Reuse Head Gasket?

[CRSpeedy]

Eric, on page 114 of your 'Performance Handbook' you say the new style steel gaskets ( you dont specify"Head Gasket") can be reused a few times,copper coated. In the 10 tips to rebuilding a 2 stroke top end, #3 says "never reuse old gaskets"
In the racing season , I'm changing the ring, head and base gaket every 2 or 3 weeks . I used to change the whole top end every time I took the head off. I'd rather save the $12 on the head gasket but I just assumed that you were not supposed to ever reuse the head gasket.
Has any one else ever reused their head gasket?
Thanks

 

[jmics19067]

I have reused copper head gaskets <old air cooled bike from the 70's> but first I annealed it. By slowly and evenly heating and then slowly and evenly letting it cool you can take out the work hardness out of a lot of different metals. I cooked the head gasket in an old toaster oven at 200 degrees<f> for 20 minutes 300 for 20 400 for 20 500 for20 then back down 400 for 20 etc..... Needless to say the toaster oven didn't last long and I probably spent more money on electricty than what the new head gasket would cost. heh neat trick if you do do that is to throw a few copper pennies from the 60's or earlier in there<except 1943 pennies>. After you annealed them you can amaze your friends with your strength by bending them in 1/2 in between your thumb and forefinger. Of coarse when they try to do it with a standard hardened penny they can't. hehe might be able to get a free top end that way :) Has to be a true copper penny though, 1943 was steel and I think in the late 60's they started using lots of zinc in them

I have also had a bike that I could take off the cylinder without taking off the head. Take the spark plug out so you dont have to fight compression. But this makes it extremely difficult to inspect ,deglaze and clean the cylinder properly. An overabundance of patience and time must exceed the lack of money for it to be worth it.

I would definately try the copper coat spray on an old steel gasket if the gasket pulled off nice and clean but I would have bought a new gasket just in case. That way if there is a problem all you have to do is drain the coolant and pull the head. If there isn't a problem just save it for when you do need it. If you are tearing the bike down every other weekend it won't be long before you will need it.

One thing I must ask though is that if you are that serious about racing that you do the top end that often. Would the 12$ be worth a possible DNF ?

 

[Studboy]

I believe that it says to never reuse paper gaskets.

 

[Rcannon]

I think Eric's book was refering to the "O" ring type gaskets. My Yz 250 has these. Yamaha is very proud of them. Based on what I paid I think mine may have been the last two on earth.

It looks as if soemone could easily reuse them.

 

[Studboy]

Let me reiterate. He says that you can reuse metal head gaskets when coated with a copper sealer. You can also reuse O-Ring gaskets if they are in good shape (my sleds have these on the heads, very handy.) But on any head/base gasket DO NOT reuse paper gaskets.

 

[CRSpeedy]

Ok thanks guys. I might try the" leave the head on the jug trick" to see if there's room to get it off. I guess I could try reusing the head gasket,and have a new one in the box , in case it leaks. Thanks again

 

[CRSpeedy]

jmics, My son races and practices on the same CR125. We usually go to the track, the Sat. before the race, he probably rides 3 or 4 hrs. then races about an hour or a little more on Sunday. Sometimes we go to the track during the week. The book says change the ring every 7.5 hrs, I try to change it about every 10 to 15 hrs. Sometimes I feel like telling him he cant practice cause he;s wearing the bike out but that's why we bought it. Do you think I'm changing the ring or top end too often ? The first ring I went over 20 hrs and the engine had no compression. but still ran, I found that the ring end, or little tip at the end had broken off. I have over 30 hrs on the top end on the CR250 . Seems like the smaller the engine, the more maintenance there is.

 

[jmics19067]

yes the smaller the engine the more maintenance. The higher revving and greater loads placed on the engine to try and accomplish the same work of a bigger engine does cost you.

I can't tell you if you are doing maintenance too often to be cost effective. if you had a loss of compression at 20 hrs then doing it at 15 only makes perfect sense.

 

[Jaybird]

CRSpeedy,
Get out your measuring instruments and see if you are changing them out too often or not.

 

[marcusgunby]

The late model cr pistons come with a ring gap of 19 thous-this is considered worn out on most bikes.If you use a wiseco it comes gapped at 12 thous and a vertex is gapped at 10 thou-any of these will last longer than the std one.Worth thinking about.

 

[DEANSFASTWAY]

Marcus ever notice that Honda125 rings are deeper than Yamaha 125 rings by like 4 thousandths .

 

[CRSpeedy]

Marcus Gunby, You sound like you know this engine a little anyway. My CR125 has an "A" cylinder which is supposed to be smaller than an "B" cylinder. Since this engine seems to be loose, have you heard of any one using a "B" piston in a "A" cylinder. Or maybe this would only make the ring gap larger. What do you think? Two different Honda dealers told me that the same ring goes with both pistons . Didn't really want to go to Wiseco cause, no shop I know of, carries them in stock.
Thanks for the help guys