seal and vent for ign on 74 harescrambler

[auto]

Guys, my first post.  I have been working for months restoring a 74 1/2 harescramber.  I'm down to finals and have this vent on the ign cover.  My 88 Husky Auto has the motoplat ign and never needed a vent. However, I have made a point to blue silicone the cover and check it after every race.  Any personal experiences/pointers on the Penton would be appreciated.

[Larry Perkins]

Condensation would build up in there and the vent seemed to help back in the day.

Larry P

[auto]

Larry, thanks for the intel.  Will re-install with a vent tube attached.

[Daniel P. McEntee]

I always vent the ignition case cover of any bike I know will do through some water, no mater what kind of ignition it has. Way back in the day, I also very carefully sealed the ignition case cover on my bikes and when I did post race check out, there was always water inside when I removed the cover. I was finally educated on the fact that when the hot engine hits cold water, the rapid contraction will create a vacuum that will pull water through the tiniest crack or crevasse. I vented the case cover and ran a tube up through the frame almost to the handle bars and never had a problem. If you have a bike with magnesium cases, you will want to do this to prevent even condensation from collecting inside to prevent corrosion.
  Type at you later,
   Dan McEntee

[brian kirby]

If I put a vent, I put it on the bottom and not the top, a vent on the bottom allows condensation or water from a creek to drain. No matter what you do you need to remove the cover occasionally in dry weather and every ride in wet conditions to remove moisture.

Brian

[auto]

I had not thought about the condensation issue.  Every time I pull the cover off the auto it has a tiny bit of moisture in there. Thanks for answering my questions.

David Rozell