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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: NMPete on June 30, 2026, 03:14:22 PM

Title: K75 Renovation
Post by: NMPete on June 30, 2026, 03:14:22 PM

Hi - I finally finished (after a year) renovating a '85 K75 barn find. Thanks to everybody who helped with advice on fixing numerous issues.

So, took it out for a good first long ride (120 mi) on a hot day, 1 hour lunch (bike in hot sun) and got gas.  I noticed the gas was boiling!  Rode home, no missing or anything.  Opened the gas cap and gas spewed out all over the bike!

So, here is THE MIRACLE: it didn't catch on fire.  I then combed this forum and found several discussions on boiling gas; one with a picture of a burned up bike.

My fix:  I added a lot more insulation under the tank and relocated the pressure regulator.  This seems to have eliminated the boiling gas problem.

I do enjoy riding it, so smooth and easy to shift, etc..

Thanks again for all your help.

(https://motobrick.com/gallery/4/8401-300626145917.jpeg)

Title: Re: K75 Renovation
Post by: Laitch on June 30, 2026, 06:18:57 PM

Research and determination win the day, congratulations!  icon_cheers

Title: Re: K75 Renovation
Post by: Edward on June 30, 2026, 11:44:11 PM

I had steaming gas on top of my engine over the years—no big deal. I stop the bike, tip it to pour the gas off, and then ride on to my repair spot. Those regulators give out now and again. That reminds me to stash one on board or keep a spare next to the current one. They tend to fail on long trips if they're going to die.