Timing cover gasket - Commando or Atlas - Make a difference?

Johnnymac · Feb 14, 2015

Hi Guys,

I was wondering if there is any difference between the Commando timing cover gasket and the Atlas one? I sent my timing cover off to AMR in Arizona for the Nortec anti-wetsump mod and they sent me a fairly thick timing cover gasket that my buddy says is for a Commando. He says that the Atlas ones are thinner. Any truth to that? I would hope that the guy at AMR would have sent me the correct one for an Atlas.

texasSlick · Feb 14, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

I did not get a gasket with my AMR mod. I would think a thin gasket would work for both Cdo and Atlas.

You should feel a slight pushback from the oil pump seal....too thick a gasket will reduce any pushback.

My AMR mod included a "fat" O ring for the oil pump seal. I used a std gasket (guessing 0.015 thick). I haven't cranked up the old Atlas yet, so I cannot comment further.

Slick

Johnnymac · Feb 14, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

texasSlick said:
I did not get a gasket with my AMR mod. I would think a thin gasket would work for both Cdo and Atlas.

You should feel a slight pushback from the oil pump seal....too thick a gasket will reduce any pushback.

My AMR mod included a "fat" O ring for the oil pump seal. I used a std gasket (guessing 0.15 thick). I haven't cranked up the old Atlas yet, so I cannot comment further.

Slick

Thanks Slick. My AMR mod didn't come with a gasket, but I bought one from him. I have to pull the cover off again anyway to put on the new K2FC magneto so I should be able to see if that fat o-ring was snug up against the cover.

NoLongerHere · Feb 15, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

Have you a gasket behind the oil pump? The thicker gasket is used when you have. I have been told that you need about 10thou stand off from cover to case to get the right sort of compression on the nipple seal for a Dommie. If needed shims are available for the pump to do this. However I'd check that gap measurement just in case as I didn't write it down when told and I'd hate to be responsible for your blown engine.

texasSlick · Feb 15, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

I agree with Dommie Nater....the standoff, or push off, should be about 10 thou. His explanation about thickness of timing cover gasket being related to any oil pump gasket makes sense. My Atlas never had a gasket behind the oil pump.....I just smear a thin film of non-hardening gasket sealer on the pump face.

Don't forget....the check ball will pop out when you pull the timing cover. I have not tried it, but perhaps you can insert the ball retention tool and secure it BEFORE removing the cover. OTH, you do not want to scratch the ball surface with the tool point and compromise the seal.

Slick

Johnnymac · Feb 15, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

Yes, I have the thin gasket behind the oil pump. When I pulled the pump when I bought the bike I was shocked there was no gasket at all, not even a smudge of gasket sealer.

Thanks guys! Hopefully some day I will actually get to ride this bike.

texasSlick · Feb 15, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

Johnny.... One more point.....if necessary you can use one or more brass (fiber should work as well) washers on the oil pump nipple under the fat O ring. My Atlas originally had one such brass washer.

Slick

kernel65 · Feb 15, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

There evidently is a difference between Commando and Atlas. The two are different part numbers and do not cross-refernce. This service bulletin outlines the use of an Atlas gasket on a Commando. It does say the 06-1092 "will service" the Atlas and mentions thicknesses.

Timing cover gasket - Commando or Atlas - Make a difference?

Jeandr · Feb 17, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

The Commando gasket is slightly different to account for the point wires, if you use an Atlas gasket, you will get an (another???) oil leak.

Jean

NoLongerHere · Feb 17, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

texasSlick said:
Don't forget....the check ball will pop out when you pull the timing cover. I have not tried it, but perhaps you can insert the ball retention tool and secure it BEFORE removing the cover. OTH, you do not want to scratch the ball surface with the tool point and compromise the seal.

Slick

What's this check ball you mention, is that part of the modification?

Johnnymac · Feb 17, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

Dommie Nator said:
texasSlick said:

Don't forget....the check ball will pop out when you pull the timing cover. I have not tried it, but perhaps you can insert the ball retention tool and secure it BEFORE removing the cover. OTH, you do not want to scratch the ball surface with the tool point and compromise the seal.

Slick

Click to expand...

What's this check ball you mention, is that part of the modification?

It is all prt of the AMR/Nortec Mod. http://www.amr-of-tucson.com/nortech.html

NoLongerHere · Feb 17, 2015

Re: Timing cover gasket - Commando or Atlas - Make a differe

Johnnymac said:
Dommie Nator said:

texasSlick said:

Don't forget....the check ball will pop out when you pull the timing cover. I have not tried it, but perhaps you can insert the ball retention tool and secure it BEFORE removing the cover. OTH, you do not want to scratch the ball surface with the tool point and compromise the seal.

Slick

Click to expand...

What's this check ball you mention, is that part of the modification?

Click to expand...

It is all prt of the AMR/Nortec Mod. http://www.amr-of-tucson.com/nortech.html

OK, thanks.