Cylinder base sealant, expensive Stihl silicone or hi temp red RTV ??

kspakland · Nov 21, 2011

I am going to re-ring and freshen up a friend's MS310, and since there is no cylinder base gasket, I see where Stihl uses a red silicone.

Do I REALLY need to buy the expensive Stihl brand sealant, or can I use standard high temp red RTV silicone?

Also, any suggestions you guys may have regarding the "freshen up" would be appreciated.

Since the crank seals appear good and there are no issues there, I don't see the need to take the crankcase apart.

Just new rings on the top end, new gaskets where needed, new fuel lines and a carb kit.

lone wolf · Nov 21, 2011

Yamabond ids the best stuff out there.Should be 7.00.

Brian VT · Nov 21, 2011

lone wolf said:
Yamabond ids the best stuff out there.Should be 7.00.

Yamabond 4.

Jacob J. · Nov 21, 2011

My vote is for Yamabond as well. The old-school Dirko that Stihl sold was the same grey sealer as Yamabond, which resisted fuel and heat really well. The newer red Dirko that Stihl sells isn't much better than red RTV.

RTV silicone is not good for sealing engines. If you don't have access to Yamabond or a decent bike shop nearby, then that Ultra Copper or whatever it's called, will work.

Saw Dr. · Nov 21, 2011

I paid the $20 for the Dirko, and have never had one come back with the sealant leaking. $20 is not that hard to absorb in 1 or 2 rebuilds.

Whatever you use, make sure it is fuel-proof. Many RTV type sealers are not. The bottom end of that engine will be in constant contact with fuel. If that sealant leaks, you will have an air leak and possibly a scored top end very soon.

Fish · Nov 21, 2011

kspakland said:
I am going to re-ring and freshen up a friend's MS310, and since there is no cylinder base gasket, I see where Stihl uses a red silicone.

Do I REALLY need to buy the expensive Stihl brand sealant, or can I use standard high temp red RTV silicone?

Also, any suggestions you guys may have regarding the "freshen up" would be appreciated.

Since the crank seals appear good and there are no issues there, I don't see the need to take the crankcase apart.

Just new rings on the top end, new gaskets where needed, new fuel lines and a carb kit.

You will definitely be taking the "crankcase" apart.....

Fish · Nov 21, 2011

When you remove the engine from the plastic crankcase, it will look like this......

Stihl MS290, Engine Long Block , NEW | eBay

OH_Varmntr · Nov 21, 2011

High-Temp Red works if you have no access to Yamabond.

Brian VT · Nov 21, 2011

Fish said:
You will definitely be taking the "crankcase" apart.....

Yah, 310 is clamshell.

Fish · Nov 21, 2011

Brian VT said:
Yamabond 4.

I prefer "Lethal Weapon 3".....

Nitroman · Nov 21, 2011

ThreeBond, Evinrude crankcase sealant same stuff, all essentially same stuff. I use Three-Bond cause I have lots of it since I rebuild snowmachines often.

dave_376 · Nov 21, 2011

A few years ago I was looking for yamaBond and had trouble finding it. I ended up with ThreeBond, it looked the same and I never had a problem with it. If I was shopping for a new tube now I would look for yamabond

russhd1997 · Nov 21, 2011

I started a thread like this yesterday asking about sealer for a MS180 crankcase. One of the responses to that was Hondabond which is the same as ThreeBond and Yamabond. I googled "Hondabond substitute" today and found that Permatex Ultra Grey is the same thing.

Bowtie · Nov 21, 2011

I have been using the John Deere white sealer they use on their diesel engines for a while and it has been working very well. 10 bucks a tube and it is fuel/oil proof. It is very good stuff. Just another alternative...

Fish · Nov 21, 2011

whatever.......

about any sealer will do....

ol'homey · Nov 21, 2011

Anyone tried good ol' Permatex 2B ? I've used it on a lot of things including in place of a base gasket on a couple of old Homies without any problems. It's fuel/oil resistant. I just put a thin coat on both surfaces, wait for a few minutes to let it get tacky and put 'er together. I know it's not as good as the stuff mentioned so far, but it is available at any parts store and it hasn't failed me yet.

Brian VT · Nov 21, 2011

Nitroman said:
I rebuild snowmachines often.

I wouldn't think that you'd need to make snow in Alaska.

Wicked500R · Nov 22, 2011

I just went to my local cycle shop to get Yamabond and the dude handed me Yamabond 6.. I hope its the right stuff....

Slamm · Nov 22, 2011

I used Threebond 1211, has worked on 3 saws now with no issue.

Sam

nmurph · Nov 22, 2011

No, you want 4..

Yamaha Motor Corporation, USA - Adhesives & Loctite® Yamabond 4 Motorsports

vs

Yamaha Motor Corporation, USA - Adhesives & Loctite® Yamabond 6B (Black)

Cylinder base sealant, expensive Stihl silicone or hi temp red RTV ??

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