I just rebuilt my 06 yz 250 and used yamabond, the thin black sealant. That stuff does not go on very thick or easy. Has anyone had any cases leak from using this stuff?


This is the picture forum, so lets see what you're talking about.

yamabond is grey or white, and you put just enough on to change the color of the case, and that will be enough, it wont leak, we've done hundreds of different engines with yamabond and i haven't heard of one leaking

+1 it wont leak... very thin bead is all that is needed to seal the cases. I have never used anything else and have rebuilt lots of bottom ends and never had one leak.


The stuff I use is black, never leaks.

Edited by mikeylikesit

Been using Three Bond 1280 , also re badged as sold as the familiar "Yammi-bondi" gray formula for many years sealing case halfs. Excellent trusted sealant ! I believe Honda has the same formula called Honda-bonda :D

Edited by Polar_Bus

Suzuki-bond is the same too. The stuff is like magic always grey in my tubes though.

Only issue I had with it was guy who rebuilt my bike before I bought it didn't clean the Yamabond from where the two case halves come together. There was a small bulge of Yamabond so the base of the cylinder didn't sit completely flush, causing a base gasket failure. Razor blade to remove excess yamabond and new gasket fixed it.

Just sealed up my cases last week. Rode ALLLL weekend. Went out to the shop last night and didn't see any leaks. I just slather on with my finger. Thin on both halves.

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