125-200cc WB165 over heating

motocrossmr,

I'll bring my spare set of o-rings along on Sunday. If you don't get yours in time, you're welcome to them. Don't want you missing the first HS of the season!

You guys rock! We have an awesome group of helpfull members on this site. I'm glad you found the problem good luck this weekend end guys.

Blue-Cold-Richer, Red-Hot-Leaner. Dave, let me know what you end up with jetting wise. I'm close to you, but have a 178 main, as I'm riding 1000-2000'. I'm wondering if I need to swap from JD Blue to NOZI needle and go up a main jet for Curly Fern Enduro.

I figured you would find a blown head gasket (Oring).

Sure thing, Norm.

Awsome! That makes me feel better! Its greatly appreciated! PM me your number if you dont mind. That way I can let you know if I need them when I arrive and we can meet up right away.

You might want to lap that head before you throw it back on.....

I was kind of in denial! I didnt want it to be a blown head gasket! I just wish I knew how it happened.

Norm, I just got the head back from Walt. Do you think it could be warped already? I only have about five hours on the top end. I have a piece of glass but not the super fine sand paper. If that how you would suggest doing it. What other reason for lapping? Just curious. Thanks!

Mostly likely you nicked the oring and after torquing the head down and pressure built up, it let go. The last topend l did on the 360, l reused the o-rings and as l was torquing down the head, l had a gut feeling that l may had nicked it, pulled the head off and the o-ring had a slight tear under inspection... if l left it on l would have had the same thing happen.

If you want to check for a warp head, grab a steel ruler and hold it up to the light checking corner to corner (use the bolt holes as reference).

If you feel you didn't really overheated the bike, it may be okay. I'd at least check it with a a straight edge, as suggested by ohmygewd.

Yeah better safe than sorry! I didnt ride it much (two 15 or 20 minute rides) and kept the coolant levels up so I dont think it was too bad but I will check for warp. I will use a straight edge or my glass with feeler gauges. I just have to find the tolerances in my manual. Thanks for all the help guys!

you should be able to get Viton oring in bulk (like hose on a reel) from most supply places.. Get some Loctite 404 or a product called "turbo glue" and make your own orings for a backup set. I have good luck with the turbo glue in industry on pressurized vessels under 100psi and less than 300*f.. i would still run OEM but its nice to be able to whip a fresh set out whenever you need.

If your head is warped let me know and I will make something happen. I would be really surprised if it was warped but you never know.

I had this exact problem on a cr250- yes it was the orings

But that is one of the easiest fixes. Much easier than a pump seal or other issues.

Have you thought about pulling your jug and flushing out your bottom end? Antifreeze is a killer on bearings. Then use a little two stroke oil to pour on your bearings/rotate your crank. On o ring installation. Lube both rings with little two stroke oil or silicone spray. So when you torque them down, they move in the groove to adjust. If the groove is dry, the o ring can't move to adjust/ squish properly. Should run a tap down your jug threads to make sure your bolts aren't bottoming ount. Then use oil on the head bolts so they torque to correct readings. Also, you use a scotch brite pad to clean your grooves/head surface, won't damage the surfaces. Just a thought.

Thanks for the tips! I changed my oil after the first time the bike over heated and there wasnt any coolant in the bottom end. I am going to drain it again once I get the new o-rings installed to make sure its still good. My bolt holes should be okay. I originally had studs installed but switched over to the bolts. I will check the depth anyway and chase the threads to make sure they are good. I usaully lube the bolts up so that I get the correct amount of torque on them. Thanks again!

You are correct! I was just nervous about being able to get the parts in time. Luckily the dealer overnighted them and if it doesnt work out dfeckel was nice enough to offer up his spare set on Sunday!

Walt, if the head is warped would I be able to get away with a new OEM one for now? I know you did work on the head but I wasnt sure what. I have a brand new head I could use temporarily if need be. I guess I should check to see if its warped before jumping to conclusions!