"Low Power SS440, need some help"

Had this problem on a number of SS440's over the years. Unfortunately it turned out to be a blown piston skirt most of the time. The engine would start easy enough and idle fine but no power under load and sounds like its pulling way too much air when you open the throttle. By comparison, when I lose a crank seal it gets hard to start and backfires a lot.
 
Hi Everyone,

First of all, thanks to everyone who has taken the time to read my long confusing thread and offered advice. It's much appreciated and hopefully I can get this thing back up and running and take a ride with some of you up in WI.

I spent some time in the garage tonight working on my sled. A quick background for everyone:
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1. Summer of 2015 I had sled stored in back of my barn and would go back ~1/mo or so and start it up and let run for a few min. In the fall I pulled into the front to go over it and noticed that my oil tank had leaked all into my belly pan so I did a few starts with a dry oil tank while it was stored. I don't know how long it ran with no oil, but probably <10min total.
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2. Diagnosis of the oil leak was that when I rebuilt my Autolube pump the season before, I installed a bent driveshaft (shaft between input gear and pump with worm gears on it) and did a 300mi ride in winter of 2015... I replaced the parts that appeared to be worn from this and then attempted my trip in winter of 2016 which the pages above detail the low power issue and attempted diagnostics.
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3. Fast forward to tonight and my plan was to swap out the Autolube pump with a spare that I came across (doesn't appear to have been taken apart). Then perform a leakdown as suggested by others. Started to prepare motor for pump swap and I noticed this PTO seal when I pulled my clutch:

image1.JPG

As you can tell this is with the motor removed. I saw the oil and figured this was blowby from bad seals. Can anyone confirm?

If seals are in order I'll order a set and install. I'll be able to inspect the piston skirts at this time too. Now that the motor is out and maybe coming apart is there anything else I need to take a look at? I had installed a fresh pair of pistons & seals ~500mi ago, but might have done it in with the no oil...:o|

Also, there was a question about a plugged exhaust port. I looked up the pipe and didn't see anything.

image2.JPG
 
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the outer seal you are showing is just a dust cover the crank seal in the next one in behind the gear that drives the oil pump .....
 
Yamaha Nutz said:
the outer seal you are showing is just a dust cover the crank seal in the next one in behind the gear that drives the oil pump .....
Click to expand...

Yea, I remembered after posting. When I rebuilt 500mi ago, I did replace all of the seals. Had to get the oil gear pressed off to replace the PTO crank seal.
 
Looks to be weeping. I dont know if you would be able to peek in the gear housing and see much of the inner seal. I forgot they had the housing as part of the case.
 
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Yea, I put a healthy amount of grease in that cavity when I rebuilt so not sure if it's just the grease. Either way I'll be able to tell with leakdown test.

Does anyone have experience running sled without oil and being ok?


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I ran my Exciter sx out of oil years ago...I thought I filled my tank the last time I had it out and didnt check it before heading out. I destroyed the mag cylinder beyond use. Needed new piston, rings and a re-plate.
 
Could survive just idle if cool enough and enough residue oil in crank... for a little while ... Recall Doo's etech in Rev and some boats didn't pump oil while idling
to pass emissions and no visible smoke .. expect water cooled and limited time idling..
..
on topic and a little off topic ...my 93 VK540 had dual injection pipes into the fuel line before the fuel pump ,,, was told it was because when they were direct
into manifold , they tended to blast out a great cloud of smoke after spooling down from a high speed run as the high RPM of pump gave the extra oil
even though you were snapped off the throttle , (when you hit the throttle again) ..... End result , if you have been idling ,,, when you accelerate hard, it will need
to burn up all the bowl , lines and pump of idle mixture fuel before it sees any real amt of oil...
I don't ride hard , but I used the manifold injection from the older engine when I rebuilt mine (wasn't an oil failure but expect an ether can in intake)..
Good luck ... go eat some turkey..... Sorry , USA is Columbus Day .... Not sure what you eat for that..
Ron
 
Working on one right now. The oil line from the autolube pump to the intake manifold on a 480 Venture had fallen off. I tore down the top end and found the piston scored on the PTO side but only minor aluminum deposited om the cylinder wall. I replaced the piston and rings, lightly honed the cylinder and fired it up. Unfortunately it has a knock that sounds like a connecting rod bearing is shot. Sometimes you are lucky and just lose a top end but other times you are not so lucky. Crank seemed to rotate smoothly during the rebuild so you can't always tell how much damage is done until you tear it right down.

I generally run 80:1 Amsoil Sabre mix in my tank to save my crank if I lose the autolube.
 
Hi All,
Since I had the motor out to replace the autolube pump and also re-install the reed cages, I decided to just go ahead and replace the crank seals for good measure. A few items:
1. Is there a replacement grommet available for the harness that routes to the magneto? Mine is crumbling.
Magneto Harness.JPG

2. The OD of my flywheel has some rust on it. Does this matter? I figured all of what mattered was on the inside which is clean.
Flywheel.JPG

3. The pistons look pretty good after only 500mi, but I didn't get any pics of the piston skirts or cyl walls yet. Will do so tonight.
PTO Piston.JPGNon-PTO Piston.JPG

4. The crankcase had some carbon at the bottom. Is this from running too rich during some of my diagnostics?
Bottom end.JPG

5. I inspected my crank bearings for any radial play and didn't feel any, so that is good. There is the normal side-side, but doesn't appear to be any wear. I'm hoping that running it low on oil only wore the seals down and didn't cause any metal damage.
 
About time you come back with some updates, lol. Let's see those piston skirts!

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Pistons & Cyl

Hi All,
Here are the pictures of pistons and cylinders. I had a light hone done on the cyl when I last rebuilt.

IMG_1069.JPGIMG_1070.JPGIMG_1071.JPGIMG_1072.JPGIMG_1064.JPGIMG_1065.JPGIMG_1066.JPGIMG_1067.JPG
 
Is my eyes playing with me or are those head gaskets too big?. You got some scuffing on the pistons... Those pistons are they cast or forged?

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Dallas4Stoke said:
Is my eyes playing with me or are those head gaskets too big?. You got some scuffing on the pistons... Maybe lack of oil or not letting it warm up before you ride. Those pistons are they cast or forged?

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Click to expand...



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Dallas4Stoke said:
Is my eyes playing with me or are those head gaskets too big?. You got some scuffing on the pistons... Those pistons are they cast or forged?

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Click to expand...

I think the head gasket was at an angle when I took the picture so it looks oversized. They fit well when down on the surface, but I did notice that I put them in backwards since they cover the bolt holes a little bit.

I think they were just cast pistons from Parts Unlimited when I rebuilt it in 2011

So scuffing can be from running a cold engine or lack of oil? I do know that I idled the engine with the oil tank empty by accident in the summer of 2015 and I think that is what led to all of my winter 2016 issues. Do you think these pistons could be reused if I was sure to keep oil in tank and properly warm up the engine before riding?
 
Use your nail and see if it catches in the grooves. If it does...replace.

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Correct me if i'm wrong but I would assume that the 440 has a cast liner like the 540 SRV does. Which would mean that could wear also. I would at least measure the piston and the bore and see what your piston to wall clearance is. The spec is differance for different pistons, look on the box or online for what ever piston you have. If you don't have a good mic and either snap gauges or a bore gauge, any machinist or engine rebuilder should be able to do it in 5 min.
If clearance is to big you will have piston rocking, leaking rings and blow by. Your engines apart now, seems like the time to do it right, or you might end up doing again next year. Nothing feels and sounds better then a tight, crisp engine
 
Correct on the cast iron bore. I would also measure it and the piston if it's not too damaged. I don't see any blowby though. When you put the case back together use Yamabond for the case halfs. Also put some oil on those cylinders to prevent further rusting. Still think your original problem was with the ignition.

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