replace the exhaust valve on a 110

[zoomerman]

hey i have to replace the exhaust valve on my 1980 110 i droped the engine so it would be easyer to get at taking the cylinder off wat do i need to replace it and how??

[TeamGeek6]

Valves are easy to change especially with a spring compressor, but the bigger question is whether the valve seat or guide are damaged. Also, itll have to be lapped into the old seat to ensure a seal.

Why is it being changed? Is the seat burned?

[zoomerman]

my 10 year old brother put a spark plug in it that was too long and wrecked the valve

[TeamGeek6]

YUK! That might do it. Insert the new valve in the guide upside down - straight in and out, and then look for scratches on the valve stem - and be sure that it doesnt hang up in the guide. If its damaged the guide, itll show on the stem.

Then get some "lapping compound" (Permatex brand is what I use) and lap the seat and put it back together. It has to be lapped because the new valve wont have the same pattern as the valve seat and a leak is likely.

Get valve lapping compound and one of those rubber grinding tools for hand use, usually a wooden stick with two suction cup things on the ends. Lap it until both the valve and seat have a uniform grey appearance but dont overdo it.

[zoomerman]

hey i don't know 2 much about it do * take the cylinder off??

[TeamGeek6]

Just take the head off, the valves are in the head. Its important to both remove and later reinstall the head bolts in the proper order (known as cross -tightening) to avoid warping the head. Either get a service manual, or find someone here that has the same engine, or post a picture of the head.

There should be no reason to remove the cylinder unless the pistons been damaged, that will be evident when the head is removed.

[zoomerman]

well then i would need a new head then??

[TeamGeek6]

Very unlikely, unless it is severely damaged, and a bent valve usually cannot cause that much damage.

If you can post some pictures of the top of the engine, I canhelp you take it apart.

[zoomerman]

k i'll post some pics do that

[zoomerman]

here r the pics

[zoomerman]

oh here s one more

[slothminx]

well im going to beat you to it TG6 :D ok you will need to start by taking the cdi sensor cover off. you can see the two screws on it top and bottom. ok next im guessing you will be able to see a sprocket and chain this will need to have the 3?? bolts around the middle undone and then the sprocket should come off the end of the cam. now you need to undo the valve clearence adjustment cap and take it off there are two top and bottom they are the 17mm ones it is easier if you take them off now rather than when you have the head off the engine. next you will need to undo the four bolts on top of the engine on the bit the engine mount is bolted to. that top cap sould now be free and slide off the studs. You should now be able to see that tops of the valves and the valve springs now in therory what you should do next is wiggle and pull the head gently and it should come off but sometimes they are stuck and you need to get a screwdriver and gently prise it off. pull the head off very very slowly and check nothing is still attached if not proceed but make sure that the sprocket with the chain does not drop down as you will need to get the sprocket for the cam timing back in the right place.now it is best once you have the head off to zip tie the sprockts to the chain in the same place so that you dont accidentlay move it as it is a pain to get it lined up again.

now we go onto dismantling the head. first you will take the cover off on the side of the head so you can remove the camthe bit you need to take off is, as you have the head sitting with the combustion chamber face down its the one with 3 screws above the spark plug. once you have this off you should see the other end of the cam. there will be two other holes in these are the little pins that hold the rockers in place you need to fish these out. using a bolt of the right size that you can screw into the end is good, but there are other ways. once you have these pins out the rockers are loose take them out. you can now remove the cam. this is done by turning it to the right oint ond pulling it out the cdi sensor side, just fiddle around with this it shouldnt take you too long to work out. once the cam is out its just the case of getting the valve out. this is done by getting your valve spring compressor popping it on and then removing the collets (dont know if there called somthing different on the big island;)) then the valve springs should come off and you damaged valve can be replaced. all you need to do once you have lapped the new one in is reverse all the steps.

i hope i havent missed out too much .but there may be some small details i have missed. all i can say is good luck and if you have any problems just post in here.

will

[zoomerman]

k i'll try it tomorrow

[zoomerman]

hey i can't get the head off i'm prying it open but i can't get it off and the cdi it's not wat * say i think

[TeamGeek6]

Go for it sloth. yuo know it better than I.

[zoomerman]

hey i got the head apart so i'm going 2 order the valves and put it bak together i hop it works but i have to set the timine again so how do * do that??