cylinder base gasket leak

[JZ05220r]

Doing a leakdown test after throwing the top end back on and I found a tiny leak at the base gasket just below the reeds/intake. When using soapy water to visualize the leak, It’s a small enough leak where it creates more of a foam/fizz rather than big bubbles like you would see with a bigger leak It’s to the right of where the cases mate. I don’t believe it’s the case mating area as it’s perfectly seamless with my finger there. I was wondering how to get around this. I ordered another new gasket so I’m not gonna be riding the 220 this weekend like I planned. What can I do to insure this will not leak next time around.

[SS109]

I always put a really thin layer of grease on both sides of my gaskets to help them seal and make future removal easier. Make sure when you install the new one is tighten the cylinder down evenly, nut to nut, as you go to help insure a good seal. If for some reason that doesn't work ten there is an issue with one of the surfaces and you need to figure out what it is.

[jakeslouw]

Nothing wrong with putting a very thin layer of gasket maker on each side of the gasket before you put it in.
Loctite RTV comes to mind.

[SS109]

Avoid any sealant that is silicone based as it does not play well with gasoline.

[jakeslouw]

Avoid any sealant that is silicone based as it does not play well with gasoline.

Good point, and most of them are acidic and will eat aluminium. I've seen a KTM clutch cover trashed because the owner bonded a plastic guard on with a normal silicon sealer. The silicon leached acid and ate the clutch cover.

[JZ05220r]

Avoid any sealant that is silicone based as it does not play well with gasoline.

Will threebond 1211 be safe? I did torque as evenly as I could with a torque wrench in 4 stages. Thanks

[kdx633]

hylomar works the best use on everything except head gaskets

[jakeslouw]

Will threebond 1211 be safe? I did torque as evenly as I could with a torque wrench in 4 stages. Thanks

Product spec says yes

https://threebond-europe.com/products/tb1211/

".........to prevent oil, water, gasoline and chemical leaks"

[JZ05220r]

Will threebond 1211 be safe? I did torque as evenly as I could with a torque wrench in 4 stages. Thanks

Product spec says yes

https://threebond-europe.com/products/tb1211/

".........to prevent oil, water, gasoline and chemical leaks"

Thank you for that

[kdxdazz]

threebond 1211 is all i use these days,its basically gold standard for sealants, can even be used for head gaskets which i have done many times, threebond 1104 is also an option but its really difficult to remove, rtv shouldn't be used , one issue with base gasket installation is the studs tend to build up corrosion at the base of the stud, this needs to be removed then run a bottle brush through the stud holes on the cylinder to avoid any loose flakes' landing on the base gasket during installation

[JZ05220r]

threebond 1211 is all i use these days,its basically gold standard for sealants, can even be used for head gaskets which i have done many times, threebond 1104 is also an option but its really difficult to remove, rtv shouldn't be used , one issue with base gasket installation is the studs tend to build up corrosion at the base of the stud, this needs to be removed then run a bottle brush through the stud holes on the cylinder to avoid any loose flakes' landing on the base gasket during installation

While I didn’t go that the extra mile to get rid of the corrosion on the studs, I did get a new base gasket install with the threebond on the problem area plus a very light coat everywhere else. Hoping it doesn’t show up on a leak test any more. If not the bike will be together tomorrow. Thanks

[jakeslouw]

threebond 1211 is all i use these days,its basically gold standard for sealants, can even be used for head gaskets which i have done many times, threebond 1104 is also an option but its really difficult to remove, rtv shouldn't be used , one issue with base gasket installation is the studs tend to build up corrosion at the base of the stud, this needs to be removed then run a bottle brush through the stud holes on the cylinder to avoid any loose flakes' landing on the base gasket during installation

Hmmm you might be onto something. I've watched so many How To vids I'm not sure if this was for the KDX, but I seem to recall some guy had crankcase gas going past the threads at the bottom of one of the studs?

[JZ05220r]

First ride tomorrow. The threebond seemed to work I could not detect any bubbles in that area. If there still is then it was an insanely tiny leak. Hoping all goes well this time around.

[KDXGarage]

LET THIS MAN RIDE!! :-)