1st test
2nd test with oil
hi all .. This is a king quad 300

1st off I did a compression test with throttle wide open I got a reading of 120 psi

Then I did a second test and this time put some oil in the cylinder and got a reading of just around 150 can anyone tell me if this is good or bad ? And if its bad what can I do to fix it I posted some pics also...

Second problem is I have a bad rattle or ticking if you wanna call it that in the top end it kinda gets better when I'm in like 4th gear I can still hear it but it kinds goes away I've adjusted valves and it didn't get better I posted a video link here

https://youtu.be/Qlneq5beW2w

 

 

Thanks the rattle is more of a loud ticking noise

 

120psi compression is fine, you don't need new rings, unless it is burning oil. A tap from the top end can be all sorts of things, piston slap, a worn cam, rocker loose on it's shaft, cam chain worn, valve seat loose, etc.

We took in a Bruin, part ex about 5 years ago, about 4 years ago some idiot we lent it to as a courtesy bike must have "lightly seized" it, as it has had loud piston slap ever since. It has been on "light duties" since then, but it is still going, still rattling.

 

​​​​​​Ticking/rattle/banging just symantics. Best of luck with the rebuild.

 

OK guys thanks I did post a video link not sure if you looked at it and yes its burning oil and there is blow by sometimes the plug has oil on it as far as a rebuild how far should I go ? New rings pistion and can chain just to be safe ? I'd hate to rebuild it and still have this annoyinng rattle

 

Me personally, if I am going to put forth the time and effort into doing the bottom, I would drop all new internals since they are exposed already. You will then be comfortable that all of the little things are good.
Keep valves and heads replacing all seals and gaskets. Keep cylinders unless they show signs of high heat. Keep cases replacing seals and gaskets. Drop a cam and associated parts also. Has ignition been upgraded? It is currently laying out.

 

Sounds a bit more like cam chain, I think it is too rapid for valves or piston slap.

You need to take the cylinder off before getting parts, as you don't know what you need until you measure everything. If the cylinder is badly worn it will need a re-bore, and may already have had one (or more) so you need to measure to find out what piston, if any, you need. If the bore is OK, measure the piston, if the skirt is under min size or scored, you need a new one, again, if it has had a re-bore, or needs one, the correct oversize. You may just need new rings, again the correct size for the bore. Before removing chain, check if there is adjustment left on the cam chain tensioner, if not, you need a new chain, check chain guides for wear and replace if needed. Check cam and followers for wear. All sizes will be in the workshop manual, as are torque settings, get one.

 

Get a shop manual, it will help with procedures and specs. Completely disassemble and check everything. Anything questionable replace it. Better to be conservative the first time than to be frustrated later.

 

Thanks for the help and directions its gunna be a rebuild in the winter is only 3 months from now so that's when I'll do it I appreciate the help in the mean time u mention to check the cam tensinor ? Can the chain be tight end ? If so how