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Discussion Starter #1
New to the forum hopefully I'm posting in the correct place.. Just picked up a non-running Grizzly 350 as a project. Was told it ran 4-6 month ago but wouldn't fire after sitting (I'm thinking not). Anyhow it has fuel and spark and no start even on starting fluid. Decided to check compression (should have done this first) and its 30psi. Is there anything that could cause this other than needing a rebuild, or do I need to get a cylinder/top end kit off amazon a service manual and go for it? Any thoughts/suggestions would be appreciated. I'm pretty good with carbs and other external small engine issues, but rarely get into the internals.
 

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Discussion Starter #2
I just did a wet compression test and it doubled to 60psi.. I'm thinking this thing must have been seriously overheated and have a scored piston wall. Any way I could tell if the bottom end was serviceable before I replace the top end? All I know is the oil that's in it looks new and it sounds normal turning over with the starter..
 

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You wont know the extent of damage or what is worn until you tear it down and inspect.
Tear the head of it and see how things look.
 

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Have you checked the valve lash? Since it doubled with the wet compression I think they are unlikely, but it will not hurt to try.
 

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Discussion Starter #5
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I stuck a bore scope down the plug hole to take a look and the cylinder is definitely toast. I will post again when I get it apart.. How is the best way to tell if the head is OK? Take the cam out and see if everything else feels tight?
 

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Ouch. Yup she's toast
 

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Been thinking about your thread and wonder about your intentions for the end result. Quick buck or going to keep and use the bike?
To have the head check properly can eat up a small budget, I would go ahead and get o.e.m. replacement parts, from the pictures the top end looks bad. Just out of curiosity, whats the rest of the bike look like?
 

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Been thinking about your thread and wonder about your intentions for the end result. Quick buck or going to keep and use the bike?
To have the head check properly can eat up a small budget, I would go ahead and get o.e.m. replacement parts, from the pictures the top end looks bad. Just out of curiosity, whats the rest of the bike look like?
Depending on how it turns out I think I may keep it for a while. My riding is mainly just to/from the deer stand and the bike might get 30-50hrs a year put on it. I'm hesitant to put very much money into it at least initially considering I don't know the condition of the transmission or the bottom end.. My plan when I get it apart is to inspect the head the best I can, see if the rod bearing feels tight and if so put in a top end kit like this:


Reviews seem positive and one of their kits for a warrior 350 has like 35 good reviews.

The rest of the bike is really in pretty decent shape. Has the original tires which are getting close to needing replacement, but still its only been ridden 1 set of tires worth.. I also know the brakes don't work. Plastics are all good.
 

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Nice rebuild kit! Hopefully it will be available again. May we see pics of your bike?
 

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Discussion Starter #10
Nice rebuild kit! Hopefully it will be available again. May we see pics of your bike?
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It was in one piece before I took it apart.. haha

Its a 2wd which is ok with me.. My current bike that I've had for 25 years is a 1982 Honda ATC200 Three wheeler.. So my standards are pretty low. The old 3 wheeler still runs good but would be nice to have suspension other than my butt, electric start and reverse.. You know.... luxuries.
 

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I bet that bike was sunk, then ran some which wore out the top end.
If you don't split the case, I would consider filling with diesel to soak and give'r a few turns every now and then to move debris to the drain plug, then rinse with sea foam a couple times, then proper engine oil and a couple filter changes.
 

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I bet that bike was sunk, then ran some which wore out the top end.
If you don't split the case, I would consider filling with diesel to soak and give'r a few turns every now and then to debris to the drain plug, then rinse with sea foam a couple times, then proper engine oil and a couple filter changes.
I think you're correct.. There was evidence of mud inside the airbox that they had attempted to clean out, and the airbox drain was clogged with dirt.. Carb was pretty clean inside though.
 

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Discussion Starter #13
98577


Got it apart today.. Thankfully head and connecting rod seem to be in good shape.. Going to put that cheap top end kit in it and see what happens. Looks like it got badly overheated to me.
 

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Discussion Starter #14
I just finished getting the wrist pin off and it was
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seized to the rod.. I used the ball joint press and a deep socket slightly smaller than the pin.. I think this was at least part of the problem or maybe the result? They were pretty much welded together along a single line all around the inside of the rod right in the middle of the wrist pin. In some places its raised and in others its a grove. I'm thinking I'm just going to polish it as best as I can with a dremel tool, lube it up good and hope for the best. Anyone got any tips for getting this any better? I realize that replacing the Rod is the only right way to do this.. but that just isn't going to happen for a couple reasons: 1. Rod and crank are one assembly you order together, are expensive and require me to completely disassemble the engine. 2. Its an old 4-wheeler not a space ship. Thoughts?
 

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I did my first start today and it fired up and sounds really good. Only ran it for 8ish min varying the throttle some to let it warm up. I had my infrared heat gun on the cylinder head and I shut it off when I caught a temp around 250, but from what I'm reading that's not unusual for an air cooled engine such as this. Any idea what temps I should be seeing on the cylinder/head on this thing? It has a weep hole in the head you can crack open to ensure oil is making it up there and it is. Put 15w-40 delvac in it for this first run.
 

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I did my first start today and it fired up and sounds really good. Only ran it for 8ish min varying the throttle some to let it warm up. I had my infrared heat gun on the cylinder head and I shut it off when I caught a temp around 250, but from what I'm reading that's not unusual for an air cooled engine such as this. Any idea what temps I should be seeing on the cylinder/head on this thing? It has a weep hole in the head you can crack open to ensure oil is making it up there and it is. Put 15w-40 delvac in it for this first run.
Congrats! Hope she keeps running good and strong for ya!
 

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I did my first start today and it fired up and sounds really good. Only ran it for 8ish min varying the throttle some to let it warm up. I had my infrared heat gun on the cylinder head and I shut it off when I caught a temp around 250, but from what I'm reading that's not unusual for an air cooled engine such as this. Any idea what temps I should be seeing on the cylinder/head on this thing? It has a weep hole in the head you can crack open to ensure oil is making it up there and it is. Put 15w-40 delvac in it for this first run.
'Good On Ya'.....as for the temp to look for, I bet it gets a lot hotter under load than a water cooled engine, but haven't seen a number for this temp. The exhaust pipe will be many hundreds of degrees, hot enough the light a stick match on my water cooled 660, but not so hot as to become soft.
With all the scratches on the old piston I would consider running a little sea foam in the case for a few minutes, then change the oil a couple times to flush out the case.
 

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Discussion Starter #19
'Good On Ya'.....as for the temp to look for, I bet it gets a lot hotter under load than a water cooled engine, but haven't seen a number for this temp. The exhaust pipe will be many hundreds of degrees, hot enough the light a stick match on my water cooled 660, but not so hot as to become soft.
With all the scratches on the old piston I would consider running a little sea foam in the case for a few minutes, then change the oil a couple times to flush out the case.
I know sea foam is a great solvent for cleaning out carbon or sludged up motors, but you think it would help to carry metal shavings to the filter better than straight oil? There was definetly some grey paste (metal) under the oil filter when I changed it. I don't think I'm going to let this oil/filter go over an hour before changing it, and will probably go a few hours on the next change then call it good.
 

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Just thinking the sea form can help remove any hot thick oil and paste from the case, and oil filters are cheap.
 
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