dome 10.5-1 comp piston in 185s

[83185s]

well since my stator blew i decided to go ahead and take out the old pos oil burnin std piston that i had to put another full quart of oil in every 2 hours of riding..yes it was that bad..so im puttin in the new one..10.5-1 compression 30 over piston..well i put it in one way and it hits the head completely stopping the engine..i put it in the other and it makes a tapping noise ( i assume its tapping the head now) and it doesnt stop but since my flywheel houseing and stuff is off i see my cam chain just kinda loosening and tightning up..im thinkin..uh wtf..so i got a ?...what is causeing the piston to hit the head..the gaskets are new..should i use 2 gaskets instead of one on the head/jug gasket?? i would jsut like to know why its hittin the head really

[200xkwit]

i dont think your pistion is hitting your head. check your valves

[TheOlderFox]

There are probably notches in the piston that the vavles go into at TDC to prevent the two from hitting. If the piston is in backwards, the notches won't line up. The correct way, your vavles may be miss adjusted and just hitting the piston causing the tapping. I don't remember with Honda, but Yamaha has an arrow on the piston that points to the front of the engine. Check your valves. Make sure they are not bent and that the seat is ok. Then check the gap on the adjuster.

[Curtis-Tecate3]

STOP what you are doing. Your valvetrain is out of time and the valves are opening at the wrong time making contact with the piston. You have likely damaged at least one of your valves depending on how much force you applied when trying to turn the engine over. Make sure that all of your timing marks for the valvetrain (cam sprocket, crankshaft etc.) are correct per the manual and start over. The 10.5-1 piston should not even come close to contacting the head unless someone went way overboard on shaving the head itself.

Curtis.

[MTS]

if you where putting that much oil in your bike, i would take the valves and springs apart and check to see there ok, sounds like the seals are utterly toasy =(

[Studytime]

If you simply look at a cam lobe and think about the physics behind it you'll derive that max lift can only happen for a short amount of time.

Additionaly, max lift does NOT occur at TDC. So in order for this to happen you either, as has been said, went WAY overboard shaving the head or your timing is off.

Hopefully you didn't break anything.

Studytime

[83185s]

o know there wasnt any real force on the valves..i didnt have the head bolts in on purpose cause i didnt know if they would hit or not..i was thinkin ahead..i used a ratchet and the nut that goes over the flywheel to turn the engine over...im not sure if it was in time but the valves didnt touch the piston when it came up...i still dont have the stator and i didnt put the flywheel on because of that..so it prolly isnt in time..the piston IS IN RIGHT ...the way i put it in the first time completely stopped the engine from moving when it got to tdc...i flipped it around and now it barely taps..i havent shaved the head and i didnt plan on it since its only a 185...i probly do need to put new valve seals in but i dont have a valve spring compressor tool thingy..and i dont feel like getting a valve spring to the head like some dumb people i know have...and i dont trust myself to touch the valves anyway...lol..i dont mess with tranny's and i dont mess with valves..but i did have to take the engine side case off yesterday to get the wristpin out...my finger slipped off from the oil and it fell under the crank..lol..im about to part it out but im not sure i want to yet..anyway the valves arent damaged from the new piston but prolly need new seals from the old one that burn oil real bad

[TheOlderFox]

Double check the timing and the valve gap. If you are off a couple of teeth on the cam, they could be opening late. If you want to remove the valves I find the poorman's way works better then the spring compressor. I have one of the tools and it don't use it. Take a large nut, cut about 1/3 or the nut off so there is a gap to get plyers into. Put that on the capped end of the valve and take a D-clamp and tighten down on the valve face and the nut. This will relieve the pressure so you can remove the valve keys. Back off the pressure and you can remove the valve. With a pair of needle nose, you can get the keys back in for assembly.

[83185s]

thats cool...but there is one problem..lol..i gues i prolyl shoulda stated this earlier..one of the hex nuts that hold the top of the head to the bottom of the head is stuck..its also stripped out so i tried channel-locks (pliers) and couldnt get it..the next thing im gonna do is find some vise grips..hopefully they will work