needs it or not. If I remember right, the stock PZ's were right around 100 PSI. 120 sounds high for a stock motor but should be fun. I could be wrong, that was a couple hundred years ago. Throw er in there and good luck with it Rob

[racerrob]

Hey Dave, thanks for the info. I did pick the 94ST up as the "donor' sled so started tearing it down today. Stripping the sled down to the chassis so will have a few Phazer parts to get rid of along with the good parts from the
motor that went poof. Crank case, oil pump, heads, jugs & 1 good piston..LOL.

[vmaxx4]

Okay, there is a fair amount of oil in the belly pan as the pics show. Now,
the pto-oil pump side of the motor showed oil dropping down, but could not find a definate spot. Whole bottom of the crank case had a coating of oil.
Here is also a pic of the oil pump gear & there is a grease like oil here, so is that the leak?? Wierd.

Was the exhaust manifold gasket leaking?

[racerrob]

Vamxx4: Nope, have not found ANY evidence of leakage of ANYTHING
on the motor. A bit frustrating to say the least!!

Not sure if some dirt got in the carb or ????
The piston does not look that lean, beat up from the rod bearing explosion & the plug sure did not "read" lean:2dontknow .

So, am leaning towards a premature rod bearing failure, maybe some rust from sitting, but have NEVER had that as a problem since we live in a low humidity climate, I start the sleds every couple months etc.etc.:2dontknow

Then I look at the "donor" sled I got & once I got under the hood & shields, holy crap this motor & chassis is filthy with some loose bolts, screws, hoses etc but looks good otherwise??

Now wouldnt ya know, the sled I have is a 93, the donor sled is a 94. Motors should be exact right???

Check out the pics of the electrical for the stator, oops, different type of plugs, individual on the 93 & 2 plugs for the 94 so, some careful electrical work to be done with new plugs & solder!!!:cussing:

Check out the differences of the 2 chassis', my wifes is a 93 with 2355 miles & the doner is a 94 with 2460 miles...interesting huh ???

Oh well, its all fun...so they tell me!!!:frech32:

All input is appreciated.:4fzfpi:

Rob

[Ike]

That is lots of crap on the donor sled!! Probably never cleaned + sat outside under a pinetree with it´s squirrels throwing pinecones to it.

Ike

[racerrob]

:agree: :agree:

Hey Ike, you hit it on the head, there were pine & fir needles in the belly pan, a couple "baby" cones & there was actually an accumalation of "powder & dirt" in corners of the frame under the chain case & tie rod ends right side!!

I am amazed how some folks take care of their sleds etc.:frech32:

Oh well, just so the darn motor works right when done!!

Rob

[racerrob]

Still wondering why we lost this motor. Have not found the
quote " Smoking gun" yet.

But, while starting to sort through what parts etc where going from the 93 motor to the donor 94 motor I focused on working on the reeds.
While I was told the 93 had Boyssens, it in fact DID not. So, I got a set & installed them last night on the 93 cages. When I tore the 93 down, I did not take notice of the gaskets or which reed was with which cylinder. I was focused on the pistons themselves & oil leaks I saw.:frech32:

Now last night as I start to clean the 94 engine, examine pistons & attack the 93 reeds, I suddenly notice that there are 2 different colored gaskets on the 93's reed cages. Hmmmmmmmmm. So that tells me someone was in there & replaced 1 gasket but not the other.......have no clue why.

So, the question here is, could a bad gasket leak here take out the rod bearing etc. Again, the confusion on my part is while it was a meltdown, the plug not the head did not look THAT lean, & the piston, while beat up from the shrapnel of the rod bearing & is showing lean signs for sure, it is not melted in the ways I have seen pistons go before from a lean condition.

Am curious if it was sucking air through a possible bad gasket on the reed cage & if so, wouldnt the piston have gotten the old "hot melted spot" & looked a lot worse before the rod bearing went???...Hmmmmm???:2dontknow

This is mechanical CSI............LOL!!!:4fzfpi:

And for those that wonder why I am now attacking the sled since it is spring, we still have lots of snow!! The mountains got between 18-20" this past Thur-Sat morning, so am trying to get the wifes sled back on line for a few more rides!!

Rob

[luckyone]

looking at the picture it looks like the upper piston to rod area was lubed so i dont think the pump is the culpret. what it looks like to me is contamination started in the big end rod bearing(probably from the excellent gas quality of today!) just stand there and watch your tailpipe on your car or truck and see the water drain out like a spicket!causing rust to form in the needle cage and excessive heat thus burning off the thin layer of oil that lubricates it and then comes failure of the cage sending the needle bearings up the transfer ports in to the top of the pistons where they get squished between the piston and head causing the top of the piston to expand in that area . now the surface of the piston is touching the cylinder causing the scratches in the cylinder walls.i think the crank will be ok but you would have to buy a rod kit and the lower rod pin.and have a competent machine shop separate and press the new pin in with the new rod. back in the days when i worked at the yamaha shop it cost 75.00 to do it+ parts cost. that was back in 96

[4with4]

:agree: I don't beleive you had a lack of fuel there. I still beleive there was a problem with the rod bearing being pitted or getting a bit of rust on it one summer and failing prematurely. You're lucky your wife realized that the rod knocking was serious and shut it down.

Ian

[racerrob]

Well, took awhile, but got the 94 Phazer motor installed this weekend.
It was more cost effective to get a different sled & put this motor in my wifes 93 Phazer2

Stripped the 94ST chassis, transferred the carbs, covers starter etc. good stuff from the 93 to the 94 & added in the new Boysen reeds & installed it this weekend. Got it fired up Sun night. Sounds good, hope to do a shakedown ride this Sat. The 94 sled cosmetically was a real "pig pen" so there was a lot of cleaning required before that motor was going in the 93!!

Oh yeah, on a side note, I now have a nice inventory of used Phazer2 ST parts if anyone is looking for Phazer stuff!!

I think it turned out okay & hope the thing runs a long time!!:4fzfpi:
Here are a few pics, the 1st one is of the "donor" sled as I was stripping it down.

Thanks to those here that shared some good pointers on the 485 motor & a few other things.!!:653:

Rob

[vmax4rules]

Nice work!