[OBD]

I have a 2005 350 Rancher 2wd ES project. I have the tank off and have done a general carb cleaning. Valve clearance adjusted. I was wondering if while it is torn down, should I take the head off for any reason?
I checked the compression, and it builds up to about 170. The plug has been black and wet prior to carb cleaning. Do I need to take the head off and clean it?

 

[OBD]

Sorry, compression is about 110.
I need to proofread ....

 

[SlammedRanger]

110 seems alittle low. But i could be wrong as i work with sports quads that stock are 128 and up from there. General rule of thumb is under 100 isnt good. You are getting a tad close. Try doing a wet compression test after you do the dry one. Add a small amount of motor oil in the sparkplug hole and crank it again. See if the number goes up alot. If it does a rebuild is in your near future. Also when doing a compression test you have to have a fully charged battery and the throttle held wide open. See if that changes your 110 number. If it does then your good to go.

 

[mac102004]

97psi is standard according to the service manual, don’t forget these have an automatic decompression release on the camshaft, so they don’t show compression like the older utility engines or any of the sport quad engines.


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[OBD]

I did decide to remove the head. At least I decided to try. The head is stuck really well to the cylinder, and I don't want to bang on it. Any clever ways to gently get it loose?

 

[SlammedRanger]

I always tap it with a rubber mallet. Or if its really stuck i get a 2x4 and tap upward on it. But what ever i use i always make sure its a softer material then the head is made of.

 

[SamUK]

As previously said, a leather or rubber mallet usually works, persevere, work your way around the head slowly. Don’t rush or get frustrated and it will lift eventually.

 

[OBD]

I got the head off. I don't have any before pictures, but the valves were really caked with carbon. I got it somewhat cleaned up before taking the pics. I did find out that the jug is bored .50 over already. I'm glad the wall of the cylinder and the piston look pretty good. The valve seats look pretty good to me, but I have little experience with valve repair.

 

[Obd Zee]

Hey y'all. Yes I am the same OBD, but I lost my password, and forgot the email address that I used, so I started over.

I got the heads back on, and cleaned the carb well. It runs good most of the time, then it starts missing. It doesn't miss in a pattern, just once in a while, but it is enough that the engine quits sometimes. Does that sound like my coil is going bad, or still have trash in the carb.?
Another question. Is a 350 bored .50 over a 400? I was pretty good at trigonometry in high school, but that was a long time ago.
Thanks

 

[shadetree]

Hey y'all. Yes I am the same OBD, but I lost my password, and forgot the email address that I used, so I started over.

I got the heads back on, and cleaned the carb well. It runs good most of the time, then it starts missing. It doesn't miss in a pattern, just once in a while, but it is enough that the engine quits sometimes. Does that sound like my coil is going bad, or still have trash in the carb.?
Another question. Is a 350 bored .50 over a 400? I was pretty good at trigonometry in high school, but that was a long time ago.
Thanks

no, .50 over does not make it a 400cc engine...lol. did you check cylinder for being out of round ?. did you check connecting rod for play at top and bottom ?. trx350 ranchers are very bad about going through crank rods.

 

[shadetree]

after looking at your cylinder pics closer ^^^, I see a lot of ring gap !.

 

[Obd Zee]

No, Shadetree, I didn't. I don't have the tools to measure the cylinder, and I don't know what to check for 'play'.
Not sure what you are getting at. I'm not a pro wrencher, as you can tell. Seems to me that if the compression is good, the ring gap shouldn't matter. Are you suggesting that the cylinder may be bored beyond safety limits?
Could a out-of-round cylinder, or play, or ring gap, be the cause of the miss that was the issue I asked about?

 

[shadetree]

No, Shadetree, I didn't. I don't have the tools to measure the cylinder, and I don't know what to check for 'play'.
Not sure what you are getting at. I'm not a pro wrencher, as you can tell. Seems to me that if the compression is good, the ring gap shouldn't matter. Are you suggesting that the cylinder may be bored beyond safety limits?
Could a out-of-round cylinder, or play, or ring gap, be the cause of the miss that was the issue I asked about?

spark plug is black either from running rich ?, or oil rings worn out. when I say check for play, once the top end is off, piston removed ( MAKE SURE YOU PUT A RAG IN THAT BIG OLE HOLE WHEN TAKING CIRCLIP OUT OF PISTON ! ), take the wrist pin, push it just inside the top of the connecting rod, to where the end is flush with the other side, now take your hand, and lift up, push down on the long end, the wrist pin SHOULD NOT move either way. after this check, grab the connecting rod, while crank his not moving, lift the rod all the way up, gently lift up, push down on just the rod, there should not be any movement at the lower end of the rod where it sits on the crank bearing !!. you really need the service manual to check specs. but in your case, lets just let you wing it, and go all the way old school. one thing that hurts by doing this is, you wont be able to tell if the cylinder is out of round ?, but you still can check ring gap !. remove the top ring off the piston, slide it down inside the cylinder edge wise, once down inside the cylinder a good ways, flip the ring to where its sitting in there like it would be on the piston, have a look at the ring end gap, if its too wide ?, this is a problem. make sure you pay attention to which way you remove the top ring from piston!!, IT HAS TO GO BACK ON PISTON THE SAME WAY YOU REMOVED IT !!. now do the second ring, same way/same test. then do the oil rings, becareful..oil rings bend very easy !!. ring gap should not be much on all rings. if they are ?, then you can try new rings. but I would have the cylinder checked for being out of limit specs, as well as condition of crank before I went any further !.