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Discussion Starter · #1 ·
My son came walking home after leaving in the rhino. He told me smoke came from the intake area and wouldn't start again. Before I rip into this thing can any of you point me in the right direction. I have verified spark and tried starting fluid with no luck. I am still waiting on my compression tester.
 

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Does it sound different when cranking like it has lost compression? Normaly, you'd hear a weeeee, wah, weeeee, wah. The Wah being the compressing stroke. If it just weeees, then you could be looking at many different things.
 

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Discussion Starter · #3 ·
Does it sound different when cranking like it has lost compression? Normaly, you'd hear a weeeee, wah, weeeee, wah. The Wah being the compressing stroke. If it just weeees, then you could be looking at many different things.
I will have to take a closer look at the sound. I only noticed it doing the cranking noise but didn't sound like the engine was even engaging with the starter.
 

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Hopefully what happened to mine didn't happen to yours. The PO adjusted the valves and didn't put the auto-decompress together correctly. That caused it to be engaged the whole time
it was running. I dropped a valve about 8 miles from camp. Good luck.
 

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Discussion Starter · #5 ·
Leak down tester arrived today and it is in the red and can hear the air coming from the exhaust
 

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Discussion Starter · #6 ·
Forget what I said about it coming from the exhaust. I have the magneto cover off because the first thing I wanted to check was the shear key. Once I found tdc I could feel and hear the air coming from down behind the flywheel any opinions.
 

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You picked up a leak down tester instead of a compression gauge? You might just be hearing blow-by which is normal. If using the tester correctly, it should give you a reading. What percent does it say?

You mentioned that you don't think the "engine was engaging with the starter". Is the engine even cranking over? Any chance you can film what it is doing and upload a video to YouTube?
 

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Discussion Starter · #8 ·
You picked up a leak down tester instead of a compression gauge? You might just be hearing blow-by which is normal. If using the tester correctly, it should give you a reading. What percent does it say?

You mentioned that you don't think the "engine was engaging with the starter". Is the engine even cranking over? Any chance you can film what it is doing and upload a video to YouTube?
I started off with a regular compression tester and had the pedal to the floor and was barely getting any compression which led me to checking the shear key which was good. Then went and ordered a leakdown tester found tdc and was getting air from the lower part of the case behind the flywheel and could feel it also and a strong smell of gas. After posting I checked and found it was coming from the dipstick hole also. My leak down tester which is color coded went from set point down to the red and I am guessing was about 80%. I have not put the magneto cover back on yet so not sure I want to try and turn it over at this time.
 

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From what you describe I'd say the piston/rings/cylinder have a problem.

If the valves were bad you would have air blowing through the exhaust or intake ports with the leakdown test. The only way air would be getting into the crankcase is by blowing through the cylinder.

Time for a bore scope or top end removal.
 

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X2 on new
Top end with 80% leak!!!



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Discussion Starter · #11 ·
Has this engine been apart before? Just a guess-Key ridden flywheel ,loose or sheered key way will give you some of your
Describe issues: Are TDC on the flywheel and piston true? Is there clearance on all intake and exhaust rocker arms at TDC-I back them off ,leak it down and relash -locking down the crank helps-proves the the valve condition-if flywheel is the issue the engine will spin with the plug out ok -not always with it installed-sounds like no compression ,timing is off the chart-


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I believe it has been apart before. The previous owner did a lot of mods and has been rolled 3 times. Not by me. I am going to dig more into it this weekend.
 

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Discussion Starter · #12 ·
From what you describe I'd say the piston/rings/cylinder have a problem.

If the valves were bad you would have air blowing through the exhaust or intake ports with the leakdown test. The only way air would be getting into the crankcase is by blowing through the cylinder.

Time for a bore scope or top end removal.
That is what I am leaning towards probably start tearing into it this weekend.
 

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Sometimes when stuff
Like this happens it’s more positive then negative in the long run. Nice to know your ride is built correctly and you can troubleshoot & correct something when it’s not. Let us know what you find….


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... probably start tearing into it this weekend.
Let us know how it goes.

I'd still stick a camera in there first. Cheap borescopes only cost $30 or so. And you can look at all kinds of things around the house, like what your wife has jammed in her desk drawer.
 

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Discussion Starter · #15 ·
Let us know how it goes.

I'd still stick a camera in there first. Cheap borescopes only cost $30 or so. And you can look at all kinds of things around the house, like what your wife has jammed in her desk drawer.
Lol. I have one and stuck in in there after I got home today and notice some chips out of the top edge of the piston so I started tearing it down and sure enough there was some significant maring on the cylinder wall. Now for some damn reason the wrist pin is being a pain in the ass so back to it tomorrow. I will also post some pics.
 

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Discussion Starter · #16 ·
Sometimes when stuff
Like this happens it’s more positive then negative in the long run. Nice to know your ride is built correctly and you can troubleshoot & correct something when it’s not. Let us know what you find….


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Piston, rings and bore are shot.
 
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