My first build - gasket?!

B

Boredomfiend

New Member
So I finished my first build about 4 days ago. Since then, I've been trying to break it in a bit, get the performance levels to balance so I'd know how it was running. Problem was, I couldnt get it to idle no matter what I tried, the choke ran better than the normal, and day by day the normal was running worse and worse.

Couldnt figure it out. scratg

Today I went in to reinforce all my connections (I'm already using high grade steel posts, so I added a 2nd strong nut to each one with lock-tite, red or blue) and I noticed that the carberator was soaked with gas. I looked around until I saw the intake gasket... and could only find a couple shred left, on the outside of both bolts. Nothing left near the intake. I replaced it with a high-heat liquid gasket and sealed it back up. Now its running stronger than it did when I first put it together, and it idles like a champ.
.bld.

Is it common for the intake gasket to last less than an hour of run-time? Was this a fluke or should I just automatically replace it as soon as my kit arrives?

More importantly (rather, more immediate..) should I be concerned about the other gaskets failing? Do I need to upgrade the engine and exhaust gaskets or are those usually ok?


TheDave
Long Beach, CA

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.mbv. Motorized Mtn Bike - NEW Engine 66c
 
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Yeah the intake gasket is trash. You can make your own, coat it with gasket sealant and bolt it up.
 
Boredomfiend said:
Is it common for the intake gasket to last less than an hour of run-time? Was this a fluke or should I just automatically replace it as soon as my kit arrives?

More importantly (rather, more immediate..) should I be concerned about the other gaskets failing? Do I need to upgrade the engine and exhaust gaskets or are those usually ok?
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Out of a few dozen engines about half had intake gasket disintgrate within the first month or two. I replaced with Fedex envelope cardboard and not one problem so far. What the heck is that red stuff they make those out of?

Strangely no problems with other gaskets though.
 
Maniac Mechanic has an exellent copper exhaust gasket on his site. You'll never need another one till you have a second bike.
 
Junster said:
Maniac Mechanic has an exellent copper exhaust gasket on his site. You'll never need another one till you have a second bike.
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I agree, a HD copper or aluminum exhaust gasket and no need to worry! Paper/fiber for exhaust doesn't cut it.
 
I purchased the copper gasket from Manic Mechanic.Once installed (thinking it was sealed) 5 or so miles down the road there is oil spitting out all over from the gasket not being sealed correctly.Should I use some gasket sealer on the copper gasket or what should I do? Thanks.
 
Often times the mating surfaces themselves are flawed badly. Rough and unfinished - even the best of gaskets will have trouble sealing unless the area is dressed and made flush.
 
Ah yes.I guess when the new Dremel gets here,I'll have a use for it:) I don't prefer using gasket sealant as it can be a messy look.Other than that,is there something one would suggest for the copper gasket?
 
erm, fer mating surfaces - it's best to pull the studs out and use a bit of fine sandpaper on a piece of glass to dress the faces, a Dremel is a wonderful tool - but not so much for this application as you'd prolly gouge more than you'd flatten.

"Best case scenario" you wouldn't need gaskets at all if the faces were "perfect" - but that's unlikely lol The copper gasket really is best - there must be a flaw somewhere.
 
Well just took another look at the copper gasket I received from Manic last Friday,it is bent on the ride side of the gasket.Right now I have a few paper gasket materials (poorly made) that I put onto the exhaust,hopefully they will work intill I can figure something out for the copper gasket.I don't want to do much to the bike as I'm still awaiting for the mounting kit from Manic Mechanic but I really want to get out n ride!
 
I see no point at all in those aluminum and copper gaskets. The CYLINDER is made of aluminum. If you have to machine the surface then it makes most sense to go with no gasket at all.

As mentioned I had excellent result using Fedex envelope for the intake and I can't see anything better than the stock exhasut gasket. It compresses and seals perfectly even if the surfaces are off.
 
Metal gaskets are supposed to be a slightly softer alloy than what they're bolted to, as such they conform to the slight surface irregularities and seal very well if properly torqued.

Unlike the traditional paper gaskets they are not permeable and can be reused almost infinitely. They are also FAR more pressure resistant than any paper gasket could dream of.

Having said that - I just cut my own from a quality, thick gasket material lol, but if I actually had the copper ones I'd use 'em ;)
 
If the copper gasket isn't flat use something to flatten it. Just be gentle you won't have to hit it very hard. A few strokes with a flat file that's wider then the mating face of your exhaust will true it up and you'll have to more worries. It's impossible to make these kits at this price and have them be perfect.
 
use a flat file and smooth out the surface of the muffler flange. flaws in the castind and 'ridges' are common. replace the gasket with a metalic one and use COPPER PLUS heat resistant gasket sealer/maker available most autoparts stores.
reapply each time you disassemble.
 
Anyone ever use permatex coppercoat on these gaskets... I reused head gaskets on a honda civic with coppercoat without a hitch ...just let it cure brushed on another coat let it cure and no problems.
 
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