My son has recently bought a Honda NS125F (liquid cooled) and the head gasket has gone. He bought another, but on trying to fit it he found that the engine had been re-bored at some point and the standard gasket won't fit.
What's the best way to overcome this problem please?
2007-12-02 08:01:48 · 8 answers · asked by Great Eskape 5 in Cars & Transportation ➔ Motorcycles
I'd make sure you have the right gasket. If you have the old one, compare them and see if they match. If the gasket is a metal clad gasket like most are, I sure wouldn't go grinding or cutting on it. As far as it being exposed in the combustion chamber, they are anyway. That's why they are metal clad, to conduct the heat the head and block. Even head gaskets that are not totally metal clad have a metal ring afixed to them to conduct heat. Cut the metal out and them you have fire directly against the fiberous gasket material and the gasket material doesn't conduct heat very well at all. In short, it it's the right gasket, put it on and if not, get the right one. Also make sure you don't have it side to side or upside down.
2007-12-02 11:33:07 · answer #1 · answered by bikinkawboy 7 · 0⤊ 0⤋
I agree with the chap above, most head gaskets have a ring of soft metal at the point of most stress, (surrounding where the bore ends) which crushes down and prevents gas leaks. Definitely don't trim it, especially as it's liquid cooled with that beiung circulated around the negine... catastrophic faIlure looms.
Rebores are normally fractions of a millimeter and not really significant enough to affect gasket sizes. If it obviously doesn't fit then it may be the wrong gasket.
2007-12-02 14:17:56 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Aside from doing the right thing and replace the cylinder and piston /rings,make sure the gasket is the correct one for your application.If so,you can try to trim the fire ring(the metal part of the gasket)with a dremel.
Another thing to watch out for is if the cylinder had a coating on it(i.e,nikasil.). if it did,then most likely the motor will go bad much sooner if not recoated.
2007-12-02 08:15:32 · answer #3 · answered by scott_renegade2000 2 · 0⤊ 0⤋
It doesn't have to be an exact fit, as long as it isn't too large and impeding piston travel.
Just place the gasket over the pistons, secure it in place with a few drops of superglue, get a VERY sharp blade and trim off the excess. Remove any bits that have fallen into the combustion chambers.
If I can do it on a V6 it can be done on a 125.
2007-12-02 08:09:58 · answer #4 · answered by Bum Gravy. 5 · 0⤊ 2⤋
in fairness this is not rocket science. make one, it is easy enough you can buy gasket sealent and as far as super glue is concerned (the mind boggles) You can get gasket sealent a new invention been around what 20-30 years. Yes check your old gasket, you can use that as a template to make a new one. You can buy gasket paper of various types and if your old one is no good as a template then place the pape/card over the block and with a very light hammer tap out the outline then get a pair of scissors to cut out. wallai one new gasket. I only say this as you don't know what spec the rebore is and it good be anything. i do hope this helps and good luck
2007-12-02 22:06:38 · answer #5 · answered by scooterboy 3 · 0⤊ 2⤋
Find out where the modification came from and they should be able to supply a "stock" item to replace the damaged gasket.
You'd be better off getting a standard block and piston from either a breakers or an after market dealer.
You could actually try
BUSTERS web site as they market both the stock and oversized cylinder barrels.
So they could help
Enjoy..
2007-12-02 19:59:28 · answer #6 · answered by Philip P 7 · 0⤊ 0⤋
If the gasket is just a sheet of material, it can
be trimmed to fit.
If it incorporates a ring around the cylinder opening,
you must purchase the proper gasket.
2007-12-02 08:13:32 · answer #7 · answered by Irv S 7 · 5⤊ 0⤋
buy the correct one
2007-12-02 08:04:55 · answer #8 · answered by cgreenemax 2 · 0⤊ 1⤋